pwm: Changes for v5.3-rc1

This set of changes contains a new driver for SiFive SoCs as well as
 enhancements to the core (device links are used to track dependencies
 between PWM providers and consumers, support for PWM controllers via
 ACPI, sysfs will now suspend/resume PWMs that it has claimed) and
 various existing drivers.
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Merge tag 'pwm/for-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

Pull pwm updates from Thierry Reding:
 "This set of changes contains a new driver for SiFive SoCs as well as
  enhancements to the core (device links are used to track dependencies
  between PWM providers and consumers, support for PWM controllers via
  ACPI, sysfs will now suspend/resume PWMs that it has claimed) and
  various existing drivers"

* tag 'pwm/for-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (37 commits)
  pwm: fsl-ftm: Make sure to unlock mutex on failure
  pwm: fsl-ftm: Use write protection for prescaler & polarity
  pwm: fsl-ftm: More relaxed permissions for updating period
  pwm: atmel-hlcdc: Add compatible for SAM9X60 HLCDC's PWM
  pwm: bcm2835: Improve precision of PWM
  leds: pwm: Support ACPI via firmware-node framework
  pwm: Add support referencing PWMs from ACPI
  pwm: rcar: Remove suspend/resume support
  pwm: sysfs: Add suspend/resume support
  pwm: Add power management descriptions
  pwm: meson: Add documentation to the driver
  pwm: meson: Add support PWM_POLARITY_INVERSED when disabling
  pwm: meson: Don't cache struct pwm_state internally
  pwm: meson: Read the full hardware state in meson_pwm_get_state()
  pwm: meson: Simplify the calculation of the pre-divider and count
  pwm: meson: Move pwm_set_chip_data() to meson_pwm_request()
  pwm: meson: Add the per-channel register offsets and bits in a struct
  pwm: meson: Add the meson_pwm_channel data to struct meson_pwm
  pwm: meson: Pass struct pwm_device to meson_pwm_calc()
  pwm: meson: Don't duplicate the polarity internally
  ...

Documentation/devicetree/bindings/pwm/ingenic,jz47xx-pwm.txt

@@ -2,10 +2,7 @@ Ingenic JZ47xx PWM Controller
 =============================
 
 Required properties:
-- compatible: One of:
+- compatible: Should be "ingenic,jz4740-pwm"
-  * "ingenic,jz4740-pwm"
-  * "ingenic,jz4770-pwm"
-  * "ingenic,jz4780-pwm"
 - #pwm-cells: Should be 3. See pwm.txt in this directory for a description
   of the cells format.
 - clocks : phandle to the external clock.

Documentation/devicetree/bindings/pwm/pwm-sifive.txt

@@ -0,0 +1,33 @@
+SiFive PWM controller
+
+Unlike most other PWM controllers, the SiFive PWM controller currently only
+supports one period for all channels in the PWM. All PWMs need to run at
+the same period. The period also has significant restrictions on the values
+it can achieve, which the driver rounds to the nearest achievable period.
+PWM RTL that corresponds to the IP block version numbers can be found
+here:
+
+https://github.com/sifive/sifive-blocks/tree/master/src/main/scala/devices/pwm
+
+Required properties:
+- compatible: Should be "sifive,<chip>-pwm" and "sifive,pwm<version>".
+  Supported compatible strings are: "sifive,fu540-c000-pwm" for the SiFive
+  PWM v0 as integrated onto the SiFive FU540 chip, and "sifive,pwm0" for the
+  SiFive PWM v0 IP block with no chip integration tweaks.
+  Please refer to sifive-blocks-ip-versioning.txt for details.
+- reg: physical base address and length of the controller's registers
+- clocks: Should contain a clock identifier for the PWM's parent clock.
+- #pwm-cells: Should be 3. See pwm.txt in this directory
+  for a description of the cell format.
+- interrupts: one interrupt per PWM channel
+
+Examples:
+
+pwm:  pwm@10020000 {
+	compatible = "sifive,fu540-c000-pwm", "sifive,pwm0";
+	reg = <0x0 0x10020000 0x0 0x1000>;
+	clocks = <&tlclk>;
+	interrupt-parent = <&plic>;
+	interrupts = <42 43 44 45>;
+	#pwm-cells = <3>;
+};

Documentation/devicetree/bindings/pwm/pwm-stm32-lp.txt

@@ -11,8 +11,10 @@ Required parameters:
 			bindings defined in pwm.txt.
 
 Optional properties:
-- pinctrl-names: 	Set to "default".
+- pinctrl-names: 	Set to "default". An additional "sleep" state can be
-- pinctrl-0: 		Phandle pointing to pin configuration node for PWM.
+			defined to set pins in sleep state when in low power.
+- pinctrl-n: 		Phandle(s) pointing to pin configuration node for PWM,
+			respectively for "default" and "sleep" states.
 
 Example:
 	timer@40002400 {
@@ -21,7 +23,8 @@ Example:
 		pwm {
 			compatible = "st,stm32-pwm-lp";
 			#pwm-cells = <3>;
-			pinctrl-names = "default";
+			pinctrl-names = "default", "sleep";
 			pinctrl-0 = <&lppwm1_pins>;
+			pinctrl-1 = <&lppwm1_sleep_pins>;
 		};
 	};

Documentation/devicetree/bindings/pwm/pwm-stm32.txt

@@ -8,6 +8,8 @@ Required parameters:
 - pinctrl-names: 	Set to "default".
 - pinctrl-0: 		List of phandles pointing to pin configuration nodes for PWM module.
 			For Pinctrl properties see ../pinctrl/pinctrl-bindings.txt
+- #pwm-cells:		Should be set to 3. This PWM chip uses the default 3 cells
+			bindings defined in pwm.txt.
 
 Optional parameters:
 - st,breakinput:	One or two <index level filter> to describe break input configurations.
@@ -28,6 +30,7 @@ Example:
 
 		pwm {
 			compatible = "st,stm32-pwm";
+			#pwm-cells = <3>;
 			pinctrl-0	= <&pwm1_pins>;
 			pinctrl-names	= "default";
 			st,breakinput = <0 1 5>;

Documentation/pwm.txt

@@ -65,6 +65,10 @@ period). struct pwm_args contains 2 fields (period and polarity) and should
 be used to set the initial PWM config (usually done in the probe function
 of the PWM user). PWM arguments are retrieved with pwm_get_args().
 
+All consumers should really be reconfiguring the PWM upon resume as
+appropriate. This is the only way to ensure that everything is resumed in
+the proper order.
+
 Using PWMs with the sysfs interface
 -----------------------------------
 
@@ -141,6 +145,9 @@ The implementation of ->get_state() (a method used to retrieve initial PWM
 state) is also encouraged for the same reason: letting the PWM user know
 about the current PWM state would allow him to avoid glitches.
 
+Drivers should not implement any power management. In other words,
+consumers should implement it as described in the "Using PWMs" section.
+
 Locking
 -------
 

drivers/leds/leds-pwm.c

@@ -72,7 +72,7 @@ static inline size_t sizeof_pwm_leds_priv(int num_leds)
 }
 
 static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
-		       struct led_pwm *led, struct device_node *child)
+		       struct led_pwm *led, struct fwnode_handle *fwnode)
 {
 	struct led_pwm_data *led_data = &priv->leds[priv->num_leds];
 	struct pwm_args pargs;
@@ -85,8 +85,8 @@ static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
 	led_data->cdev.max_brightness = led->max_brightness;
 	led_data->cdev.flags = LED_CORE_SUSPENDRESUME;
 
-	if (child)
+	if (fwnode)
-		led_data->pwm = devm_of_pwm_get(dev, child, NULL);
+		led_data->pwm = devm_fwnode_pwm_get(dev, fwnode, NULL);
 	else
 		led_data->pwm = devm_pwm_get(dev, led->name);
 	if (IS_ERR(led_data->pwm)) {
@@ -111,7 +111,8 @@ static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
 	if (!led_data->period && (led->pwm_period_ns > 0))
 		led_data->period = led->pwm_period_ns;
 
-	ret = devm_of_led_classdev_register(dev, child, &led_data->cdev);
+	ret = devm_of_led_classdev_register(dev, to_of_node(fwnode),
+					    &led_data->cdev);
 	if (ret == 0) {
 		priv->num_leds++;
 		led_pwm_set(&led_data->cdev, led_data->cdev.brightness);
@@ -123,27 +124,35 @@ static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
 	return ret;
 }
 
-static int led_pwm_create_of(struct device *dev, struct led_pwm_priv *priv)
+static int led_pwm_create_fwnode(struct device *dev, struct led_pwm_priv *priv)
 {
-	struct device_node *child;
+	struct fwnode_handle *fwnode;
 	struct led_pwm led;
 	int ret = 0;
 
 	memset(&led, 0, sizeof(led));
 
-	for_each_child_of_node(dev->of_node, child) {
+	device_for_each_child_node(dev, fwnode) {
-		led.name = of_get_property(child, "label", NULL) ? :
+		ret = fwnode_property_read_string(fwnode, "label", &led.name);
-			   child->name;
+		if (ret && is_of_node(fwnode))
+			led.name = to_of_node(fwnode)->name;
 
-		led.default_trigger = of_get_property(child,
+		if (!led.name) {
-						"linux,default-trigger", NULL);
+			fwnode_handle_put(fwnode);
-		led.active_low = of_property_read_bool(child, "active-low");
+			return -EINVAL;
-		of_property_read_u32(child, "max-brightness",
+		}
-				     &led.max_brightness);
 
-		ret = led_pwm_add(dev, priv, &led, child);
+		fwnode_property_read_string(fwnode, "linux,default-trigger",
+					    &led.default_trigger);
+
+		led.active_low = fwnode_property_read_bool(fwnode,
+							   "active-low");
+		fwnode_property_read_u32(fwnode, "max-brightness",
+					 &led.max_brightness);
+
+		ret = led_pwm_add(dev, priv, &led, fwnode);
 		if (ret) {
-			of_node_put(child);
+			fwnode_handle_put(fwnode);
 			break;
 		}
 	}
@@ -161,7 +170,7 @@ static int led_pwm_probe(struct platform_device *pdev)
 	if (pdata)
 		count = pdata->num_leds;
 	else
-		count = of_get_child_count(pdev->dev.of_node);
+		count = device_get_child_node_count(&pdev->dev);
 
 	if (!count)
 		return -EINVAL;
@@ -179,7 +188,7 @@ static int led_pwm_probe(struct platform_device *pdev)
 				break;
 		}
 	} else {
-		ret = led_pwm_create_of(&pdev->dev, priv);
+		ret = led_pwm_create_fwnode(&pdev->dev, priv);
 	}
 
 	if (ret)

drivers/pwm/Kconfig

@@ -401,6 +401,17 @@ config PWM_SAMSUNG
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-samsung.
 
+config PWM_SIFIVE
+	tristate "SiFive PWM support"
+	depends on OF
+	depends on COMMON_CLK
+	depends on RISCV || COMPILE_TEST
+	help
+	  Generic PWM framework driver for SiFive SoCs.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-sifive.
+
 config PWM_SPEAR
 	tristate "STMicroelectronics SPEAr PWM support"
 	depends on PLAT_SPEAR

drivers/pwm/Makefile

@@ -39,6 +39,7 @@ obj-$(CONFIG_PWM_RCAR)		+= pwm-rcar.o
 obj-$(CONFIG_PWM_RENESAS_TPU)	+= pwm-renesas-tpu.o
 obj-$(CONFIG_PWM_ROCKCHIP)	+= pwm-rockchip.o
 obj-$(CONFIG_PWM_SAMSUNG)	+= pwm-samsung.o
+obj-$(CONFIG_PWM_SIFIVE)	+= pwm-sifive.o
 obj-$(CONFIG_PWM_SPEAR)		+= pwm-spear.o
 obj-$(CONFIG_PWM_STI)		+= pwm-sti.o
 obj-$(CONFIG_PWM_STM32)		+= pwm-stm32.o

drivers/pwm/core.c

@@ -6,6 +6,7 @@
  * Copyright (C) 2011-2012 Avionic Design GmbH
  */
 
+#include <linux/acpi.h>
 #include <linux/module.h>
 #include <linux/pwm.h>
 #include <linux/radix-tree.h>
@@ -626,8 +627,35 @@ static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
 	return ERR_PTR(-EPROBE_DEFER);
 }
 
+static struct device_link *pwm_device_link_add(struct device *dev,
+					       struct pwm_device *pwm)
+{
+	struct device_link *dl;
+
+	if (!dev) {
+		/*
+		 * No device for the PWM consumer has been provided. It may
+		 * impact the PM sequence ordering: the PWM supplier may get
+		 * suspended before the consumer.
+		 */
+		dev_warn(pwm->chip->dev,
+			 "No consumer device specified to create a link to\n");
+		return NULL;
+	}
+
+	dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
+	if (!dl) {
+		dev_err(dev, "failed to create device link to %s\n",
+			dev_name(pwm->chip->dev));
+		return ERR_PTR(-EINVAL);
+	}
+
+	return dl;
+}
+
 /**
  * of_pwm_get() - request a PWM via the PWM framework
+ * @dev: device for PWM consumer
  * @np: device node to get the PWM from
  * @con_id: consumer name
  *
@@ -645,10 +673,12 @@ static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
  * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
  * error code on failure.
  */
-struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
+struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
+			      const char *con_id)
 {
 	struct pwm_device *pwm = NULL;
 	struct of_phandle_args args;
+	struct device_link *dl;
 	struct pwm_chip *pc;
 	int index = 0;
 	int err;
@@ -679,6 +709,14 @@ struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
 	if (IS_ERR(pwm))
 		goto put;
 
+	dl = pwm_device_link_add(dev, pwm);
+	if (IS_ERR(dl)) {
+		/* of_xlate ended up calling pwm_request_from_chip() */
+		pwm_free(pwm);
+		pwm = ERR_CAST(dl);
+		goto put;
+	}
+
 	/*
 	 * If a consumer name was not given, try to look it up from the
 	 * "pwm-names" property if it exists. Otherwise use the name of
@@ -700,6 +738,85 @@ put:
 }
 EXPORT_SYMBOL_GPL(of_pwm_get);
 
+#if IS_ENABLED(CONFIG_ACPI)
+static struct pwm_chip *device_to_pwmchip(struct device *dev)
+{
+	struct pwm_chip *chip;
+
+	mutex_lock(&pwm_lock);
+
+	list_for_each_entry(chip, &pwm_chips, list) {
+		struct acpi_device *adev = ACPI_COMPANION(chip->dev);
+
+		if ((chip->dev == dev) || (adev && &adev->dev == dev)) {
+			mutex_unlock(&pwm_lock);
+			return chip;
+		}
+	}
+
+	mutex_unlock(&pwm_lock);
+
+	return ERR_PTR(-EPROBE_DEFER);
+}
+#endif
+
+/**
+ * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
+ * @fwnode: firmware node to get the "pwm" property from
+ *
+ * Returns the PWM device parsed from the fwnode and index specified in the
+ * "pwms" property or a negative error-code on failure.
+ * Values parsed from the device tree are stored in the returned PWM device
+ * object.
+ *
+ * This is analogous to of_pwm_get() except con_id is not yet supported.
+ * ACPI entries must look like
+ * Package () {"pwms", Package ()
+ *     { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
+ *
+ * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
+ * error code on failure.
+ */
+static struct pwm_device *acpi_pwm_get(struct fwnode_handle *fwnode)
+{
+	struct pwm_device *pwm = ERR_PTR(-ENODEV);
+#if IS_ENABLED(CONFIG_ACPI)
+	struct fwnode_reference_args args;
+	struct acpi_device *acpi;
+	struct pwm_chip *chip;
+	int ret;
+
+	memset(&args, 0, sizeof(args));
+
+	ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
+	if (ret < 0)
+		return ERR_PTR(ret);
+
+	acpi = to_acpi_device_node(args.fwnode);
+	if (!acpi)
+		return ERR_PTR(-EINVAL);
+
+	if (args.nargs < 2)
+		return ERR_PTR(-EPROTO);
+
+	chip = device_to_pwmchip(&acpi->dev);
+	if (IS_ERR(chip))
+		return ERR_CAST(chip);
+
+	pwm = pwm_request_from_chip(chip, args.args[0], NULL);
+	if (IS_ERR(pwm))
+		return pwm;
+
+	pwm->args.period = args.args[1];
+	pwm->args.polarity = PWM_POLARITY_NORMAL;
+
+	if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
+		pwm->args.polarity = PWM_POLARITY_INVERSED;
+#endif
+
+	return pwm;
+}
+
 /**
  * pwm_add_table() - register PWM device consumers
  * @table: array of consumers to register
@@ -754,6 +871,7 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
 	const char *dev_id = dev ? dev_name(dev) : NULL;
 	struct pwm_device *pwm;
 	struct pwm_chip *chip;
+	struct device_link *dl;
 	unsigned int best = 0;
 	struct pwm_lookup *p, *chosen = NULL;
 	unsigned int match;
@@ -761,7 +879,11 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
 
 	/* look up via DT first */
 	if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
-		return of_pwm_get(dev->of_node, con_id);
+		return of_pwm_get(dev, dev->of_node, con_id);
+
+	/* then lookup via ACPI */
+	if (dev && is_acpi_node(dev->fwnode))
+		return acpi_pwm_get(dev->fwnode);
 
 	/*
 	 * We look up the provider in the static table typically provided by
@@ -838,6 +960,12 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
 	if (IS_ERR(pwm))
 		return pwm;
 
+	dl = pwm_device_link_add(dev, pwm);
+	if (IS_ERR(dl)) {
+		pwm_free(pwm);
+		return ERR_CAST(dl);
+	}
+
 	pwm->args.period = chosen->period;
 	pwm->args.polarity = chosen->polarity;
 
@@ -930,7 +1058,7 @@ struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
 	if (!ptr)
 		return ERR_PTR(-ENOMEM);
 
-	pwm = of_pwm_get(np, con_id);
+	pwm = of_pwm_get(dev, np, con_id);
 	if (!IS_ERR(pwm)) {
 		*ptr = pwm;
 		devres_add(dev, ptr);
@@ -942,6 +1070,44 @@ struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
 }
 EXPORT_SYMBOL_GPL(devm_of_pwm_get);
 
+/**
+ * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
+ * @dev: device for PWM consumer
+ * @fwnode: firmware node to get the PWM from
+ * @con_id: consumer name
+ *
+ * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
+ * acpi_pwm_get() for a detailed description.
+ *
+ * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
+ * error code on failure.
+ */
+struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
+				       struct fwnode_handle *fwnode,
+				       const char *con_id)
+{
+	struct pwm_device **ptr, *pwm = ERR_PTR(-ENODEV);
+
+	ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	if (is_of_node(fwnode))
+		pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
+	else if (is_acpi_node(fwnode))
+		pwm = acpi_pwm_get(fwnode);
+
+	if (!IS_ERR(pwm)) {
+		*ptr = pwm;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return pwm;
+}
+EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
+
 static int devm_pwm_match(struct device *dev, void *res, void *data)
 {
 	struct pwm_device **p = res;

drivers/pwm/pwm-atmel-hlcdc.c

@@ -235,6 +235,7 @@ static const struct of_device_id atmel_hlcdc_dt_ids[] = {
 		.compatible = "atmel,sama5d4-hlcdc",
 		.data = &atmel_hlcdc_pwm_sama5d3_errata,
 	},
+	{	.compatible = "microchip,sam9x60-hlcdc", },
 	{ /* sentinel */ },
 };
 MODULE_DEVICE_TABLE(of, atmel_hlcdc_dt_ids);

drivers/pwm/pwm-bcm2835.c

@@ -70,7 +70,7 @@ static int bcm2835_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 		return -EINVAL;
 	}
 
-	scaler = NSEC_PER_SEC / rate;
+	scaler = DIV_ROUND_CLOSEST(NSEC_PER_SEC, rate);
 
 	if (period_ns <= MIN_PERIOD) {
 		dev_err(pc->dev, "period %d not supported, minimum %d\n",
@@ -78,8 +78,10 @@ static int bcm2835_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 		return -EINVAL;
 	}
 
-	writel(duty_ns / scaler, pc->base + DUTY(pwm->hwpwm));
+	writel(DIV_ROUND_CLOSEST(duty_ns, scaler),
-	writel(period_ns / scaler, pc->base + PERIOD(pwm->hwpwm));
+	       pc->base + DUTY(pwm->hwpwm));
+	writel(DIV_ROUND_CLOSEST(period_ns, scaler),
+	       pc->base + PERIOD(pwm->hwpwm));
 
 	return 0;
 }

drivers/pwm/pwm-fsl-ftm.c

@@ -34,17 +34,19 @@ struct fsl_ftm_soc {
 	bool has_enable_bits;
 };
 
+struct fsl_pwm_periodcfg {
+	enum fsl_pwm_clk clk_select;
+	unsigned int clk_ps;
+	unsigned int mod_period;
+};
+
 struct fsl_pwm_chip {
 	struct pwm_chip chip;
-
 	struct mutex lock;
-
-	unsigned int cnt_select;
-	unsigned int clk_ps;
-
 	struct regmap *regmap;
 
-	int period_ns;
+	/* This value is valid iff a pwm is running */
+	struct fsl_pwm_periodcfg period;
 
 	struct clk *ipg_clk;
 	struct clk *clk[FSL_PWM_CLK_MAX];
@@ -57,6 +59,33 @@ static inline struct fsl_pwm_chip *to_fsl_chip(struct pwm_chip *chip)
 	return container_of(chip, struct fsl_pwm_chip, chip);
 }
 
+static void ftm_clear_write_protection(struct fsl_pwm_chip *fpc)
+{
+	u32 val;
+
+	regmap_read(fpc->regmap, FTM_FMS, &val);
+	if (val & FTM_FMS_WPEN)
+		regmap_update_bits(fpc->regmap, FTM_MODE, FTM_MODE_WPDIS,
+				   FTM_MODE_WPDIS);
+}
+
+static void ftm_set_write_protection(struct fsl_pwm_chip *fpc)
+{
+	regmap_update_bits(fpc->regmap, FTM_FMS, FTM_FMS_WPEN, FTM_FMS_WPEN);
+}
+
+static bool fsl_pwm_periodcfg_are_equal(const struct fsl_pwm_periodcfg *a,
+					const struct fsl_pwm_periodcfg *b)
+{
+	if (a->clk_select != b->clk_select)
+		return false;
+	if (a->clk_ps != b->clk_ps)
+		return false;
+	if (a->mod_period != b->mod_period)
+		return false;
+	return true;
+}
+
 static int fsl_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	int ret;
@@ -87,89 +116,58 @@ static void fsl_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 	clk_disable_unprepare(fpc->ipg_clk);
 }
 
-static int fsl_pwm_calculate_default_ps(struct fsl_pwm_chip *fpc,
+static unsigned int fsl_pwm_ticks_to_ns(struct fsl_pwm_chip *fpc,
-					enum fsl_pwm_clk index)
+					  unsigned int ticks)
 {
-	unsigned long sys_rate, cnt_rate;
+	unsigned long rate;
-	unsigned long long ratio;
+	unsigned long long exval;
 
-	sys_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_SYS]);
+	rate = clk_get_rate(fpc->clk[fpc->period.clk_select]);
-	if (!sys_rate)
+	exval = ticks;
-		return -EINVAL;
+	exval *= 1000000000UL;
-
+	do_div(exval, rate >> fpc->period.clk_ps);
-	cnt_rate = clk_get_rate(fpc->clk[fpc->cnt_select]);
+	return exval;
-	if (!cnt_rate)
-		return -EINVAL;
-
-	switch (index) {
-	case FSL_PWM_CLK_SYS:
-		fpc->clk_ps = 1;
-		break;
-	case FSL_PWM_CLK_FIX:
-		ratio = 2 * cnt_rate - 1;
-		do_div(ratio, sys_rate);
-		fpc->clk_ps = ratio;
-		break;
-	case FSL_PWM_CLK_EXT:
-		ratio = 4 * cnt_rate - 1;
-		do_div(ratio, sys_rate);
-		fpc->clk_ps = ratio;
-		break;
-	default:
-		return -EINVAL;
-	}
-
-	return 0;
 }
 
-static unsigned long fsl_pwm_calculate_cycles(struct fsl_pwm_chip *fpc,
+static bool fsl_pwm_calculate_period_clk(struct fsl_pwm_chip *fpc,
-					      unsigned long period_ns)
+					 unsigned int period_ns,
+					 enum fsl_pwm_clk index,
+					 struct fsl_pwm_periodcfg *periodcfg
+					 )
 {
-	unsigned long long c, c0;
+	unsigned long long c;
+	unsigned int ps;
 
-	c = clk_get_rate(fpc->clk[fpc->cnt_select]);
+	c = clk_get_rate(fpc->clk[index]);
 	c = c * period_ns;
 	do_div(c, 1000000000UL);
 
-	do {
+	if (c == 0)
-		c0 = c;
+		return false;
-		do_div(c0, (1 << fpc->clk_ps));
-		if (c0 <= 0xFFFF)
-			return (unsigned long)c0;
-	} while (++fpc->clk_ps < 8);
 
-	return 0;
+	for (ps = 0; ps < 8 ; ++ps, c >>= 1) {
-}
+		if (c <= 0x10000) {
-
+			periodcfg->clk_select = index;
-static unsigned long fsl_pwm_calculate_period_cycles(struct fsl_pwm_chip *fpc,
+			periodcfg->clk_ps = ps;
-						     unsigned long period_ns,
+			periodcfg->mod_period = c - 1;
-						     enum fsl_pwm_clk index)
+			return true;
-{
+		}
-	int ret;
-
-	ret = fsl_pwm_calculate_default_ps(fpc, index);
-	if (ret) {
-		dev_err(fpc->chip.dev,
-			"failed to calculate default prescaler: %d\n",
-			ret);
-		return 0;
 	}
-
+	return false;
-	return fsl_pwm_calculate_cycles(fpc, period_ns);
 }
 
-static unsigned long fsl_pwm_calculate_period(struct fsl_pwm_chip *fpc,
+static bool fsl_pwm_calculate_period(struct fsl_pwm_chip *fpc,
-					      unsigned long period_ns)
+				     unsigned int period_ns,
+				     struct fsl_pwm_periodcfg *periodcfg)
 {
 	enum fsl_pwm_clk m0, m1;
-	unsigned long fix_rate, ext_rate, cycles;
+	unsigned long fix_rate, ext_rate;
+	bool ret;
 
-	cycles = fsl_pwm_calculate_period_cycles(fpc, period_ns,
+	ret = fsl_pwm_calculate_period_clk(fpc, period_ns, FSL_PWM_CLK_SYS,
-			FSL_PWM_CLK_SYS);
+					   periodcfg);
-	if (cycles) {
+	if (ret)
-		fpc->cnt_select = FSL_PWM_CLK_SYS;
+		return true;
-		return cycles;
-	}
 
 	fix_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_FIX]);
 	ext_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_EXT]);
@@ -182,158 +180,185 @@ static unsigned long fsl_pwm_calculate_period(struct fsl_pwm_chip *fpc,
 		m1 = FSL_PWM_CLK_FIX;
 	}
 
-	cycles = fsl_pwm_calculate_period_cycles(fpc, period_ns, m0);
+	ret = fsl_pwm_calculate_period_clk(fpc, period_ns, m0, periodcfg);
-	if (cycles) {
+	if (ret)
-		fpc->cnt_select = m0;
+		return true;
-		return cycles;
-	}
 
-	fpc->cnt_select = m1;
+	return fsl_pwm_calculate_period_clk(fpc, period_ns, m1, periodcfg);
-
-	return fsl_pwm_calculate_period_cycles(fpc, period_ns, m1);
 }
 
-static unsigned long fsl_pwm_calculate_duty(struct fsl_pwm_chip *fpc,
+static unsigned int fsl_pwm_calculate_duty(struct fsl_pwm_chip *fpc,
-					    unsigned long period_ns,
+					   unsigned int duty_ns)
-					    unsigned long duty_ns)
 {
 	unsigned long long duty;
-	u32 val;
 
-	regmap_read(fpc->regmap, FTM_MOD, &val);
+	unsigned int period = fpc->period.mod_period + 1;
-	duty = (unsigned long long)duty_ns * (val + 1);
+	unsigned int period_ns = fsl_pwm_ticks_to_ns(fpc, period);
+
+	duty = (unsigned long long)duty_ns * period;
 	do_div(duty, period_ns);
 
-	return (unsigned long)duty;
+	return (unsigned int)duty;
 }
 
-static int fsl_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+static bool fsl_pwm_is_any_pwm_enabled(struct fsl_pwm_chip *fpc,
-			  int duty_ns, int period_ns)
+				       struct pwm_device *pwm)
 {
-	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
+	u32 val;
-	u32 period, duty;
 
-	mutex_lock(&fpc->lock);
+	regmap_read(fpc->regmap, FTM_OUTMASK, &val);
+	if (~val & 0xFF)
+		return true;
+	else
+		return false;
+}
 
+static bool fsl_pwm_is_other_pwm_enabled(struct fsl_pwm_chip *fpc,
+					 struct pwm_device *pwm)
+{
+	u32 val;
+
+	regmap_read(fpc->regmap, FTM_OUTMASK, &val);
+	if (~(val | BIT(pwm->hwpwm)) & 0xFF)
+		return true;
+	else
+		return false;
+}
+
+static int fsl_pwm_apply_config(struct fsl_pwm_chip *fpc,
+				struct pwm_device *pwm,
+				struct pwm_state *newstate)
+{
+	unsigned int duty;
+	u32 reg_polarity;
+
+	struct fsl_pwm_periodcfg periodcfg;
+	bool do_write_period = false;
+
+	if (!fsl_pwm_calculate_period(fpc, newstate->period, &periodcfg)) {
+		dev_err(fpc->chip.dev, "failed to calculate new period\n");
+		return -EINVAL;
+	}
+
+	if (!fsl_pwm_is_any_pwm_enabled(fpc, pwm))
+		do_write_period = true;
 	/*
 	 * The Freescale FTM controller supports only a single period for
-	 * all PWM channels, therefore incompatible changes need to be
+	 * all PWM channels, therefore verify if the newly computed period
-	 * refused.
+	 * is different than the current period being used. In such case
+	 * we allow to change the period only if no other pwm is running.
 	 */
-	if (fpc->period_ns && fpc->period_ns != period_ns) {
+	else if (!fsl_pwm_periodcfg_are_equal(&fpc->period, &periodcfg)) {
-		dev_err(fpc->chip.dev,
+		if (fsl_pwm_is_other_pwm_enabled(fpc, pwm)) {
-			"conflicting period requested for PWM %u\n",
+			dev_err(fpc->chip.dev,
-			pwm->hwpwm);
+				"Cannot change period for PWM %u, disable other PWMs first\n",
-		mutex_unlock(&fpc->lock);
+				pwm->hwpwm);
-		return -EBUSY;
+			return -EBUSY;
-	}
-
-	if (!fpc->period_ns && duty_ns) {
-		period = fsl_pwm_calculate_period(fpc, period_ns);
-		if (!period) {
-			dev_err(fpc->chip.dev, "failed to calculate period\n");
-			mutex_unlock(&fpc->lock);
-			return -EINVAL;
 		}
+		if (fpc->period.clk_select != periodcfg.clk_select) {
+			int ret;
+			enum fsl_pwm_clk oldclk = fpc->period.clk_select;
+			enum fsl_pwm_clk newclk = periodcfg.clk_select;
 
-		regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_PS_MASK,
+			ret = clk_prepare_enable(fpc->clk[newclk]);
-				   fpc->clk_ps);
+			if (ret)
-		regmap_write(fpc->regmap, FTM_MOD, period - 1);
+				return ret;
-
+			clk_disable_unprepare(fpc->clk[oldclk]);
-		fpc->period_ns = period_ns;
+		}
+		do_write_period = true;
 	}
 
-	mutex_unlock(&fpc->lock);
+	ftm_clear_write_protection(fpc);
 
-	duty = fsl_pwm_calculate_duty(fpc, period_ns, duty_ns);
+	if (do_write_period) {
+		regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_CLK_MASK,
+				   FTM_SC_CLK(periodcfg.clk_select));
+		regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_PS_MASK,
+				   periodcfg.clk_ps);
+		regmap_write(fpc->regmap, FTM_MOD, periodcfg.mod_period);
+
+		fpc->period = periodcfg;
+	}
+
+	duty = fsl_pwm_calculate_duty(fpc, newstate->duty_cycle);
 
 	regmap_write(fpc->regmap, FTM_CSC(pwm->hwpwm),
 		     FTM_CSC_MSB | FTM_CSC_ELSB);
 	regmap_write(fpc->regmap, FTM_CV(pwm->hwpwm), duty);
 
+	reg_polarity = 0;
+	if (newstate->polarity == PWM_POLARITY_INVERSED)
+		reg_polarity = BIT(pwm->hwpwm);
+
+	regmap_update_bits(fpc->regmap, FTM_POL, BIT(pwm->hwpwm), reg_polarity);
+
+	newstate->period = fsl_pwm_ticks_to_ns(fpc,
+					       fpc->period.mod_period + 1);
+	newstate->duty_cycle = fsl_pwm_ticks_to_ns(fpc, duty);
+
+	ftm_set_write_protection(fpc);
+
 	return 0;
 }
 
-static int fsl_pwm_set_polarity(struct pwm_chip *chip,
+static int fsl_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
-				struct pwm_device *pwm,
+			 struct pwm_state *newstate)
-				enum pwm_polarity polarity)
 {
 	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
-	u32 val;
+	struct pwm_state *oldstate = &pwm->state;
+	int ret = 0;
 
-	regmap_read(fpc->regmap, FTM_POL, &val);
+	/*
+	 * oldstate to newstate : action
+	 *
+	 * disabled to disabled : ignore
+	 * enabled to disabled : disable
+	 * enabled to enabled : update settings
+	 * disabled to enabled : update settings + enable
+	 */
 
-	if (polarity == PWM_POLARITY_INVERSED)
+	mutex_lock(&fpc->lock);
-		val |= BIT(pwm->hwpwm);
-	else
-		val &= ~BIT(pwm->hwpwm);
 
-	regmap_write(fpc->regmap, FTM_POL, val);
+	if (!newstate->enabled) {
+		if (oldstate->enabled) {
+			regmap_update_bits(fpc->regmap, FTM_OUTMASK,
+					   BIT(pwm->hwpwm), BIT(pwm->hwpwm));
+			clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
+			clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
+		}
 
-	return 0;
+		goto end_mutex;
-}
-
-static int fsl_counter_clock_enable(struct fsl_pwm_chip *fpc)
-{
-	int ret;
-
-	/* select counter clock source */
-	regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_CLK_MASK,
-			   FTM_SC_CLK(fpc->cnt_select));
-
-	ret = clk_prepare_enable(fpc->clk[fpc->cnt_select]);
-	if (ret)
-		return ret;
-
-	ret = clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
-	if (ret) {
-		clk_disable_unprepare(fpc->clk[fpc->cnt_select]);
-		return ret;
 	}
 
-	return 0;
+	ret = fsl_pwm_apply_config(fpc, pwm, newstate);
-}
+	if (ret)
+		goto end_mutex;
 
-static int fsl_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+	/* check if need to enable */
-{
+	if (!oldstate->enabled) {
-	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
+		ret = clk_prepare_enable(fpc->clk[fpc->period.clk_select]);
-	int ret;
+		if (ret)
+			goto end_mutex;
 
-	mutex_lock(&fpc->lock);
+		ret = clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
-	regmap_update_bits(fpc->regmap, FTM_OUTMASK, BIT(pwm->hwpwm), 0);
+		if (ret) {
+			clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
+			goto end_mutex;
+		}
 
-	ret = fsl_counter_clock_enable(fpc);
+		regmap_update_bits(fpc->regmap, FTM_OUTMASK, BIT(pwm->hwpwm),
+				   0);
+	}
+
+end_mutex:
 	mutex_unlock(&fpc->lock);
-
 	return ret;
 }
 
-static void fsl_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
-{
-	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
-	u32 val;
-
-	mutex_lock(&fpc->lock);
-	regmap_update_bits(fpc->regmap, FTM_OUTMASK, BIT(pwm->hwpwm),
-			   BIT(pwm->hwpwm));
-
-	clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
-	clk_disable_unprepare(fpc->clk[fpc->cnt_select]);
-
-	regmap_read(fpc->regmap, FTM_OUTMASK, &val);
-	if ((val & 0xFF) == 0xFF)
-		fpc->period_ns = 0;
-
-	mutex_unlock(&fpc->lock);
-}
-
 static const struct pwm_ops fsl_pwm_ops = {
 	.request = fsl_pwm_request,
 	.free = fsl_pwm_free,
-	.config = fsl_pwm_config,
+	.apply = fsl_pwm_apply,
-	.set_polarity = fsl_pwm_set_polarity,
-	.enable = fsl_pwm_enable,
-	.disable = fsl_pwm_disable,
 	.owner = THIS_MODULE,
 };
 
@@ -357,6 +382,8 @@ static int fsl_pwm_init(struct fsl_pwm_chip *fpc)
 static bool fsl_pwm_volatile_reg(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
+	case FTM_FMS:
+	case FTM_MODE:
 	case FTM_CNT:
 		return true;
 	}
@@ -474,7 +501,7 @@ static int fsl_pwm_suspend(struct device *dev)
 			continue;
 
 		clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
-		clk_disable_unprepare(fpc->clk[fpc->cnt_select]);
+		clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
 	}
 
 	return 0;
@@ -496,7 +523,7 @@ static int fsl_pwm_resume(struct device *dev)
 		if (!pwm_is_enabled(pwm))
 			continue;
 
-		clk_prepare_enable(fpc->clk[fpc->cnt_select]);
+		clk_prepare_enable(fpc->clk[fpc->period.clk_select]);
 		clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
 	}
 

drivers/pwm/pwm-jz4740.c

@@ -63,7 +63,15 @@ static void jz4740_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	uint32_t ctrl = jz4740_timer_get_ctrl(pwm->hwpwm);
 
-	/* Disable PWM output.
+	/*
+	 * Set duty > period. This trick allows the TCU channels in TCU2 mode to
+	 * properly return to their init level.
+	 */
+	jz4740_timer_set_duty(pwm->hwpwm, 0xffff);
+	jz4740_timer_set_period(pwm->hwpwm, 0x0);
+
+	/*
+	 * Disable PWM output.
 	 * In TCU2 mode (channel 1/2 on JZ4750+), this must be done before the
 	 * counter is stopped, while in TCU1 mode the order does not matter.
 	 */
@@ -74,17 +82,16 @@ static void jz4740_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 	jz4740_timer_disable(pwm->hwpwm);
 }
 
-static int jz4740_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
-			     int duty_ns, int period_ns)
+			    struct pwm_state *state)
 {
 	struct jz4740_pwm_chip *jz4740 = to_jz4740(pwm->chip);
 	unsigned long long tmp;
 	unsigned long period, duty;
 	unsigned int prescaler = 0;
 	uint16_t ctrl;
-	bool is_enabled;
 
-	tmp = (unsigned long long)clk_get_rate(jz4740->clk) * period_ns;
+	tmp = (unsigned long long)clk_get_rate(jz4740->clk) * state->period;
 	do_div(tmp, 1000000000);
 	period = tmp;
 
@@ -96,16 +103,14 @@ static int jz4740_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	if (prescaler == 6)
 		return -EINVAL;
 
-	tmp = (unsigned long long)period * duty_ns;
+	tmp = (unsigned long long)period * state->duty_cycle;
-	do_div(tmp, period_ns);
+	do_div(tmp, state->period);
 	duty = period - tmp;
 
 	if (duty >= period)
 		duty = period - 1;
 
-	is_enabled = jz4740_timer_is_enabled(pwm->hwpwm);
+	jz4740_pwm_disable(chip, pwm);
-	if (is_enabled)
-		jz4740_pwm_disable(chip, pwm);
 
 	jz4740_timer_set_count(pwm->hwpwm, 0);
 	jz4740_timer_set_duty(pwm->hwpwm, duty);
@@ -116,18 +121,7 @@ static int jz4740_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 
 	jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
 
-	if (is_enabled)
+	switch (state->polarity) {
-		jz4740_pwm_enable(chip, pwm);
-
-	return 0;
-}
-
-static int jz4740_pwm_set_polarity(struct pwm_chip *chip,
-		struct pwm_device *pwm, enum pwm_polarity polarity)
-{
-	uint32_t ctrl = jz4740_timer_get_ctrl(pwm->pwm);
-
-	switch (polarity) {
 	case PWM_POLARITY_NORMAL:
 		ctrl &= ~JZ_TIMER_CTRL_PWM_ACTIVE_LOW;
 		break;
@@ -137,16 +131,17 @@ static int jz4740_pwm_set_polarity(struct pwm_chip *chip,
 	}
 
 	jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
+
+	if (state->enabled)
+		jz4740_pwm_enable(chip, pwm);
+
 	return 0;
 }
 
 static const struct pwm_ops jz4740_pwm_ops = {
 	.request = jz4740_pwm_request,
 	.free = jz4740_pwm_free,
-	.config = jz4740_pwm_config,
+	.apply = jz4740_pwm_apply,
-	.set_polarity = jz4740_pwm_set_polarity,
-	.enable = jz4740_pwm_enable,
-	.disable = jz4740_pwm_disable,
 	.owner = THIS_MODULE,
 };
 
@@ -184,8 +179,6 @@ static int jz4740_pwm_remove(struct platform_device *pdev)
 #ifdef CONFIG_OF
 static const struct of_device_id jz4740_pwm_dt_ids[] = {
 	{ .compatible = "ingenic,jz4740-pwm", },
-	{ .compatible = "ingenic,jz4770-pwm", },
-	{ .compatible = "ingenic,jz4780-pwm", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, jz4740_pwm_dt_ids);

drivers/pwm/pwm-meson.c

@@ -1,65 +1,40 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
 /*
- * This file is provided under a dual BSD/GPLv2 license.  When using or
+ * PWM controller driver for Amlogic Meson SoCs.
- * redistributing this file, you may do so under either license.
  *
- * GPL LICENSE SUMMARY
+ * This PWM is only a set of Gates, Dividers and Counters:
+ * PWM output is achieved by calculating a clock that permits calculating
+ * two periods (low and high). The counter then has to be set to switch after
+ * N cycles for the first half period.
+ * The hardware has no "polarity" setting. This driver reverses the period
+ * cycles (the low length is inverted with the high length) for
+ * PWM_POLARITY_INVERSED. This means that .get_state cannot read the polarity
+ * from the hardware.
+ * Setting the duty cycle will disable and re-enable the PWM output.
+ * Disabling the PWM stops the output immediately (without waiting for the
+ * current period to complete first).
+ *
+ * The public S912 (GXM) datasheet contains some documentation for this PWM
+ * controller starting on page 543:
+ * https://dl.khadas.com/Hardware/VIM2/Datasheet/S912_Datasheet_V0.220170314publicversion-Wesion.pdf
+ * An updated version of this IP block is found in S922X (G12B) SoCs. The
+ * datasheet contains the description for this IP block revision starting at
+ * page 1084:
+ * https://dn.odroid.com/S922X/ODROID-N2/Datasheet/S922X_Public_Datasheet_V0.2.pdf
  *
  * Copyright (c) 2016 BayLibre, SAS.
  * Author: Neil Armstrong <narmstrong@baylibre.com>
  * Copyright (C) 2014 Amlogic, Inc.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of version 2 of the GNU General Public License as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, see <http://www.gnu.org/licenses/>.
- * The full GNU General Public License is included in this distribution
- * in the file called COPYING.
- *
- * BSD LICENSE
- *
- * Copyright (c) 2016 BayLibre, SAS.
- * Author: Neil Armstrong <narmstrong@baylibre.com>
- * Copyright (C) 2014 Amlogic, Inc.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- *   * Redistributions of source code must retain the above copyright
- *     notice, this list of conditions and the following disclaimer.
- *   * Redistributions in binary form must reproduce the above copyright
- *     notice, this list of conditions and the following disclaimer in
- *     the documentation and/or other materials provided with the
- *     distribution.
- *   * Neither the name of Intel Corporation nor the names of its
- *     contributors may be used to endorse or promote products derived
- *     from this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <linux/bitfield.h>
+#include <linux/bits.h>
 #include <linux/clk.h>
 #include <linux/clk-provider.h>
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
+#include <linux/math64.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
@@ -70,7 +45,8 @@
 
 #define REG_PWM_A		0x0
 #define REG_PWM_B		0x4
-#define PWM_HIGH_SHIFT		16
+#define PWM_LOW_MASK		GENMASK(15, 0)
+#define PWM_HIGH_MASK		GENMASK(31, 16)
 
 #define REG_MISC_AB		0x8
 #define MISC_B_CLK_EN		BIT(23)
@@ -80,13 +56,33 @@
 #define MISC_A_CLK_DIV_SHIFT	8
 #define MISC_B_CLK_SEL_SHIFT	6
 #define MISC_A_CLK_SEL_SHIFT	4
-#define MISC_CLK_SEL_WIDTH	2
+#define MISC_CLK_SEL_MASK	0x3
 #define MISC_B_EN		BIT(1)
 #define MISC_A_EN		BIT(0)
 
-static const unsigned int mux_reg_shifts[] = {
+#define MESON_NUM_PWMS		2
-	MISC_A_CLK_SEL_SHIFT,
+
-	MISC_B_CLK_SEL_SHIFT
+static struct meson_pwm_channel_data {
+	u8		reg_offset;
+	u8		clk_sel_shift;
+	u8		clk_div_shift;
+	u32		clk_en_mask;
+	u32		pwm_en_mask;
+} meson_pwm_per_channel_data[MESON_NUM_PWMS] = {
+	{
+		.reg_offset	= REG_PWM_A,
+		.clk_sel_shift	= MISC_A_CLK_SEL_SHIFT,
+		.clk_div_shift	= MISC_A_CLK_DIV_SHIFT,
+		.clk_en_mask	= MISC_A_CLK_EN,
+		.pwm_en_mask	= MISC_A_EN,
+	},
+	{
+		.reg_offset	= REG_PWM_B,
+		.clk_sel_shift	= MISC_B_CLK_SEL_SHIFT,
+		.clk_div_shift	= MISC_B_CLK_DIV_SHIFT,
+		.clk_en_mask	= MISC_B_CLK_EN,
+		.pwm_en_mask	= MISC_B_EN,
+	}
 };
 
 struct meson_pwm_channel {
@@ -94,8 +90,6 @@ struct meson_pwm_channel {
 	unsigned int lo;
 	u8 pre_div;
 
-	struct pwm_state state;
-
 	struct clk *clk_parent;
 	struct clk_mux mux;
 	struct clk *clk;
@@ -109,8 +103,8 @@ struct meson_pwm_data {
 struct meson_pwm {
 	struct pwm_chip chip;
 	const struct meson_pwm_data *data;
+	struct meson_pwm_channel channels[MESON_NUM_PWMS];
 	void __iomem *base;
-	u8 inverter_mask;
 	/*
 	 * Protects register (write) access to the REG_MISC_AB register
 	 * that is shared between the two PWMs.
@@ -125,12 +119,16 @@ static inline struct meson_pwm *to_meson_pwm(struct pwm_chip *chip)
 
 static int meson_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 {
-	struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
+	struct meson_pwm *meson = to_meson_pwm(chip);
+	struct meson_pwm_channel *channel;
 	struct device *dev = chip->dev;
 	int err;
 
-	if (!channel)
+	channel = pwm_get_chip_data(pwm);
-		return -ENODEV;
+	if (channel)
+		return 0;
+
+	channel = &meson->channels[pwm->hwpwm];
 
 	if (channel->clk_parent) {
 		err = clk_set_parent(channel->clk, channel->clk_parent);
@@ -149,9 +147,7 @@ static int meson_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 		return err;
 	}
 
-	chip->ops->get_state(chip, pwm, &channel->state);
+	return pwm_set_chip_data(pwm, channel);
-
-	return 0;
 }
 
 static void meson_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
@@ -162,21 +158,19 @@ static void meson_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 		clk_disable_unprepare(channel->clk);
 }
 
-static int meson_pwm_calc(struct meson_pwm *meson,
+static int meson_pwm_calc(struct meson_pwm *meson, struct pwm_device *pwm,
-			  struct meson_pwm_channel *channel, unsigned int id,
+			  struct pwm_state *state)
-			  unsigned int duty, unsigned int period)
 {
-	unsigned int pre_div, cnt, duty_cnt;
+	struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
+	unsigned int duty, period, pre_div, cnt, duty_cnt;
 	unsigned long fin_freq = -1;
-	u64 fin_ps;
 
-	if (~(meson->inverter_mask >> id) & 0x1)
+	duty = state->duty_cycle;
+	period = state->period;
+
+	if (state->polarity == PWM_POLARITY_INVERSED)
 		duty = period - duty;
 
-	if (period == channel->state.period &&
-	    duty == channel->state.duty_cycle)
-		return 0;
-
 	fin_freq = clk_get_rate(channel->clk);
 	if (fin_freq == 0) {
 		dev_err(meson->chip.dev, "invalid source clock frequency\n");
@@ -184,24 +178,19 @@ static int meson_pwm_calc(struct meson_pwm *meson,
 	}
 
 	dev_dbg(meson->chip.dev, "fin_freq: %lu Hz\n", fin_freq);
-	fin_ps = (u64)NSEC_PER_SEC * 1000;
-	do_div(fin_ps, fin_freq);
-
-	/* Calc pre_div with the period */
-	for (pre_div = 0; pre_div <= MISC_CLK_DIV_MASK; pre_div++) {
-		cnt = DIV_ROUND_CLOSEST_ULL((u64)period * 1000,
-					    fin_ps * (pre_div + 1));
-		dev_dbg(meson->chip.dev, "fin_ps=%llu pre_div=%u cnt=%u\n",
-			fin_ps, pre_div, cnt);
-		if (cnt <= 0xffff)
-			break;
-	}
 
+	pre_div = div64_u64(fin_freq * (u64)period, NSEC_PER_SEC * 0xffffLL);
 	if (pre_div > MISC_CLK_DIV_MASK) {
 		dev_err(meson->chip.dev, "unable to get period pre_div\n");
 		return -EINVAL;
 	}
 
+	cnt = div64_u64(fin_freq * (u64)period, NSEC_PER_SEC * (pre_div + 1));
+	if (cnt > 0xffff) {
+		dev_err(meson->chip.dev, "unable to get period cnt\n");
+		return -EINVAL;
+	}
+
 	dev_dbg(meson->chip.dev, "period=%u pre_div=%u cnt=%u\n", period,
 		pre_div, cnt);
 
@@ -215,8 +204,8 @@ static int meson_pwm_calc(struct meson_pwm *meson,
 		channel->lo = cnt;
 	} else {
 		/* Then check is we can have the duty with the same pre_div */
-		duty_cnt = DIV_ROUND_CLOSEST_ULL((u64)duty * 1000,
+		duty_cnt = div64_u64(fin_freq * (u64)duty,
-						 fin_ps * (pre_div + 1));
+				     NSEC_PER_SEC * (pre_div + 1));
 		if (duty_cnt > 0xffff) {
 			dev_err(meson->chip.dev, "unable to get duty cycle\n");
 			return -EINVAL;
@@ -233,73 +222,43 @@ static int meson_pwm_calc(struct meson_pwm *meson,
 	return 0;
 }
 
-static void meson_pwm_enable(struct meson_pwm *meson,
+static void meson_pwm_enable(struct meson_pwm *meson, struct pwm_device *pwm)
-			     struct meson_pwm_channel *channel,
-			     unsigned int id)
 {
-	u32 value, clk_shift, clk_enable, enable;
+	struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
-	unsigned int offset;
+	struct meson_pwm_channel_data *channel_data;
 	unsigned long flags;
+	u32 value;
 
-	switch (id) {
+	channel_data = &meson_pwm_per_channel_data[pwm->hwpwm];
-	case 0:
-		clk_shift = MISC_A_CLK_DIV_SHIFT;
-		clk_enable = MISC_A_CLK_EN;
-		enable = MISC_A_EN;
-		offset = REG_PWM_A;
-		break;
-
-	case 1:
-		clk_shift = MISC_B_CLK_DIV_SHIFT;
-		clk_enable = MISC_B_CLK_EN;
-		enable = MISC_B_EN;
-		offset = REG_PWM_B;
-		break;
-
-	default:
-		return;
-	}
 
 	spin_lock_irqsave(&meson->lock, flags);
 
 	value = readl(meson->base + REG_MISC_AB);
-	value &= ~(MISC_CLK_DIV_MASK << clk_shift);
+	value &= ~(MISC_CLK_DIV_MASK << channel_data->clk_div_shift);
-	value |= channel->pre_div << clk_shift;
+	value |= channel->pre_div << channel_data->clk_div_shift;
-	value |= clk_enable;
+	value |= channel_data->clk_en_mask;
 	writel(value, meson->base + REG_MISC_AB);
 
-	value = (channel->hi << PWM_HIGH_SHIFT) | channel->lo;
+	value = FIELD_PREP(PWM_HIGH_MASK, channel->hi) |
-	writel(value, meson->base + offset);
+		FIELD_PREP(PWM_LOW_MASK, channel->lo);
+	writel(value, meson->base + channel_data->reg_offset);
 
 	value = readl(meson->base + REG_MISC_AB);
-	value |= enable;
+	value |= channel_data->pwm_en_mask;
 	writel(value, meson->base + REG_MISC_AB);
 
 	spin_unlock_irqrestore(&meson->lock, flags);
 }
 
-static void meson_pwm_disable(struct meson_pwm *meson, unsigned int id)
+static void meson_pwm_disable(struct meson_pwm *meson, struct pwm_device *pwm)
 {
-	u32 value, enable;
 	unsigned long flags;
-
+	u32 value;
-	switch (id) {
-	case 0:
-		enable = MISC_A_EN;
-		break;
-
-	case 1:
-		enable = MISC_B_EN;
-		break;
-
-	default:
-		return;
-	}
 
 	spin_lock_irqsave(&meson->lock, flags);
 
 	value = readl(meson->base + REG_MISC_AB);
-	value &= ~enable;
+	value &= ~meson_pwm_per_channel_data[pwm->hwpwm].pwm_en_mask;
 	writel(value, meson->base + REG_MISC_AB);
 
 	spin_unlock_irqrestore(&meson->lock, flags);
@@ -316,64 +275,97 @@ static int meson_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 		return -EINVAL;
 
 	if (!state->enabled) {
-		meson_pwm_disable(meson, pwm->hwpwm);
+		if (state->polarity == PWM_POLARITY_INVERSED) {
-		channel->state.enabled = false;
+			/*
+			 * This IP block revision doesn't have an "always high"
+			 * setting which we can use for "inverted disabled".
+			 * Instead we achieve this using the same settings
+			 * that we use a pre_div of 0 (to get the shortest
+			 * possible duration for one "count") and
+			 * "period == duty_cycle". This results in a signal
+			 * which is LOW for one "count", while being HIGH for
+			 * the rest of the (so the signal is HIGH for slightly
+			 * less than 100% of the period, but this is the best
+			 * we can achieve).
+			 */
+			channel->pre_div = 0;
+			channel->hi = ~0;
+			channel->lo = 0;
 
-		return 0;
+			meson_pwm_enable(meson, pwm);
-	}
+		} else {
-
+			meson_pwm_disable(meson, pwm);
-	if (state->period != channel->state.period ||
-	    state->duty_cycle != channel->state.duty_cycle ||
-	    state->polarity != channel->state.polarity) {
-		if (state->polarity != channel->state.polarity) {
-			if (state->polarity == PWM_POLARITY_NORMAL)
-				meson->inverter_mask |= BIT(pwm->hwpwm);
-			else
-				meson->inverter_mask &= ~BIT(pwm->hwpwm);
 		}
-
+	} else {
-		err = meson_pwm_calc(meson, channel, pwm->hwpwm,
+		err = meson_pwm_calc(meson, pwm, state);
-				     state->duty_cycle, state->period);
 		if (err < 0)
 			return err;
 
-		channel->state.polarity = state->polarity;
+		meson_pwm_enable(meson, pwm);
-		channel->state.period = state->period;
-		channel->state.duty_cycle = state->duty_cycle;
-	}
-
-	if (state->enabled && !channel->state.enabled) {
-		meson_pwm_enable(meson, channel, pwm->hwpwm);
-		channel->state.enabled = true;
 	}
 
 	return 0;
 }
 
+static unsigned int meson_pwm_cnt_to_ns(struct pwm_chip *chip,
+					struct pwm_device *pwm, u32 cnt)
+{
+	struct meson_pwm *meson = to_meson_pwm(chip);
+	struct meson_pwm_channel *channel;
+	unsigned long fin_freq;
+	u32 fin_ns;
+
+	/* to_meson_pwm() can only be used after .get_state() is called */
+	channel = &meson->channels[pwm->hwpwm];
+
+	fin_freq = clk_get_rate(channel->clk);
+	if (fin_freq == 0)
+		return 0;
+
+	fin_ns = div_u64(NSEC_PER_SEC, fin_freq);
+
+	return cnt * fin_ns * (channel->pre_div + 1);
+}
+
 static void meson_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
 				struct pwm_state *state)
 {
 	struct meson_pwm *meson = to_meson_pwm(chip);
-	u32 value, mask;
+	struct meson_pwm_channel_data *channel_data;
+	struct meson_pwm_channel *channel;
+	u32 value, tmp;
 
 	if (!state)
 		return;
 
-	switch (pwm->hwpwm) {
+	channel = &meson->channels[pwm->hwpwm];
-	case 0:
+	channel_data = &meson_pwm_per_channel_data[pwm->hwpwm];
-		mask = MISC_A_EN;
-		break;
-
-	case 1:
-		mask = MISC_B_EN;
-		break;
-
-	default:
-		return;
-	}
 
 	value = readl(meson->base + REG_MISC_AB);
-	state->enabled = (value & mask) != 0;
+
+	tmp = channel_data->pwm_en_mask | channel_data->clk_en_mask;
+	state->enabled = (value & tmp) == tmp;
+
+	tmp = value >> channel_data->clk_div_shift;
+	channel->pre_div = FIELD_GET(MISC_CLK_DIV_MASK, tmp);
+
+	value = readl(meson->base + channel_data->reg_offset);
+
+	channel->lo = FIELD_GET(PWM_LOW_MASK, value);
+	channel->hi = FIELD_GET(PWM_HIGH_MASK, value);
+
+	if (channel->lo == 0) {
+		state->period = meson_pwm_cnt_to_ns(chip, pwm, channel->hi);
+		state->duty_cycle = state->period;
+	} else if (channel->lo >= channel->hi) {
+		state->period = meson_pwm_cnt_to_ns(chip, pwm,
+						    channel->lo + channel->hi);
+		state->duty_cycle = meson_pwm_cnt_to_ns(chip, pwm,
+							channel->hi);
+	} else {
+		state->period = 0;
+		state->duty_cycle = 0;
+	}
 }
 
 static const struct pwm_ops meson_pwm_ops = {
@@ -433,8 +425,17 @@ static const struct meson_pwm_data pwm_axg_ao_data = {
 	.num_parents = ARRAY_SIZE(pwm_axg_ao_parent_names),
 };
 
+static const char * const pwm_g12a_ao_ab_parent_names[] = {
+	"xtal", "aoclk81", "fclk_div4", "fclk_div5"
+};
+
+static const struct meson_pwm_data pwm_g12a_ao_ab_data = {
+	.parent_names = pwm_g12a_ao_ab_parent_names,
+	.num_parents = ARRAY_SIZE(pwm_g12a_ao_ab_parent_names),
+};
+
 static const char * const pwm_g12a_ao_cd_parent_names[] = {
-	"aoclk81", "xtal",
+	"xtal", "aoclk81",
 };
 
 static const struct meson_pwm_data pwm_g12a_ao_cd_data = {
@@ -478,7 +479,7 @@ static const struct of_device_id meson_pwm_matches[] = {
 	},
 	{
 		.compatible = "amlogic,meson-g12a-ao-pwm-ab",
-		.data = &pwm_axg_ao_data
+		.data = &pwm_g12a_ao_ab_data
 	},
 	{
 		.compatible = "amlogic,meson-g12a-ao-pwm-cd",
@@ -488,8 +489,7 @@ static const struct of_device_id meson_pwm_matches[] = {
 };
 MODULE_DEVICE_TABLE(of, meson_pwm_matches);
 
-static int meson_pwm_init_channels(struct meson_pwm *meson,
+static int meson_pwm_init_channels(struct meson_pwm *meson)
-				   struct meson_pwm_channel *channels)
 {
 	struct device *dev = meson->chip.dev;
 	struct clk_init_data init;
@@ -498,7 +498,7 @@ static int meson_pwm_init_channels(struct meson_pwm *meson,
 	int err;
 
 	for (i = 0; i < meson->chip.npwm; i++) {
-		struct meson_pwm_channel *channel = &channels[i];
+		struct meson_pwm_channel *channel = &meson->channels[i];
 
 		snprintf(name, sizeof(name), "%s#mux%u", dev_name(dev), i);
 
@@ -509,8 +509,9 @@ static int meson_pwm_init_channels(struct meson_pwm *meson,
 		init.num_parents = meson->data->num_parents;
 
 		channel->mux.reg = meson->base + REG_MISC_AB;
-		channel->mux.shift = mux_reg_shifts[i];
+		channel->mux.shift =
-		channel->mux.mask = BIT(MISC_CLK_SEL_WIDTH) - 1;
+				meson_pwm_per_channel_data[i].clk_sel_shift;
+		channel->mux.mask = MISC_CLK_SEL_MASK;
 		channel->mux.flags = 0;
 		channel->mux.lock = &meson->lock;
 		channel->mux.table = NULL;
@@ -525,31 +526,16 @@ static int meson_pwm_init_channels(struct meson_pwm *meson,
 
 		snprintf(name, sizeof(name), "clkin%u", i);
 
-		channel->clk_parent = devm_clk_get(dev, name);
+		channel->clk_parent = devm_clk_get_optional(dev, name);
-		if (IS_ERR(channel->clk_parent)) {
+		if (IS_ERR(channel->clk_parent))
-			err = PTR_ERR(channel->clk_parent);
+			return PTR_ERR(channel->clk_parent);
-			if (err == -EPROBE_DEFER)
-				return err;
-
-			channel->clk_parent = NULL;
-		}
 	}
 
 	return 0;
 }
 
-static void meson_pwm_add_channels(struct meson_pwm *meson,
-				   struct meson_pwm_channel *channels)
-{
-	unsigned int i;
-
-	for (i = 0; i < meson->chip.npwm; i++)
-		pwm_set_chip_data(&meson->chip.pwms[i], &channels[i]);
-}
-
 static int meson_pwm_probe(struct platform_device *pdev)
 {
-	struct meson_pwm_channel *channels;
 	struct meson_pwm *meson;
 	struct resource *regs;
 	int err;
@@ -567,19 +553,13 @@ static int meson_pwm_probe(struct platform_device *pdev)
 	meson->chip.dev = &pdev->dev;
 	meson->chip.ops = &meson_pwm_ops;
 	meson->chip.base = -1;
-	meson->chip.npwm = 2;
+	meson->chip.npwm = MESON_NUM_PWMS;
 	meson->chip.of_xlate = of_pwm_xlate_with_flags;
 	meson->chip.of_pwm_n_cells = 3;
 
 	meson->data = of_device_get_match_data(&pdev->dev);
-	meson->inverter_mask = BIT(meson->chip.npwm) - 1;
 
-	channels = devm_kcalloc(&pdev->dev, meson->chip.npwm,
+	err = meson_pwm_init_channels(meson);
-				sizeof(*channels), GFP_KERNEL);
-	if (!channels)
-		return -ENOMEM;
-
-	err = meson_pwm_init_channels(meson, channels);
 	if (err < 0)
 		return err;
 
@@ -589,8 +569,6 @@ static int meson_pwm_probe(struct platform_device *pdev)
 		return err;
 	}
 
-	meson_pwm_add_channels(meson, channels);
-
 	platform_set_drvdata(pdev, meson);
 
 	return 0;

drivers/pwm/pwm-rcar.c

@@ -254,50 +254,11 @@ static const struct of_device_id rcar_pwm_of_table[] = {
 };
 MODULE_DEVICE_TABLE(of, rcar_pwm_of_table);
 
-#ifdef CONFIG_PM_SLEEP
-static struct pwm_device *rcar_pwm_dev_to_pwm_dev(struct device *dev)
-{
-	struct rcar_pwm_chip *rcar_pwm = dev_get_drvdata(dev);
-	struct pwm_chip *chip = &rcar_pwm->chip;
-
-	return &chip->pwms[0];
-}
-
-static int rcar_pwm_suspend(struct device *dev)
-{
-	struct pwm_device *pwm = rcar_pwm_dev_to_pwm_dev(dev);
-
-	if (!test_bit(PWMF_REQUESTED, &pwm->flags))
-		return 0;
-
-	pm_runtime_put(dev);
-
-	return 0;
-}
-
-static int rcar_pwm_resume(struct device *dev)
-{
-	struct pwm_device *pwm = rcar_pwm_dev_to_pwm_dev(dev);
-	struct pwm_state state;
-
-	if (!test_bit(PWMF_REQUESTED, &pwm->flags))
-		return 0;
-
-	pm_runtime_get_sync(dev);
-
-	pwm_get_state(pwm, &state);
-
-	return rcar_pwm_apply(pwm->chip, pwm, &state);
-}
-#endif /* CONFIG_PM_SLEEP */
-static SIMPLE_DEV_PM_OPS(rcar_pwm_pm_ops, rcar_pwm_suspend, rcar_pwm_resume);
-
 static struct platform_driver rcar_pwm_driver = {
 	.probe = rcar_pwm_probe,
 	.remove = rcar_pwm_remove,
 	.driver = {
 		.name = "pwm-rcar",
-		.pm	= &rcar_pwm_pm_ops,
 		.of_match_table = of_match_ptr(rcar_pwm_of_table),
 	}
 };

drivers/pwm/pwm-sifive.c

@@ -0,0 +1,339 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2017-2018 SiFive
+ * For SiFive's PWM IP block documentation please refer Chapter 14 of
+ * Reference Manual : https://static.dev.sifive.com/FU540-C000-v1.0.pdf
+ *
+ * Limitations:
+ * - When changing both duty cycle and period, we cannot prevent in
+ *   software that the output might produce a period with mixed
+ *   settings (new period length and old duty cycle).
+ * - The hardware cannot generate a 100% duty cycle.
+ * - The hardware generates only inverted output.
+ */
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+#include <linux/bitfield.h>
+
+/* Register offsets */
+#define PWM_SIFIVE_PWMCFG		0x0
+#define PWM_SIFIVE_PWMCOUNT		0x8
+#define PWM_SIFIVE_PWMS			0x10
+#define PWM_SIFIVE_PWMCMP0		0x20
+
+/* PWMCFG fields */
+#define PWM_SIFIVE_PWMCFG_SCALE		GENMASK(3, 0)
+#define PWM_SIFIVE_PWMCFG_STICKY	BIT(8)
+#define PWM_SIFIVE_PWMCFG_ZERO_CMP	BIT(9)
+#define PWM_SIFIVE_PWMCFG_DEGLITCH	BIT(10)
+#define PWM_SIFIVE_PWMCFG_EN_ALWAYS	BIT(12)
+#define PWM_SIFIVE_PWMCFG_EN_ONCE	BIT(13)
+#define PWM_SIFIVE_PWMCFG_CENTER	BIT(16)
+#define PWM_SIFIVE_PWMCFG_GANG		BIT(24)
+#define PWM_SIFIVE_PWMCFG_IP		BIT(28)
+
+/* PWM_SIFIVE_SIZE_PWMCMP is used to calculate offset for pwmcmpX registers */
+#define PWM_SIFIVE_SIZE_PWMCMP		4
+#define PWM_SIFIVE_CMPWIDTH		16
+#define PWM_SIFIVE_DEFAULT_PERIOD	10000000
+
+struct pwm_sifive_ddata {
+	struct pwm_chip	chip;
+	struct mutex lock; /* lock to protect user_count */
+	struct notifier_block notifier;
+	struct clk *clk;
+	void __iomem *regs;
+	unsigned int real_period;
+	unsigned int approx_period;
+	int user_count;
+};
+
+static inline
+struct pwm_sifive_ddata *pwm_sifive_chip_to_ddata(struct pwm_chip *c)
+{
+	return container_of(c, struct pwm_sifive_ddata, chip);
+}
+
+static int pwm_sifive_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct pwm_sifive_ddata *ddata = pwm_sifive_chip_to_ddata(chip);
+
+	mutex_lock(&ddata->lock);
+	ddata->user_count++;
+	mutex_unlock(&ddata->lock);
+
+	return 0;
+}
+
+static void pwm_sifive_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct pwm_sifive_ddata *ddata = pwm_sifive_chip_to_ddata(chip);
+
+	mutex_lock(&ddata->lock);
+	ddata->user_count--;
+	mutex_unlock(&ddata->lock);
+}
+
+static void pwm_sifive_update_clock(struct pwm_sifive_ddata *ddata,
+				    unsigned long rate)
+{
+	unsigned long long num;
+	unsigned long scale_pow;
+	int scale;
+	u32 val;
+	/*
+	 * The PWM unit is used with pwmzerocmp=0, so the only way to modify the
+	 * period length is using pwmscale which provides the number of bits the
+	 * counter is shifted before being feed to the comparators. A period
+	 * lasts (1 << (PWM_SIFIVE_CMPWIDTH + pwmscale)) clock ticks.
+	 * (1 << (PWM_SIFIVE_CMPWIDTH + scale)) * 10^9/rate = period
+	 */
+	scale_pow = div64_ul(ddata->approx_period * (u64)rate, NSEC_PER_SEC);
+	scale = clamp(ilog2(scale_pow) - PWM_SIFIVE_CMPWIDTH, 0, 0xf);
+
+	val = PWM_SIFIVE_PWMCFG_EN_ALWAYS |
+	      FIELD_PREP(PWM_SIFIVE_PWMCFG_SCALE, scale);
+	writel(val, ddata->regs + PWM_SIFIVE_PWMCFG);
+
+	/* As scale <= 15 the shift operation cannot overflow. */
+	num = (unsigned long long)NSEC_PER_SEC << (PWM_SIFIVE_CMPWIDTH + scale);
+	ddata->real_period = div64_ul(num, rate);
+	dev_dbg(ddata->chip.dev,
+		"New real_period = %u ns\n", ddata->real_period);
+}
+
+static void pwm_sifive_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+				 struct pwm_state *state)
+{
+	struct pwm_sifive_ddata *ddata = pwm_sifive_chip_to_ddata(chip);
+	u32 duty, val;
+
+	duty = readl(ddata->regs + PWM_SIFIVE_PWMCMP0 +
+		     pwm->hwpwm * PWM_SIFIVE_SIZE_PWMCMP);
+
+	state->enabled = duty > 0;
+
+	val = readl(ddata->regs + PWM_SIFIVE_PWMCFG);
+	if (!(val & PWM_SIFIVE_PWMCFG_EN_ALWAYS))
+		state->enabled = false;
+
+	state->period = ddata->real_period;
+	state->duty_cycle =
+		(u64)duty * ddata->real_period >> PWM_SIFIVE_CMPWIDTH;
+	state->polarity = PWM_POLARITY_INVERSED;
+}
+
+static int pwm_sifive_enable(struct pwm_chip *chip, bool enable)
+{
+	struct pwm_sifive_ddata *ddata = pwm_sifive_chip_to_ddata(chip);
+	int ret;
+
+	if (enable) {
+		ret = clk_enable(ddata->clk);
+		if (ret) {
+			dev_err(ddata->chip.dev, "Enable clk failed\n");
+			return ret;
+		}
+	}
+
+	if (!enable)
+		clk_disable(ddata->clk);
+
+	return 0;
+}
+
+static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			    struct pwm_state *state)
+{
+	struct pwm_sifive_ddata *ddata = pwm_sifive_chip_to_ddata(chip);
+	struct pwm_state cur_state;
+	unsigned int duty_cycle;
+	unsigned long long num;
+	bool enabled;
+	int ret = 0;
+	u32 frac;
+
+	if (state->polarity != PWM_POLARITY_INVERSED)
+		return -EINVAL;
+
+	ret = clk_enable(ddata->clk);
+	if (ret) {
+		dev_err(ddata->chip.dev, "Enable clk failed\n");
+		return ret;
+	}
+
+	mutex_lock(&ddata->lock);
+	cur_state = pwm->state;
+	enabled = cur_state.enabled;
+
+	duty_cycle = state->duty_cycle;
+	if (!state->enabled)
+		duty_cycle = 0;
+
+	/*
+	 * The problem of output producing mixed setting as mentioned at top,
+	 * occurs here. To minimize the window for this problem, we are
+	 * calculating the register values first and then writing them
+	 * consecutively
+	 */
+	num = (u64)duty_cycle * (1U << PWM_SIFIVE_CMPWIDTH);
+	frac = DIV_ROUND_CLOSEST_ULL(num, state->period);
+	/* The hardware cannot generate a 100% duty cycle */
+	frac = min(frac, (1U << PWM_SIFIVE_CMPWIDTH) - 1);
+
+	if (state->period != ddata->approx_period) {
+		if (ddata->user_count != 1) {
+			ret = -EBUSY;
+			goto exit;
+		}
+		ddata->approx_period = state->period;
+		pwm_sifive_update_clock(ddata, clk_get_rate(ddata->clk));
+	}
+
+	writel(frac, ddata->regs + PWM_SIFIVE_PWMCMP0 +
+	       pwm->hwpwm * PWM_SIFIVE_SIZE_PWMCMP);
+
+	if (state->enabled != enabled)
+		pwm_sifive_enable(chip, state->enabled);
+
+exit:
+	clk_disable(ddata->clk);
+	mutex_unlock(&ddata->lock);
+	return ret;
+}
+
+static const struct pwm_ops pwm_sifive_ops = {
+	.request = pwm_sifive_request,
+	.free = pwm_sifive_free,
+	.get_state = pwm_sifive_get_state,
+	.apply = pwm_sifive_apply,
+	.owner = THIS_MODULE,
+};
+
+static int pwm_sifive_clock_notifier(struct notifier_block *nb,
+				     unsigned long event, void *data)
+{
+	struct clk_notifier_data *ndata = data;
+	struct pwm_sifive_ddata *ddata =
+		container_of(nb, struct pwm_sifive_ddata, notifier);
+
+	if (event == POST_RATE_CHANGE)
+		pwm_sifive_update_clock(ddata, ndata->new_rate);
+
+	return NOTIFY_OK;
+}
+
+static int pwm_sifive_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct pwm_sifive_ddata *ddata;
+	struct pwm_chip *chip;
+	struct resource *res;
+	int ret;
+
+	ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
+	if (!ddata)
+		return -ENOMEM;
+
+	mutex_init(&ddata->lock);
+	chip = &ddata->chip;
+	chip->dev = dev;
+	chip->ops = &pwm_sifive_ops;
+	chip->of_xlate = of_pwm_xlate_with_flags;
+	chip->of_pwm_n_cells = 3;
+	chip->base = -1;
+	chip->npwm = 4;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	ddata->regs = devm_ioremap_resource(dev, res);
+	if (IS_ERR(ddata->regs)) {
+		dev_err(dev, "Unable to map IO resources\n");
+		return PTR_ERR(ddata->regs);
+	}
+
+	ddata->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(ddata->clk)) {
+		if (PTR_ERR(ddata->clk) != -EPROBE_DEFER)
+			dev_err(dev, "Unable to find controller clock\n");
+		return PTR_ERR(ddata->clk);
+	}
+
+	ret = clk_prepare_enable(ddata->clk);
+	if (ret) {
+		dev_err(dev, "failed to enable clock for pwm: %d\n", ret);
+		return ret;
+	}
+
+	/* Watch for changes to underlying clock frequency */
+	ddata->notifier.notifier_call = pwm_sifive_clock_notifier;
+	ret = clk_notifier_register(ddata->clk, &ddata->notifier);
+	if (ret) {
+		dev_err(dev, "failed to register clock notifier: %d\n", ret);
+		goto disable_clk;
+	}
+
+	ret = pwmchip_add(chip);
+	if (ret < 0) {
+		dev_err(dev, "cannot register PWM: %d\n", ret);
+		goto unregister_clk;
+	}
+
+	platform_set_drvdata(pdev, ddata);
+	dev_dbg(dev, "SiFive PWM chip registered %d PWMs\n", chip->npwm);
+
+	return 0;
+
+unregister_clk:
+	clk_notifier_unregister(ddata->clk, &ddata->notifier);
+disable_clk:
+	clk_disable_unprepare(ddata->clk);
+
+	return ret;
+}
+
+static int pwm_sifive_remove(struct platform_device *dev)
+{
+	struct pwm_sifive_ddata *ddata = platform_get_drvdata(dev);
+	bool is_enabled = false;
+	struct pwm_device *pwm;
+	int ret, ch;
+
+	for (ch = 0; ch < ddata->chip.npwm; ch++) {
+		pwm = &ddata->chip.pwms[ch];
+		if (pwm->state.enabled) {
+			is_enabled = true;
+			break;
+		}
+	}
+	if (is_enabled)
+		clk_disable(ddata->clk);
+
+	clk_disable_unprepare(ddata->clk);
+	ret = pwmchip_remove(&ddata->chip);
+	clk_notifier_unregister(ddata->clk, &ddata->notifier);
+
+	return ret;
+}
+
+static const struct of_device_id pwm_sifive_of_match[] = {
+	{ .compatible = "sifive,pwm0" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, pwm_sifive_of_match);
+
+static struct platform_driver pwm_sifive_driver = {
+	.probe = pwm_sifive_probe,
+	.remove = pwm_sifive_remove,
+	.driver = {
+		.name = "pwm-sifive",
+		.of_match_table = pwm_sifive_of_match,
+	},
+};
+module_platform_driver(pwm_sifive_driver);
+
+MODULE_DESCRIPTION("SiFive PWM driver");
+MODULE_LICENSE("GPL v2");

drivers/pwm/pwm-stm32-lp.c

@@ -13,6 +13,7 @@
 #include <linux/mfd/stm32-lptimer.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/pwm.h>
 
@@ -223,6 +224,29 @@ static int stm32_pwm_lp_remove(struct platform_device *pdev)
 	return pwmchip_remove(&priv->chip);
 }
 
+static int __maybe_unused stm32_pwm_lp_suspend(struct device *dev)
+{
+	struct stm32_pwm_lp *priv = dev_get_drvdata(dev);
+	struct pwm_state state;
+
+	pwm_get_state(&priv->chip.pwms[0], &state);
+	if (state.enabled) {
+		dev_err(dev, "The consumer didn't stop us (%s)\n",
+			priv->chip.pwms[0].label);
+		return -EBUSY;
+	}
+
+	return pinctrl_pm_select_sleep_state(dev);
+}
+
+static int __maybe_unused stm32_pwm_lp_resume(struct device *dev)
+{
+	return pinctrl_pm_select_default_state(dev);
+}
+
+static SIMPLE_DEV_PM_OPS(stm32_pwm_lp_pm_ops, stm32_pwm_lp_suspend,
+			 stm32_pwm_lp_resume);
+
 static const struct of_device_id stm32_pwm_lp_of_match[] = {
 	{ .compatible = "st,stm32-pwm-lp", },
 	{},
@@ -235,6 +259,7 @@ static struct platform_driver stm32_pwm_lp_driver = {
 	.driver	= {
 		.name = "stm32-pwm-lp",
 		.of_match_table = of_match_ptr(stm32_pwm_lp_of_match),
+		.pm = &stm32_pwm_lp_pm_ops,
 	},
 };
 module_platform_driver(stm32_pwm_lp_driver);

drivers/pwm/pwm-stm32.c

@@ -608,6 +608,8 @@ static int stm32_pwm_probe(struct platform_device *pdev)
 	priv->regmap = ddata->regmap;
 	priv->clk = ddata->clk;
 	priv->max_arr = ddata->max_arr;
+	priv->chip.of_xlate = of_pwm_xlate_with_flags;
+	priv->chip.of_pwm_n_cells = 3;
 
 	if (!priv->regmap || !priv->clk)
 		return -EINVAL;

drivers/pwm/sysfs.c

@@ -18,6 +18,7 @@ struct pwm_export {
 	struct device child;
 	struct pwm_device *pwm;
 	struct mutex lock;
+	struct pwm_state suspend;
 };
 
 static struct pwm_export *child_to_pwm_export(struct device *child)
@@ -372,10 +373,111 @@ static struct attribute *pwm_chip_attrs[] = {
 };
 ATTRIBUTE_GROUPS(pwm_chip);
 
+/* takes export->lock on success */
+static struct pwm_export *pwm_class_get_state(struct device *parent,
+					      struct pwm_device *pwm,
+					      struct pwm_state *state)
+{
+	struct device *child;
+	struct pwm_export *export;
+
+	if (!test_bit(PWMF_EXPORTED, &pwm->flags))
+		return NULL;
+
+	child = device_find_child(parent, pwm, pwm_unexport_match);
+	if (!child)
+		return NULL;
+
+	export = child_to_pwm_export(child);
+	put_device(child);	/* for device_find_child() */
+
+	mutex_lock(&export->lock);
+	pwm_get_state(pwm, state);
+
+	return export;
+}
+
+static int pwm_class_apply_state(struct pwm_export *export,
+				 struct pwm_device *pwm,
+				 struct pwm_state *state)
+{
+	int ret = pwm_apply_state(pwm, state);
+
+	/* release lock taken in pwm_class_get_state */
+	mutex_unlock(&export->lock);
+
+	return ret;
+}
+
+static int pwm_class_resume_npwm(struct device *parent, unsigned int npwm)
+{
+	struct pwm_chip *chip = dev_get_drvdata(parent);
+	unsigned int i;
+	int ret = 0;
+
+	for (i = 0; i < npwm; i++) {
+		struct pwm_device *pwm = &chip->pwms[i];
+		struct pwm_state state;
+		struct pwm_export *export;
+
+		export = pwm_class_get_state(parent, pwm, &state);
+		if (!export)
+			continue;
+
+		state.enabled = export->suspend.enabled;
+		ret = pwm_class_apply_state(export, pwm, &state);
+		if (ret < 0)
+			break;
+	}
+
+	return ret;
+}
+
+static int __maybe_unused pwm_class_suspend(struct device *parent)
+{
+	struct pwm_chip *chip = dev_get_drvdata(parent);
+	unsigned int i;
+	int ret = 0;
+
+	for (i = 0; i < chip->npwm; i++) {
+		struct pwm_device *pwm = &chip->pwms[i];
+		struct pwm_state state;
+		struct pwm_export *export;
+
+		export = pwm_class_get_state(parent, pwm, &state);
+		if (!export)
+			continue;
+
+		export->suspend = state;
+		state.enabled = false;
+		ret = pwm_class_apply_state(export, pwm, &state);
+		if (ret < 0) {
+			/*
+			 * roll back the PWM devices that were disabled by
+			 * this suspend function.
+			 */
+			pwm_class_resume_npwm(parent, i);
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static int __maybe_unused pwm_class_resume(struct device *parent)
+{
+	struct pwm_chip *chip = dev_get_drvdata(parent);
+
+	return pwm_class_resume_npwm(parent, chip->npwm);
+}
+
+static SIMPLE_DEV_PM_OPS(pwm_class_pm_ops, pwm_class_suspend, pwm_class_resume);
+
 static struct class pwm_class = {
 	.name = "pwm",
 	.owner = THIS_MODULE,
 	.dev_groups = pwm_chip_groups,
+	.pm = &pwm_class_pm_ops,
 };
 
 static int pwmchip_sysfs_match(struct device *parent, const void *data)

include/linux/pwm.h

@@ -405,12 +405,16 @@ struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc,
 		const struct of_phandle_args *args);
 
 struct pwm_device *pwm_get(struct device *dev, const char *con_id);
-struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id);
+struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
+			      const char *con_id);
 void pwm_put(struct pwm_device *pwm);
 
 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id);
 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
 				   const char *con_id);
+struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
+				       struct fwnode_handle *fwnode,
+				       const char *con_id);
 void devm_pwm_put(struct device *dev, struct pwm_device *pwm);
 #else
 static inline struct pwm_device *pwm_request(int pwm_id, const char *label)
@@ -493,7 +497,8 @@ static inline struct pwm_device *pwm_get(struct device *dev,
 	return ERR_PTR(-ENODEV);
 }
 
-static inline struct pwm_device *of_pwm_get(struct device_node *np,
+static inline struct pwm_device *of_pwm_get(struct device *dev,
+					    struct device_node *np,
 					    const char *con_id)
 {
 	return ERR_PTR(-ENODEV);
@@ -516,6 +521,13 @@ static inline struct pwm_device *devm_of_pwm_get(struct device *dev,
 	return ERR_PTR(-ENODEV);
 }
 
+static inline struct pwm_device *
+devm_fwnode_pwm_get(struct device *dev, struct fwnode_handle *fwnode,
+		    const char *con_id)
+{
+	return ERR_PTR(-ENODEV);
+}
+
 static inline void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
 {
 }