platform/x86: Add driver for GPD pocket custom fan controller

Add a driver for the GPD pocket device's custom fan controller, which
gets controlled through 2 GPIOs listed in a FAN02501 ACPI device.

Cc: James <kernel@madingley.org>
Suggested-by: James <kernel@madingley.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

MAINTAINERS

@@ -5947,6 +5947,12 @@ L:	linux-input@vger.kernel.org
 S:	Maintained
 F:	drivers/input/touchscreen/goodix.c
 
+GPD POCKET FAN DRIVER
+M:	Hans de Goede <hdegoede@redhat.com>
+L:	platform-driver-x86@vger.kernel.org
+S:	Maintained
+F:	drivers/platform/x86/gpd-pocket-fan.c
+
 GPIO ACPI SUPPORT
 M:	Mika Westerberg <mika.westerberg@linux.intel.com>
 M:	Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/x86/Kconfig

@@ -258,6 +258,18 @@ config AMILO_RFKILL
 	  This is a driver for enabling wifi on some Fujitsu-Siemens Amilo
 	  laptops.
 
+config GPD_POCKET_FAN
+	tristate "GPD Pocket Fan Controller support"
+	depends on ACPI
+	depends on THERMAL
+	---help---
+	  Driver for the GPD Pocket vendor specific FAN02501 ACPI device
+	  which controls the fan speed on the GPD Pocket.
+
+	  Without this driver the fan on the Pocket will stay off independent
+	  of the CPU temperature. Say Y or M if the kernel may be used on a
+	  GPD pocket.
+
 config TC1100_WMI
 	tristate "HP Compaq TC1100 Tablet WMI Extras"
 	depends on !X86_64

drivers/platform/x86/Makefile

@@ -29,6 +29,7 @@ obj-$(CONFIG_HP_ACCEL)		+= hp_accel.o
 obj-$(CONFIG_HP_WIRELESS)	+= hp-wireless.o
 obj-$(CONFIG_HP_WMI)		+= hp-wmi.o
 obj-$(CONFIG_AMILO_RFKILL)	+= amilo-rfkill.o
+obj-$(CONFIG_GPD_POCKET_FAN)	+= gpd-pocket-fan.o
 obj-$(CONFIG_TC1100_WMI)	+= tc1100-wmi.o
 obj-$(CONFIG_SONY_LAPTOP)	+= sony-laptop.o
 obj-$(CONFIG_IDEAPAD_LAPTOP)	+= ideapad-laptop.o

drivers/platform/x86/gpd-pocket-fan.c

@@ -0,0 +1,193 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * GPD Pocket fan controller driver
+ *
+ * Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
+ */
+
+#include <linux/acpi.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/thermal.h>
+#include <linux/workqueue.h>
+
+static int temp_limits[3] = { 55000, 60000, 65000 };
+module_param_array(temp_limits, int, NULL, 0444);
+MODULE_PARM_DESC(temp_limits,
+		 "Milli-celcius values above which the fan speed increases");
+
+static int hysteresis = 3000;
+module_param(hysteresis, int, 0444);
+MODULE_PARM_DESC(hysteresis,
+		 "Hysteresis in milli-celcius before lowering the fan speed");
+
+struct gpd_pocket_fan_data {
+	struct device *dev;
+	struct thermal_zone_device *dts0;
+	struct thermal_zone_device *dts1;
+	struct gpio_desc *gpio0;
+	struct gpio_desc *gpio1;
+	struct delayed_work work;
+	int last_speed;
+};
+
+static void gpd_pocket_fan_set_speed(struct gpd_pocket_fan_data *fan, int speed)
+{
+	if (speed == fan->last_speed)
+		return;
+
+	gpiod_direction_output(fan->gpio0, !!(speed & 1));
+	gpiod_direction_output(fan->gpio1, !!(speed & 2));
+
+	fan->last_speed = speed;
+}
+
+static void gpd_pocket_fan_worker(struct work_struct *work)
+{
+	struct gpd_pocket_fan_data *fan =
+		container_of(work, struct gpd_pocket_fan_data, work.work);
+	int t0, t1, temp, speed, i;
+
+	if (thermal_zone_get_temp(fan->dts0, &t0) ||
+	    thermal_zone_get_temp(fan->dts1, &t1)) {
+		dev_warn(fan->dev, "Error getting temperature\n");
+		queue_delayed_work(system_wq, &fan->work,
+				   msecs_to_jiffies(1000));
+		return;
+	}
+
+	temp = max(t0, t1);
+
+	speed = fan->last_speed;
+
+	/* Determine minimum speed */
+	for (i = 0; i < ARRAY_SIZE(temp_limits); i++) {
+		if (temp < temp_limits[i])
+			break;
+	}
+	if (speed < i)
+		speed = i;
+
+	/* Use hysteresis before lowering speed again */
+	for (i = 0; i < ARRAY_SIZE(temp_limits); i++) {
+		if (temp <= (temp_limits[i] - hysteresis))
+			break;
+	}
+	if (speed > i)
+		speed = i;
+
+	if (fan->last_speed <= 0 && speed)
+		speed = 3; /* kick start motor */
+
+	gpd_pocket_fan_set_speed(fan, speed);
+
+	/* When mostly idle (low temp/speed), slow down the poll interval. */
+	queue_delayed_work(system_wq, &fan->work,
+			   msecs_to_jiffies(4000 / (speed + 1)));
+}
+
+static void gpd_pocket_fan_force_update(struct gpd_pocket_fan_data *fan)
+{
+	fan->last_speed = -1;
+	mod_delayed_work(system_wq, &fan->work, 0);
+}
+
+static int gpd_pocket_fan_probe(struct platform_device *pdev)
+{
+	struct gpd_pocket_fan_data *fan;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(temp_limits); i++) {
+		if (temp_limits[i] < 40000 || temp_limits[i] > 70000) {
+			dev_err(&pdev->dev, "Invalid temp-limit %d (must be between 40000 and 70000)\n",
+				temp_limits[i]);
+			return -EINVAL;
+		}
+	}
+	if (hysteresis < 1000 || hysteresis > 10000) {
+		dev_err(&pdev->dev, "Invalid hysteresis %d (must be between 1000 and 10000)\n",
+			hysteresis);
+		return -EINVAL;
+	}
+
+	fan = devm_kzalloc(&pdev->dev, sizeof(*fan), GFP_KERNEL);
+	if (!fan)
+		return -ENOMEM;
+
+	fan->dev = &pdev->dev;
+	INIT_DELAYED_WORK(&fan->work, gpd_pocket_fan_worker);
+
+	/* Note this returns a "weak" reference which we don't need to free */
+	fan->dts0 = thermal_zone_get_zone_by_name("soc_dts0");
+	if (IS_ERR(fan->dts0))
+		return -EPROBE_DEFER;
+
+	fan->dts1 = thermal_zone_get_zone_by_name("soc_dts1");
+	if (IS_ERR(fan->dts1))
+		return -EPROBE_DEFER;
+
+	fan->gpio0 = devm_gpiod_get_index(fan->dev, NULL, 0, GPIOD_ASIS);
+	if (IS_ERR(fan->gpio0))
+		return PTR_ERR(fan->gpio0);
+
+	fan->gpio1 = devm_gpiod_get_index(fan->dev, NULL, 1, GPIOD_ASIS);
+	if (IS_ERR(fan->gpio1))
+		return PTR_ERR(fan->gpio1);
+
+	gpd_pocket_fan_force_update(fan);
+
+	platform_set_drvdata(pdev, fan);
+	return 0;
+}
+
+static int gpd_pocket_fan_remove(struct platform_device *pdev)
+{
+	struct gpd_pocket_fan_data *fan = platform_get_drvdata(pdev);
+
+	cancel_delayed_work_sync(&fan->work);
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int gpd_pocket_fan_suspend(struct device *dev)
+{
+	struct gpd_pocket_fan_data *fan = dev_get_drvdata(dev);
+
+	gpd_pocket_fan_set_speed(fan, 0);
+	return 0;
+}
+
+static int gpd_pocket_fan_resume(struct device *dev)
+{
+	struct gpd_pocket_fan_data *fan = dev_get_drvdata(dev);
+
+	gpd_pocket_fan_force_update(fan);
+	return 0;
+}
+#endif
+static SIMPLE_DEV_PM_OPS(gpd_pocket_fan_pm_ops,
+			 gpd_pocket_fan_suspend,
+			 gpd_pocket_fan_resume);
+
+static struct acpi_device_id gpd_pocket_fan_acpi_match[] = {
+	{ "FAN02501" },
+	{},
+};
+MODULE_DEVICE_TABLE(acpi, gpd_pocket_fan_acpi_match);
+
+static struct platform_driver gpd_pocket_fan_driver = {
+	.probe	= gpd_pocket_fan_probe,
+	.remove	= gpd_pocket_fan_remove,
+	.driver	= {
+		.name			= "gpd_pocket_fan",
+		.acpi_match_table	= gpd_pocket_fan_acpi_match,
+		.pm			= &gpd_pocket_fan_pm_ops,
+	 },
+};
+
+module_platform_driver(gpd_pocket_fan_driver);
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com");
+MODULE_DESCRIPTION("GPD pocket fan driver");
+MODULE_LICENSE("GPL");