gpio: Add driver for TI TPIC2810

Add driver for TI TPIC2810 8-Bit LED Driver with I2C Interface.

The TPIC2810 has 8 open-drain outputs that can but used to drive
LEDs and other low-side switched resistive loads.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/Kconfig

@@ -739,6 +739,14 @@ config GPIO_SX150X
 	  8 bits:  sx1508q
 	  16 bits: sx1509q
 
+config GPIO_TPIC2810
+	tristate "TPIC2810 8-Bit I2C GPO expander"
+	help
+	  Say yes here to enable the GPO driver for the TI TPIC2810 chip.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called gpio-tpic2810.
+
 endmenu
 
 menu "MFD GPIO expanders"

drivers/gpio/Makefile

@@ -97,6 +97,7 @@ obj-$(CONFIG_GPIO_TC3589X)	+= gpio-tc3589x.o
 obj-$(CONFIG_ARCH_TEGRA)	+= gpio-tegra.o
 obj-$(CONFIG_GPIO_TIMBERDALE)	+= gpio-timberdale.o
 obj-$(CONFIG_GPIO_PALMAS)	+= gpio-palmas.o
+obj-$(CONFIG_GPIO_TPIC2810)	+= gpio-tpic2810.o
 obj-$(CONFIG_GPIO_TPS6586X)	+= gpio-tps6586x.o
 obj-$(CONFIG_GPIO_TPS65910)	+= gpio-tps65910.o
 obj-$(CONFIG_GPIO_TPS65912)	+= gpio-tps65912.o

drivers/gpio/gpio-tpic2810.c

@@ -0,0 +1,167 @@
+/*
+ * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/
+ *	Andrew F. Davis <afd@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether expressed or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License version 2 for more details.
+ */
+
+#include <linux/gpio/driver.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+
+#define TPIC2810_WS_COMMAND 0x44
+
+/**
+ * struct tpic2810 - GPIO driver data
+ * @chip: GPIO controller chip
+ * @client: I2C device pointer
+ * @buffer: Buffer for device register
+ * @lock: Protects write sequences
+ */
+struct tpic2810 {
+	struct gpio_chip chip;
+	struct i2c_client *client;
+	u8 buffer;
+	struct mutex lock;
+};
+
+static int tpic2810_get_direction(struct gpio_chip *chip,
+				  unsigned offset)
+{
+	/* This device always output */
+	return 0;
+}
+
+static int tpic2810_direction_input(struct gpio_chip *chip,
+				    unsigned offset)
+{
+	/* This device is output only */
+	return -EINVAL;
+}
+
+static int tpic2810_direction_output(struct gpio_chip *chip,
+				     unsigned offset, int value)
+{
+	/* This device always output */
+	return 0;
+}
+
+static void tpic2810_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct tpic2810 *gpio = gpiochip_get_data(chip);
+
+	mutex_lock(&gpio->lock);
+
+	if (value)
+		gpio->buffer |= BIT(offset);
+	else
+		gpio->buffer &= ~BIT(offset);
+
+	i2c_smbus_write_byte_data(gpio->client, TPIC2810_WS_COMMAND,
+				  gpio->buffer);
+
+	mutex_unlock(&gpio->lock);
+}
+
+static void tpic2810_set_multiple(struct gpio_chip *chip, unsigned long *mask,
+				  unsigned long *bits)
+{
+	struct tpic2810 *gpio = gpiochip_get_data(chip);
+
+	mutex_lock(&gpio->lock);
+
+	/* clear bits under mask */
+	gpio->buffer &= ~(*mask);
+	/* set bits under mask */
+	gpio->buffer |= ((*mask) & (*bits));
+
+	i2c_smbus_write_byte_data(gpio->client, TPIC2810_WS_COMMAND,
+				  gpio->buffer);
+
+	mutex_unlock(&gpio->lock);
+}
+
+static struct gpio_chip template_chip = {
+	.label			= "tpic2810",
+	.owner			= THIS_MODULE,
+	.get_direction		= tpic2810_get_direction,
+	.direction_input	= tpic2810_direction_input,
+	.direction_output	= tpic2810_direction_output,
+	.set			= tpic2810_set,
+	.set_multiple		= tpic2810_set_multiple,
+	.base			= -1,
+	.ngpio			= 8,
+	.can_sleep		= true,
+};
+
+static const struct of_device_id tpic2810_of_match_table[] = {
+	{ .compatible = "ti,tpic2810" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, tpic2810_of_match_table);
+
+static int tpic2810_probe(struct i2c_client *client,
+			  const struct i2c_device_id *id)
+{
+	struct tpic2810 *gpio;
+	int ret;
+
+	gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
+	if (!gpio)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, gpio);
+
+	gpio->chip = template_chip;
+	gpio->chip.parent = &client->dev;
+
+	gpio->client = client;
+
+	mutex_init(&gpio->lock);
+
+	ret = gpiochip_add_data(&gpio->chip, gpio);
+	if (ret < 0) {
+		dev_err(&client->dev, "Unable to register gpiochip\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int tpic2810_remove(struct i2c_client *client)
+{
+	struct tpic2810 *gpio = i2c_get_clientdata(client);
+
+	gpiochip_remove(&gpio->chip);
+
+	return 0;
+}
+
+static const struct i2c_device_id tpic2810_id_table[] = {
+	{ "tpic2810", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(i2c, tpic2810_id_table);
+
+static struct i2c_driver tpic2810_driver = {
+	.driver = {
+		.name = "tpic2810",
+		.of_match_table = tpic2810_of_match_table,
+	},
+	.probe = tpic2810_probe,
+	.remove = tpic2810_remove,
+	.id_table = tpic2810_id_table,
+};
+module_i2c_driver(tpic2810_driver);
+
+MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
+MODULE_DESCRIPTION("TPIC2810 8-Bit LED Driver GPIO Driver");
+MODULE_LICENSE("GPL v2");