gpio: palmas: add dt support

Palmas GPIO controller bindings

Required properties:

- compatible:

  - "ti,palams-gpio" for palma series of the GPIO controller

  - "ti,tps80036-gpio" for Palma series device TPS80036.

  - "ti,tps65913-gpio" for palma series device TPS65913.

  - "ti,tps65914-gpio" for palma series device TPS65914.

- #gpio-cells : Should be two.

  - first cell is the gpio pin number

  - second cell is used to specify the gpio polarity:

      0 = active high

      1 = active low

- gpio-controller : Marks the device node as a GPIO controller.

Note: This gpio node will be sub node of palmas node.

Example:

	palmas: tps65913@58 {

		:::::::::::

		palmas_gpio: palmas_gpio {

			compatible = "ti,palmas-gpio";

			gpio-controller;

			#gpio-cells = <2>;

		};

		:::::::::::

	};

	palmas_gpio->gpio_chip.get	= palmas_gpio_get;

	palmas_gpio->gpio_chip.dev = &pdev->dev;

#ifdef CONFIG_OF_GPIO

	palmas_gpio->gpio_chip.of_node = palmas->dev->of_node;

	palmas_gpio->gpio_chip.of_node = pdev->dev.of_node;

#endif

	palmas_pdata = dev_get_platdata(palmas->dev);

	if (palmas_pdata && palmas_pdata->gpio_base)

	return gpiochip_remove(&palmas_gpio->gpio_chip);

}

static struct of_device_id of_palmas_gpio_match[] = {

	{ .compatible = "ti,palmas-gpio"},

	{ .compatible = "ti,tps65913-gpio"},

	{ .compatible = "ti,tps65914-gpio"},

	{ .compatible = "ti,tps80036-gpio"},

	{ },

};

MODULE_DEVICE_TABLE(of, of_palmas_gpio_match);

static struct platform_driver palmas_gpio_driver = {

	.driver.name	= "palmas-gpio",

	.driver.owner	= THIS_MODULE,

	.driver.of_match_table = of_palmas_gpio_match,

	.probe		= palmas_gpio_probe,

	.remove		= palmas_gpio_remove,

};