Commit adce1183 authored by Thierry Reding's avatar Thierry Reding Committed by Bartosz Golaszewski
Browse files

gpio: tegra186: Add debounce support 



The GPIO controller found on Tegra186 and later supports debouncing for
inputs for up to 255 ms.

Signed-off-by: default avatarThierry Reding <treding@nvidia.com>
Signed-off-by: default avatarBartosz Golaszewski <bgolaszewski@baylibre.com>
parent 22635ed8

drivers/gpio/gpio-tegra186.c

+38 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ 
#define  TEGRA186_GPIO_ENABLE_CONFIG_TRIGGER_TYPE_DOUBLE_EDGE (0x3 << 2)

#define  TEGRA186_GPIO_ENABLE_CONFIG_TRIGGER_TYPE_MASK (0x3 << 2)

#define  TEGRA186_GPIO_ENABLE_CONFIG_TRIGGER_LEVEL BIT(4)

#define  TEGRA186_GPIO_ENABLE_CONFIG_DEBOUNCE BIT(5)

#define  TEGRA186_GPIO_ENABLE_CONFIG_INTERRUPT BIT(6)



#define TEGRA186_GPIO_DEBOUNCE_CONTROL 0x04
@@ -217,6 +218,42 @@ static void tegra186_gpio_set(struct gpio_chip *chip, unsigned int offset, 
	writel(value, base + TEGRA186_GPIO_OUTPUT_VALUE);

}



static int tegra186_gpio_set_config(struct gpio_chip *chip,

				    unsigned int offset,

				    unsigned long config)

{

	struct tegra_gpio *gpio = gpiochip_get_data(chip);

	u32 debounce, value;

	void __iomem *base;



	base = tegra186_gpio_get_base(gpio, offset);

	if (base == NULL)

		return -ENXIO;



	if (pinconf_to_config_param(config) != PIN_CONFIG_INPUT_DEBOUNCE)

		return -ENOTSUPP;



	debounce = pinconf_to_config_argument(config);



	/*

	 * The Tegra186 GPIO controller supports a maximum of 255 ms debounce

	 * time.

	 */

	if (debounce > 255000)

		return -EINVAL;



	debounce = DIV_ROUND_UP(debounce, USEC_PER_MSEC);



	value = TEGRA186_GPIO_DEBOUNCE_CONTROL_THRESHOLD(debounce);

	writel(value, base + TEGRA186_GPIO_DEBOUNCE_CONTROL);



	value = readl(base + TEGRA186_GPIO_ENABLE_CONFIG);

	value |= TEGRA186_GPIO_ENABLE_CONFIG_DEBOUNCE;

	writel(value, base + TEGRA186_GPIO_ENABLE_CONFIG);



	return 0;

}



static int tegra186_gpio_of_xlate(struct gpio_chip *chip,

				  const struct of_phandle_args *spec,

				  u32 *flags)
@@ -539,6 +576,7 @@ static int tegra186_gpio_probe(struct platform_device *pdev) 
	gpio->gpio.direction_output = tegra186_gpio_direction_output;

	gpio->gpio.get = tegra186_gpio_get,

	gpio->gpio.set = tegra186_gpio_set;

	gpio->gpio.set_config = tegra186_gpio_set_config;



	gpio->gpio.base = -1;