pinctrl / gpio: Introduce .set_config() callback for GPIO chips

Currently we already have two pin configuration related callbacks
available for GPIO chips .set_single_ended() and .set_debounce(). In
future we expect to have even more, which does not scale well if we need
to add yet another callback to the GPIO chip structure for each possible
configuration parameter.

Better solution is to reuse what we already have available in the
generic pinconf.

To support this, we introduce a new .set_config() callback for GPIO
chips. The callback takes a single packed pin configuration value as
parameter. This can then be extended easily beyond what is currently
supported by just adding new types to the generic pinconf enum.

If the GPIO driver is backed up by a pinctrl driver the GPIO driver can
just assign gpiochip_generic_config() (introduced in this patch) to
.set_config and that will take care configuration requests are directed
to the pinctrl driver.

We then convert the existing drivers over .set_config() and finally
remove the .set_single_ended() and .set_debounce() callbacks.

Suggested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-tegra.c

@@ -238,6 +238,18 @@ static int tegra_gpio_set_debounce(struct gpio_chip *chip, unsigned int offset,
 	return 0;
 }
 
+static int tegra_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
+				 unsigned long config)
+{
+	u32 debounce;
+
+	if (pinconf_to_config_param(config) != PIN_CONFIG_INPUT_DEBOUNCE)
+		return -ENOTSUPP;
+
+	debounce = pinconf_to_config_argument(config);
+	return tegra_gpio_set_debounce(chip, offset, debounce);
+}
+
 static int tegra_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
 {
 	struct tegra_gpio_info *tgi = gpiochip_get_data(chip);
@@ -615,7 +627,7 @@ static int tegra_gpio_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, tgi);
 
 	if (config->debounce_supported)
-		tgi->gc.set_debounce = tegra_gpio_set_debounce;
+		tgi->gc.set_config = tegra_gpio_set_config;
 
 	tgi->bank_info = devm_kzalloc(&pdev->dev, tgi->bank_count *
 				      sizeof(*tgi->bank_info), GFP_KERNEL);