watchdog: gpio: Convert to use GPIO descriptors

This converts the GPIO watchdog driver to use GPIO descriptors
instead of relying on the old method to read out GPIO numbers
from the device tree and then using those with the old GPIO
API.

The descriptor API keeps track of whether the line is active
low so we can remove all active low handling and rely on the
GPIO descriptor to deal with this for us.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/gpio_wdt.c

@@ -12,7 +12,8 @@
 #include <linux/err.h>
 #include <linux/delay.h>
 #include <linux/module.h>
-#include <linux/of_gpio.h>
+#include <linux/gpio/consumer.h>
+#include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/watchdog.h>
 
@@ -25,8 +26,7 @@ enum {
 };
 
 struct gpio_wdt_priv {
-	int			gpio;
-	bool			active_low;
+	struct gpio_desc	*gpiod;
 	bool			state;
 	bool			always_running;
 	unsigned int		hw_algo;
@@ -35,11 +35,12 @@ struct gpio_wdt_priv {
 
 static void gpio_wdt_disable(struct gpio_wdt_priv *priv)
 {
-	gpio_set_value_cansleep(priv->gpio, !priv->active_low);
+	/* Eternal ping */
+	gpiod_set_value_cansleep(priv->gpiod, 1);
 
 	/* Put GPIO back to tristate */
 	if (priv->hw_algo == HW_ALGO_TOGGLE)
-		gpio_direction_input(priv->gpio);
+		gpiod_direction_input(priv->gpiod);
 }
 
 static int gpio_wdt_ping(struct watchdog_device *wdd)
@@ -50,13 +51,13 @@ static int gpio_wdt_ping(struct watchdog_device *wdd)
 	case HW_ALGO_TOGGLE:
 		/* Toggle output pin */
 		priv->state = !priv->state;
-		gpio_set_value_cansleep(priv->gpio, priv->state);
+		gpiod_set_value_cansleep(priv->gpiod, priv->state);
 		break;
 	case HW_ALGO_LEVEL:
 		/* Pulse */
-		gpio_set_value_cansleep(priv->gpio, !priv->active_low);
+		gpiod_set_value_cansleep(priv->gpiod, 1);
 		udelay(1);
-		gpio_set_value_cansleep(priv->gpio, priv->active_low);
+		gpiod_set_value_cansleep(priv->gpiod, 0);
 		break;
 	}
 	return 0;
@@ -66,8 +67,8 @@ static int gpio_wdt_start(struct watchdog_device *wdd)
 {
 	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
 
-	priv->state = priv->active_low;
-	gpio_direction_output(priv->gpio, priv->state);
+	priv->state = 0;
+	gpiod_direction_output(priv->gpiod, priv->state);
 
 	set_bit(WDOG_HW_RUNNING, &wdd->status);
 
@@ -104,9 +105,8 @@ static int gpio_wdt_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
 	struct gpio_wdt_priv *priv;
-	enum of_gpio_flags flags;
+	enum gpiod_flags gflags;
 	unsigned int hw_margin;
-	unsigned long f = 0;
 	const char *algo;
 	int ret;
 
@@ -116,29 +116,22 @@ static int gpio_wdt_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, priv);
 
-	priv->gpio = of_get_gpio_flags(np, 0, &flags);
-	if (!gpio_is_valid(priv->gpio))
-		return priv->gpio;
-
-	priv->active_low = flags & OF_GPIO_ACTIVE_LOW;
-
 	ret = of_property_read_string(np, "hw_algo", &algo);
 	if (ret)
 		return ret;
 	if (!strcmp(algo, "toggle")) {
 		priv->hw_algo = HW_ALGO_TOGGLE;
-		f = GPIOF_IN;
+		gflags = GPIOD_IN;
 	} else if (!strcmp(algo, "level")) {
 		priv->hw_algo = HW_ALGO_LEVEL;
-		f = priv->active_low ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
+		gflags = GPIOD_OUT_LOW;
 	} else {
 		return -EINVAL;
 	}
 
-	ret = devm_gpio_request_one(dev, priv->gpio, f,
-				    dev_name(dev));
-	if (ret)
-		return ret;
+	priv->gpiod = devm_gpiod_get(dev, NULL, gflags);
+	if (IS_ERR(priv->gpiod))
+		return PTR_ERR(priv->gpiod);
 
 	ret = of_property_read_u32(np,
 				   "hw_margin_ms", &hw_margin);