Input: gpio_keys - add support for GPIO descriptors

GPIO descriptors are the preferred way over legacy GPIO numbers
nowadays. Convert the driver to use GPIO descriptors internally but
still allow passing legacy GPIO numbers from platform data to support
existing platforms.

Based on commits 633a21d80b4a2cd6 ("input: gpio_keys_polled: Add support
for GPIO descriptors") and 1ae5ddb6f8837558 ("Input: gpio_keys_polled -
request GPIO pin as input.").

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/keyboard/gpio_keys.c

@@ -26,6 +26,7 @@
 #include <linux/gpio_keys.h>
 #include <linux/workqueue.h>
 #include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/of_gpio.h>
@@ -35,6 +36,7 @@
 struct gpio_button_data {
 	const struct gpio_keys_button *button;
 	struct input_dev *input;
+	struct gpio_desc *gpiod;
 
 	struct timer_list release_timer;
 	unsigned int release_delay;	/* in msecs, for IRQ-only buttons */
@@ -140,7 +142,7 @@ static void gpio_keys_disable_button(struct gpio_button_data *bdata)
 		 */
 		disable_irq(bdata->irq);
 
-		if (gpio_is_valid(bdata->button->gpio))
+		if (bdata->gpiod)
 			cancel_delayed_work_sync(&bdata->work);
 		else
 			del_timer_sync(&bdata->release_timer);
@@ -358,19 +360,20 @@ static void gpio_keys_gpio_report_event(struct gpio_button_data *bdata)
 	const struct gpio_keys_button *button = bdata->button;
 	struct input_dev *input = bdata->input;
 	unsigned int type = button->type ?: EV_KEY;
-	int state = gpio_get_value_cansleep(button->gpio);
+	int state;
 
+	state = gpiod_get_value_cansleep(bdata->gpiod);
 	if (state < 0) {
-		dev_err(input->dev.parent, "failed to get gpio state\n");
+		dev_err(input->dev.parent,
+			"failed to get gpio state: %d\n", state);
 		return;
 	}
 
-	state = (state ? 1 : 0) ^ button->active_low;
 	if (type == EV_ABS) {
 		if (state)
 			input_event(input, type, button->code, button->value);
 	} else {
-		input_event(input, type, button->code, !!state);
+		input_event(input, type, button->code, state);
 	}
 	input_sync(input);
 }
@@ -456,7 +459,7 @@ static void gpio_keys_quiesce_key(void *data)
 {
 	struct gpio_button_data *bdata = data;
 
-	if (gpio_is_valid(bdata->button->gpio))
+	if (bdata->gpiod)
 		cancel_delayed_work_sync(&bdata->work);
 	else
 		del_timer_sync(&bdata->release_timer);
@@ -478,18 +481,30 @@ static int gpio_keys_setup_key(struct platform_device *pdev,
 	bdata->button = button;
 	spin_lock_init(&bdata->lock);
 
+	/*
+	 * Legacy GPIO number, so request the GPIO here and
+	 * convert it to descriptor.
+	 */
 	if (gpio_is_valid(button->gpio)) {
+		unsigned flags = GPIOF_IN;
+
+		if (button->active_low)
+			flags |= GPIOF_ACTIVE_LOW;
 
-		error = devm_gpio_request_one(&pdev->dev, button->gpio,
-					      GPIOF_IN, desc);
+		error = devm_gpio_request_one(&pdev->dev, button->gpio, flags,
+					      desc);
 		if (error < 0) {
 			dev_err(dev, "Failed to request GPIO %d, error %d\n",
 				button->gpio, error);
 			return error;
 		}
 
+		bdata->gpiod = gpio_to_desc(button->gpio);
+		if (!bdata->gpiod)
+			return -EINVAL;
+
 		if (button->debounce_interval) {
-			error = gpio_set_debounce(button->gpio,
+			error = gpiod_set_debounce(bdata->gpiod,
 					button->debounce_interval * 1000);
 			/* use timer if gpiolib doesn't provide debounce */
 			if (error < 0)
@@ -500,7 +515,7 @@ static int gpio_keys_setup_key(struct platform_device *pdev,
 		if (button->irq) {
 			bdata->irq = button->irq;
 		} else {
-			irq = gpio_to_irq(button->gpio);
+			irq = gpiod_to_irq(bdata->gpiod);
 			if (irq < 0) {
 				error = irq;
 				dev_err(dev,
@@ -575,7 +590,7 @@ static void gpio_keys_report_state(struct gpio_keys_drvdata *ddata)
 
 	for (i = 0; i < ddata->pdata->nbuttons; i++) {
 		struct gpio_button_data *bdata = &ddata->data[i];
-		if (gpio_is_valid(bdata->button->gpio))
+		if (bdata->gpiod)
 			gpio_keys_gpio_report_event(bdata);
 	}
 	input_sync(input);