pwm-backlight: switch to gpiod interface

Switch to the new gpiod interface, which allows to handle GPIO
properties such as active low transparently and removes a whole bunch of
code.

There are still a couple of users of this driver that rely on passing
the enable GPIO number through platform data, so a fallback mechanism
using a GPIO number is still available to avoid breaking them. It will
be removed once current users have switched to the GPIO lookup tables
provided by the gpiod interface.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

2 files changed, 30 insertions, 44 deletions

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index fa7f5c35b7fb..cc49347bbcc0 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -10,8 +10,8 @@
  * published by the Free Software Foundation.
  */
 
+#include <linux/gpio/consumer.h>
 #include <linux/gpio.h>
-#include <linux/of_gpio.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
@@ -32,8 +32,7 @@ struct pwm_bl_data {
         unsigned int            *levels;
         bool                    enabled;
         struct regulator        *power_supply;
-        int                     enable_gpio;
-        unsigned long           enable_gpio_flags;
+        struct gpio_desc        *enable_gpio;
         unsigned int            scale;
         int                     (*notify)(struct device *,
                                           int brightness);
@@ -54,12 +53,8 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness)
         if (err < 0)
                 dev_err(pb->dev, "failed to enable power supply\n");
 
-        if (gpio_is_valid(pb->enable_gpio)) {
-                if (pb->enable_gpio_flags & PWM_BACKLIGHT_GPIO_ACTIVE_LOW)
-                        gpio_set_value(pb->enable_gpio, 0);
-                else
-                        gpio_set_value(pb->enable_gpio, 1);
-        }
+        if (pb->enable_gpio)
+                gpiod_set_value(pb->enable_gpio, 1);
 
         pwm_enable(pb->pwm);
         pb->enabled = true;
@@ -73,12 +68,8 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb)
         pwm_config(pb->pwm, 0, pb->period);
         pwm_disable(pb->pwm);
 
-        if (gpio_is_valid(pb->enable_gpio)) {
-                if (pb->enable_gpio_flags & PWM_BACKLIGHT_GPIO_ACTIVE_LOW)
-                        gpio_set_value(pb->enable_gpio, 1);
-                else
-                        gpio_set_value(pb->enable_gpio, 0);
-        }
+        if (pb->enable_gpio)
+                gpiod_set_value(pb->enable_gpio, 0);
 
         regulator_disable(pb->power_supply);
         pb->enabled = false;
@@ -148,7 +139,6 @@ static int pwm_backlight_parse_dt(struct device *dev,
                                   struct platform_pwm_backlight_data *data)
 {
         struct device_node *node = dev->of_node;
-        enum of_gpio_flags flags;
         struct property *prop;
         int length;
         u32 value;
@@ -189,14 +179,6 @@ static int pwm_backlight_parse_dt(struct device *dev,
                 data->max_brightness--;
         }
 
-        data->enable_gpio = of_get_named_gpio_flags(node, "enable-gpios", 0,
-                                                    &flags);
-        if (data->enable_gpio == -EPROBE_DEFER)
-                return -EPROBE_DEFER;
-
-        if (gpio_is_valid(data->enable_gpio) && (flags & OF_GPIO_ACTIVE_LOW))
-                data->enable_gpio_flags |= PWM_BACKLIGHT_GPIO_ACTIVE_LOW;
-
         return 0;
 }
 
@@ -256,8 +238,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
         } else
                 pb->scale = data->max_brightness;
 
-        pb->enable_gpio = data->enable_gpio;
-        pb->enable_gpio_flags = data->enable_gpio_flags;
         pb->notify = data->notify;
         pb->notify_after = data->notify_after;
         pb->check_fb = data->check_fb;
@@ -265,26 +245,38 @@ static int pwm_backlight_probe(struct platform_device *pdev)
         pb->dev = &pdev->dev;
         pb->enabled = false;
 
-        if (gpio_is_valid(pb->enable_gpio)) {
-                unsigned long flags;
-
-                if (pb->enable_gpio_flags & PWM_BACKLIGHT_GPIO_ACTIVE_LOW)
-                        flags = GPIOF_OUT_INIT_HIGH;
+        pb->enable_gpio = devm_gpiod_get(&pdev->dev, "enable");
+        if (IS_ERR(pb->enable_gpio)) {
+                ret = PTR_ERR(pb->enable_gpio);
+                if (ret == -ENOENT)
+                        pb->enable_gpio = NULL;
                 else
-                        flags = GPIOF_OUT_INIT_LOW;
+                        goto err_alloc;
+        }
 
-                ret = gpio_request_one(pb->enable_gpio, flags, "enable");
+        /*
+         * Compatibility fallback for drivers still using the integer GPIO
+         * platform data. Must go away soon.
+         */
+        if (!pb->enable_gpio && gpio_is_valid(data->enable_gpio)) {
+                ret = devm_gpio_request_one(&pdev->dev, data->enable_gpio,
+                                            GPIOF_OUT_INIT_HIGH, "enable");
                 if (ret < 0) {
                         dev_err(&pdev->dev, "failed to request GPIO#%d: %d\n",
-                                pb->enable_gpio, ret);
+                                data->enable_gpio, ret);
                         goto err_alloc;
                 }
+
+                pb->enable_gpio = gpio_to_desc(data->enable_gpio);
         }
 
+        if (pb->enable_gpio)
+                gpiod_direction_output(pb->enable_gpio, 1);
+
         pb->power_supply = devm_regulator_get(&pdev->dev, "power");
         if (IS_ERR(pb->power_supply)) {
                 ret = PTR_ERR(pb->power_supply);
-                goto err_gpio;
+                goto err_alloc;
         }
 
         pb->pwm = devm_pwm_get(&pdev->dev, NULL);
@@ -295,7 +287,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
                 if (IS_ERR(pb->pwm)) {
                         dev_err(&pdev->dev, "unable to request legacy PWM\n");
                         ret = PTR_ERR(pb->pwm);
-                        goto err_gpio;
+                        goto err_alloc;
                 }
         }
 
@@ -320,7 +312,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
         if (IS_ERR(bl)) {
                 dev_err(&pdev->dev, "failed to register backlight\n");
                 ret = PTR_ERR(bl);
-                goto err_gpio;
+                goto err_alloc;
         }
 
         if (data->dft_brightness > data->max_brightness) {
@@ -336,9 +328,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
         platform_set_drvdata(pdev, bl);
         return 0;
 
-err_gpio:
-        if (gpio_is_valid(pb->enable_gpio))
-                gpio_free(pb->enable_gpio);
 err_alloc:
         if (data->exit)
                 data->exit(&pdev->dev);
diff --git a/include/linux/pwm_backlight.h b/include/linux/pwm_backlight.h
index 2de2e275b2cb..efdd9227a49c 100644
--- a/include/linux/pwm_backlight.h
+++ b/include/linux/pwm_backlight.h
@@ -6,9 +6,6 @@
 
 #include <linux/backlight.h>
 
-/* TODO: convert to gpiod_*() API once it has been merged */
-#define PWM_BACKLIGHT_GPIO_ACTIVE_LOW   (1 << 0)
-
 struct platform_pwm_backlight_data {
         int pwm_id;
         unsigned int max_brightness;
@@ -16,8 +13,8 @@ struct platform_pwm_backlight_data {
         unsigned int lth_brightness;
         unsigned int pwm_period_ns;
         unsigned int *levels;
+        /* TODO remove once all users are switched to gpiod_* API */
         int enable_gpio;
-        unsigned long enable_gpio_flags;
         int (*init)(struct device *dev);
         int (*notify)(struct device *dev, int brightness);
         void (*notify_after)(struct device *dev, int brightness);