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>

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index fa7f5c35b7fbe0d567e675119f7b17a6320f3570..cc49347bbcc0766019fd077f776b2dd19f8d6d49 100644 (file)
--- 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 2de2e275b2cbd1390ec6693d8f436b05352da16a..efdd9227a49c9c9e77e7b74fff7e891df27935b7 100644 (file)
--- 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);