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/include/linux/pwm_backlight.h b/include/linux/pwm_backlight.h
index 2de2e27..efdd922 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 @@
 	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);