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Commit 22ceeee1 authored by Thierry Reding's avatar Thierry Reding Committed by Thierry Reding
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pwm-backlight: Add power supply support 



Backlights require a power supply to work properly. This commit adds a
regulator to power up and power down the backlight.

Signed-off-by: default avatarThierry Reding <treding@nvidia.com>
parent 8265b2e4

Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt

+2 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ Required properties: 
      last value in the array represents a 100% duty cycle (brightest).

  - default-brightness-level: the default brightness level (index into the

      array defined by the "brightness-levels" property)

  - power-supply: regulator for supply voltage



Optional properties:

  - pwm-names: a list of names for the PWM devices specified in the
@@ -29,5 +30,6 @@ Example: 
		brightness-levels = <0 4 8 16 32 64 128 255>;

		default-brightness-level = <6>;



		power-supply = <&vdd_bl_reg>;

		enable-gpios = <&gpio 58 0>;

	};

drivers/video/backlight/pwm_bl.c

+13 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/err.h>

#include <linux/pwm.h>

#include <linux/pwm_backlight.h>

#include <linux/regulator/consumer.h>

#include <linux/slab.h>



struct pwm_bl_data {
@@ -30,6 +31,7 @@ struct pwm_bl_data { 
	unsigned int		lth_brightness;

	unsigned int		*levels;

	bool			enabled;

	struct regulator	*power_supply;

	int			enable_gpio;

	unsigned long		enable_gpio_flags;

	int			(*notify)(struct device *,
@@ -60,6 +62,10 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness, 


	pwm_config(pb->pwm, duty_cycle, pb->period);



	err = regulator_enable(pb->power_supply);

	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);
@@ -86,6 +92,7 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb) 
			gpio_set_value(pb->enable_gpio, 0);

	}



	regulator_disable(pb->power_supply);

	pb->enabled = false;

}
@@ -268,6 +275,12 @@ static int pwm_backlight_probe(struct platform_device *pdev) 
		}

	}



	pb->power_supply = devm_regulator_get(&pdev->dev, "power");

	if (IS_ERR(pb->power_supply)) {

		ret = PTR_ERR(pb->power_supply);

		goto err_gpio;

	}



	pb->pwm = devm_pwm_get(&pdev->dev, NULL);

	if (IS_ERR(pb->pwm)) {

		dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");