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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: Thierry Reding <treding@nvidia.com>
This commit is contained in:
Thierry Reding 2013-08-30 12:38:34 +02:00 committed by Thierry Reding
parent 8265b2e4e6
commit 22ceeee16e
2 changed files with 15 additions and 0 deletions
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2
Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
View File

@ -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>;
};

13
drivers/video/backlight/pwm_bl.c
View File

@ -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");