Many backlights require a power supply to work properly. This commit uses a power-supply regulator, if available, to power up and power down the panel.
Signed-off-by: Thierry Reding <tred...@nvidia.com> --- .../bindings/video/backlight/pwm-backlight.txt | 2 ++ drivers/video/backlight/pwm_bl.c | 21 +++++++++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt index 052eb03..3898f26 100644 --- a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt +++ b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt @@ -15,6 +15,7 @@ Optional properties: - pwm-names: a list of names for the PWM devices specified in the "pwms" property (see PWM binding[0]) - enable-gpios: a list of GPIOs to enable and disable the backlight + - power-supply: regulator for supply voltage [0]: Documentation/devicetree/bindings/pwm/pwm.txt @@ -28,4 +29,5 @@ Example: default-brightness-level = <6>; enable-gpios = <&gpio 58 0>; + power-supply = <&vdd_bl_reg>; }; diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index 506810c..a2b3876 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -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 { @@ -29,6 +30,7 @@ struct pwm_bl_data { unsigned int period; unsigned int lth_brightness; unsigned int *levels; + struct regulator *power_supply; int enable_gpio; unsigned long enable_gpio_flags; int (*notify)(struct device *, @@ -56,6 +58,12 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness, pwm_config(pb->pwm, duty_cycle, pb->period); + if (pb->power_supply) { + 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); @@ -76,6 +84,9 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb) else gpio_set_value(pb->enable_gpio, 0); } + + if (pb->power_supply) + regulator_disable(pb->power_supply); } static int pwm_backlight_update_status(struct backlight_device *bl) @@ -253,6 +264,16 @@ static int pwm_backlight_probe(struct platform_device *pdev) } } + pb->power_supply = devm_regulator_get_optional(&pdev->dev, "power"); + if (IS_ERR(pb->power_supply)) { + if (PTR_ERR(pb->power_supply) != -ENODEV) { + ret = PTR_ERR(pb->power_supply); + goto err_gpio; + } + + pb->power_supply = NULL; + } + 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"); -- 1.8.4 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html