diff options
| author |   Heiko Stuebner <heiko@sntech.de> | 2018-11-09 10:48:57 +0100 |
|---|---|---|
| committer |   Lee Jones <lee.jones@linaro.org> | 2018-11-27 12:10:51 +0000 |
| commit | e4c8ae3e3d6d473bfbfbb5db234792b9f8ddab3b (patch) | |
| tree | e4174f69235037d15ff9529599d884c1b2d692cc /drivers/video | |
| parent | Linux 4.20-rc1 (diff) | |
| download | linux-dev-e4c8ae3e3d6d473bfbfbb5db234792b9f8ddab3b.tar.xz linux-dev-e4c8ae3e3d6d473bfbfbb5db234792b9f8ddab3b.zip | |
backlight: pwm_bl: Re-add driver internal enabled tracking
Commit e6bcca0890b9 ("backlight: pwm_bl: Switch to using "atomic" PWM API")
removed the driver internal enabled tracking in favor of simply checking
the pwm state.
This can lead to issues as all of gpio-, regulator- and pwm-state are used
to determine the initial state and the bootloader or kernel can leave them
in an inconsistent state at boot.
In my case on rk3399-kevin, the pwm backlight is build as module and the
kernel disables the supply regulator as unused while keeping the pwm running
thus pwm_bl calling pwm_backlight_power_off() during probe and creating an
unmatched regulator-disable call, as it never got enabled from the pwm-bl
before.
To prevent these consistency issues, reintroduce the driver-internal
tracking of the enabled state.
Fixes: e6bcca0890b9 ("backlight: pwm_bl: Switch to using "atomic" PWM API")
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Diffstat (limited to 'drivers/video')
| -rw-r--r-- | drivers/video/backlight/pwm_bl.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index 678b27063198..bcd08b41765d 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -30,6 +30,7 @@ struct pwm_bl_data { struct device *dev; unsigned int lth_brightness; unsigned int *levels; + bool enabled; struct regulator *power_supply; struct gpio_desc *enable_gpio; unsigned int scale; @@ -50,7 +51,7 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb) int err; pwm_get_state(pb->pwm, &state); - if (state.enabled) + if (pb->enabled) return; err = regulator_enable(pb->power_supply); @@ -65,6 +66,8 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb) if (pb->enable_gpio) gpiod_set_value_cansleep(pb->enable_gpio, 1); + + pb->enabled = true; } static void pwm_backlight_power_off(struct pwm_bl_data *pb) @@ -72,7 +75,7 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb) struct pwm_state state; pwm_get_state(pb->pwm, &state); - if (!state.enabled) + if (!pb->enabled) return; if (pb->enable_gpio) @@ -86,6 +89,7 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb) pwm_apply_state(pb->pwm, &state); regulator_disable(pb->power_supply); + pb->enabled = false; } static int compute_duty_cycle(struct pwm_bl_data *pb, int brightness) @@ -483,6 +487,7 @@ static int pwm_backlight_probe(struct platform_device *pdev) pb->check_fb = data->check_fb; pb->exit = data->exit; pb->dev = &pdev->dev; + pb->enabled = false; pb->post_pwm_on_delay = data->post_pwm_on_delay; pb->pwm_off_delay = data->pwm_off_delay; |