From 8b58c9edccdbb58ec34df3a41375263a315db2c6 Mon Sep 17 00:00:00 2001 From: Thierry Reding Date: Fri, 18 Oct 2013 10:46:24 +0200 Subject: pwm-backlight: Fix brightness adjustment Split adjustment of the brightness (by changing the PWM duty cycle) from the power on sequence. This fixes an issue where the brightness can no longer be updated once the backlight has been enabled. Reported-by: Marc Dietrich Signed-off-by: Thierry Reding (cherry picked from commit e4bfeda96872bfe6015cd360008b77cd3b981b2b) --- drivers/video/backlight/pwm_bl.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-) (limited to 'drivers') diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index 174ecdaebf1b..5fa9388714c4 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -45,21 +45,11 @@ struct pwm_bl_data { static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness) { - unsigned int lth = pb->lth_brightness; int duty_cycle, err; if (pb->enabled) return; - if (pb->levels) - duty_cycle = pb->levels[brightness]; - else - duty_cycle = brightness; - - duty_cycle = (duty_cycle * (pb->period - lth) / pb->scale) + lth; - - 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"); @@ -94,10 +84,24 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb) pb->enabled = false; } +static int compute_duty_cycle(struct pwm_bl_data *pb, int brightness) +{ + unsigned int lth = pb->lth_brightness; + int duty_cycle; + + if (pb->levels) + duty_cycle = pb->levels[brightness]; + else + duty_cycle = brightness; + + return (duty_cycle * (pb->period - lth) / pb->scale) + lth; +} + static int pwm_backlight_update_status(struct backlight_device *bl) { struct pwm_bl_data *pb = bl_get_data(bl); int brightness = bl->props.brightness; + int duty_cycle; if (bl->props.power != FB_BLANK_UNBLANK || bl->props.fb_blank != FB_BLANK_UNBLANK || @@ -107,9 +111,11 @@ static int pwm_backlight_update_status(struct backlight_device *bl) if (pb->notify) brightness = pb->notify(pb->dev, brightness); - if (brightness > 0) + if (brightness > 0) { + duty_cycle = compute_duty_cycle(pb, brightness); + pwm_config(pb->pwm, duty_cycle, pb->period); pwm_backlight_power_on(pb, brightness); - else + } else pwm_backlight_power_off(pb); if (pb->notify_after) -- cgit v1.2.3