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pwm-backlight: Track enable state

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Follow up patches will add support for more complex means of powering
the backlight on and off such as using a regulator. To prevent calls to
the regulator API from becoming unbalanced, keep track of the enabled
state internally.

Signed-off-by: Thierry Reding <treding@nvidia.com>
This commit is contained in:
Thierry Reding 2013-10-02 18:01:02 +02:00 committed by Thierry Reding
parent 62b744a87c
commit 97c3843711
1 changed files with 11 additions and 0 deletions
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11
drivers/video/backlight/pwm_bl.c
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@ -27,6 +27,7 @@ struct pwm_bl_data {
unsigned int period; unsigned int period;
unsigned int lth_brightness; unsigned int lth_brightness;
unsigned int *levels; unsigned int *levels;
bool enabled;
int (*notify)(struct device *, int (*notify)(struct device *,
int brightness); int brightness);
void (*notify_after)(struct device *, void (*notify_after)(struct device *,
@ -40,6 +41,9 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness,
{ {
int duty_cycle, err; int duty_cycle, err;
if (pb->enabled)
return;
if (pb->levels) { if (pb->levels) {
duty_cycle = pb->levels[brightness]; duty_cycle = pb->levels[brightness];
max = pb->levels[max]; max = pb->levels[max];
@ -52,12 +56,18 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness,
pwm_config(pb->pwm, duty_cycle, pb->period); pwm_config(pb->pwm, duty_cycle, pb->period);
pwm_enable(pb->pwm); pwm_enable(pb->pwm);
pb->enabled = true;
} }
static void pwm_backlight_power_off(struct pwm_bl_data *pb) static void pwm_backlight_power_off(struct pwm_bl_data *pb)
{ {
if (!pb->enabled)
return;
pwm_config(pb->pwm, 0, pb->period); pwm_config(pb->pwm, 0, pb->period);
pwm_disable(pb->pwm); pwm_disable(pb->pwm);
pb->enabled = false;
} }
static int pwm_backlight_update_status(struct backlight_device *bl) static int pwm_backlight_update_status(struct backlight_device *bl)
@ -216,6 +226,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
pb->check_fb = data->check_fb; pb->check_fb = data->check_fb;
pb->exit = data->exit; pb->exit = data->exit;
pb->dev = &pdev->dev; pb->dev = &pdev->dev;
pb->enabled = false;
pb->pwm = devm_pwm_get(&pdev->dev, NULL); pb->pwm = devm_pwm_get(&pdev->dev, NULL);
if (IS_ERR(pb->pwm)) { if (IS_ERR(pb->pwm)) {