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| author | Sascha Hauer <s.hauer@pengutronix.de> | 2015-11-18 16:41:00 +0100 |
|---|---|---|
| committer | Sascha Hauer <s.hauer@pengutronix.de> | 2015-11-23 09:46:27 +0100 |
| commit | 42c797b091a153762c9a49738db46e8e84f64ad6 (patch) | |
| tree | 5c4767761bedd16751e18e4e9d1e2eb02c19932f /drivers/video/backlight-pwm.c | |
| parent | ea682776db018af2d249097f1a682ef0881e3d0e (diff) | |
| download | barebox-42c797b091a153762c9a49738db46e8e84f64ad6.tar.gz barebox-42c797b091a153762c9a49738db46e8e84f64ad6.tar.xz | |
video: pwm-backlight: Honour discrete brightness levels from dt
If probed from device tree we have an array of pwm duty cycle levels
in the brightness-levels property. Although the driver parsed the property,
the values have been ignored. Make use of these flags so that the driver
can work for example with inverted PWMs.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'drivers/video/backlight-pwm.c')
| -rw-r--r-- | drivers/video/backlight-pwm.c | 27 |
1 files changed, 20 insertions, 7 deletions
diff --git a/drivers/video/backlight-pwm.c b/drivers/video/backlight-pwm.c index ba6f9bcb41..91435f8d0a 100644 --- a/drivers/video/backlight-pwm.c +++ b/drivers/video/backlight-pwm.c @@ -39,6 +39,7 @@ struct pwm_backlight { int enable_active_high; int max_value; int enabled; + unsigned int scale; }; static int backlight_pwm_enable(struct pwm_backlight *pwm_backlight) @@ -87,18 +88,26 @@ static int backlight_pwm_disable(struct pwm_backlight *pwm_backlight) return 0; } +static int compute_duty_cycle(struct pwm_backlight *pwm_backlight, int brightness) +{ + int duty_cycle; + + if (pwm_backlight->levels) + duty_cycle = pwm_backlight->levels[brightness]; + else + duty_cycle = brightness; + + return duty_cycle * pwm_backlight->period / pwm_backlight->scale; +} + static int backlight_pwm_set(struct backlight_device *backlight, int brightness) { struct pwm_backlight *pwm_backlight = container_of(backlight, struct pwm_backlight, backlight); - unsigned long long duty = pwm_backlight->period; - unsigned int max = pwm_backlight->backlight.brightness_max; - - duty *= brightness; - do_div(duty, max); - pwm_config(pwm_backlight->pwm, duty, pwm_backlight->period); + pwm_config(pwm_backlight->pwm, compute_duty_cycle(pwm_backlight, brightness), + pwm_backlight->period); if (brightness) return backlight_pwm_enable(pwm_backlight); @@ -113,7 +122,7 @@ static int pwm_backlight_parse_dt(struct device_d *dev, struct property *prop; int length; u32 value; - int ret; + int ret, i; enum of_gpio_flags flags; if (!node) @@ -141,6 +150,10 @@ static int pwm_backlight_parse_dt(struct device_d *dev, if (ret < 0) return ret; + for (i = 0; i <= pwm_backlight->backlight.brightness_max; i++) + if (pwm_backlight->levels[i] > pwm_backlight->scale) + pwm_backlight->scale = pwm_backlight->levels[i]; + ret = of_property_read_u32(node, "default-brightness-level", &value); if (ret < 0) |