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@xxxxxxxxxxxxxx>
---
drivers/video/backlight-pwm.c | 27 ++++++++++++++++++++-------
1 file changed, 20 insertions(+), 7 deletions(-)
diff --git a/drivers/video/backlight-pwm.c b/drivers/video/backlight-pwm.c
index ba6f9bc..91435f8 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)
--
2.6.2
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