video: backlight: fix pwm's duty cycle calculation

For levels equal to the maximum value, the duty cycle must be equal to
the period.

Signed-off-by: Dario Binacchi <dariobin@libero.it>
Reviewed-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Dario Binacchi 2020-10-11 14:28:04 +02:00 committed by Anatolij Gustschin
parent f9b94055bd
commit 76c2ff3e5f
2 changed files with 7 additions and 7 deletions

View File

@ -63,7 +63,7 @@ static int set_pwm(struct pwm_backlight_priv *priv)
int ret;
duty_cycle = priv->period_ns * (priv->cur_level - priv->min_level) /
(priv->max_level - priv->min_level + 1);
(priv->max_level - priv->min_level);
ret = pwm_set_config(priv->pwm, priv->channel, priv->period_ns,
duty_cycle);
if (ret)

View File

@ -40,7 +40,7 @@ static int dm_test_panel(struct unit_test_state *uts)
ut_assertok(sandbox_pwm_get_config(pwm, 0, &period_ns, &duty_ns,
&enable, &polarity));
ut_asserteq(1000, period_ns);
ut_asserteq(170 * 1000 / 256, duty_ns);
ut_asserteq(170 * 1000 / 255, duty_ns);
ut_asserteq(true, enable);
ut_asserteq(false, polarity);
ut_asserteq(1, sandbox_gpio_get_value(gpio, 1));
@ -49,29 +49,29 @@ static int dm_test_panel(struct unit_test_state *uts)
ut_assertok(panel_set_backlight(dev, 40));
ut_assertok(sandbox_pwm_get_config(pwm, 0, &period_ns, &duty_ns,
&enable, &polarity));
ut_asserteq(64 * 1000 / 256, duty_ns);
ut_asserteq(64 * 1000 / 255, duty_ns);
ut_assertok(panel_set_backlight(dev, BACKLIGHT_MAX));
ut_assertok(sandbox_pwm_get_config(pwm, 0, &period_ns, &duty_ns,
&enable, &polarity));
ut_asserteq(255 * 1000 / 256, duty_ns);
ut_asserteq(255 * 1000 / 255, duty_ns);
ut_assertok(panel_set_backlight(dev, BACKLIGHT_MIN));
ut_assertok(sandbox_pwm_get_config(pwm, 0, &period_ns, &duty_ns,
&enable, &polarity));
ut_asserteq(0 * 1000 / 256, duty_ns);
ut_asserteq(0 * 1000 / 255, duty_ns);
ut_asserteq(1, sandbox_gpio_get_value(gpio, 1));
ut_assertok(panel_set_backlight(dev, BACKLIGHT_DEFAULT));
ut_assertok(sandbox_pwm_get_config(pwm, 0, &period_ns, &duty_ns,
&enable, &polarity));
ut_asserteq(true, enable);
ut_asserteq(170 * 1000 / 256, duty_ns);
ut_asserteq(170 * 1000 / 255, duty_ns);
ut_assertok(panel_set_backlight(dev, BACKLIGHT_OFF));
ut_assertok(sandbox_pwm_get_config(pwm, 0, &period_ns, &duty_ns,
&enable, &polarity));
ut_asserteq(0 * 1000 / 256, duty_ns);
ut_asserteq(0 * 1000 / 255, duty_ns);
ut_asserteq(0, sandbox_gpio_get_value(gpio, 1));
ut_asserteq(false, regulator_get_enable(reg));