diff options
| author | Alper Nebi Yasak <alpernebiyasak@gmail.com> | 2020-10-22 23:49:26 +0300 |
|---|---|---|
| committer | Anatolij Gustschin <agust@denx.de> | 2021-04-10 17:07:12 +0300 |
| commit | fefa713b1843cf13d3132bfe0cf27710938c5d92 (patch) | |
| tree | 4ae09212a60da99436d30eb24b3f9d041553cdbe /include/pwm.h | |
| parent | 9749d2ea29e1a535c9ea8f850db8b6abe6df7b15 (diff) | |
| download | u-boot-fefa713b1843cf13d3132bfe0cf27710938c5d92.tar.xz | |
video: backlight: Support PWMs without a known period_ns
The PWM device provided by Chrome OS EC doesn't really support anything
other than setting a relative duty cycle. To support it as a backlight,
this patch makes the PWM period optional in the device tree and pretends
the valid brightness range is its period_ns.
Also adds a sandbox test for a PWM channel that has a fixed period,
checking that the resulting duty_cycle matches on a set_config() even if
the requested period_ns can't be set.
Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'include/pwm.h')
| -rw-r--r-- | include/pwm.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/include/pwm.h b/include/pwm.h index f9959706ce..668551e4b8 100644 --- a/include/pwm.h +++ b/include/pwm.h @@ -17,6 +17,10 @@ struct pwm_ops { /** * set_config() - Set the PWM configuration * + * Change both the PWM device's period and it's duty period if + * possible. Otherwise, set an appropriate duty period that best + * matches the given period_ns / duty_ns ratio for the device. + * * @dev: PWM device to update * @channel: PWM channel to update * @period_ns: PWM period in nanoseconds @@ -51,6 +55,10 @@ struct pwm_ops { /** * pwm_set_config() - Set the PWM configuration * + * Change both the PWM device's period and it's duty period if + * possible. Otherwise, set an appropriate duty period that best + * matches the given period_ns / duty_ns ratio for the device. + * * @dev: PWM device to update * @channel: PWM channel to update * @period_ns: PWM period in nanoseconds |