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| author | Alper Nebi Yasak <alpernebiyasak@gmail.com> | 2020-10-22 23:49:27 +0300 |
|---|---|---|
| committer | Anatolij Gustschin <agust@denx.de> | 2021-04-10 17:08:39 +0300 |
| commit | 1b9ee2882e6bd1c17ab2ec86249aa0347af68242 (patch) | |
| tree | 97c0a555eae842b114c8fbbc22e2b1acd48c8773 /include/cros_ec.h | |
| parent | fefa713b1843cf13d3132bfe0cf27710938c5d92 (diff) | |
| download | u-boot-1b9ee2882e6bd1c17ab2ec86249aa0347af68242.tar.xz | |
pwm: Add a driver for Chrome OS EC PWM
This PWM is used in rk3399-gru-bob and rk3399-gru-kevin to control
the display brightness. We can only change the duty cycle, so on
set_config() we just try to match the duty cycle that dividing duty_ns
by period_ns gives us. To disable, we set the duty cycle to zero while
keeping the old value for when we want to re-enable it.
The cros_ec_set_pwm_duty() function is taken from Depthcharge's
cros_ec_set_bl_pwm_duty() but modified to use the generic pwm type.
The driver itself is very loosely based on rk_pwm.c for the general pwm
driver structure.
The devicetree binding file is from Linux, before it was converted to
YAML at 5df5a577a6b4 ("dt-bindings: pwm: Convert google,cros-ec-pwm.txt
to YAML format") in their repo.
Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'include/cros_ec.h')
| -rw-r--r-- | include/cros_ec.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/include/cros_ec.h b/include/cros_ec.h index eddc23d48f..9396b4d246 100644 --- a/include/cros_ec.h +++ b/include/cros_ec.h @@ -513,6 +513,19 @@ int cros_ec_efs_verify(struct udevice *dev, enum ec_flash_region region); int cros_ec_battery_cutoff(struct udevice *dev, uint8_t flags); /** + * cros_ec_set_pwm_duty() - Set duty cycle of a generic pwm + * + * Note that duty value needs to be passed to the EC as a 16 bit number + * for increased precision. + * + * @param dev CROS-EC device + * @param index Index of the pwm + * @param duty Desired duty cycle, in 0..EC_PWM_MAX_DUTY range. + * @return 0 if OK, -ve on error + */ +int cros_ec_set_pwm_duty(struct udevice *dev, uint8_t index, uint16_t duty); + +/** * cros_ec_read_limit_power() - Check if power is limited by batter/charger * * Sometimes the battery is low and / or the device is connected to a charger |