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>
diff --git a/drivers/misc/cros_ec.c b/drivers/misc/cros_ec.c
index ebfa7c4..7904d5c 100644
--- a/drivers/misc/cros_ec.c
+++ b/drivers/misc/cros_ec.c
@@ -1170,6 +1170,23 @@
return 0;
}
+int cros_ec_set_pwm_duty(struct udevice *dev, uint8_t index, uint16_t duty)
+{
+ struct ec_params_pwm_set_duty p;
+ int ret;
+
+ p.duty = duty;
+ p.pwm_type = EC_PWM_TYPE_GENERIC;
+ p.index = index;
+
+ ret = ec_command(dev, EC_CMD_PWM_SET_DUTY, 0, &p, sizeof(p),
+ NULL, 0);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
int cros_ec_set_ldo(struct udevice *dev, uint8_t index, uint8_t state)
{
struct ec_params_ldo_set params;