> This patch adds support for "default-state" devicetree property, which > allows to defer pwm init to first use of led. > > This allows to configure the PWM early in bootloader to let the LED > blink until an application in Linux userspace sets something different. > > Signed-off-by: Denis Osterland-Heim <denis.osterl...@diehl.com> > Acked-by: Jacek Anaszewski <jacek.anaszew...@gmail.com>
> +#define LEDS_PWM_DEFSTATE_OFF 0
> +#define LEDS_PWM_DEFSTATE_ON 1
> +#define LEDS_PWM_DEFSTATE_KEEP 2
Turn this into enum; no need for prefix as this is private to the driver.
> struct led_pwm {
> const char *name;
> const char *default_trigger;
> u8 active_low;
> + u8 default_state;
> unsigned int max_brightness;
> };
>
> @@ -88,7 +93,30 @@ static int led_pwm_add(struct device *dev, struct
> led_pwm_priv *priv,
>
> led_data->cdev.brightness_set_blocking = led_pwm_set;
>
> - pwm_init_state(led_data->pwm, &led_data->pwmstate);
> + /* init PWM state */
> + if (led->default_state == LEDS_PWM_DEFSTATE_KEEP) {
> + pwm_get_state(led_data->pwm, &led_data->pwmstate);
> + if (!led_data->pwmstate.period) {
> + led->default_state = LEDS_PWM_DEFSTATE_OFF;
> + dev_warn(dev,
> + "failed to read period for %s, default to off",
> + led->name);
> + }
> + }
> + if (led->default_state != LEDS_PWM_DEFSTATE_KEEP)
> + pwm_init_state(led_data->pwm, &led_data->pwmstate);
> +
> + /* set brightness */
> + if (led->default_state == LEDS_PWM_DEFSTATE_ON)
> + led_data->cdev.brightness = led->max_brightness;
> + else if (led->default_state == LEDS_PWM_DEFSTATE_KEEP) {
> + uint64_t brightness;
> +
> + brightness = led->max_brightness;
> + brightness *= led_data->pwmstate.duty_cycle;
> + do_div(brightness, led_data->pwmstate.period);
> + led_data->cdev.brightness = brightness;
> + }
Try to clean this up... switch() might help. Maybe two of them.
> @@ -134,6 +166,16 @@ static int led_pwm_create_fwnode(struct device *dev,
> struct led_pwm_priv *priv)
> fwnode_property_read_u32(fwnode, "max-brightness",
> &led.max_brightness);
>
> + if (!fwnode_property_read_string(fwnode, "default-state",
> + &state)) {
> + if (!strcmp(state, "keep"))
> + led.default_state = LEDS_PWM_DEFSTATE_KEEP;
> + else if (!strcmp(state, "on"))
> + led.default_state = LEDS_PWM_DEFSTATE_ON;
> + else
> + led.default_state = LEDS_PWM_DEFSTATE_OFF;
> + }
Actually... Move the enum to core, and add helper for this. We don't
want to see this duplicated.
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Get rid of this.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures)
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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