Commit e46cb6d0 authored by Eddie James's avatar Eddie James Committed by Pavel Machek
Browse files

leds: pca955x: Implement the default-state property 



In order to retain the LED state after a system reboot, check the
documented default-state device tree property during initialization.
Modify the behavior of the probe according to the property.

Signed-off-by: default avatarEddie James <eajames@linux.ibm.com>
Signed-off-by: default avatarPavel Machek <pavel@ucw.cz>
parent 7086625f

drivers/leds/leds-pca955x.c

+46 −8
Original line number Diff line number Diff line
@@ -129,6 +129,7 @@ struct pca955x_led { 
	int			led_num;	/* 0 .. 15 potentially */

	char			name[32];

	u32			type;

	int			default_state;

	const char		*default_trigger;

};
@@ -439,6 +440,7 @@ pca955x_get_pdata(struct i2c_client *client, struct pca955x_chipdef *chip) 


	device_for_each_child_node(&client->dev, child) {

		const char *name;

		const char *state;

		u32 reg;

		int res;
@@ -457,6 +459,18 @@ pca955x_get_pdata(struct i2c_client *client, struct pca955x_chipdef *chip) 
		fwnode_property_read_u32(child, "type", &led->type);

		fwnode_property_read_string(child, "linux,default-trigger",

					    &led->default_trigger);



		if (!fwnode_property_read_string(child, "default-state",

						 &state)) {

			if (!strcmp(state, "keep"))

				led->default_state = LEDS_GPIO_DEFSTATE_KEEP;

			else if (!strcmp(state, "on"))

				led->default_state = LEDS_GPIO_DEFSTATE_ON;

			else

				led->default_state = LEDS_GPIO_DEFSTATE_OFF;

		} else {

			led->default_state = LEDS_GPIO_DEFSTATE_OFF;

		}

	}



	pdata->num_leds = chip->bits;
@@ -485,6 +499,7 @@ static int pca955x_probe(struct i2c_client *client, 
	int i, err;

	struct pca955x_platform_data *pdata;

	int ngpios = 0;

	bool keep_pwm = false;



	chip = &pca955x_chipdefs[id->driver_data];

	adapter = client->adapter;
@@ -565,14 +580,35 @@ static int pca955x_probe(struct i2c_client *client, 
			led->brightness_set_blocking = pca955x_led_set;

			led->brightness_get = pca955x_led_get;



			err = devm_led_classdev_register(&client->dev, led);

			if (pdata->leds[i].default_state ==

			    LEDS_GPIO_DEFSTATE_OFF) {

				err = pca955x_led_set(led, LED_OFF);

				if (err)

					return err;

			} else if (pdata->leds[i].default_state ==

				   LEDS_GPIO_DEFSTATE_ON) {

				err = pca955x_led_set(led, LED_FULL);

				if (err)

					return err;

			}



			/* Turn off LED */

			err = pca955x_led_set(led, LED_OFF);

			err = devm_led_classdev_register(&client->dev, led);

			if (err)

				return err;



			/*

			 * For default-state == "keep", let the core update the

			 * brightness from the hardware, then check the

			 * brightness to see if it's using PWM1. If so, PWM1

			 * should not be written below.

			 */

			if (pdata->leds[i].default_state ==

			    LEDS_GPIO_DEFSTATE_KEEP) {

				if (led->brightness != LED_FULL &&

				    led->brightness != LED_OFF &&

				    led->brightness != LED_HALF)

					keep_pwm = true;

			}

		}

	}
@@ -581,10 +617,12 @@ static int pca955x_probe(struct i2c_client *client, 
	if (err)

		return err;



	if (!keep_pwm) {

		/* PWM1 is used for variable brightness, default to OFF */

		err = pca955x_write_pwm(client, 1, 0);

		if (err)

			return err;

	}



	/* Set to fast frequency so we do not see flashing */

	err = pca955x_write_psc(client, 0, 0);