From e46cb6d0c760a5b15e38138845fad99628fafcb8 Mon Sep 17 00:00:00 2001 From: Eddie James Date: Fri, 16 Jul 2021 17:03:29 -0500 Subject: [PATCH] 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: Eddie James Signed-off-by: Pavel Machek --- drivers/leds/leds-pca955x.c | 54 +++++++++++++++++++++++++++++++------ 1 file changed, 46 insertions(+), 8 deletions(-) diff --git a/drivers/leds/leds-pca955x.c b/drivers/leds/leds-pca955x.c index e47ba7c3b7c7d8..fa1d77d86ef67b 100644 --- a/drivers/leds/leds-pca955x.c +++ b/drivers/leds/leds-pca955x.c @@ -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; + 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; + } + err = devm_led_classdev_register(&client->dev, led); if (err) return err; - /* Turn off LED */ - err = pca955x_led_set(led, LED_OFF); - 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; - /* PWM1 is used for variable brightness, default to OFF */ - err = pca955x_write_pwm(client, 1, 0); - 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);