| Message ID | 20210429205002.70245-3-eajames@linux.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | leds: Support retaining state for the PCA955x | expand |
On Fri, 30 Apr 2021, at 06:19, Eddie James wrote: > Read the retain-state-shutdown device tree property to set the > existing LED_RETAIN_AT_SHUTDOWN flag. Then check the flag when > unregistering, and if set, don't set the brightness to OFF. This > is useful for systems that want to keep the HW state of the LED > across reboots. > > Signed-off-by: Eddie James <eajames@linux.ibm.com> > --- > drivers/leds/led-class.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c > index 2e495ff67856..f2f29318d312 100644 > --- a/drivers/leds/led-class.c > +++ b/drivers/leds/led-class.c > @@ -354,10 +354,15 @@ int led_classdev_register_ext(struct device *parent, > if (ret < 0) > return ret; > > - if (init_data->fwnode) > + if (init_data->fwnode) { > fwnode_property_read_string(init_data->fwnode, > "linux,default-trigger", > &led_cdev->default_trigger); > + > + if (fwnode_property_present(init_data->fwnode, > + "retain-state-shutdown")) > + led_cdev->flags |= LED_RETAIN_AT_SHUTDOWN; This is what we need, but I notice the pca955x driver is calling through devm_led_classdev_register() which passes NULL through init_data. So we won't get the result we want from this series as I understand it. Andrew
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c index 2e495ff67856..f2f29318d312 100644 --- a/drivers/leds/led-class.c +++ b/drivers/leds/led-class.c @@ -354,10 +354,15 @@ int led_classdev_register_ext(struct device *parent, if (ret < 0) return ret; - if (init_data->fwnode) + if (init_data->fwnode) { fwnode_property_read_string(init_data->fwnode, "linux,default-trigger", &led_cdev->default_trigger); + + if (fwnode_property_present(init_data->fwnode, + "retain-state-shutdown")) + led_cdev->flags |= LED_RETAIN_AT_SHUTDOWN; + } } else { proposed_name = led_cdev->name; } @@ -448,7 +453,8 @@ void led_classdev_unregister(struct led_classdev *led_cdev) /* Stop blinking */ led_stop_software_blink(led_cdev); - led_set_brightness(led_cdev, LED_OFF); + if (!(led_cdev->flags & LED_RETAIN_AT_SHUTDOWN)) + led_set_brightness(led_cdev, LED_OFF); flush_work(&led_cdev->set_brightness_work);
Read the retain-state-shutdown device tree property to set the existing LED_RETAIN_AT_SHUTDOWN flag. Then check the flag when unregistering, and if set, don't set the brightness to OFF. This is useful for systems that want to keep the HW state of the LED across reboots. Signed-off-by: Eddie James <eajames@linux.ibm.com> --- drivers/leds/led-class.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)