Hi Enric,
LED subsystem core already registers its pm ops.
(see drivers/leds/led-class.c and leds_class_dev_pm_ops).
It results in setting brightness of all LED class devices marked
with LED_CORE_SUSPENDRESUME flag to 0 on suspend and bringing
back previous brightness on resume.
In this case you would have to track the state of all LED
class devices exposed by leds-gpio and call
pinctrl_pm_select_sleep_state() when they all are off.
Now, if in this state and turning any of the LEDs on,
then pinctrl_pm_select_default_state() would have to be called.
Compare the following patch:
commit a8c170b015ff6695641bdfbdb74729411ba1e9e5
Author: Matt Ranostay <mranostay@xxxxxxxxx>
Date: Fri Oct 28 18:20:42 2016 -0700
leds: pca963x: enable low-power state
Allow chip to enter low power state when no LEDs are being lit or in
blink mode.
On 01/20/2017 05:45 PM, Enric Balletbo i Serra wrote:
> This patch allows users to use an alternate pinctrl "sleep" in order to
> clamp outputs to a wanted state at suspend.
>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
> ---
> drivers/leds/leds-gpio.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/drivers/leds/leds-gpio.c b/drivers/leds/leds-gpio.c
> index d400dca..a2e9bdb 100644
> --- a/drivers/leds/leds-gpio.c
> +++ b/drivers/leds/leds-gpio.c
> @@ -20,6 +20,7 @@
> #include <linux/platform_device.h>
> #include <linux/property.h>
> #include <linux/slab.h>
> +#include <linux/pm.h>
>
> struct gpio_led_data {
> struct led_classdev cdev;
> @@ -269,12 +270,31 @@ static void gpio_led_shutdown(struct platform_device *pdev)
> }
> }
>
> +#ifdef CONFIG_PM_SLEEP
> +static int gpio_led_suspend(struct device *dev)
> +{
> + pinctrl_pm_select_sleep_state(dev);
> +
> + return 0;
> +}
> +
> +static int gpio_led_resume(struct device *dev)
> +{
> + pinctrl_pm_select_default_state(dev);
> +
> + return 0;
> +}
> +#endif
> +
> +static SIMPLE_DEV_PM_OPS(gpio_led_pm, gpio_led_suspend, gpio_led_resume);
> +
> static struct platform_driver gpio_led_driver = {
> .probe = gpio_led_probe,
> .shutdown = gpio_led_shutdown,
> .driver = {
> .name = "leds-gpio",
> .of_match_table = of_gpio_leds_match,
> + .pm = &gpio_led_pm,
> },
> };
>
>
--
Best regards,
Jacek Anaszewski
