Re: [PATCH v5 2/8] leds: document additional use of blink_set for hardware control

[Randy Dunlap]

On 11/12/21 7:35 AM, Ansuel Smith wrote:
> diff --git a/Documentation/leds/leds-class.rst b/Documentation/leds/leds-class.rst
> index e5d266919a19..fa6e1cfc4628 100644
> --- a/Documentation/leds/leds-class.rst
> +++ b/Documentation/leds/leds-class.rst
> @@ -202,6 +202,23 @@ hardware mode and any software only trigger will reject activation.
>   On init an LED driver that support a hardware mode should reset every blink mode
>   set by default.
>   
> +Once a trigger has declared support for hardware-controlled blinks, it will use
> +blink_set() to try to offload his trigger on activation/configuration.

                                 this trigger

> +blink_set() will return 0 if the requested modes set in trigger_data can be
> +controlled by hardware or an error if both of the bitmap modes are not supported by
> +the hardware or there was a problem in the configuration.
> +
> +Following blink_set logic, setting brightness to LED_OFF with hardware control active
> +will reset any active blink mode and disable hardware control setting the LED to off.
> +
> +It's in the LED driver's interest to know how to elaborate the trigger data and report support
> +for a particular set of blink modes. For this exact reason explicit support for the specific
> +trigger is mandatory or the driver returns -EOPNOTSUPP if asked to enter hardware mode
> +with a not supported trigger.
> +If the driver returns -EOPNOTSUPP on hw_control_configure(), the trigger activation will
> +fail as the driver doesn't support that specific hardware blink mode or doesn't know
> +how to handle the provided trigger data.


--
~Randy