Re: [RFC PATCH v4 2/8] leds: document additional use of blink_set for hardware control
From: Randy Dunlap <hidden>
Date: 2021-11-11 02:28:16
Also in:
linux-devicetree, linux-doc, linux-leds, lkml
Hi Ansuel, Sorry -- I screwed this one up a little bit on the previous iteration. On 11/10/21 5:34 PM, Ansuel Smith wrote:
quoted hunk ↗ jump to hunk
diff --git a/Documentation/leds/leds-class.rst b/Documentation/leds/leds-class.rst index 0175954717a3..c06a18b811de 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 a LED driver that support a hardware mode should reset every blink mode set by default. +Once a trigger has declared support for hardware-controller blinks, it will use
hardware-controlled
+blink_set() to try to offload his trigger on activation/configuration. +blink_set() will return 0 if the requested modes set in trigger_data can be +controlled by hardware or an error if both the mode bitmap is not supported by
maybe: 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 modes or doesn't know
mode
+how to handle the provided trigger data.
thanks. -- ~Randy