On Wed, 14 May 2025, Jacek Anaszewski wrote: > On 5/14/25 17:28, Lee Jones wrote: > > On Mon, 12 May 2025, Jacek Anaszewski wrote: > > > > > Hi Geert, > > > > > > On 5/12/25 09:13, Geert Uytterhoeven wrote: > > > > Hi Jacek, > > > > > > > > Thanks for your answer! > > > > > > You're welcome. > > > > > > > On Sat, 10 May 2025 at 14:43, Jacek Anaszewski > > > > <jacek.anaszewski@xxxxxxxxx> wrote: > > > > > On 5/8/25 15:49, Lee Jones wrote: > > > > > > On Thu, 08 May 2025, Wolfram Sang wrote: > > > > > > > On Thu, Apr 17, 2025 at 01:39:14PM +0200, Geert Uytterhoeven wrote: > > > > > > > > On Thu, 17 Apr 2025 at 11:33, Wolfram Sang > > > > > > > > <wsa+renesas@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > > > > > > Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx> > > > > > > > > > --- > > > > > > > > > > > > > > > > > > Changes since v2: > > > > > > > > > * using function, color, function-enumerator properties now > > > > > > > > > > > > > > > > > > Honestly, this is better than using node names? With V2, the LEDs were > > > > > > > > > named as in the schematics, now they are called: > > > > > > > > > > > > > > > > > > lrwxrwxrwx 1 root root 0 May 12 12:10 green:programming-0 -> ../../devices/platform/leds/leds/green:programming-0 > > > > > > > > > lrwxrwxrwx 1 root root 0 May 12 12:10 green:programming-1 -> ../../devices/platform/leds/leds/green:programming-1 > > > > > > > > > lrwxrwxrwx 1 root root 0 May 12 12:10 green:programming-2 -> ../../devices/platform/leds/leds/green:programming-2 > > > > > > > > > ... > > > > > > > > > > > > > > > > > > Which gets even more confusing if we might later add LEDs not on this > > > > > > > > > board, but on the expansion board. 'green:programming-8' sits where? > > > > > > > > > > > > > > > > > > I really wonder, but if this is the official way now... > > > > > > > > > > > > > > > > Good point! So I'm inclined to take v2... > > > > > > > > > > > > > > > > Let's raise this with the LED people. I don't want to fight Pavel when > > > > > > > > v2 hits the CiP tree ;-) > > > > > > > > > > > > > > So, if there is no other opinion here, can we remove function, color, > > > > > > > function-enumerator and just use the node names which match the > > > > > > > schematics? Basically apply V2? > > > > > > > > > > > > I didn't author the semantics nor the rules surrounding them, but I am > > > > > > obliged to enforce them. Therefore "LED people" say, please stick to > > > > > > convention as stated in the present documentation: > > > > > > > > > > > > https://docs.kernel.org/leds/leds-class.html#led-device-naming > > > > > > > > > > > > Please note that a "debug" (LED_FUNCTION_DEBUG) option already exists if > > > > > > that is more appropriate to your use-case. > > > > > > > > > > > > Let's also bring Jacek into the conversion, since I know that he did a > > > > > > bunch of work around this topic. > > > > > > > > > > The question is if the LED name from the schematics tells anything to > > > > > the user of the equipment? > > > > > > > > As this is a development board and not a finished product, I would > > > > answer yes. > > > > > > OK. > > > > > > > > The idea behind LED naming is to facilitate matching the LED class > > > > > device name as reported by the system with the LED location on the > > > > > equipment. > > > > > > > > > > The LED naming standardization intended to enforce consistent > > > > > LED naming, and not allowing to add multiple interchangeable > > > > > names like wifi/wlan. It also helps to keep LED name sections order in > > > > > accordance with Linux documentation, which before had been often > > > > > abused by allowing to assign anything to the now deprecated 'label' > > > > > DT property. > > > > > > > > I agree this all makes perfect sense for a final product, where the > > > > purpose of each LED is clear, and sometimes indicated by an icon > > > > on the case. > > > > For a development board, some LEDs may have a fixed purpose. > > > > But typically there is also a collection of generic user LEDs, which > > > > do not have a fixed purpose, and are identified by a label on the > > > > schematics. Imposing an arbitrary numbering scheme on the latter is > > > > confusing for the user (developer). > > > > > > Using DT child node name for LED class device name is only > > > a last resort fallback. However if it is devboard and we want to have > > > a reference to the schematics then I'd say it makes sense to take > > > LED names from DT nodes. What about the colors? Are the LEDs replaceable > > > or soldered? > > > > Looks like this option does what you want: > > > > https://github.com/torvalds/linux/blob/master/drivers/leds/led-core.c#L578 > > > > For this to execute you need to provide init_data when calling > > *led_classdev_register*(), omit the; label, function, color_present DT > > properties and also init_data's default_label attribute. At which point > > the DT node name should be taken as the LED class name. > > Yep, I know how it works, I wrote that code after all. Sorry for the ambiguity. I was attempting to address Wolfram. > Here, I wanted to clarify whether it wouldn't make sense to stick to > the approach with 'function' and 'color' properties if LEDs are fixed > on the board and the colors are known. > > From [0] I infer that LEDs are green, so we should use 'color' DT > property definitely. And as a 'function' we can assign plain text "pcaN" > if you feel it makes sense for that board. The 'function' documentation specifically says to use one of the predefined LED_FUNCTION_* entries. If we are officially accepting caveats to that, we should probably update it. > This way you'll get LED name "pcaN:green", that will be according to > the naming standard. > > So the node would look like this, for the pca1 LED: > > led-1 { function = "pca1"; color = <LED_COLOR_GREEN>; default-state = > "keep"; }; > > [0] > https://patchwork.kernel.org/project/linux-renesas-soc/patch/20250328153134.2881-11-wsa+renesas@xxxxxxxxxxxxxxxxxxxx/#26336000 -- Lee Jones [李琼斯]
