On 19/10/2023 15.54, Marek Vasut wrote: > On 10/19/23 11:58, Rasmus Villemoes wrote: >> If the driver's own .bind method has populated uc_plat->label, don't >> override that. This is necessary for an upcoming driver for ti,lp5562, >> where the DT binding unfortunately says to use "chan-name" and not >> "label". >> >> Signed-off-by: Rasmus Villemoes <rasmus.villem...@prevas.dk> >> --- >> drivers/led/led-uclass.c | 4 +++- >> 1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/led/led-uclass.c b/drivers/led/led-uclass.c >> index 5a5d07b9a7..0232fa84de 100644 >> --- a/drivers/led/led-uclass.c >> +++ b/drivers/led/led-uclass.c >> @@ -71,7 +71,9 @@ static int led_post_bind(struct udevice *dev) >> struct led_uc_plat *uc_plat = dev_get_uclass_plat(dev); >> const char *default_state; >> - uc_plat->label = dev_read_string(dev, "label"); >> + if (!uc_plat->label) >> + uc_plat->label = dev_read_string(dev, "label"); >> + > > One thing I have to wonder about is, why does this controller have label > property in the top-level node , what is that used for ? > > (see Linux Documentation/devicetree/bindings/leds/leds-lp55xx.yaml) > > Reviewed-by: Marek Vasut <ma...@denx.de>
Reading the linux driver, it seems that the top-level label, if any, is used as part of the naming for individual channels if they don't have individual chan-name properties: if (pdata->led_config[chan].name) { led->cdev.name = pdata->led_config[chan].name; } else { snprintf(name, sizeof(name), "%s:channel%d", pdata->label ? : chip->cl->name, chan); led->cdev.name = name; } but I think the rationale in d1188adb2dabc is a bit weak, since the only example also does have individual chan-name properties. [Complete aside: At first I thought it was related to the multi-color LED work that has been ongoing for many many years (I think there was an LWN article at some point), where this could be exposed as a single multi-color LED, as opposed to the "traditional" three/four individual LEDs. In the former case, there would only be one sysfs entry, but with attributes exposing the multicolor functionality. I must admit I don't know the status of that work, when something reaches v31, http://archive.lwn.net:8080/linux-kernel/20200722071055.GA8984@amd/t/ , it's hard to know if it ever lands, or if pieces of it has landed.] Rasmus