| Message ID | 20221124204807.1593241-1-mmkurbanov@sberdevices.ru |
|---|---|
| Headers | show |
| Series | leds: add aw20xx driver | expand |
Hi. Thank you for quick reply. On 25.11.2022 11:29, Krzysztof Kozlowski wrote: >> + >> + imax: >> + maxItems: 1 >> + description: >> + Maximum supply current, see dt-bindings/leds/leds-aw200xx.h > > No. Use existing properties from common.yaml. This looks like > led-max-microamp and it is per LED, not per entire device. The AW200XX LED chip does not support imax setup per led. Imax is the global parameter over the all leds. I suppose, it's better to add vendor prefix or take minimum from all subnodes? How do you think? >> +/* Global max current (IMAX) */ >> +#define AW200XX_IMAX_3_3MA 8 >> +#define AW200XX_IMAX_6_7MA 9 > > No. Bindings are not for storing register constants. Feel free to store > here IDs (ID start from 0 or 1 and is incremented by 1)... but how the > IMAX even matches any need for "ID"? IMAX can be chosen from the predefined values in the datasheet (10mA, 20mA, etc). Do you mean the IMAX should be round down to nearest supported value in the driver?
On 28/11/2022 18:43, Martin Kurbanov wrote: > Hi. Thank you for quick reply. > > On 25.11.2022 11:29, Krzysztof Kozlowski wrote: >>> + >>> + imax: >>> + maxItems: 1 >>> + description: >>> + Maximum supply current, see dt-bindings/leds/leds-aw200xx.h >> >> No. Use existing properties from common.yaml. This looks like >> led-max-microamp and it is per LED, not per entire device. > > The AW200XX LED chip does not support imax setup per led. > Imax is the global parameter over the all leds. I suppose, it's better > to add vendor prefix or take minimum from all subnodes? > How do you think? Have in mind that led-max-microamp is a required property in some cases, so skipping it and using per-device properties does not solve the problem of adjusting proper currents. What if each LED you set for something which in total gives more than your imax? > > >>> +/* Global max current (IMAX) */ >>> +#define AW200XX_IMAX_3_3MA 8 >>> +#define AW200XX_IMAX_6_7MA 9 >> >> No. Bindings are not for storing register constants. Feel free to store >> here IDs (ID start from 0 or 1 and is incremented by 1)... but how the >> IMAX even matches any need for "ID"? > > IMAX can be chosen from the predefined values in the > datasheet (10mA, 20mA, etc). Do you mean the IMAX should be round down > to nearest supported value in the driver? What Linux driver support does not matter here. Bindings should reflect hardware and the same time not store register constants but logical values (for current this is in uA). Best regards, Krzysztof
Hello Krzysztof, On Fri, Dec 02, 2022 at 05:41:37PM +0100, Krzysztof Kozlowski wrote: > On 28/11/2022 18:43, Martin Kurbanov wrote: > > Hi. Thank you for quick reply. > > > > On 25.11.2022 11:29, Krzysztof Kozlowski wrote: > >>> + > >>> + imax: > >>> + maxItems: 1 > >>> + description: > >>> + Maximum supply current, see dt-bindings/leds/leds-aw200xx.h > >> > >> No. Use existing properties from common.yaml. This looks like > >> led-max-microamp and it is per LED, not per entire device. > > > > The AW200XX LED chip does not support imax setup per led. > > Imax is the global parameter over the all leds. I suppose, it's better > > to add vendor prefix or take minimum from all subnodes? > > How do you think? > > Have in mind that led-max-microamp is a required property in some cases, > so skipping it and using per-device properties does not solve the > problem of adjusting proper currents. What if each LED you set for > something which in total gives more than your imax? > You are right. From my point of view too, we must build our solutions from HW capabilities. In the current situation, AW200XX chips support global Imax value, so it's acceptable decision to use vendor prefix for global imax parameter, why not? ...
On 02/12/2022 19:53, Dmitry Rokosov wrote: > Hello Krzysztof, > > On Fri, Dec 02, 2022 at 05:41:37PM +0100, Krzysztof Kozlowski wrote: >> On 28/11/2022 18:43, Martin Kurbanov wrote: >>> Hi. Thank you for quick reply. >>> >>> On 25.11.2022 11:29, Krzysztof Kozlowski wrote: >>>>> + >>>>> + imax: >>>>> + maxItems: 1 >>>>> + description: >>>>> + Maximum supply current, see dt-bindings/leds/leds-aw200xx.h >>>> >>>> No. Use existing properties from common.yaml. This looks like >>>> led-max-microamp and it is per LED, not per entire device. >>> >>> The AW200XX LED chip does not support imax setup per led. >>> Imax is the global parameter over the all leds. I suppose, it's better >>> to add vendor prefix or take minimum from all subnodes? >>> How do you think? >> >> Have in mind that led-max-microamp is a required property in some cases, >> so skipping it and using per-device properties does not solve the >> problem of adjusting proper currents. What if each LED you set for >> something which in total gives more than your imax? >> > > You are right. From my point of view too, we must build our solutions from > HW capabilities. And there was no proposal to go around HW capabilities. We talk only about representation. > In the current situation, AW200XX chips support global > Imax value, so it's acceptable decision to use vendor prefix for global > imax parameter, why not? Jacek made his statement some time ago quite clear: https://lore.kernel.org/all/5785F17D.3010108@samsung.com/ "If you question the idea of having different maximum brightness per sub-LEDs controlled by the same device, then it means that you have objections to the entire idea of LED subsystem max_brightness property, whereas it has been broadly accepted and successfully used for years." Best regards, Krzysztof