On 12/02/2018 07:10, Viresh Kumar wrote: > On 09-02-18, 13:14, Daniel Lezcano wrote: >> Right. The semantic is unclear. The expected cooling-cells value is >> always 2 (the code ignore values greater than two and yell if it is less >> than 2). And the cooling-device binding tells there are two states. > > They are fixed to 2 as we don't need to use it differently for now. > But that's more about how Linux is using this stuff. The binding still > needs to provide a way to have more cells than just 2. > >> So the question is why do we need a cooling-cells as the information is >> pointless here (always 2) ? > > To show that the device is a "cooling-device" and I see that > consistent with everything else in DT, for example: interrupt-cells, > gpio-cells, clock-cells, reset-cells, dma-cells. The "*-cells" > properties is used widely to tell what the device can behave as, i.e. > a cooling-device in our case. Ah, yes. That's right. Well I don't know. If that is the way the other drivers are doing, I suppose we should keep it as it is. > Now we always use 2 parameters exactly is a different thing all > together :) > >> I see this field is artificially used to tell the cpufreq driver "please >> register me as a cooling device". This is inconsistent from my pov. > > But that's how its used for every other controller, what's different > here ? > >> Furthermore, the thermal-zone with the cooling device binds with the CPU >> phandle, not the cooling-cells. > > Yeah, because that's the device really. > >> Putting apart the device binding changes discussion for the moment. Why >> not register the cpufreq driver in all the cases and then drop > > s/cpufreq driver/cpufreq cooling driver/ ?? yes. >> cooling-cells ? So when the opps are present, its registers in the >> cpufreq->ready callback. > > How will someone tell if they don't need the cooling infrastructure ? > Specially for multiplatform thing. They don't define a cooling device in the DT ? -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
