On Mon Jul 8, 2024 at 4:59 AM CEST, Fenglin Wu wrote: > > > On 7/5/2024 10:23 PM, Luca Weiss wrote: > > On Fri Jul 5, 2024 at 9:55 AM CEST, Fenglin Wu via B4 Relay wrote: > >> From: Fenglin Wu <quic_fenglinw@xxxxxxxxxxx> > >> > >> The flash module has status bits to indicate different thermal > >> conditions which are called as OTSTx. For each OTSTx status, > >> there is a recommended total flash current for all channels to > >> prevent the flash module entering into higher thermal level. > >> For example, the total flash current should be limited to 1000mA/500mA > >> respectively when the HW reaches the OTST1/OTST2 thermal level. > > > > Hi Fenglin, > > > > Only semi-related to this patch, but I wanted to ask. > > > > Since most phones with a flash also have a thermistor for the flash led, > > is there any plan to add support to be able to declare the flash led to > > be a "cooling-device" for the relevant thermal zone? That way from a > > Linux thermal API standpoint when the zone gets too hot that it can ask > > the driver to throttle the brightness or turn the LED off completely. > > > > Right now the only action the kernel can take is with type 'critical' to > > just kill the entire system to mitigate the thermal situation. > > > > Regards > > Luca > > > > Hi Luca, > > This change provides the ability to throttle flash current based on the > thermal status sensed by the temperature sensor inside the flash module > HW , it doesn't need to register anything in Linux thermal framework. > > For the case that you mentioned, when an external thermistor is > installed nearby the flash LED component and normally the ADC_TM driver > registers a thermal_zone device with it, I agree that having the flash > LED driver providing a thermal_cooling device so that any cooling > mapping policy could be defined between the thermal sensor and the > cooling device would be a good option for better system level thermal > control. I would assume that this could be added in flash LED framework > driver instead of the client drivers considering this should be a common > request because of the big thermal dissipation of flash LED? Right, the LED core getting the ability to register a cooling device would probably be a reasonable solution, that way any flash LED driver would be cooling-ready. Apart from decreasing brightness - or worst case turning the LED off completely I can't think of many other actions that could be taken anyways? Pavel, Lee, your opinion? Regards Luca > > Fenglin > >> > >> --- > >> base-commit: ca66b10a11da3c445c9c0ca1184f549bbe9061f2 > >> change-id: 20240507-qcom_flash_thermal_derating-260b1f3c757c > >> > >> Best regards, > >
