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?
Fenglin
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base-commit: ca66b10a11da3c445c9c0ca1184f549bbe9061f2
change-id: 20240507-qcom_flash_thermal_derating-260b1f3c757c
Best regards,
