On 24/03/2025 05:21, Peng Fan wrote: > On Tue, Mar 18, 2025 at 02:48:05PM +0100, Krzysztof Kozlowski wrote: >> On 18/03/2025 13:38, Peng Fan wrote: >>>> Also the commit message doesn't tell anything about the existing DTS >>>> files. >>>> Do we have this device described in any in the kernel? Do we have any >>>> googled examples? Why I'm asking because often the issue is the >>>> incorrect setting of the polarity, which needs to be carefully checked, >>>> esp. for the voltage regulators case. >>> >>> >>> Under arch/arm/boot/dts/samsung/, a few dtsi files have the property >>> with results from output of >>> `grep "s5m8767" ./arch/arm/boot/dts/samsung/ -rn | grep gpios` >>> >>> Exynos5250-spring.dts uses GPIO_ACTIVE_LOW. >>> Others use GPIO_ACTIVE_HIGH. >>> >> These are old devices and not many people are actually providing tests, >> so you need to preserve existing ABI. IOW, if previously GPIO flags were >> ignored, meaning "1" is ACTIVE_HIGH, then you must preserve this behavior. > > Per google, > Manual Reset function is for Hardware reset in the Active mode. Why are you mentioning the reset functions? Which properties are these? > If MR1B and MR2B is kept low during the VLDO3 is active state, the > system makes all internal presetting registers as default in the > active mode (automatic power on sequence). If this hardware reset > function is not required, connect MRB pin to high. > > So the reset is ACTIVE LOW if my understanding is correct. > > To keep DTS unchanged, we need update polarity in gpiolib to > force GPIO_ACTIVE_LOW. How are you going to achieve it if one DTS has LOW and other has HIGH? > > please see whether this is ok for you. I don't understand how this is related to the issue I raised. Best regards, Krzysztof
