Thu, Oct 05, 2023 at 11:58:38AM +0900, AKASHI Takahiro kirjoitti: > This is a revised version of my previous RFC[1]. Although I modified > the commits to make them look SCMI-independent, they are still posted > as RFC because I have never tested them on real hardware. > > (background) > I'm currently working on implementing SCMI pinctrl/gpio drivers > on U-Boot[2]. Although the pinctrl driver for the kernel[3] was submitted > by EPAM, it doesn't contain the gpio driver and I believe that we should > discuss a couple of points on the kernel side to finalize my design for > U-Boot. > > So this RFC is intended for reviews, especially to raise some issues. > > 1) how to obtain a value on an input pin > All the existing gpio drivers are set to obtain a value on an input > pin by accessing the hardware directly. In SCMI case, however, this is > just impossible in its nature and must be supported via a protocol > using "Input-value" configuration type. (See the spec[4], table-23.) > > The current pinconf framework is missing the feature (the pinconf > parameter and a helper function). See patch#1, #2 and #3. > > Please note that there is an issue around the pin configuration in > EPAM's current pinctrl driver as I commented[5]. > > 2) DT bindings > I would like to propose a generic binding for pinctrl based gpio driver. > This allows a "consumer" driver to handle gpio pins like as other > normal gpio controllers support. (patch#5) > > 3) generic GPIO driver > Based on (2), I tried to prototype a generic driver in patch#4. > Thanks to a set of existing pinctrl_gpio helper functions, except (1), > It seems that the driver can be implemented not relying on pin controller > specific code, at least for SCMI pinctrl. > > I will appreciate any comments. Any comment here: I'm listed as a designated reviewer of GPIO patches, why am I not Cc'ed on this? I definitely have some comments against the code (no DT, though). Please, use (up-to-date) MAINTAINERS in your v3. -- With Best Regards, Andy Shevchenko
