On Tue Jan 14, 2025 at 3:33 PM CET, Linus Walleij wrote: > On Mon, Jan 13, 2025 at 1:43 PM Mathieu Dubois-Briand > My most generic feedback is if you have looked at using > select GPIO_REGMAP for this driver? > > The regmap utility library is very helpful, look how other driver > selecting GPIO_REGMAP gets default implementations > from the library just git grep GPIO_REGMAP drivers/gpio/ > I tried to switch to GPIO_REGMAP and I really like it overall, as it does simplify a lot the code. However, I identified two features that I was not able to port so far: the request()/free() callbacks and the interrupts. So for the request()/free() callbacks, I cannot add them anymore, as they are set on the gpio_chip structure, and this structure is hidden behind the gpio_regmap structure. I could easily modify the gpio_regmap_config structure and gpio_regmap_register() to allow to provide these callbacks, but is this acceptable? Or should I switch to a different way to prevent concurrent use of the same pin? I saw you mentioned the possibility of defining pin control. On the IRQ side, before switching to GPIO_REGMAP, I was able to define the IRQ configuration using the irq member of the gpio_chip structure. This does create the IRQ domain for me in a quite straightforward way. Again, I will not be able to do that anymore, as the gpio_chip structure is hidden. I saw I can specify my own irq_domain in gpio_regmap_config, so that would be a way, but I was wondering if there is any way to have something as easy as previously. I had a quick look at existing drivers using GPIO_REGMAP and providing IRQ support: I believe they are all using REGMAP_IRQ. And I believe I cannot use REGMAP_IRQ here, as if I understood correctly, I would need to have a register telling me exactly on which GPIO I have a pending interrupt and I don't have such a thing: all I know is there was an interrupt related to the GPIOs, and then I have to compare each GPIO with the previous known state to know which pin is affected. Do you have any thought about this? Best regards, Mathieu -- Mathieu Dubois-Briand, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
