On 04.08.2018 16:01, Dmitry Osipenko wrote: > On Friday, 3 August 2018 20:24:56 MSK Linus Walleij wrote: >> On Thu, Aug 2, 2018 at 1:31 PM Stefan Agner <stefan@xxxxxxxx> wrote: >> > A while back at least using those init lists were not well received even >> > for GPIO/pinctrl drivers: >> > >> > https://lore.kernel.org/lkml/CACRpkdYk0zW12qNXgOstTLmdVDYacu0Un+8quTN+J_az >> > Oic7AA@xxxxxxxxxxxxxx/T/#mf0596982324a6489b5537b0531ac5aed60a316ba >> You shouldn't listen too much to that guy he's not trustworthy. ;-) >> >> > I still think we should make an exception for GPIO/pinctrl and use >> > earlier initcalls. Platform GPIO/pinctrl drivers provide basic >> > infrastructure often used by many other drivers, we want to have them >> > loaded early. It avoids unnecessary EPROBE_DEFER and hence probably even >> > boots faster. >> >> When we have the pin control and GPIO at different initlevels it makes me >> uneasy because I feel we have implicit init dependencies that seem more >> than a little fragile. > > Yes, it is not very good. > Btw, just noticed this now: GPIO driver -> arch_initcall pinctrl driver -> subsys_initcall And arch is before subsys. So we initialize GPIO driver first? But isn't pinctrl required for the GPIO range? Afaik, especially with gpio-ranges enabled, the GPIO probe will return -EPROBE_DEFER (I think due to pinctrl_get_device_gpio_range). So my intuition would be that it should be the other way around... -- Stefan >> My recent thinking has involved the component method used in DRM drivers >> such as drivers/gpu/drm/vc4/vc4_drv.c where a few different component >> subdrivers are linked together at bind time (not probe time!) into a master >> component. >> Rob was no big fan of this but the DRM people like it and I was thinking to >> make a try at it. >> >> This way we could at least probe and bind the pin control and GPIO drivers >> at the *same* initlevel and express the dependencies between them >> somewhat. > > Sounds interesting, maybe you could help to convert Tegra drivers to a such > method and others will follow afterwards. > >> > This should definitely go in, at least as a stop gap solution. >> >> Agreed. (And patch applied.) > > The best solution will be to fix the deferred probing, it's awkward that it > could break suspend-resume order. Hopefully somebody with a good knowledge of > driver/base will manage to fix it eventually. -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
