Hello Heiko, On 01/08/2016 11:42 PM, Heiko Stuebner wrote: > Am Freitag, 8. Januar 2016, 09:22:31 schrieb Javier Martinez Canillas: >>> For example: >>> we need enable wifi module power to via the WL_REG_ON >>> pin, we need enable it as the regulator if this pin is connected to >>> the gpio of cpu. >> >> This part confuses me, so does your chip have an actual regulator that >> needs to be enabled or is just a fake regulator whose gpio property is >> used not to enable the regulator but to toggle the WL_REG_ON pin of >> the WiFi chip? > > another option would be to use the reset-gpio-handles. rk3288-veyron and I > think some Exynos as well use it that way. > Yes I know, my point was that the reset-gpios property should be used instead of a fake regulator if what's needed is to toggle a chip pin. > >>> Maybe, someone will say that can pull up/down from dts. >>> Unfortunately some SoCs can't support pinctrl pull up/down in >>> internal. >> >> Can you please elaborate on this? AFAIU this limitation is the reason >> why you went with the regulator approach so I think it deserve a more >> deep explanation. > > On the rk3036 each pin has an individual unchangable pull direction. So it's > either no bias or pulling in the predefined direction (the pin_default bias > option). > I think each change has to be justified on its own so I would say that having a regulator enabled as a part of a SDIO chip's power sequencing is something needed for many platforms, and that this provider should be extended to support that (something like commit msg in patch 05/12). And then in the kylin DTS change (patch 08/12), I would explain why a chained regulators approach is used/needed instead of the reset-gpios due any platform limitations. > > Heiko > Best regards, -- Javier Martinez Canillas Open Source Group Samsung Research America -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
