On 30 November 2016 at 14:11, Javier Martinez Canillas <javier@xxxxxxxxxxxx> wrote: > Hello Matt, > > On Tue, Nov 29, 2016 at 10:20 PM, Matt Ranostay > <matt@ranostay.consulting> wrote: >> On Tue, Nov 29, 2016 at 9:13 AM, Javier Martinez Canillas > > [snip] > >> >> >>>> +- pwndn-gpio: contains a power down GPIO specifier. >>>> +- reset-gpio: contains a reset GPIO specifier. >>>> + >>> >>> I wonder if we really need a custom power sequence provider for just >>> this SDIO WiFI chip though. AFAICT the only missing piece in >>> mmc-pwrseq-simple is the power down GPIO property, so maybe >>> mmc-pwrseq-simple could be extended instead to have an optional >>> powerdown-gpios property and instead in the Marvell SD8787 DT binding >>> can be mentioned which mmc-pwrseq-simple properties are required for >>> the device. >>> >> >> The reason we didn't do that is we need delay between the two >> assertions/desertions of GPIOs. It wouldn't seems good practice to >> hack the pwrseq-simple for this... >> > > Yes, I noticed that. I wouldn't say that it would be a hack for the > pwrseq-simple since it already has a "post-power-on-delay-ms" DT > property, so AFAICT it would just be adding a "pre-power-on-delay-ms" > property for your use case. > > It would also be more consistent since it would support a delay for > pre and post power callbacks. It would also make you avoid hardcoding > the 300 msec wait, in case other device has a similar need but with a > different wait time. > > In summary, I think that devices having a power (or power down) and > enable GPIO, and needing to wait between the GPIO toggling are common. > So I would prefer to make pwrseq-simple usable for these instead of > adding device specific power sequence providers. But it's just my > opinion and not my call :-) This is a good idea. Please try out this approach. [...] Kind regards Uffe
