Messages in this thread | | | Subject | Re: [PATCH v2 06/12] mmc: pwrseq: add support for power-on sequencing through DT | From | Javier Martinez Canillas <> | Date | Fri, 8 Jan 2016 09:22:31 -0300 |
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Hello Caesar,
On 01/07/2016 05:25 AM, Caesar Wang wrote: > This patch enables support for power-on sequencing of SDIO > peripherals through DT. >
I think the subject line and this first paragraph are misleading since the simple power sequence provider already supports power-on sequencing.
This patch does not add or enable support but extends the current support to also enable a regulator as a part of the SDIO chip power on sequencing.
> In general, it's quite common that wifi modules and other similar > peripherals have several signals in addition to the SDIO interface that > needs wiggling before the module will power on. > > 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?
> 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.
> Anyway, we can add this patch to supprt the power-on sequencing for
s/supprt/support
> sdio. > > Signed-off-by: Caesar Wang <wxt@rock-chips.com> >
Best regards, -- Javier Martinez Canillas Open Source Group Samsung Research America
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