From: Heiko Stuebner <heiko@sntech.de>
To: Javier Martinez Canillas <javier@osg.samsung.com>
Cc: Caesar Wang <wxt@rock-chips.com>,
Ulf Hansson <ulf.hansson@linaro.org>,
linux-rockchip@lists.infradead.org, leecam@google.com,
leozwang@google.com, keescook@google.com,
Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
Alexandre Courbot <acourbot@nvidia.com>,
NeilBrown <neil@brown.name>
Subject: Re: [PATCH v2 06/12] mmc: pwrseq: add support for power-on sequencing through DT
Date: Sat, 09 Jan 2016 03:42:03 +0100 [thread overview]
Message-ID: <6960259.dpUH8KWsNS@phil> (raw)
In-Reply-To: <568FAA07.1010509@osg.samsung.com>
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.
> > 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).
Heiko
next prev parent reply other threads:[~2016-01-09 2:42 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-07 8:25 [PATCH v2 00/12] Add the family patches to support for kylin board Caesar Wang
2016-01-07 8:25 ` [PATCH v2 06/12] mmc: pwrseq: add support for power-on sequencing through DT Caesar Wang
2016-01-08 12:22 ` Javier Martinez Canillas
2016-01-09 2:42 ` Heiko Stuebner [this message]
2016-01-11 16:02 ` Javier Martinez Canillas
[not found] ` <5693D226.2000307-JPH+aEBZ4P+UEJcrhfAQsw@public.gmane.org>
2016-01-15 9:15 ` Caesar Wang
2016-01-07 10:44 ` [PATCH v2 00/12] Add the family patches to support for kylin board Heiko Stuebner
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