From: Peter Chen <hzpeterchen@gmail.com>
To: Joshua Clayton <stillcompiling@gmail.com>
Cc: Philipp Zabel <p.zabel@pengutronix.de>,
Peter Chen <peter.chen@nxp.com>,
mark.rutland@arm.com, devicetree@vger.kernel.org,
ulf.hansson@linaro.org, stephen.boyd@linaro.org,
oscar@naiandei.net, arnd@arndb.de, pawel.moll@arm.com,
linux-pm@vger.kernel.org, gregkh@linuxfoundation.org,
k.kozlowski@samsung.com, linux-usb@vger.kernel.org,
sre@kernel.org, robh+dt@kernel.org, mail@maciej.szmigiero.name,
broonie@kernel.org, stern@rowland.harvard.edu,
festevam@gmail.com, troy.kisky@boundarydevices.com,
shawnguo@kernel.org, s.hauer@pengutronix.de,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/6] binding-doc: power: pwrseq-generic: add binding doc for generic power sequence library
Date: Fri, 8 Jul 2016 10:39:13 +0800 [thread overview]
Message-ID: <20160708023913.GD27779@shlinux2> (raw)
In-Reply-To: <577EEB63.3020007@gmail.com>
On Thu, Jul 07, 2016 at 04:53:07PM -0700, Joshua Clayton wrote:
>
>
> On 07/07/2016 02:47 AM, Philipp Zabel wrote:
> > Am Donnerstag, den 07.07.2016, 17:14 +0800 schrieb Peter Chen:
> >> Add binding doc for generic power sequence library.
> >>
> >> Signed-off-by: Peter Chen <peter.chen@nxp.com>
> >> ---
> >> .../bindings/power/pwrseq/pwrseq-generic.txt | 56 ++++++++++++++++++++++
> >> 1 file changed, 56 insertions(+)
> >> create mode 100644 Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt
> >>
> >> diff --git a/Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt b/Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt
> >> new file mode 100644
> >> index 0000000..4b23834
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt
> >> @@ -0,0 +1,56 @@
> >> +The generic power sequence library
> >> +
> >> +Some hard-wired USB/MMC devices need to do power sequence to let the
> >> +device work normally, the typical power sequence like: enable USB
> >> +PHY clock, toggle reset pin, etc. But current Linux USB driver
> >> +lacks of such code to do it, it may cause some hard-wired USB devices
> >> +works abnormal or can't be recognized by controller at all. The
> >> +power sequence will be done before this device can be found at USB
> >> +bus.
> >> +
> >> +The power sequence properties is under the device node.
> >> +
> >> +Required properties:
> >> +- power-sequence: this device needs to do power sequence before enumeration
> >> +
> >> +Optional properties:
> >> +- clocks: the input clock for device.
> >> +- clock-name: must be "pwrseq-clk"
> > The "-clk" in the clock name is redundant.
> >
> >> +- pwrseq-reset-gpios: Should specify the GPIO for reset.
> >> +- pwrseq-reset-duration-us: the duration in microsecond for assert reset signal.
> > I understand you want to make it explicit that this GPIO is for the
> > pwrseq library, but are we really gaining anything over just calling
> > these reset-gpios and reset-duration-us?
> > The same applies to the clock name above.
> using reset-gpios makes sense to me too.
> The above "power-sequence" might then be better called "reset-on-init",
> But really, if a device has a reset gpio shouldn't the default behavior be to
> reset it on boot and when coming back from sleep?
> Is a special property even needed?
The power sequence does not include reset process only, it may include clock
and power as well.
--
Best Regards,
Peter Chen
next prev parent reply other threads:[~2016-07-08 2:39 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-07 9:14 [PATCH 0/6] power: add power sequence library Peter Chen
[not found] ` <1467882892-27589-1-git-send-email-peter.chen-3arQi8VN3Tc@public.gmane.org>
2016-07-07 9:14 ` [PATCH 1/6] binding-doc: power: pwrseq-generic: add binding doc for generic " Peter Chen
[not found] ` <1467882892-27589-2-git-send-email-peter.chen-3arQi8VN3Tc@public.gmane.org>
2016-07-07 9:47 ` Philipp Zabel
[not found] ` <1467884834.4236.36.camel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2016-07-07 23:53 ` Joshua Clayton
2016-07-08 2:39 ` Peter Chen [this message]
2016-07-08 2:37 ` Peter Chen
2016-07-07 9:14 ` [PATCH 2/6] power: add " Peter Chen
2016-07-07 9:14 ` [PATCH 3/6] binding-doc: usb: usb-device: add optional properties for power sequence Peter Chen
2016-07-07 9:14 ` [PATCH 4/6] usb: core: add power sequence handling for USB devices Peter Chen
2016-07-07 9:14 ` [PATCH 5/6] usb: chipidea: host: let the hcd know's parent device node Peter Chen
2016-07-07 22:56 ` Stephen Boyd
2016-07-08 1:54 ` Peter Chen
2016-07-07 9:14 ` [PATCH 6/6] ARM: dts: imx6qdl-udoo.dtsi: fix onboard USB HUB property Peter Chen
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