From: Peter Chen <hzpeterchen@gmail.com>
To: Stephen Boyd <stephen.boyd@linaro.org>
Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
Ulf Hansson <ulf.hansson@linaro.org>,
Sebastian Reichel <sre@kernel.org>,
Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>,
David Woodhouse <dwmw2@infradead.org>,
Javier Martinez Canillas <javier@osg.samsung.com>,
linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org,
linux-pm@vger.kernel.org, Alan Stern <stern@rowland.harvard.edu>,
linux-usb@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
Pawel Moll <pawel.moll@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Ian Campbell <ijc+devicetree@hellion.org.uk>,
Kumar Gala <galak@codeaurora.org>, Kukjin Kim <kgene@kernel.org>,
devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-samsung-soc@vger.kernel.org
Subject: Re: [PATCH v3 09/12] EXAMPLE CODE: usb: port: Parse pwrseq phandle from Device Tree
Date: Thu, 2 Jun 2016 09:24:19 +0800 [thread overview]
Message-ID: <20160602012419.GA7953@shlinux2> (raw)
In-Reply-To: <146480499491.3686.4996610748316511864@sboyd-linaro>
On Wed, Jun 01, 2016 at 11:16:34AM -0700, Stephen Boyd wrote:
> Quoting Peter Chen (2016-06-01 05:05:20)
> > On Wed, Jun 01, 2016 at 01:57:23AM -0700, Stephen Boyd wrote:
> > > Quoting Krzysztof Kozlowski (2016-06-01 01:02:18)
> > > > Parse usb-pwrseq property from Device Tree to get the phandle to pwrseq
> > > > device. The pwrseq device will be used by USB hub to cycle the power
> > > > before activating ports.
> > > >
> > > > Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
> > >
> > > Drive by review comment.
> > >
> > > I was hoping this would help me with a problem I'm having where I have a
> > > hub (smsc4604) that needs to be taken out of reset before my HSIC
> > > controller sends a USB reset to it, but it seems this is more about
> > > doing some sort of power on sequence after enumeration?
> > >
> >
> > No, you may need to do reset before enumeration, the general purpose of
> > reset is eliminate unstable hardware state, and let the controller find
> > the device.
> >
> > Try to do it at bootloader to see if it works for you.
> >
>
> Sorry the bootloader doesn't do this so that doesn't work for me.
I mean try to see if the HUB can work if you reset it at bootloader.
If it works, it means you need to do reset before enumeration, and you
don't need to do anything after enumeration.
--
Best Regards,
Peter Chen
next prev parent reply other threads:[~2016-06-02 1:29 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-01 8:02 [PATCH v3 00/12] usb/mmc/power: Generic power sequence (and fix USB/LAN when TFTP booting) Krzysztof Kozlowski
2016-06-01 8:02 ` [PATCH v3 01/12] power/mmc: Move pwrseq drivers to power/pwrseq Krzysztof Kozlowski
2016-06-01 8:02 ` [PATCH v3 02/12] MAINTAINERS: Retain Ulf Hansson as the same maintainer of pwrseq Krzysztof Kozlowski
2016-06-01 8:02 ` [PATCH v3 03/12] power: pwrseq: Enable COMPILE_TEST for drivers Krzysztof Kozlowski
2016-06-01 8:02 ` [PATCH v3 04/12] power: pwrseq: Remove mmc prefix from mmc_pwrseq Krzysztof Kozlowski
2016-06-01 8:02 ` [PATCH v3 05/12] power: pwrseq: Generalize mmc_pwrseq operations by removing mmc prefix Krzysztof Kozlowski
2016-06-01 8:02 ` [PATCH v3 06/12] power: pwrseq: simple: Add support for regulator and generic property Krzysztof Kozlowski
2016-06-03 2:02 ` Rob Herring
2016-06-03 12:35 ` Krzysztof Kozlowski
2016-06-06 3:22 ` Peter Chen
2016-06-07 9:29 ` Krzysztof Kozlowski
2016-06-08 19:03 ` Rob Herring
2016-06-09 2:34 ` Chen-Yu Tsai
2016-06-09 5:11 ` Krzysztof Kozlowski
2016-06-01 8:02 ` [PATCH v3 07/12] power: pwrseq: Add support for USB hubs with external power Krzysztof Kozlowski
2016-06-01 8:02 ` [PATCH v3 08/12] usb: hub: Handle deferred probe Krzysztof Kozlowski
2016-06-01 8:02 ` [PATCH v3 09/12] EXAMPLE CODE: usb: port: Parse pwrseq phandle from Device Tree Krzysztof Kozlowski
2016-06-01 8:57 ` Stephen Boyd
2016-06-01 9:06 ` Krzysztof Kozlowski
2016-06-01 12:05 ` Peter Chen
2016-06-01 18:16 ` Stephen Boyd
2016-06-02 1:24 ` Peter Chen [this message]
2016-06-01 8:02 ` [PATCH v3 10/12] EXAMPLE CODE: usb: hub: Power sequence the ports on activation Krzysztof Kozlowski
2016-06-01 8:02 ` [PATCH v3 11/12] ARM: dts: exynos: Switch the buck8 to GPIO mode on Odroid U3 Krzysztof Kozlowski
2016-06-01 8:02 ` [PATCH v3 12/12] ARM: dts: exynos: Fix LAN and HUB after bootloader initialization " Krzysztof Kozlowski
2016-06-01 11:59 ` Peter Chen
2016-06-02 7:26 ` Krzysztof Kozlowski
2016-06-02 7:58 ` Peter Chen
2016-06-06 20:43 ` [PATCH v3 00/12] usb/mmc/power: Generic power sequence (and fix USB/LAN when TFTP booting) Heiko Stübner
2016-06-07 6:03 ` Krzysztof Kozlowski
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