From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Chen Subject: Re: [PATCH 1/6] binding-doc: power: pwrseq-generic: add binding doc for generic power sequence library Date: Fri, 8 Jul 2016 10:37:17 +0800 Message-ID: <20160708023717.GC27779@shlinux2> References: <1467882892-27589-1-git-send-email-peter.chen@nxp.com> <1467882892-27589-2-git-send-email-peter.chen@nxp.com> <1467884834.4236.36.camel@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1467884834.4236.36.camel@pengutronix.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Philipp Zabel Cc: mark.rutland@arm.com, Peter Chen , ulf.hansson@linaro.org, stephen.boyd@linaro.org, k.kozlowski@samsung.com, festevam@gmail.com, pawel.moll@arm.com, stern@rowland.harvard.edu, devicetree@vger.kernel.org, mail@maciej.szmigiero.name, arnd@arndb.de, linux-pm@vger.kernel.org, s.hauer@pengutronix.de, troy.kisky@boundarydevices.com, robh+dt@kernel.org, linux-arm-kernel@lists.infradead.org, oscar@naiandei.net, gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, sre@kernel.org, broonie@kernel.org, shawnguo@kernel.org List-Id: devicetree@vger.kernel.org On Thu, Jul 07, 2016 at 11:47:14AM +0200, 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 > > --- > > .../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. > > > +Below is the example of USB power sequence properties on USB device > > +nodes which have two level USB hubs. > > + > > +&usbotg1 { > > + vbus-supply = <®_usb_otg1_vbus>; > > + pinctrl-names = "default"; > > + pinctrl-0 = <&pinctrl_usb_otg1_id>; > > + status = "okay"; > > + > > + #address-cells = <1>; > > + #size-cells = <0>; > > + hub: genesys@1 { > > + compatible = "usb5e3,608"; > > + reg = <1>; > > + > > + power-sequence; > > + clocks = <&clks IMX6SX_CLK_CKO>; > > + clock-names = "pwrseq-clk"; > > + pwrseq-reset-gpios = <&gpio4 5 GPIO_ACTIVE_LOW>; /* hub reset pin */ > > + pwrseq-reset-duration-us = <10>; > > + > > + #address-cells = <1>; > > + #size-cells = <0>; > > + ethernet: asix@1 { > > + compatible = "usbb95,1708"; > > + reg = <1>; > > + > > + power-sequence; > > + clocks = <&clks IMX6SX_CLK_IPG>; > > + clock-names = "pwrseq-clk"; > > + pwrseq-reset-gpios = <&gpio4 6 GPIO_ACTIVE_LOW>; /* ethernet_rst */ > > + pwrseq-reset-duration-us = <15>; > > + }; > > This looks weird. The hub and ethernet chips don't have "pwrseq" clock > and reset input pins. I'd remove the clock-names and pwrseq- reset > prefix. > I agree with you, and will keep property name like last version [1]. -- Best Regards, Peter Chen