From: Peter Chen <peter.chen-KZfg59tc24xl57MIdRCFDg@public.gmane.org> To: Philipp Zabel <p.zabel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> Cc: shawnguo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org, stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, pawel.moll-5wv7dgnIgG8@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, festevam-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, patryk-6+2coLtxvIyvnle+31E0rA@public.gmane.org, linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, balbi-l0cyMroinI0@public.gmane.org Subject: Re: [PATCH 2/3] doc: dt-binding: generic onboard USB HUB Date: Wed, 9 Dec 2015 16:09:34 +0800 [thread overview] Message-ID: <20151209080933.GA941@shlinux2> (raw) In-Reply-To: <1449568249.3691.15.camel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> On Tue, Dec 08, 2015 at 10:50:49AM +0100, Philipp Zabel wrote: > Hi Peter, > > Am Dienstag, den 08.12.2015, 09:37 +0800 schrieb Peter Chen: > > Add dt-binding documentation for generic onboard USB HUB. > > > > Signed-off-by: Peter Chen <peter.chen-KZfg59tc24xl57MIdRCFDg@public.gmane.org> > > --- > > .../bindings/usb/generic-onboard-hub.txt | 28 ++++++++++++++++++++++ > > 1 file changed, 28 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/usb/generic-onboard-hub.txt > > > > diff --git a/Documentation/devicetree/bindings/usb/generic-onboard-hub.txt b/Documentation/devicetree/bindings/usb/generic-onboard-hub.txt > > new file mode 100644 > > index 0000000..ea92205 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/usb/generic-onboard-hub.txt > > @@ -0,0 +1,28 @@ > > +Generic Onboard USB HUB > >+ > > +Required properties: > > +- compatible: should be "generic-onboard-hub" > > This something we don't have to define ad-hoc. The hub hangs off an USB > controller, right? The "Open Firmware recommended practice: USB" > document already describes how to represent USB devices in a generic > manner: > http://www.firmware.org/1275/bindings/usb/usb-1_0.ps > > Is there a reason not to reuse this? > > The usb hub node would be a child of the usb controller node, and it > could use > compatible = "usb,class9"; /* bDeviceClass 9 (Hub) */ > Before writing this driver, I did consider how to let the USB core handle device tree, but without good solution. The controller (platform) driver should not handle specific USB device described at device tree, since we want this handling to be generic. And the USB device may not be recognized by controller without handling its properties, like clock, reset pins. With your suggestion, the dts likes below usbh1: usb@02184000 { compatible = "fsl,imx6q-usb", "fsl,imx27-usb"; reg = <0x02184000 0x200>; interrupts = <0 43 IRQ_TYPE_LEVEL_HIGH>; clocks = <&clks IMX6QDL_CLK_USBOH3>; usb_hub@1 { compatible = "usb,class9" clocks = <&clks USB_HUB_CLK>; .... }; }; I don't know how to handle above at USB bus, if you have any suggestions, give me some tips please. > > > +Optional properties: > > +- clocks: the input clock for HUB. > > + > > +- clock-names: Should be "external_clk" > > Is clock-names necessary for a single clock? > > > +- hub-reset-gpios: Should specify the GPIO for reset. > > I'd prefer that to be just "reset-gpios", it is the only reset property > in the hub node after all. And use the GPIO_ACTIVE_HIGH/LOW flags to > indicate polarity. I will change to "clk" and "reset-gpios". > > > +- hub-reset-active-high: the active reset signal is high, if this property is > > + not set, the active reset signal is low. > > Then this could be dropped. > > > +- hub-reset-duration-us: the duration for assert reset signal, the time unit > > + is microsecond. > > And consequently, this could just be called "reset-duration-us". > It might make sense to define the same for other reset GPIOs, too. > The Freescale FEC, for example, has "phy-reset-duration" (in ms) > already. > Agree. By the way: Felipe suggest using generic reset gpio driver to handle above, I find you have written similar things before [1], why it can't be accepted? [1]http://comments.gmane.org/gmane.linux.ports.arm.kernel/255129 -- Best Regards, Peter Chen -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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From: peter.chen@freescale.com (Peter Chen) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 2/3] doc: dt-binding: generic onboard USB HUB Date: Wed, 9 Dec 2015 16:09:34 +0800 [thread overview] Message-ID: <20151209080933.GA941@shlinux2> (raw) In-Reply-To: <1449568249.3691.15.camel@pengutronix.de> On Tue, Dec 08, 2015 at 10:50:49AM +0100, Philipp Zabel wrote: > Hi Peter, > > Am Dienstag, den 08.12.2015, 09:37 +0800 schrieb Peter Chen: > > Add dt-binding documentation for generic onboard USB HUB. > > > > Signed-off-by: Peter Chen <peter.chen@freescale.com> > > --- > > .../bindings/usb/generic-onboard-hub.txt | 28 ++++++++++++++++++++++ > > 1 file changed, 28 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/usb/generic-onboard-hub.txt > > > > diff --git a/Documentation/devicetree/bindings/usb/generic-onboard-hub.txt b/Documentation/devicetree/bindings/usb/generic-onboard-hub.txt > > new file mode 100644 > > index 0000000..ea92205 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/usb/generic-onboard-hub.txt > > @@ -0,0 +1,28 @@ > > +Generic Onboard USB HUB > >+ > > +Required properties: > > +- compatible: should be "generic-onboard-hub" > > This something we don't have to define ad-hoc. The hub hangs off an USB > controller, right? The "Open Firmware recommended practice: USB" > document already describes how to represent USB devices in a generic > manner: > http://www.firmware.org/1275/bindings/usb/usb-1_0.ps > > Is there a reason not to reuse this? > > The usb hub node would be a child of the usb controller node, and it > could use > compatible = "usb,class9"; /* bDeviceClass 9 (Hub) */ > Before writing this driver, I did consider how to let the USB core handle device tree, but without good solution. The controller (platform) driver should not handle specific USB device described at device tree, since we want this handling to be generic. And the USB device may not be recognized by controller without handling its properties, like clock, reset pins. With your suggestion, the dts likes below usbh1: usb at 02184000 { compatible = "fsl,imx6q-usb", "fsl,imx27-usb"; reg = <0x02184000 0x200>; interrupts = <0 43 IRQ_TYPE_LEVEL_HIGH>; clocks = <&clks IMX6QDL_CLK_USBOH3>; usb_hub at 1 { compatible = "usb,class9" clocks = <&clks USB_HUB_CLK>; .... }; }; I don't know how to handle above at USB bus, if you have any suggestions, give me some tips please. > > > +Optional properties: > > +- clocks: the input clock for HUB. > > + > > +- clock-names: Should be "external_clk" > > Is clock-names necessary for a single clock? > > > +- hub-reset-gpios: Should specify the GPIO for reset. > > I'd prefer that to be just "reset-gpios", it is the only reset property > in the hub node after all. And use the GPIO_ACTIVE_HIGH/LOW flags to > indicate polarity. I will change to "clk" and "reset-gpios". > > > +- hub-reset-active-high: the active reset signal is high, if this property is > > + not set, the active reset signal is low. > > Then this could be dropped. > > > +- hub-reset-duration-us: the duration for assert reset signal, the time unit > > + is microsecond. > > And consequently, this could just be called "reset-duration-us". > It might make sense to define the same for other reset GPIOs, too. > The Freescale FEC, for example, has "phy-reset-duration" (in ms) > already. > Agree. By the way: Felipe suggest using generic reset gpio driver to handle above, I find you have written similar things before [1], why it can't be accepted? [1]http://comments.gmane.org/gmane.linux.ports.arm.kernel/255129 -- Best Regards, Peter Chen
next prev parent reply other threads:[~2015-12-09 8:09 UTC|newest] Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-12-08 1:37 [PATCH 0/3] USB: add generic onboard USB HUB driver Peter Chen 2015-12-08 1:37 ` Peter Chen [not found] ` <1449538670-7954-1-git-send-email-peter.chen-KZfg59tc24xl57MIdRCFDg@public.gmane.org> 2015-12-08 1:37 ` [PATCH 1/3] usb: misc: generic_onboard_hub: " Peter Chen 2015-12-08 1:37 ` Peter Chen [not found] ` <1449538670-7954-2-git-send-email-peter.chen-KZfg59tc24xl57MIdRCFDg@public.gmane.org> 2015-12-08 2:59 ` Felipe Balbi 2015-12-08 2:59 ` Felipe Balbi [not found] ` <87poyhmyrc.fsf-HgARHv6XitJaoMGHk7MhZQC/G2K4zDHf@public.gmane.org> 2015-12-08 9:18 ` Peter Chen 2015-12-08 9:18 ` Peter Chen 2015-12-08 13:55 ` Felipe Balbi 2015-12-08 13:55 ` Felipe Balbi [not found] ` <87k2opm4ee.fsf-HgARHv6XitJaoMGHk7MhZQC/G2K4zDHf@public.gmane.org> 2015-12-09 8:45 ` Peter Chen 2015-12-09 8:45 ` Peter Chen 2015-12-08 3:16 ` kbuild test robot 2015-12-08 3:16 ` kbuild test robot [not found] ` <201512081150.hIfZ22cp%fengguang.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> 2015-12-08 9:36 ` Peter Chen 2015-12-08 9:36 ` Peter Chen 2015-12-08 6:19 ` Sascha Hauer 2015-12-08 6:19 ` Sascha Hauer [not found] ` <20151208061905.GM11966-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> 2015-12-08 9:26 ` Peter Chen 2015-12-08 9:26 ` Peter Chen 2015-12-08 9:44 ` Sascha Hauer 2015-12-08 9:44 ` Sascha Hauer [not found] ` <20151208094402.GP11966-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> 2015-12-09 8:23 ` Peter Chen 2015-12-09 8:23 ` Peter Chen 2015-12-08 9:48 ` Arnd Bergmann 2015-12-08 9:48 ` Arnd Bergmann 2015-12-09 8:14 ` Peter Chen 2015-12-09 8:14 ` Peter Chen 2015-12-08 15:36 ` Mathieu Poirier 2015-12-08 15:36 ` Mathieu Poirier [not found] ` <CANLsYkwfLSQKEw1a-Y_dguu-yutnTeQv73cMxPFooMjzTv4n1A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2015-12-09 8:50 ` Peter Chen 2015-12-09 8:50 ` Peter Chen 2015-12-09 8:57 ` Lucas Stach 2015-12-09 8:57 ` Lucas Stach [not found] ` <1449651460.3118.22.camel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> 2015-12-09 9:00 ` Peter Chen 2015-12-09 9:00 ` Peter Chen 2015-12-09 9:13 ` Lucas Stach 2015-12-09 9:13 ` Lucas Stach [not found] ` <1449652391.3118.24.camel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> 2015-12-09 9:29 ` Peter Chen 2015-12-09 9:29 ` Peter Chen 2015-12-09 9:10 ` Arnd Bergmann 2015-12-09 9:10 ` Arnd Bergmann 2015-12-09 9:08 ` Peter Chen 2015-12-09 9:08 ` Peter Chen 2015-12-08 1:37 ` [PATCH 2/3] doc: dt-binding: generic onboard USB HUB Peter Chen 2015-12-08 1:37 ` Peter Chen [not found] ` <1449538670-7954-3-git-send-email-peter.chen-KZfg59tc24xl57MIdRCFDg@public.gmane.org> 2015-12-08 2:30 ` Fabio Estevam 2015-12-08 2:30 ` Fabio Estevam [not found] ` <CAOMZO5DfBW3hxp5odbefLQCmkocPy=LypVW5HJWzDkF__WD_sg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2015-12-08 9:20 ` Peter Chen 2015-12-08 9:20 ` Peter Chen 2015-12-08 9:45 ` Arnd Bergmann 2015-12-08 9:45 ` Arnd Bergmann 2015-12-08 9:50 ` Philipp Zabel 2015-12-08 9:50 ` Philipp Zabel [not found] ` <1449568249.3691.15.camel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> 2015-12-08 9:58 ` Arnd Bergmann 2015-12-08 9:58 ` Arnd Bergmann 2015-12-09 3:24 ` Rob Herring 2015-12-09 3:24 ` Rob Herring 2015-12-09 8:12 ` Peter Chen 2015-12-09 8:12 ` Peter Chen 2015-12-09 8:55 ` Arnd Bergmann 2015-12-09 8:55 ` Arnd Bergmann 2015-12-15 20:21 ` Ulf Hansson 2015-12-15 20:21 ` Ulf Hansson 2015-12-16 2:46 ` Peter Chen 2015-12-16 2:46 ` Peter Chen 2015-12-09 8:09 ` Peter Chen [this message] 2015-12-09 8:09 ` Peter Chen 2015-12-08 1:37 ` [PATCH 3/3] ARM: dts: imx6qdl-udoo.dtsi: fix onboard USB HUB property Peter Chen 2015-12-08 1:37 ` Peter Chen
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