From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kishon Vijay Abraham I Subject: Re: [PATCH v3] phy: Renesas R-Car Gen2 PHY driver Date: Fri, 23 May 2014 15:55:32 +0530 Message-ID: <537F221C.10700@ti.com> References: <201404120415.43761.sergei.shtylyov@cogentembedded.com> <534B77E2.8060901@ti.com> <53557BFE.5020908@cogentembedded.com> <53578FA8.6040607@ti.com> <537D2770.2040605@cogentembedded.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <537D2770.2040605@cogentembedded.com> Sender: linux-sh-owner@vger.kernel.org To: Sergei Shtylyov , devicetree@vger.kernel.org, robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, grant.likely@linaro.org Cc: linux-sh@vger.kernel.org, magnus.damm@gmail.com, linux-doc@vger.kernel.org, rdunlap@infradead.org List-Id: devicetree@vger.kernel.org Hi, On Thursday 22 May 2014 03:53 AM, Sergei Shtylyov wrote: > Hello. > > On 04/23/2014 02:02 PM, Kishon Vijay Abraham I wrote: > >>>>> This PHY, though formally being a part of Renesas USBHS controller, contains >>>>> the >>>>> UGCTRL2 register that controls multiplexing of the USB ports (Renesas calls >>>>> them >>>>> channels) to the different USB controllers: channel 0 can be connected to >>>>> either >>>>> PCI EHCI/OHCI or USBHS controllers, channel 2 can be connected to PCI >>>>> EHCI/OHCI >>>>> or xHCI controllers. > >>>>> This is a new driver for this USB PHY currently already supported under >>>>> drivers/ >>>>> usb/phy/. The reason for writing the new driver was the requirement that the >>>>> multiplexing of USB channels to the controller be dynamic, depending on what >>>>> USB drivers are loaded, rather than static as provided by the old driver. >>>>> The infrastructure provided by drivers/phy/phy-core.c seems to fit that >>>>> purpose >>>>> ideally. The new driver only supports device tree probing for now. > >>>>> Signed-off-by: Sergei Shtylyov > >>> [...] > >>>>> Index: linux-phy/drivers/phy/phy-rcar-gen2.c >>>>> =================================================================== >>>>> --- /dev/null >>>>> +++ linux-phy/drivers/phy/phy-rcar-gen2.c >>>>> @@ -0,0 +1,283 @@ > >>> [...] > >>>>> +static int rcar_gen2_phy_probe(struct platform_device *pdev) >>>>> +{ > >>> [...] > >>>>> + drv->phys[0][0].select_mask = USBHS_UGCTRL2_USB0SEL; >>>>> + drv->phys[0][0].select_value = USBHS_UGCTRL2_USB0SEL_PCI; >>>>> + drv->phys[0][1].select_mask = USBHS_UGCTRL2_USB0SEL; >>>>> + drv->phys[0][1].select_value = USBHS_UGCTRL2_USB0SEL_HS_USB; >>>>> + drv->phys[2][0].select_mask = USBHS_UGCTRL2_USB2SEL; >>>>> + drv->phys[2][0].select_value = USBHS_UGCTRL2_USB2SEL_PCI; >>>>> + drv->phys[2][1].select_mask = USBHS_UGCTRL2_USB2SEL; >>>>> + drv->phys[2][1].select_value = USBHS_UGCTRL2_USB2SEL_USB30; >>>>> + >>>>> + for (i = 0; i < NUM_USB_CHANNELS; i++) { > >>>> Instead of hard coding the number of channels, > >>> It's hard coded in the hardware. We can even decrease that number to 2 as > >> right, that's why thought dt should have that information. > > So you want a dedicated property for that or you meant something else? > >>> for the channel #1 we have nothing to do, regardless of whether it's present or >>> not... > >>>> we can model the channels (PHYs) as sub-nodes of the main PHY > >>> Hm, I don't think such representation would be adequate: the channels >>> themselves do not usually correspond to any particular PHY, that's why I used >>> #phy-cells = <2>. > >>>> in dt and use it to create individual PHYs. > >>> Well, we probably can... however, I fail to see any immediate gain from >>> it here... >>> I have to ask why you've selected this particular driver for such DT >>> representation experiments, despite it not being the first one supporting >>> multiple PHYs? > >> just that it didn't strike before.. but I think all multiple PHYs should be >> modelled this way. > > I've basically reimplemented the driver to parse the info from the subnodes > and it's now became larger in size, not smaller. :-/ Overall, I'm not content > with the changes, nor do I think such a change in the DT representation was a > great idea... I've seen someone posted a patch with subnodes and that wasn't looking too bad. Do you mind posting your patch in the list? Cheers Kishon