From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Subject: Re: [PATCH v8 4/9] mfd: Add binding document for NVIDIA Tegra XUSB Date: Thu, 14 May 2015 10:30:42 +0100 Message-ID: <20150514093042.GG22418@x1> References: <1430761002-9327-1-git-send-email-abrestic@chromium.org> <1430761002-9327-5-git-send-email-abrestic@chromium.org> <20150513143954.GA3394@x1> <55544CC5.9050001@nvidia.com> <20150514074058.GA22418@x1> <55546767.90501@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <55546767.90501@nvidia.com> Sender: linux-kernel-owner@vger.kernel.org To: Jon Hunter Cc: Andrew Bresticker , Stephen Warren , Thierry Reding , Alexandre Courbot , devicetree@vger.kernel.org, linux-tegra@vger.kernel.org, linux-usb@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Samuel Ortiz List-Id: devicetree@vger.kernel.org On Thu, 14 May 2015, Jon Hunter wrote: > On 14/05/15 08:40, Lee Jones wrote: > > On Thu, 14 May 2015, Jon Hunter wrote: > >> On 13/05/15 15:39, Lee Jones wrote: > >>> On Mon, 04 May 2015, Andrew Bresticker wrote: > >>> > >>>> Add a binding document for the XUSB host complex on NVIDIA Tegra= 124 > >>>> and later SoCs. The XUSB host complex includes a mailbox for > >>>> communication with the XUSB micro-controller and an xHCI host-co= ntroller. > >>>> > >>>> Signed-off-by: Andrew Bresticker > >>>> Cc: Rob Herring > >>>> Cc: Pawel Moll > >>>> Cc: Mark Rutland > >>>> Cc: Ian Campbell > >>>> Cc: Kumar Gala > >>>> Cc: Samuel Ortiz > >>>> Cc: Lee Jones > >>>> --- > >>>> Changes from v7: > >>>> - Move non-shared resources into child nodes. > >>>> New for v7. > >>>> --- > >>>> .../bindings/mfd/nvidia,tegra124-xusb.txt | 37 +++++++= +++++++++++++++ > >>>> 1 file changed, 37 insertions(+) > >>>> create mode 100644 Documentation/devicetree/bindings/mfd/nvidia= ,tegra124-xusb.txt > >>>> > >>>> diff --git a/Documentation/devicetree/bindings/mfd/nvidia,tegra1= 24-xusb.txt b/Documentation/devicetree/bindings/mfd/nvidia,tegra124-xus= b.txt > >>>> new file mode 100644 > >>>> index 0000000..bc50110 > >>>> --- /dev/null > >>>> +++ b/Documentation/devicetree/bindings/mfd/nvidia,tegra124-xusb= =2Etxt > >>>> @@ -0,0 +1,37 @@ > >>>> +NVIDIA Tegra XUSB host copmlex > >>>> +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D > >>>> + > >>>> +The XUSB host complex on Tegra124 and later SoCs contains an xH= CI host > >>>> +controller and a mailbox for communication with the XUSB micro-= controller. > >>>> + > >>>> +Required properties: > >>>> +-------------------- > >>>> + - compatible: For Tegra124, must contain "nvidia,tegra124-xusb= ". > >>>> + Otherwise, must contain '"nvidia,-xusb", "nvidia,tegra= 124-xusb"' > >>>> + where is tegra132. > >>>> + - reg: Must contain the base and length of the XUSB FPCI regis= ters. > >>>> + - ranges: Bus address mapping for the XUSB block. Can be empt= y since the > >>>> + mapping is 1:1. > >>>> + - #address-cells: Must be 2. > >>>> + - #size-cells: Must be 2. > >>>> + > >>>> +Example: > >>>> +-------- > >>>> + usb@0,70098000 { > >>>> + compatible =3D "nvidia,tegra124-xusb"; > >>>> + reg =3D <0x0 0x70098000 0x0 0x1000>; > >>>> + ranges; > >>>> + > >>>> + #address-cells =3D <2>; > >>>> + #size-cells =3D <2>; > >>>> + > >>>> + usb-host@0,70090000 { > >>>> + compatible =3D "nvidia,tegra124-xhci"; > >>>> + ... > >>>> + }; > >>>> + > >>>> + mailbox { > >>>> + compatible =3D "nvidia,tegra124-xusb-mbox"; > >>>> + ... > >>>> + }; > >>> > >>> This doesn't appear to be a proper MFD. I would have the USB and > >>> Mailbox devices probe seperately and use a phandle to point the U= SB > >>> device to its Mailbox. > >>> > >>> usb@xyz { > >>> mboxes =3D <&xusb-mailbox, [chan]>; > >>> }; > >>> > >> > >> I am assuming that Andrew had laid it out like this to reflect the= hw > >> structure. The mailbox and xhci controller are part of the xusb > >> sub-system and hence appear as child nodes. My understanding is th= at for > >> device-tree we want the device-tree structure to reflect the actua= l hw. > >> Is this not the case? > >=20 > > Yes, the DT files should reflect h/w. I have requested to see what > > the memory map looks like, so I might provide a more appropriate > > solution to accepting a pretty pointless MFD. >=20 > For the xusb-host has memory from 0x7009000 - 0x7009ffff. >=20 > Within this range, we have this fpci range which is defined as 0x7009= 800 > - 0x70098fff. This range is being shared between the mailbox and xhci > drivers. Looking at the drivers, we have ... >=20 > mailbox uses: 0x700980e0 - 0x700980f3 and 0x70098428 - 0x7009842b. > xhci uses: 0x70098000 - 0x700980cf and 0x70098800 - 0x70098803. >=20 > So it is a bit messy as they overlap. However, we could have ... >=20 > xusb_mbox: mailbox { > compatible =3D "nvidia,tegra124-xusb-mbox"; > reg =3D <0x0 0x700980e0 0x0 0x14>, > <0x0 0x70098428 0x0 0x4>; > ... > }; > usb-host@0,70090000 { > compatible =3D "nvidia,tegra124-xhci"; > reg =3D <0x0 0x70090000 0x0 0x8000>, =09 > <0x0 0x70098000 0x0 0x00d0>; > <0x0 0x70098800 0x0 0x0004>; > <0x0 0x70099000 0x0 0x1000>; > ... > }; >=20 > I believe that Thierry and Stephen said that they wished to avoid > multiple devices sharing the same memory ranges, and so we would need= to > divvy up the memory map as above. However, I am not sure if this is a= n > ok thing to do. > =09 > > Two solutions spring to mind. You can either call > > of_platform_populate() from the USB driver, as some already do: > >=20 > > drivers/usb/dwc3/dwc3-exynos.c: > > ret =3D of_platform_populate(node, NULL, NULL, dev); > > drivers/usb/dwc3/dwc3-keystone.c: > > error =3D of_platform_populate(node, NULL, NULL, dev); > > drivers/usb/dwc3/dwc3-omap.c: > > ret =3D of_platform_populate(node, NULL, NULL, dev); > > drivers/usb/dwc3/dwc3-qcom.c: > > ret =3D of_platform_populate(node, NULL, NULL, qdwc->dev); > > drivers/usb/dwc3/dwc3-st.c: > > ret =3D of_platform_populate(node, NULL, NULL, dev); > > drivers/usb/musb/musb_am335x.c: > > ret =3D of_platform_populate(pdev->dev.of_node, NULL, NULL, &pd= ev->dev); > >=20 > > Or use the "simple-mfd", which is currently in -next: > >=20 > > git show next/master:Documentation/devicetree/bindings/mfd/mfd.tx= t >=20 > That is nice. Sounds like the "simple-bus" style of device but for an That's precisely what it does. FYI: You 'can' use "simple-bus" and it will do the right thing, but as an MFD isn't really a bus, it was decided to create something a little more fitting. > mfd. Based upon the above, let me know if you think we could use the > "simple-mfd"? I do. :) --=20 Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org =E2=94=82 Open source software for ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog