Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933224AbbENKXX (ORCPT ); Thu, 14 May 2015 06:23:23 -0400 Received: from mail-wi0-f180.google.com ([209.85.212.180]:35545 "EHLO mail-wi0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932821AbbENKXU (ORCPT ); Thu, 14 May 2015 06:23:20 -0400 Date: Thu, 14 May 2015 11:23:15 +0100 From: Lee Jones To: Jon Hunter Cc: Thierry Reding , Andrew Bresticker , Stephen Warren , 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 Subject: Re: [PATCH v8 4/9] mfd: Add binding document for NVIDIA Tegra XUSB Message-ID: <20150514102315.GI22418@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> <20150514093042.GG22418@x1> <5554746A.4000608@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <5554746A.4000608@nvidia.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6894 Lines: 170 On Thu, 14 May 2015, Jon Hunter wrote: > On 14/05/15 10:30, Lee Jones wrote: > > 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 Tegra124 > >>>>>> and later SoCs. The XUSB host complex includes a mailbox for > >>>>>> communication with the XUSB micro-controller and an xHCI host-controller. > >>>>>> > >>>>>> 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,tegra124-xusb.txt b/Documentation/devicetree/bindings/mfd/nvidia,tegra124-xusb.txt > >>>>>> new file mode 100644 > >>>>>> index 0000000..bc50110 > >>>>>> --- /dev/null > >>>>>> +++ b/Documentation/devicetree/bindings/mfd/nvidia,tegra124-xusb.txt > >>>>>> @@ -0,0 +1,37 @@ > >>>>>> +NVIDIA Tegra XUSB host copmlex > >>>>>> +============================== > >>>>>> + > >>>>>> +The XUSB host complex on Tegra124 and later SoCs contains an xHCI 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,tegra124-xusb"' > >>>>>> + where is tegra132. > >>>>>> + - reg: Must contain the base and length of the XUSB FPCI registers. > >>>>>> + - ranges: Bus address mapping for the XUSB block. Can be empty since the > >>>>>> + mapping is 1:1. > >>>>>> + - #address-cells: Must be 2. > >>>>>> + - #size-cells: Must be 2. > >>>>>> + > >>>>>> +Example: > >>>>>> +-------- > >>>>>> + usb@0,70098000 { > >>>>>> + compatible = "nvidia,tegra124-xusb"; > >>>>>> + reg = <0x0 0x70098000 0x0 0x1000>; > >>>>>> + ranges; > >>>>>> + > >>>>>> + #address-cells = <2>; > >>>>>> + #size-cells = <2>; > >>>>>> + > >>>>>> + usb-host@0,70090000 { > >>>>>> + compatible = "nvidia,tegra124-xhci"; > >>>>>> + ... > >>>>>> + }; > >>>>>> + > >>>>>> + mailbox { > >>>>>> + compatible = "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 USB > >>>>> device to its Mailbox. > >>>>> > >>>>> usb@xyz { > >>>>> mboxes = <&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 that for > >>>> device-tree we want the device-tree structure to reflect the actual hw. > >>>> Is this not the case? > >>> > >>> 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. > >> > >> For the xusb-host has memory from 0x7009000 - 0x7009ffff. > >> > >> Within this range, we have this fpci range which is defined as 0x7009800 > >> - 0x70098fff. This range is being shared between the mailbox and xhci > >> drivers. Looking at the drivers, we have ... > >> > >> mailbox uses: 0x700980e0 - 0x700980f3 and 0x70098428 - 0x7009842b. > >> xhci uses: 0x70098000 - 0x700980cf and 0x70098800 - 0x70098803. > >> > >> So it is a bit messy as they overlap. However, we could have ... > >> > >> xusb_mbox: mailbox { > >> compatible = "nvidia,tegra124-xusb-mbox"; > >> reg = <0x0 0x700980e0 0x0 0x14>, > >> <0x0 0x70098428 0x0 0x4>; > >> ... > >> }; > >> usb-host@0,70090000 { > >> compatible = "nvidia,tegra124-xhci"; > >> reg = <0x0 0x70090000 0x0 0x8000>, > >> <0x0 0x70098000 0x0 0x00d0>; > >> <0x0 0x70098800 0x0 0x0004>; > >> <0x0 0x70099000 0x0 0x1000>; > >> ... > >> }; > >> > >> 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 an > >> ok thing to do. > >> > >>> Two solutions spring to mind. You can either call > >>> of_platform_populate() from the USB driver, as some already do: > >>> > >>> drivers/usb/dwc3/dwc3-exynos.c: > >>> ret = of_platform_populate(node, NULL, NULL, dev); > >>> drivers/usb/dwc3/dwc3-keystone.c: > >>> error = of_platform_populate(node, NULL, NULL, dev); > >>> drivers/usb/dwc3/dwc3-omap.c: > >>> ret = of_platform_populate(node, NULL, NULL, dev); > >>> drivers/usb/dwc3/dwc3-qcom.c: > >>> ret = of_platform_populate(node, NULL, NULL, qdwc->dev); > >>> drivers/usb/dwc3/dwc3-st.c: > >>> ret = of_platform_populate(node, NULL, NULL, dev); > >>> drivers/usb/musb/musb_am335x.c: > >>> ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev); > >>> > >>> Or use the "simple-mfd", which is currently in -next: > >>> > >>> git show next/master:Documentation/devicetree/bindings/mfd/mfd.txt > >> > >> 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. :) > > Thanks Lee. > > Thierry, any objections on the above mem-mapping? If you have the mailbox as the child device and use "simple-mfd", you don't need to slice up the memory do you? -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/