Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932516AbbENLVo (ORCPT ); Thu, 14 May 2015 07:21:44 -0400 Received: from hqemgate15.nvidia.com ([216.228.121.64]:5679 "EHLO hqemgate15.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751090AbbENLVm (ORCPT ); Thu, 14 May 2015 07:21:42 -0400 X-PGP-Universal: processed; by hqnvupgp08.nvidia.com on Thu, 14 May 2015 04:19:13 -0700 Message-ID: <5554853A.6050900@nvidia.com> Date: Thu, 14 May 2015 12:21:30 +0100 From: Jon Hunter User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Lee Jones CC: Thierry Reding , Andrew Bresticker , Stephen Warren , "Alexandre Courbot" , , , , , , "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 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> <20150514102315.GI22418@x1> In-Reply-To: <20150514102315.GI22418@x1> X-Originating-IP: [10.21.134.107] X-ClientProxiedBy: UKMAIL102.nvidia.com (10.26.138.15) To UKMAIL101.nvidia.com (10.26.138.13) Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6923 Lines: 172 On 14/05/15 11:23, Lee Jones wrote: > 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? Ok, I see what you are saying and I know that was what Andrew was doing in this patch (just not with the "simple-mfd"). Cheers Jon -- 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/