Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753714AbcCZSKS (ORCPT ); Sat, 26 Mar 2016 14:10:18 -0400 Received: from mail-out.m-online.net ([212.18.0.10]:42163 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752679AbcCZSKQ (ORCPT ); Sat, 26 Mar 2016 14:10:16 -0400 X-Auth-Info: fkdxTY3ifnXK0DM+g4x48i6OIfd0/vNjEaXfVLHzrbU= Message-ID: <56F6D083.1020402@denx.de> Date: Sat, 26 Mar 2016 19:10:11 +0100 From: Marek Vasut User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.7.0 MIME-Version: 1.0 To: Vladimir Zapolskiy , "devicetree@vger.kernel.org" CC: linux-kernel@vger.kernel.org, Rob Herring , Alexey Brodkin Subject: Re: ARC dw-mshc binding compat string References: <56F66121.8050507@denx.de> <56F6C639.5000301@mentor.com> <56F6C71B.6070002@denx.de> <56F6CC68.5040408@mentor.com> In-Reply-To: <56F6CC68.5040408@mentor.com> 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: 2460 Lines: 70 On 03/26/2016 06:52 PM, Vladimir Zapolskiy wrote: > Hi Marek, > > On 26.03.2016 19:30, Marek Vasut wrote: >> On 03/26/2016 06:26 PM, Vladimir Zapolskiy wrote: >>> On 26.03.2016 12:14, Marek Vasut wrote: >>>> Hi! >>>> >>>> I noticed that arch/arc/boot/dts/axs10x_mb.dtsi uses "altr," prefix in >>>> the DT compatible string: >>>> >>>> mmc@0x15000 { >>>> compatible = "altr,socfpga-dw-mshc"; >>>> reg = < 0x15000 0x400 >; >>>> num-slots = < 1 >; >>>> fifo-depth = < 16 >; >>>> card-detect-delay = < 200 >; >>>> clocks = <&apbclk>, <&mmcclk>; >>>> clock-names = "biu", "ciu"; >>>> interrupts = < 7 >; >>>> bus-width = < 4 >; >>>> }; >>>> >>>> I don't think this is OK, since ARC is unrelated to Altera, which is >>>> what the "altr," prefix stands for. I think the socfpga-dw-mshc shim >>>> should be extended with another compatibility string, something like >>>> "snps,arc-dw-mshc" and the axs10x_mb.dtsi should be adjusted >>>> accordingly. What do you think ? >>>> >>> >>> There is "snps,dw-mshc" described in >>> Documentation/devicetree/bindings/mmc/synopsys-dw-mshc.txt and supported by >>> dw_mmc host controller driver. >> >> Thanks, that's even better. >> >> btw what do you think of using altr, prefix on non-altera system, that >> doesn't seem ok, right ? > > according to ePAPR the prefix should represent a device (IP block here > I believe) manufacturer, so it should be okay to use "altr" prefix on > non-Altera system, if Altera provides another hardware vendor with > some own IP block. In this case, it's Synopsys who provides the SD/MMC/MS core to other chip makers (Altera etc). > That said, I would rather prefer to see "snps,dw-mshc" prefix on description > of an MMC controller found on SoCFPGA series, "altr,socfpga-dw-mshc" seems > to be redundant. According to drivers/mmc/host/dw_mmc-pltfm.c , the Altera SoCFPGA one "altr,socfpga-dw-mshc" and also Imagination Technology Pistacio one "img,pistachio-dw-mshc" need specialty bit (SDMMC_CMD_USE_HOLD_REG), while the stock one "snps,dw-mshc" does not. I am not sure if the ARC one needs it as well, but most likely yes. I wonder if that bit is needed on some particular version of the DWMMC core. In that case, should we have "snps,dw-mshc" and "snps,dw-mshc-vN" binding ? Or should we use DT property to discern the need for this bit ? > -- > With best wishes, > Vladimir > -- Best regards, Marek Vasut