Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758737AbbFBL0S (ORCPT ); Tue, 2 Jun 2015 07:26:18 -0400 Received: from pandora.arm.linux.org.uk ([78.32.30.218]:59709 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756419AbbFBL0L (ORCPT ); Tue, 2 Jun 2015 07:26:11 -0400 Date: Tue, 2 Jun 2015 12:24:24 +0100 From: Russell King - ARM Linux To: Bintian Cc: Linus Walleij , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Catalin Marinas , Will Deacon , "devicetree@vger.kernel.org" , Rob Herring , =?utf-8?B?UGF3ZcWC?= Moll , Mark Rutland , "ijc+devicetree@hellion.org.uk" , Kumar Gala , Kevin Hilman , Mike Turquette , Rob Herring , Zhangfei Gao , Haojian Zhuang , Xu Wei , Jaehoon Chung , Olof Johansson , yanhaifeng@gmail.com, Stephen Boyd , xuejiancheng@huawei.com, sledge.yanwei@huawei.com, Tomeu Vizoso , Guodong Xu , jorge.ramirez-ortiz@linaro.org, Tyler Baker , Kevin Hilman , Paul Bolle , Arnd Bergmann , Marc Zyngier , xuyiping@hisilicon.com, wangbinghui@hisilicon.com, zhenwei.wang@hisilicon.com, victor.lixin@hisilicon.com, puck.chen@hisilicon.com, dan.zhao@hisilicon.com, Xinwei Hu , z.liuxinliang@huawei.com, Yunlei He , XinWei Kong , wangbintian@gmail.com, w.f@huawei.com, liguozhu@hisilicon.com Subject: Re: [PATCH v9 4/6] Documentation: DT: PL011: hi6220: add compatible string for Hisilicon designed UART Message-ID: <20150602112424.GC2067@n2100.arm.linux.org.uk> References: <1432950661-23060-1-git-send-email-bintian.wang@huawei.com> <1432950661-23060-5-git-send-email-bintian.wang@huawei.com> <556D8B98.2040703@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <556D8B98.2040703@huawei.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2167 Lines: 47 On Tue, Jun 02, 2015 at 06:55:20PM +0800, Bintian wrote: > On 2015/6/2 16:59, Linus Walleij wrote: > >On Sat, May 30, 2015 at 3:50 AM, Bintian Wang wrote: > > > >>Hisilicon does some performance enhancements based on PL011(e.g. larger > >>FIFO length), so add one compatible string "hisilicon,hi6220-uart" for > > > >That compatible string in the commit message is not even > >the same as in the patch. > The UART0 is PL011 compatible, the UART1/2 have some performance > enhancements features, so based on Mark's suggestion and I add this > compatible string just for future use. Please don't submit it with this series. This patch should not be part of this series, it should be part of the series which modifies the PL011 driver, so it can be reviewed along with those changes. Until then, I'm going to NAK this patch. The thing that worries me though is that the subject line says this is a "Hisilicon *designed* UART". If Hisilicon _designed_ this UART, presumably they have changed the *vendor* field of the UART ID _not_ to indicate that ARM Ltd designed it? If they've merely modified the parameters, and given the ARM Ltd PL011 a larger fifo, then there isn't really much of a problem - we've been here before, except the vendor has had a real vendor ID for the field (in the case of ST), plus we've had different FIFO lengths for ARM hardware too (32 bytes instead of 16 for revision 3 and above.) Lastly, if you're not having to modify the PL011 driver in any way, you don't need to have a compatible. In any case, you _shouldn't_ for AMBA devices. AMBA does not match drivers based on OF compatible strings, so using OF compatible strings with the AMBA bus is just wrong. The AMBA compatible strings are there so that the generic OF code knows how to create the devices. -- FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up according to speedtest.net. -- 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/