From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bintian Subject: Re: [PATCH v9 4/6] Documentation: DT: PL011: hi6220: add compatible string for Hisilicon designed UART Date: Tue, 2 Jun 2015 19:46:07 +0800 Message-ID: <556D977F.3000904@huawei.com> 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> <20150602112424.GC2067@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150602112424.GC2067@n2100.arm.linux.org.uk> Sender: linux-kernel-owner@vger.kernel.org To: Russell King - ARM Linux 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?UGF3ZcWCIE1vbGw=?= , 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, Ste List-Id: devicetree@vger.kernel.org Hello Russell, On 2015/6/2 19:24, Russell King - ARM Linux wrote: > 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. I agree with you and it's OK to me to remove this patch now. Could you help to ack the reset patches or I should send the version 10 without this patch? > > 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.) I think there is problem with my subject description, it's ARM designed indeed and Hisilicon just did some performance enhancements but not for UART0 in hi6220. > 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. Right. Thank you Russell. BR, Bintian