From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Bintian Wang" Subject: Re: Re: [PATCH v4 5/5] arm64: dts: Add dts files for Hisilicon Hi6220 SoC Date: Wed, 13 May 2015 15:12:07 +0800 (GMT+08:00) Message-ID: References: <1430827599-11560-1-git-send-email-bintian.wang@huawei.com> <1430827599-11560-6-git-send-email-bintian.wang@huawei.com> <20150505171349.GA30215@leverpostej> <5549877C.10408@huawei.com> <5549B9CC.1040709@huawei.com> <20150506093022.GB31001@leverpostej> <5549EE97.3020801@huawei.com> <20150506104856.GC707@leverpostej> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150506104856.GC707@leverpostej> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Mark Rutland Cc: "dan.zhao@hisilicon.com" , Catalin Marinas , "wangbinghui@hisilicon.com" , Will Deacon , "huxinwei@huawei.com" , "khilman@linaro.org" , "haojian.zhuang@linaro.org" , "yanhaifeng@gmail.com" , "rob.herring@linaro.org" , "mturquette@linaro.org" , "arnd@arndb.de" , "khilman@kernel.org" , "xuwei5@hisilicon.com" , "jh80.chung@samsung.com" , "sledge.yanwei@huawei.com" , "kong.kongxinwei@hisilicon.com" , "heyunlei@huawei.com" , "w.f@huawei.com" "zhangfei.gao@linaro.org" List-Id: devicetree@vger.kernel.org Hi Mark, > Hi, > > > > I think that given that we know the UART is not quite a PL011 we should > > > add an additional compatible string just in case some difference crops > > > up later that is problematic. > > > > > > So we'd have something like: > > > > > > compatible = "hisilicon,hi6220-uart", "arm,pl011", "arm,primecell"; > > > > > > That way we can add any optimisations or workarounds later as required. > > I understand and thanks for your suggestion. > > > > Can I do not do this work in this patch set? Because I got the > > information UART0 is PL011 compatible. Hisilicon uart engineer can do > > this work in the future, maybe for UART1/UART2. > > I am not asking you to do any driver work for this -- the current driver > should ignore the "hisilicon,hi6220-uart" string and recognise > "arm,pl011". > > I am only asking you to add the additional string to the DTS, and to > update the binding document to list the new string. That way if and when > we need the kernel to distinguish between a regular PL011 and the > hi6220-specific variant, the DTB does not need to be updated in order to > do so. How about add the following binding rule to the 2/5 patch: --------------------------- *Hisilicon Enhanced ARM AMBA Primecell PL011 serial UART Required properties: - compatible: must be "hisilicon,hi6220-uart", "arm,primecell", "arm,pl011" - reg: exactly one register range with length 0x1000 - interrupts: exactly one interrupt specifier See also bindings/serial/pl011.txt Example: uart0: uart@f8015000 { compatible = "hisilicon,hi6220-uart", "arm,pl011", "arm,primecell"; reg = <0x0 0xf8015000 0x0 0x1000>; interrupts = ; clocks = <&ao_ctrl HI6220_UART0_PCLK>, <&ao_ctrl HI6220_UART0_PCLK>; clock-names = "uartclk", "apb_pclk"; }; --------------------------- > Is UART 0 different from UART1 and UART2? Yes, but my patch just includes UART0, we do some changements for UART1/2 to improve performance. Thanks, Bintian > > Thanks, > Mark. > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel