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Mon, 12 Apr 2021 20:03:15 +0800 Received: from [10.17.3.153] (10.17.3.153) by MTKCAS32.mediatek.inc (172.27.4.170) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Mon, 12 Apr 2021 20:03:14 +0800 Message-ID: <1618228994.32225.3.camel@mhfsdcap03> Subject: Re: [RESEND] i2c: mediatek: Get device clock-stretch time via dts From: Qii Wang To: Wolfram Sang CC: , , , , , , Date: Mon, 12 Apr 2021 20:03:14 +0800 In-Reply-To: <20210407181936.GA1614@kunai> References: <1615622664-15032-1-git-send-email-qii.wang@mediatek.com> <20210406194856.GF3122@kunai> <1617797706.32076.1.camel@mhfsdcap03> <20210407181936.GA1614@kunai> X-Mailer: Evolution 3.10.4-0ubuntu2 MIME-Version: 1.0 X-TM-SNTS-SMTP: A7CFFEEEB61B385686FB02EAD7F2826708C53DF7161DB026B3C8B8AD5232F5922000:8 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210412_050928_488280_9FB8DE91 X-CRM114-Status: GOOD ( 12.71 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, 2021-04-07 at 20:19 +0200, Wolfram Sang wrote: > > Due to clock stretch, our HW IP cannot meet the ac-timing > > spec(tSU;STA,tSU;STO). > > There isn't a same delay for clock stretching, so we need pass a > > parameter which can be found through measurement to meet most > > conditions. > > What about using this existing binding? > > - i2c-scl-internal-delay-ns > Number of nanoseconds the IP core additionally needs to setup SCL. > I can't see the relationship between "i2c-scl-falling-time-ns" and clock stretching, is there a parameter related to clock stretching? If you think both of them will affect the ac-timing of SCL, at this point, "i2c-scl-falling-time-ns" maybe a good choice. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel