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<6eede805-80fd-016f-22f8-b6d25f6587af@nvidia.com> <1c12e40e-de7f-0599-a941-82760b4c7668@gmail.com> <9ef0b875-e826-43e2-207e-168d2081ff6a@nvidia.com> <4689cfe9-e7c4-48bf-217f-3a31b59b8bda@nvidia.com> <0e78c5ca-c529-1e98-891d-30351c9aae81@gmail.com> <309e3b66-9288-91ef-71b4-be73eacbbd62@nvidia.com> Message-ID: Date: Wed, 5 Aug 2020 17:47:03 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <309e3b66-9288-91ef-71b4-be73eacbbd62@nvidia.com> X-Originating-IP: [172.20.13.39] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) To HQMAIL107.nvidia.com (172.20.187.13) Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: quoted-printable Content-Language: en-US DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1596674724; bh=W+vdj5lkhs7ny55rBdX510JqVAhR+kOjhVyEBm78Hmk=; h=X-PGP-Universal:Subject:From:To:CC:References:Message-ID:Date: User-Agent:MIME-Version:In-Reply-To:X-Originating-IP: X-ClientProxiedBy:Content-Type:Content-Transfer-Encoding: Content-Language; b=h+SZNub/K/0fUQlgIJT8+3QIt19B+pkGVSh5sOOLbd2DagdV19viFf3vEjx/peROi dbWsauFpwQrSYnu3/qkM5e0n48R42EeTSU+kTPYu7fUpTZ/3QpbaqanFHFr91xosqH vox2/yPfI9caFJxshF7REmPb5+Efvcc0SYUKaU4gnjllDDReAwbwfenaX4CzDGes/9 qMfZObUKFxFyh7n/vsji3Li23r69kXyGjiEZob4w+kQ0EKi3OQnuROzaIAfMreVu0q fRWDcO3ZQFPI+PaFQRuPNzeugybDdVcoYdGE2Q6Ujn1op9YpJWtMhtBEAXeG6AfPoB BNjnUcg+xpJMA== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/5/20 11:06 AM, Sowjanya Komatineni wrote: > > On 8/5/20 10:46 AM, Sowjanya Komatineni wrote: >> >> On 8/5/20 10:34 AM, Dmitry Osipenko wrote: >>> 05.08.2020 20:29, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >>> ... >>>> UART_FST_MIPI_CAL is the clock used for calibration logic which is FSM >>>> that goes thru sequence codes and when done waits for pads to be in >>>> LP-11 to apply results. >>>> >>>> MIPI_CLK is controller gate clock which is also need to be kept=20 >>>> enabled >>>> as incase if it sees LP-11 it updates registers so its recommended to >>>> have this clock enabled. >>>> >>>> We can cancel_calibration() in CSI only when csi/sensor stream on=20 >>>> fails >>>> and in which case there will be no LP-11 so we can unconditionally >>>> disable MIPI_CLK. >>>> >>> There is no guarantee that the fail comes before the LP-11. For=20 >>> example, >>> some odd camera driver may have a complicated enable sequence which may >>> fail after enabling the hardware streaming. >> >> MIPI_CLK to keep enable is for calibration logic to update results,=20 >> but like I said calibration logic uses UART_FST_MIPI_CAL clock. So=20 >> even in case if fail happens from sensor after having pads in LP-11=20 >> then, calibration logic will still be running but result update will=20 >> not happen with clock disabled. But HW will not stuck as this is=20 >> confirmed from HW designer. > > If LP-11 happens from sensor stream (followed by fail) and by that=20 > time if calibration FSM is done and if calibration logic sees LP-11=20 > then results will be applied to pads. > > We did start of calibration before CSI stream so by the time we do=20 > sensor stream enable, calibration logic might have done with FSM and=20 > waiting for LP-11 > > Also if we see any special case, we always can use=20 > finish_calibration() instead of cancel_calibration() as well. > > finish_calibration() has extra 250ms wait time polling done bit and we=20 > can ignore its return code during fail pathway. > Confirmed from HW designer, calibration FSM to finish takes worst case=20 72uS so by the time it gets to sensor stream it will be done its=20 sequence and will be waiting for DONE bit. So disabling MIPI CAL clock on sensor stream fails is safe. >> >> >>