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<4690e682-8495-2327-87c7-c2f06a7a479d@nvidia.com> <66812127-38cf-2af3-51c0-50edbe446e73@nvidia.com> <9b4fbf9d-d651-aa35-c0a6-b8f16aeb0900@gmail.com> From: Sowjanya Komatineni Message-ID: <550f1796-67ca-5856-223d-c68360243954@nvidia.com> Date: Thu, 16 Jul 2020 17:16:36 -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: <9b4fbf9d-d651-aa35-c0a6-b8f16aeb0900@gmail.com> X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL101.nvidia.com (172.20.187.10) 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=1594944810; bh=e7ciQ4M92aTObzkBjwwPlQaDpWhA7HRPJ/6w40ZehNc=; h=X-PGP-Universal:Subject:To:CC:References:From:Message-ID:Date: User-Agent:MIME-Version:In-Reply-To:X-Originating-IP: X-ClientProxiedBy:Content-Type:Content-Transfer-Encoding: Content-Language; b=WHizPbkQ+yVcMQTr9kKLr6aNEkD238+xGSp8HgIi2sSnVUg9MxaoGtbDY8fIbNvyS RhV/V/OuY0b+wfxVAH0zmHdnfwRJdKBiyxlHnYtfEEMQTUZSidNuv6x1Ugs8hQcIsq NX1386HljzoK/AfSty9dRp0E9ximbjLg5IIAvkLtAZBjG5Pq2FCbZ8vXWC2raC35yr sFtLuvF22WBtFhabnEl2FgkllXC/VkWdhMi0a+FryT7/YyXG42esC0HIURzHZTLHjB iJT58Xat81wJz70tf0o2AiSKcX0HWgL3tdU15n3KmvQT0FKFiHWFpnLi2gMYF0thIZ q1U02be5hzP1A== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/16/20 4:47 PM, Dmitry Osipenko wrote: > 17.07.2020 02:09, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >> On 7/16/20 4:06 PM, Sowjanya Komatineni wrote: >>> On 7/16/20 4:01 PM, Dmitry Osipenko wrote: >>>> 17.07.2020 01:49, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >>>>>> What keeps MIPI clock enabled after completion of the >>>>>> tegra_mipi_calibrate() invocation? >>>>> MIPI clock is disabled at end of tegra_mipi_calibrate and is re-enabl= ed >>>>> during tegra_mipi_wait. >>>>> >>>>> I think I should fix this to keep the clock enabled till calibration >>>>> results are latched. >>>>> >>>>> All consumers of tegra_mipi_calibrate() will call tegra_mipi_wait(). >>>>> >>>>> So will remove clk_disable mipi clk at end of tegra_mipi_calibrate() >>>>> and >>>>> clk_enable mipi_clk at beginning of tegra_mipi_wait() >>>> Isn't it possible to perform the calibration after enabling CSI and >>>> before of starting the sensor streaming? >>> Currently this is what I am doing. Triggering calibration start during >>> CSI receiver being ready and then sensor streaming will happen where >>> internal MIPI CAL detects for LP -> HS transition and applies results >>> to pads. So checking for calibration results after sensor stream is >>> enabled >> 1. Calling tegra_mipi_calibrate() during CSI streaming where CSI pads >> are enabled and receiver is kept ready >> >> 2. Start Sensor stream >> >> 3. Calling tegra_mipi_wait() to check for MIPI Cal status. >> >> So as mipi cal clk need to be kept enabled till 3rd step, we can enable >> clock during tegra_mipi_calibrate() and leave it enabled and disable it >> in tegra_mipi_wait after status check. > From TRM: > > The following sequence is recommended for capturing a single frame: > > 1. Set up CSI registers for use case such as number of lanes, virtual > channel, etc. > 2. Initialize and power up CSI interface > 3. Wait for initialization time or done signal from calibration logic > 4. Power up camera through the I2C interface > 5. All CSI data and clock lanes are in stop state, LP11 > 6. Initiate frame capture through the I2C > 7. Frame done, CSI goes back to stop state, LP11 > > Hence, is it really necessary to perform the manual calibration? done signal from calibration logic will happen only when it sees LP to=20 HS transition as thats when calibration results are applied to pads and=20 then done signal is set. Also MIPI Pads calibration need to be done on every power off/on. So=20 need to do calibration and trigger it along with CSI receiver=20 programming to keep it ready and then need to check/wait for status only=20 after sensor stream happens as thats where LP->HS transition happen.