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<48977b6b-ef7e-1bdf-e3e0-2903032aa225@gmail.com> From: Sowjanya Komatineni Message-ID: Date: Wed, 29 Jul 2020 16:54:29 -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: <48977b6b-ef7e-1bdf-e3e0-2903032aa225@gmail.com> X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL111.nvidia.com (172.20.187.18) 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=1596066343; bh=jkquNxFBqS8hVnPmBZJsuDSNBn3Suh8XQ+xGK361k5o=; 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=nZidFjyln3FDOHPIAZoW2cQ3z2Y49e8sJ0EoeDeLK+Rzor9DOkb80EFFse5yyRHGz IVHak2QfzzE3JISDKGmY0ezm7P+89D/4yYlLM3Th6GeB3SUmaSmgd3XyBPey68swlD QXD5vT+bARD+6Vydp1qVsF+QcMglenAN41ZaI+l0m8U58YwW2yGaQUsGXLdaHfbPqY P6QwAbHE0MJg0wbkajDyR7AnFev/LO8FBdpKj+ZbDX9Qeoy0iv9y1g6NqSEW4dgw1m uVYXTLha+Kx6fhGXgzJRn5BstJy2c9D4LWJqMPWNCE61yHuEEEUHkQbIGbAjoId7vs wNaWih2F2lbNg== Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On 7/29/20 4:42 PM, Dmitry Osipenko wrote: > 29.07.2020 20:55, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >> On 7/29/20 10:08 AM, Dmitry Osipenko wrote: >>> 28.07.2020 19:04, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >>> ... >>>>>> +void tegra_mipi_cancel_calibration(struct tegra_mipi_device *device= ) >>>>>> +{ >>>>> Doesn't MIPI_CAL need to be reset here? >>>> No need to reset MIPI CAL >>> Could you please explain why. There is a calibration state-machine that >>> apparently needs to be returned into initial state, does it return by >>> itself? >>> >>> TRM says that MIPI block needs to be reset before of starting >>> calibration process. The reset is completely missing in the driver, I >>> assume it needs to be corrected with another patch. >> TRM documented incorrectly. There is no need to reset MIPI_CAL. >> >> MIPI CAL is FSM and it does not hang and done bit is to indicate if >> results are applied to pads or not. >> >> If we don't see done bit set meaning, MIPI CAL did not see LP-11 and >> results are not applied to pads. > But how to stop calibration from triggering on LP-11 once it has been > enabled? The reset should be needed since there is no other way to reset > the calibration state. Its a finite state machine that goes thru fixed steps of sequence codes=20 internally and holds results in registers. When it sees LP-11 results are applied to pads. If it does not see LP-11, next start will again trigger calibrating with=20 finite sequence codes. As per HW designers, we don't have to do any reverts when done bit is=20 not set. >> Also while multiple streams can happen in parallel and we can't reset >> MIPI CAL as other CSI channel streams (using other pads) may also be >> going thru calibration process in parallel depending and also DSI pads >> also are calibrated thru same MIPI CAL controller. > Perhaps this should be the case for a shared reset control API usage.