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([2a01:e0a:106d:1080:8e54:fbaf:8cb6:e9f7]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43b5184957bsm17767759f8f.5.2026.03.19.07.05.09 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 19 Mar 2026 07:05:09 -0700 (PDT) Message-ID: <4d376a1b-37d7-4d37-8579-a0053f7b91f2@linaro.org> Date: Thu, 19 Mar 2026 15:05:08 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: Neil Armstrong Reply-To: Neil Armstrong Subject: Re: [PATCH v4 2/2] phy: qcom-mipi-csi2: Add a CSI2 MIPI DPHY driver To: Bryan O'Donoghue , Vladimir Zapolskiy , Dmitry Baryshkov Cc: Bryan O'Donoghue , Vinod Koul , Kishon Vijay Abraham I , Rob Herring , Krzysztof Kozlowski , Conor Dooley , linux-arm-msm@vger.kernel.org, linux-phy@lists.infradead.org, linux-media@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260315-x1e-csi2-phy-v4-0-90c09203888d@linaro.org> <20260315-x1e-csi2-phy-v4-2-90c09203888d@linaro.org> <3f11de22-b729-4d06-b6c8-18e649e1979c@linaro.org> <80ddc2b4-d6f8-4e8d-a45e-69c05d100aa2@linaro.org> <16b10f17-ecd3-4cdd-ac3f-f64127d60ace@linaro.org> <26XTdUyQTB41Oc4D5HnMtSm_QpZRjlkljQRJVw-u1Zp3Ltn9s4LVU-LQkP6drdl3Z3GGssLCCbsVYPFEqssHcQ==@protonmail.internalid> <65e06b2e-eeb9-45af-97ac-4ae60f652361@linaro.org> <9578400d-30ac-4d8c-9295-ee4ec8af3b2c@kernel.org> Content-Language: en-US, fr Autocrypt: addr=neil.armstrong@linaro.org; keydata= xsBNBE1ZBs8BCAD78xVLsXPwV/2qQx2FaO/7mhWL0Qodw8UcQJnkrWmgTFRobtTWxuRx8WWP GTjuhvbleoQ5Cxjr+v+1ARGCH46MxFP5DwauzPekwJUD5QKZlaw/bURTLmS2id5wWi3lqVH4 BVF2WzvGyyeV1o4RTCYDnZ9VLLylJ9bneEaIs/7cjCEbipGGFlfIML3sfqnIvMAxIMZrvcl9 qPV2k+KQ7q+aXavU5W+yLNn7QtXUB530Zlk/d2ETgzQ5FLYYnUDAaRl+8JUTjc0CNOTpCeik 80TZcE6f8M76Xa6yU8VcNko94Ck7iB4vj70q76P/J7kt98hklrr85/3NU3oti3nrIHmHABEB AAHNKk5laWwgQXJtc3Ryb25nIDxuZWlsLmFybXN0cm9uZ0BsaW5hcm8ub3JnPsLAkQQTAQoA OwIbIwULCQgHAwUVCgkICwUWAgMBAAIeAQIXgBYhBInsPQWERiF0UPIoSBaat7Gkz/iuBQJk Q5wSAhkBAAoJEBaat7Gkz/iuyhMIANiD94qDtUTJRfEW6GwXmtKWwl/mvqQtaTtZID2dos04 YqBbshiJbejgVJjy+HODcNUIKBB3PSLaln4ltdsV73SBcwUNdzebfKspAQunCM22Mn6FBIxQ GizsMLcP/0FX4en9NaKGfK6ZdKK6kN1GR9YffMJd2P08EO8mHowmSRe/ExAODhAs9W7XXExw UNCY4pVJyRPpEhv373vvff60bHxc1k/FF9WaPscMt7hlkbFLUs85kHtQAmr8pV5Hy9ezsSRa GzJmiVclkPc2BY592IGBXRDQ38urXeM4nfhhvqA50b/nAEXc6FzqgXqDkEIwR66/Gbp0t3+r yQzpKRyQif3OwE0ETVkGzwEIALyKDN/OGURaHBVzwjgYq+ZtifvekdrSNl8TIDH8g1xicBYp QTbPn6bbSZbdvfeQPNCcD4/EhXZuhQXMcoJsQQQnO4vwVULmPGgtGf8PVc7dxKOeta+qUh6+ SRh3vIcAUFHDT3f/Zdspz+e2E0hPV2hiSvICLk11qO6cyJE13zeNFoeY3ggrKY+IzbFomIZY 4yG6xI99NIPEVE9lNBXBKIlewIyVlkOaYvJWSV+p5gdJXOvScNN1epm5YHmf9aE2ZjnqZGoM Mtsyw18YoX9BqMFInxqYQQ3j/HpVgTSvmo5ea5qQDDUaCsaTf8UeDcwYOtgI8iL4oHcsGtUX oUk33HEAEQEAAcLAXwQYAQIACQUCTVkGzwIbDAAKCRAWmrexpM/4rrXiB/sGbkQ6itMrAIfn M7IbRuiSZS1unlySUVYu3SD6YBYnNi3G5EpbwfBNuT3H8//rVvtOFK4OD8cRYkxXRQmTvqa3 3eDIHu/zr1HMKErm+2SD6PO9umRef8V82o2oaCLvf4WeIssFjwB0b6a12opuRP7yo3E3gTCS KmbUuLv1CtxKQF+fUV1cVaTPMyT25Od+RC1K+iOR0F54oUJvJeq7fUzbn/KdlhA8XPGzwGRy 4zcsPWvwnXgfe5tk680fEKZVwOZKIEuJC3v+/yZpQzDvGYJvbyix0lHnrCzq43WefRHI5XTT QbM0WUIBIcGmq38+OgUsMYu4NzLu7uZFAcmp6h8g Organization: Linaro In-Reply-To: <9578400d-30ac-4d8c-9295-ee4ec8af3b2c@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 3/19/26 14:17, Bryan O'Donoghue wrote: > On 19/03/2026 13:08, Vladimir Zapolskiy wrote: >>> Why do you want a media driver? Isn't PHY driver enough? >>> >> As for today CAMSS CSIPHY are already media devices, and a user applies media >> specific properties to them, for instance media bus format, resolution etc. >> Technically this might be removed from CAMSS, but if so, then it should be >> done before this new PHY driver model is applied. >> >> -- >> Best wishes, > > There's no reason to remove that from CAMSS - it would be an ABI break in user-space anyway. > > The media entity in CAMSS msm_csiphyX handles format negotiation and pipeline routing. The PHY driver handles electrical configuration. They don't conflict and there multiple cited examples of this upstream already. If csiphy component was only handling electrical configuration, the only code handling csiphy would be phy API calls, not be part of the pipeline configuration. Today, it's a media element The whole CAMSS architecture is wrong, it should be modular, each hardware module should be an independent driver and all be connected via port/endpoint and configured with the media controller API. If you _really_ want to move the "electrical configuration" part of the CSPIPHY out of camss frankendriver, fine, then first just create an internal PHY device as an aux device, then continue migrating _all_ CAMSS components into independent driver modules, then in the end re-architecture the whole DT description by adding a node per component with a proper port/endpoint representation to be configured via the media controller API. Neil > > -- > bod