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([2a00:f41:c02:ff08:cb6b:1254:75f7:f63d]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-434da0d69dfsm182153545e9.14.2024.12.10.01.09.24 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 10 Dec 2024 01:09:27 -0800 (PST) Message-ID: <835ac8c6-3fbb-4a0d-aa07-716d1c8aad7c@gmail.com> Date: Tue, 10 Dec 2024 10:09:22 +0100 Precedence: bulk X-Mailing-List: dmaengine@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 1/4] dt-bindindgs: i2c: qcom,i2c-geni: Document shared flag To: Krzysztof Kozlowski , Konrad Dybcio , Mukesh Kumar Savaliya , konrad.dybcio@linaro.org, andersson@kernel.org, andi.shyti@kernel.org, linux-arm-msm@vger.kernel.org, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org, conor+dt@kernel.org, agross@kernel.org, devicetree@vger.kernel.org, vkoul@kernel.org, linux@treblig.org, dan.carpenter@linaro.org, Frank.Li@nxp.com, konradybcio@kernel.org, bryan.odonoghue@linaro.org, krzk+dt@kernel.org, robh@kernel.org Cc: quic_vdadhani@quicinc.com References: <20241129144357.2008465-1-quic_msavaliy@quicinc.com> <20241129144357.2008465-2-quic_msavaliy@quicinc.com> <75f2cc08-e3ab-41fb-aa94-22963c4ffd82@quicinc.com> <904ae8ea-d970-4b4b-a30a-cd1b65296a9b@kernel.org> Content-Language: en-US From: Konrad Dybcio Autocrypt: addr=konradybcio@gmail.com; keydata= xsFNBF9ALYUBEADWAhxdTBWrwAgDQQzc1O/bJ5O7b6cXYxwbBd9xKP7MICh5YA0DcCjJSOum BB/OmIWU6X+LZW6P88ZmHe+KeyABLMP5s1tJNK1j4ntT7mECcWZDzafPWF4F6m4WJOG27kTJ HGWdmtO+RvadOVi6CoUDqALsmfS3MUG5Pj2Ne9+0jRg4hEnB92AyF9rW2G3qisFcwPgvatt7 TXD5E38mLyOPOUyXNj9XpDbt1hNwKQfiidmPh5e7VNAWRnW1iCMMoKqzM1Anzq7e5Afyeifz zRcQPLaqrPjnKqZGL2BKQSZDh6NkI5ZLRhhHQf61fkWcUpTp1oDC6jWVfT7hwRVIQLrrNj9G MpPzrlN4YuAqKeIer1FMt8cq64ifgTzxHzXsMcUdclzq2LTk2RXaPl6Jg/IXWqUClJHbamSk t1bfif3SnmhA6TiNvEpDKPiT3IDs42THU6ygslrBxyROQPWLI9IL1y8S6RtEh8H+NZQWZNzm UQ3imZirlPjxZtvz1BtnnBWS06e7x/UEAguj7VHCuymVgpl2Za17d1jj81YN5Rp5L9GXxkV1 aUEwONM3eCI3qcYm5JNc5X+JthZOWsbIPSC1Rhxz3JmWIwP1udr5E3oNRe9u2LIEq+wH/toH kpPDhTeMkvt4KfE5m5ercid9+ZXAqoaYLUL4HCEw+HW0DXcKDwARAQABzSVLb25yYWQgRHli Y2lvIDxrb25yYWR5YmNpb0BnbWFpbC5jb20+wsGRBBMBCAA7AhsDBQsJCAcCBhUKCQgLAgQW AgMBAh4BAheAFiEEU24if9oCL2zdAAQVR4cBcg5dfFgFAmQ5btACGQEACgkQR4cBcg5dfFhw JBAAp7+SFJq0oGQ21dulLrJZx1s1RfNi35SKegi+ueLOezipsfD9s2weu37/xE+PQ9ONDm39 Uq+plABz8grTgy19N5RZnY2gQNcN335fQWq31wk6OEhr3E04hBx94eejKI9ynXJUXOddwjCm blrqUnAhWCq0lM2Dsj1d1qUKF2wSTiQW4aNkc6izUgmGuY26WNfD52T5RHvGi8XtCNAKI1yK cCTmRY0zXIdR3bp+FnJHetjwy1ScbDiruhnaad31plRy4a+CxNeplUjWecufnWYCR3xFypNE TZm+z23CgUVmYQPNZZGO4h0SaRxnHhsewtlC9+DSaKm+7RzfbNbGRg6kxL2YG9PEqA64LAQI Vl0zkuF8xyGFcPioJ5Bg9UaN8M81xPuPwrN+Sb/PXgC/RKQ59hXI6fNAHoP9XwAAus5j0oRg BJb/+pXX9PQGtmIKJMp9l337VuCkXk/iaZ6HNWDumdeiUDA7m3vUHWVvsF5Xna+suUOSXPZ9 kwlbfHvfFpbuqr/VNN6qRpipx0vSvuDo5Ar4PoCuNDcHkmSlxMqqp8GG9oDi4cnl0XzirQpQ /rve1X50GUA7nVNagxQzvjRyZlcldVKHNIQXOR+XqEAwIGLRwqYo+iUOBZXFKHAS5EFooBJj 7QuEwSEWg7QYvOdXZOcmZGzGQa0Iq22KJgddx+DOOARkOW7yEgorBgEEAZdVAQUBAQdAwmUx xrbSCx2ksDxz7rFFGX1KmTkdRtcgC6F3NfuNYkYDAQgHwsF2BBgBCAAgFiEEU24if9oCL2zd AAQVR4cBcg5dfFgFAmQ5bvICGwwACgkQR4cBcg5dfFju1Q//Xta1ShwL0MLSC1KL1lXGXeRM 8arzfyiB5wJ9tb9U/nZvhhdfilEDLe0jKJY0RJErbdRHsalwQCrtq/1ewQpMpsRxXzAjgfRN jc4tgxRWmI+aVTzSRpywNahzZBT695hMz81cVZJoZzaV0KaMTlSnBkrviPz1nIGHYCHJxF9r cIu0GSIyUjZ/7xslxdvjpLth16H27JCWDzDqIQMtg61063gNyEyWgt1qRSaK14JIH/DoYRfn jfFQSC8bffFjat7BQGFz4ZpRavkMUFuDirn5Tf28oc5ebe2cIHp4/kajTx/7JOxWZ80U70mA cBgEeYSrYYnX+UJsSxpzLc/0sT1eRJDEhI4XIQM4ClIzpsCIN5HnVF76UQXh3a9zpwh3dk8i bhN/URmCOTH+LHNJYN/MxY8wuukq877DWB7k86pBs5IDLAXmW8v3gIDWyIcgYqb2v8QO2Mqx YMqL7UZxVLul4/JbllsQB8F/fNI8AfttmAQL9cwo6C8yDTXKdho920W4WUR9k8NT/OBqWSyk bGqMHex48FVZhexNPYOd58EY9/7mL5u0sJmo+jTeb4JBgIbFPJCFyng4HwbniWgQJZ1WqaUC nas9J77uICis2WH7N8Bs9jy0wQYezNzqS+FxoNXmDQg2jetX8en4bO2Di7Pmx0jXA4TOb9TM izWDgYvmBE8= In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 12/10/24 08:28, Krzysztof Kozlowski wrote: > On 02/12/2024 15:04, Konrad Dybcio wrote: >>>>>   > >>>>> IP blocks like SE can be shared. Here we are talking about I2C sharing. >>>>> In future it can be SPI sharing. But design wise it fits better to add >>>>> flag per SE node. Same we shall be adding for SPI too in future. >>>> >>>> >>>> How flag per SE node is relevant? I did not ask to move the property. >>>> >>>>> >>>>> Please let me know your further suggestions. >>>> We do not talk about I2C or SPI here only. We talk about entire SoC. >>>> Since beginning. Find other patch proposals and align with rest of >>>> Qualcomm developers so that you come with only one definition for this >>>> feature/characteristic. Or do you want to say that I am free to NAK all >>>> further properties duplicating this one? >> >> I'm not sure a single property name+description can fit all possible >> cases here. The hardware being "shared" can mean a number of different > > Existing property does not explain anything more, either. To recap - > this block is SE and property is named "se-shared", so basically it is > equal to just "shared". "shared" is indeed quite vague, so I was > expecting some wider work here. > > >> things, with some blocks having hardware provisions for that, while >> others may have totally none and rely on external mechanisms (e.g. >> a shared memory buffer) to indicate whether an external entity >> manages power to them. > > We have properties for that too. Qualcomm SoCs need once per year for > such shared properties. BAM has two or three. IPA has two. There are > probably even more blocks which I don't remember now. So, the problem is "driver must not toggle GPIO states", because "the bus controller must not be muxed away from the endpoint". You can come up with a number of similar problems by swapping out the quoted text. We can either describe what the driver must do (A), or what the reason for it is (B). If we go with A, we could have a property like: &i2c1 { externally-handled-resources = <(EHR_PINCTRL_STATE | EHR_CLOCK_RATE)> }; which would be a generic list of things that the OS would have to tiptoe around, fitting Linux's framework split quite well or if we go with B, we could add a property like: &i2c1 { qcom,shared-controller; }; which would hide the implementation details into the driver I could see both approaches having their place, but in this specific instance I think A would be more fitting, as the problem is quite simple. Krzysztof, thoughts? Konrad