From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f43.google.com (mail-wm1-f43.google.com [209.85.128.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7453217542 for ; Wed, 24 Jan 2024 08:02:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.43 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706083342; cv=none; b=lhPJod42QbqcFD9KoaEdS+G7m6M+y7y67CJJkFfu7KUSLi4j3dbe/pQPxHVKTo/QUot/GEDMi12mxaYLaTTIiC4Nv8epX6R4Ho8++OTmXM9ehEuRzm4/bgz+/SS36r50mCEr4AEYoIBLmIXroxyvSNvkP1uUDpsYm6LSv7qv0Co= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706083342; c=relaxed/simple; bh=4Hfelc0begR7o+ENLXp5CnX+cL21s/4RNums1N2WBP8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=GZ9hrtQvXqsVOGhXkq7rcuNQ9x+OXZ5SAEeXmUWuEZlY5ZcexySEwbns+nOin3P0P8+8r9IhSoXgfSz+g4sjMiek7+MG4tuYz/hpTW5h4+0rfyWpSLpc3D6tmjTZLvs6tWsrqvDAKvFeASw3v7We7LCGLuKAKSwLG6WG3UvlmnM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linaro.org; spf=pass smtp.mailfrom=linaro.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b=tx7SHl7o; arc=none smtp.client-ip=209.85.128.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linaro.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linaro.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="tx7SHl7o" Received: by mail-wm1-f43.google.com with SMTP id 5b1f17b1804b1-40e8d3b29f2so61388145e9.1 for ; Wed, 24 Jan 2024 00:02:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1706083338; x=1706688138; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:autocrypt:from:references:cc :to:content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=ZN84oeqX5oAPN438p7tXYjj6AH2DkVvx3dsywBY9DH0=; b=tx7SHl7oawm86MmfIRf6yqbzZaSEkEDjYwizOVA5RnvAAwZtvFzNb644RI7Qvz7Da3 qBoMn3l86S8w6roAgWkMr5dYJDH6vt20AhvfXmTrKhjG0zCDdrzZFbqVoQ7EEhOSlKuA G/qIQluqMX+7ldTDOP1fl1DtpKrgh5KgG1X44rD813KKGaAl1anQgorLeR+Ca0A1Xc4o MybgyINqHNt/d18qfMhKJT4vVQT6UFwF7m/WinJ5MFdQyUJRlYBsQd+lumcsYzQISeEJ 0qfTdvH0SHGGVDmv5cEtXtREKcXGg8IkKJAGPJ8zA6GTHra5pNJGna7vz8tQqKck2i9R i9Ww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1706083338; x=1706688138; h=content-transfer-encoding:in-reply-to:autocrypt:from:references:cc :to:content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=ZN84oeqX5oAPN438p7tXYjj6AH2DkVvx3dsywBY9DH0=; b=eWGUHlaT6q+UY8erZAYLVQNXsV8a3JmsrU9Md5eVjp5Vjcok3uLjFeQG0ypzA9iHyz 0Na5VBXbRkPSDL0qEcx2yD6OrklF2TRXLZCC3PF7gmW/v99q0Vwz0dZqKM5t7iFHnTxW 3Xjw5WcfacAKOYuj007IIoOgkyeWrTRnTAvoOA9z+s0WQyRH+ea3X+T4o9UjweugN9Dg QkkTWcfJR9Kx+ANNcV3XoKNI4nnpUlg4f2v6CNdaCW0CEC4sh6ewakF11pZqfhw9Bw4n qMYzc4dpbt0dIRf8bnK7o5ejadAxTJlqSbNLLABG/A08n9NHcHYiRp26PczTslKQkTOo np0w== X-Gm-Message-State: AOJu0YytFLE2odUoKK5J9r6WLbf49Toq4cXLGH1wDWHQkaYJGOrVeZuN 9i6zRhgLaep9FvVtn+wqW/xgehg0NE7NvNhDe+fv/9gIkJsb1mfWe5mWbZm/1XY= X-Google-Smtp-Source: AGHT+IErX4Njt5yM/RhWljDWrJUHwXoS1eBEgsRtgH1n6isz5607P1Ogc5iBNUC8OoK+KK7rKPDxUw== X-Received: by 2002:a05:600c:33a5:b0:40e:43e4:d9ca with SMTP id o37-20020a05600c33a500b0040e43e4d9camr575766wmp.179.1706083338501; Wed, 24 Jan 2024 00:02:18 -0800 (PST) Received: from [192.168.1.20] ([178.197.215.66]) by smtp.gmail.com with ESMTPSA id b9-20020a05600c4e0900b0040ec7a6d39esm382590wmq.16.2024.01.24.00.02.17 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 24 Jan 2024 00:02:17 -0800 (PST) Message-ID: Date: Wed, 24 Jan 2024 09:02:16 +0100 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: DT Query on "New Compatible vs New Property" Content-Language: en-US To: Manivannan Sadhasivam , Nikunj Kela Cc: robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, devicetree@vger.kernel.org, "Prasad Sodagudi (QUIC)" , srinivas.kandagatla@linaro.org, vincent.guittot@linaro.org, ulf.hansson@linaro.org References: <82115165-6089-4214-b47b-2c2c0dfb8c66@linaro.org> <1935cb82-648c-f079-8852-d461dc9f8609@quicinc.com> <20231214061742.GG2938@thinkpad> <66f82e2c-0c42-4ead-93f5-2136ad478df2@linaro.org> <7768258d-4748-84f7-0da2-43988138e5cc@quicinc.com> <20240123161231.GG19029@thinkpad> From: Krzysztof Kozlowski Autocrypt: addr=krzysztof.kozlowski@linaro.org; keydata= xsFNBFVDQq4BEAC6KeLOfFsAvFMBsrCrJ2bCalhPv5+KQF2PS2+iwZI8BpRZoV+Bd5kWvN79 cFgcqTTuNHjAvxtUG8pQgGTHAObYs6xeYJtjUH0ZX6ndJ33FJYf5V3yXqqjcZ30FgHzJCFUu JMp7PSyMPzpUXfU12yfcRYVEMQrmplNZssmYhiTeVicuOOypWugZKVLGNm0IweVCaZ/DJDIH gNbpvVwjcKYrx85m9cBVEBUGaQP6AT7qlVCkrf50v8bofSIyVa2xmubbAwwFA1oxoOusjPIE J3iadrwpFvsZjF5uHAKS+7wHLoW9hVzOnLbX6ajk5Hf8Pb1m+VH/E8bPBNNYKkfTtypTDUCj NYcd27tjnXfG+SDs/EXNUAIRefCyvaRG7oRYF3Ec+2RgQDRnmmjCjoQNbFrJvJkFHlPeHaeS BosGY+XWKydnmsfY7SSnjAzLUGAFhLd/XDVpb1Een2XucPpKvt9ORF+48gy12FA5GduRLhQU vK4tU7ojoem/G23PcowM1CwPurC8sAVsQb9KmwTGh7rVz3ks3w/zfGBy3+WmLg++C2Wct6nM Pd8/6CBVjEWqD06/RjI2AnjIq5fSEH/BIfXXfC68nMp9BZoy3So4ZsbOlBmtAPvMYX6U8VwD TNeBxJu5Ex0Izf1NV9CzC3nNaFUYOY8KfN01X5SExAoVTr09ewARAQABzTRLcnp5c3p0b2Yg S296bG93c2tpIDxrcnp5c3p0b2Yua296bG93c2tpQGxpbmFyby5vcmc+wsGUBBMBCgA+FiEE m9B+DgxR+NWWd7dUG5NDfTtBYpsFAmI+BxMCGwMFCRRfreEFCwkIBwIGFQoJCAsCBBYCAwEC HgECF4AACgkQG5NDfTtBYptgbhAAjAGunRoOTduBeC7V6GGOQMYIT5n3OuDSzG1oZyM4kyvO XeodvvYv49/ng473E8ZFhXfrre+c1olbr1A8pnz9vKVQs9JGVa6wwr/6ddH7/yvcaCQnHRPK mnXyP2BViBlyDWQ71UC3N12YCoHE2cVmfrn4JeyK/gHCvcW3hUW4i5rMd5M5WZAeiJj3rvYh v8WMKDJOtZFXxwaYGbvFJNDdvdTHc2x2fGaWwmXMJn2xs1ZyFAeHQvrp49mS6PBQZzcx0XL5 cU9ZjhzOZDn6Apv45/C/lUJvPc3lo/pr5cmlOvPq1AsP6/xRXsEFX/SdvdxJ8w9KtGaxdJuf rpzLQ8Ht+H0lY2On1duYhmro8WglOypHy+TusYrDEry2qDNlc/bApQKtd9uqyDZ+rx8bGxyY qBP6bvsQx5YACI4p8R0J43tSqWwJTP/R5oPRQW2O1Ye1DEcdeyzZfifrQz58aoZrVQq+innR aDwu8qDB5UgmMQ7cjDSeAQABdghq7pqrA4P8lkA7qTG+aw8Z21OoAyZdUNm8NWJoQy8m4nUP gmeeQPRc0vjp5JkYPgTqwf08cluqO6vQuYL2YmwVBIbO7cE7LNGkPDA3RYMu+zPY9UUi/ln5 dcKuEStFZ5eqVyqVoZ9eu3RTCGIXAHe1NcfcMT9HT0DPp3+ieTxFx6RjY3kYTGLOwU0EVUNc NAEQAM2StBhJERQvgPcbCzjokShn0cRA4q2SvCOvOXD+0KapXMRFE+/PZeDyfv4dEKuCqeh0 hihSHlaxTzg3TcqUu54w2xYskG8Fq5tg3gm4kh1Gvh1LijIXX99ABA8eHxOGmLPRIBkXHqJY oHtCvPc6sYKNM9xbp6I4yF56xVLmHGJ61KaWKf5KKWYgA9kfHufbja7qR0c6H79LIsiYqf92 H1HNq1WlQpu/fh4/XAAaV1axHFt/dY/2kU05tLMj8GjeQDz1fHas7augL4argt4e+jum3Nwt yupodQBxncKAUbzwKcDrPqUFmfRbJ7ARw8491xQHZDsP82JRj4cOJX32sBg8nO2N5OsFJOcd 5IE9v6qfllkZDAh1Rb1h6DFYq9dcdPAHl4zOj9EHq99/CpyccOh7SrtWDNFFknCmLpowhct9 5ZnlavBrDbOV0W47gO33WkXMFI4il4y1+Bv89979rVYn8aBohEgET41SpyQz7fMkcaZU+ok/ +HYjC/qfDxT7tjKXqBQEscVODaFicsUkjheOD4BfWEcVUqa+XdUEciwG/SgNyxBZepj41oVq FPSVE+Ni2tNrW/e16b8mgXNngHSnbsr6pAIXZH3qFW+4TKPMGZ2rZ6zITrMip+12jgw4mGjy 5y06JZvA02rZT2k9aa7i9dUUFggaanI09jNGbRA/ABEBAAHCwXwEGAEKACYCGwwWIQSb0H4O DFH41ZZ3t1Qbk0N9O0FimwUCYDzvagUJFF+UtgAKCRAbk0N9O0Fim9JzD/0auoGtUu4mgnna oEEpQEOjgT7l9TVuO3Qa/SeH+E0m55y5Fjpp6ZToc481za3xAcxK/BtIX5Wn1mQ6+szfrJQ6 59y2io437BeuWIRjQniSxHz1kgtFECiV30yHRgOoQlzUea7FgsnuWdstgfWi6LxstswEzxLZ Sj1EqpXYZE4uLjh6dW292sO+j4LEqPYr53hyV4I2LPmptPE9Rb9yCTAbSUlzgjiyyjuXhcwM qf3lzsm02y7Ooq+ERVKiJzlvLd9tSe4jRx6Z6LMXhB21fa5DGs/tHAcUF35hSJrvMJzPT/+u /oVmYDFZkbLlqs2XpWaVCo2jv8+iHxZZ9FL7F6AHFzqEFdqGnJQqmEApiRqH6b4jRBOgJ+cY qc+rJggwMQcJL9F+oDm3wX47nr6jIsEB5ZftdybIzpMZ5V9v45lUwmdnMrSzZVgC4jRGXzsU EViBQt2CopXtHtYfPAO5nAkIvKSNp3jmGxZw4aTc5xoAZBLo0OV+Ezo71pg3AYvq0a3/oGRG KQ06ztUMRrj8eVtpImjsWCd0bDWRaaR4vqhCHvAG9iWXZu4qh3ipie2Y0oSJygcZT7H3UZxq fyYKiqEmRuqsvv6dcbblD8ZLkz1EVZL6djImH5zc5x8qpVxlA0A0i23v5QvN00m6G9NFF0Le D2GYIS41Kv4Isx2dEFh+/Q== In-Reply-To: <20240123161231.GG19029@thinkpad> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 23/01/2024 17:12, Manivannan Sadhasivam wrote: > On Thu, Dec 14, 2023 at 07:18:25AM -0800, Nikunj Kela wrote: >> >> On 12/13/2023 11:49 PM, Krzysztof Kozlowski wrote: >>> On 14/12/2023 07:17, Manivannan Sadhasivam wrote: >>>> On Tue, Dec 12, 2023 at 11:06:42AM -0800, Nikunj Kela wrote: >>>>> + Linaro team >>>>> >>>>> On 12/12/2023 11:01 AM, Krzysztof Kozlowski wrote: >>>>>> On 12/12/2023 18:45, Nikunj Kela wrote: >>>>>>> We are abstracting some resources(ex. clocks) under new firmware on an >>>>>>> existing platform therefore need to make changes in certain drivers to >>>>>>> work with that firmware. We need to make a distinction between two >>>>>>> different variants of the FW. In one case, some resources will be >>>>>>> abstracted while in other case, they won't be abstracted. My query is - >>>>>>> "should we define a new compatible string for the variant with >>>>>>> abstracted resources(in FW) or we should add a new DT property keeping >>>>>>> the compatible same?" >>>>>> Hi, >>>>>> >>>>>> Usually change in the interface or behavior warrants new compatible. >>>>>> Property would be suitable if the same device, e.g. same SoC component >>>>>> with same FW, was configured differently on different boards. >>>>>> >>>> Here, the hardware is going to be the same, but the resources (clocks, >>>> regulators, etc...) will be controlled by the firmware instead of OS. >>> Yeah, that's the problem with generic questions, instead of specific... >>> "Talk is cheap." >>> >>> OK, so the hardware is exactly the same? Does FW bring any >>> incompatibilities in the interface or is it just about the clocks? I >>> guess I should not have included "with same FW" in my last statement. >>> It's true, but way too narrow. Therefore let me rephrase it: >> >> HW is exactly the same. Let me give more insight on the setup. We have been >> using the HW in virtual environment but now the ownership of certain >> resources (e.g. clock controller etc.) is handed over to a different VM(non >> Linux VM). Earlier the ownership of the resources was local to the same >> VM(Linux VM) via passthrough mode so it could directly access them however >> now Linux VM talks to non-Linux VM for its operations for resources that it >> doesn't own anymore via some interface(shared memory/doorbell).  So shall we >> use property like 'qcom, controlled-remotely' or do we need a new compatible >> for such setup? >> > > Krzysztof, just a ping on this thread. > > To summarise, the hardware is exactly same. We can consider the case of UFS. The > UFS controller is exactly same in this proposed setup but the resources of the > UFS controller are taken care by the VM. So instead of enabling the resources > one by one, Linux kernel will just ask the VM to do so using an SCMI command. > > Due to this difference, we need to make the changes in the UFS controller > driver. So we want to know if we can use a different compatible for the UFS > controller altogether in DT (this will allow Linux kernel to have a separate > driver and will simplify things) or just use a property like > "remotely-controlled" to let the driver detect this setup and take action > accordingly. What devices do we talk about? Are they released? For which other devices you want to use it? I can give you one specific answer but then it will be taken to other contexts and used for the cases it must not be used... Best regards, Krzysztof