From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f175.google.com (mail-pg1-f175.google.com [209.85.215.175]) (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 E99978F49; Tue, 29 Apr 2025 00:27:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.175 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745886452; cv=none; b=dliF335yYmD/jfm8lgaofeLjgoYK/dxjMATzHdZD98RGGrMErGSmPndav/9SuBX/6MwS3a8K6JO9hM4YhBLpVnMDowFAdGzVg05umvYeNzX25M4CAFKrGnZMDuoR9Mbc4QgG5VJrJN4Kns/76MHXBVxM8Xu1+Fr0x3sE47jiz6E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745886452; c=relaxed/simple; bh=STqvQqB9VdqroVIjQ9O9iSgbyf9AE7dywx0Kt9YQ/X8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=pIGYlfsva+64bgNVs+/zLcvQXzdW3XQyMC5A7KZIaGS6b7o3e4SmLo871f+1CpQGOtQdy6DMg/qoQUq2sna2ZBcqO9k9qrnReqhKpO56bm4Q1Bi5L/b9kB+Ac4kLLM8O+i53Hl5hsD1tw3+X78Yc5/mdkbmXUSAQozGiLRPQZDk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=roeck-us.net; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=YYB0D0Vu; arc=none smtp.client-ip=209.85.215.175 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=roeck-us.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="YYB0D0Vu" Received: by mail-pg1-f175.google.com with SMTP id 41be03b00d2f7-b1396171fb1so3447171a12.2; Mon, 28 Apr 2025 17:27:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1745886450; x=1746491250; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:sender:from:to:cc:subject:date:message-id:reply-to; bh=E4+/s+VEvuC5FXOEm8slr7X2s/XWFR6SZw6sxO8nbRQ=; b=YYB0D0VuZ3KJGi4qdy2mTQ16YPsvNmA12TLOytAFVVE4bwEnXULip/cVnz9uqxcLVX zTOfHt7zh/VFIDqNQJWXtGVzI2LHq3/7AZgqudpgSPo2B0mGqhjiMzbxuMHdO+RT+V9T /+y5Z/mfFWt7CKy0N2IG6EtN6pU28tp9VS9xR72IMjogCX0wJdUcnJ13suxtPIFPCOqi uOMgVFeX2EvUn/U6qHAdaL1+a7+iB6SzToPVeXBWFJHTWz7MtDgSUFlZrOUs33lxayyF 6s+ui3+AFrC+5QKaxa8MBdFV2zhKu+MN+oHPYU6maS3D980gFIvbwB2nGcIJ0ZXWZkvT Yuxw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1745886450; x=1746491250; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:sender:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=E4+/s+VEvuC5FXOEm8slr7X2s/XWFR6SZw6sxO8nbRQ=; b=KROGODL21z1Nql+J7ZkVqlzkv6L7oZe/RA1Kl6QO9Z9ej4/Po+pRCutSFLZIbCgzPW O1fNWLJRc6is6PCFyyV1bGjLWUuW3OgWAe9iVcOWa4n+DYx7iSfFYsiDyQV/OKL2j6VL /KoY2MTBWU+LdMze5qP+xT2McZRoj9EelencWkPCVVaGPziuNu5UsU0984X73td+M87w Austus6XpuYPiYolrPs7WM91w5nMGSKd39c6A0As2RufJvgG0V5mK/ZF5Wu7+SYuXx+G SxGjwIV6oPT/Y4y4VtrRSjz7kyQvSH4ag2ALFK/tm2LM7ymhBCq8jH9TZl0C9pCgWb5K jLFA== X-Forwarded-Encrypted: i=1; AJvYcCUFvLAn7+SnERBczbYpQRId/TNgBfkrV+z1oJ+O/pKevfuL+Til65QHac4ah/Rtvv2VjPCEr+TAzR5++Do=@vger.kernel.org, AJvYcCXI0z40bDWhqMfL5tBUq7tJVJ//4P4TdZeSYfnfAwIK+0Q1mmStrAExlffGCTT1uGawwEkl2YWFj4A6o0RT@vger.kernel.org, AJvYcCXRZs3aioD4mXKxa7vMhxqBE4mTvr6hQy4Y8bV4hVEanSNvjjqvnCCJMH026VJPoMQzuBvuzsX6OjrK@vger.kernel.org, AJvYcCXVxSQQ8uAFbLuZp8/DJtQJgMWVY8OitFzNMKmmnuEDflpd5UOgIQMiwRHIoFpd6CuDHw+GvFJYEbsV@vger.kernel.org X-Gm-Message-State: AOJu0Yz5x7UfhBD86XHhoSJS8trbrpRXXFej3OyenquZMYompa+55zZW OIxSVBgde9v1HTJggkt70IWSPkwnxX/jm8eejunGMzjUWtG3yNuS X-Gm-Gg: ASbGncsT0Kc2ShTHOIPanwozpfCRqx0kP33tXTdtwYU+yDCfbi819wPwqyRCYf3GJ6K LsEYJx515a5/aYN/zWnYsjn6WJY4sdZFKhRdJnCxVd2xYi17rUL4GJwr1Dfl8yx3LL51qXznTuL aDXB/3xDTyqcbimgQRB/6BbsIXBBQrEhQYBTZ8VME1kQrnKZv49rhJMotp6XI7xbNiAb44kAY6x iF+b7Xo8A2HoNWhVMPmny166oxTzw0mPyBuLaw29T6aXy6ZdQQF9hoEqINhzXnF3n7Tts05TRKG nPxcwXIQ9kZ5lL0+RD4gnb6G4b/wwismI1LKSdK0SJN274LMOBg+y/v8QwWAJLbfi/QZuMu7O0V aJymWjT8dbcIElg== X-Google-Smtp-Source: AGHT+IFtMnFRx2QYnId/i9jukQX75HwClFDq2N45fA22F6PtOr/3Qugyj+Xg15EKW+yWXErhqcb+JQ== X-Received: by 2002:a17:90b:554f:b0:2fe:dd2c:f8e7 with SMTP id 98e67ed59e1d1-30a21551e90mr2678098a91.10.1745886449916; Mon, 28 Apr 2025 17:27:29 -0700 (PDT) Received: from ?IPV6:2600:1700:e321:62f0:da43:aeff:fecc:bfd5? ([2600:1700:e321:62f0:da43:aeff:fecc:bfd5]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-30a244bf043sm150486a91.0.2025.04.28.17.27.28 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 28 Apr 2025 17:27:29 -0700 (PDT) Sender: Guenter Roeck Message-ID: Date: Mon, 28 Apr 2025 17:27:27 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 4/5] hwmon: pmbus: mpq8785: Implement voltage scale loop configuration To: Pawel Dembicki , linux-hwmon@vger.kernel.org Cc: Jean Delvare , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Jonathan Corbet , =?UTF-8?Q?Uwe_Kleine-K=C3=B6nig?= , Shen Lichuan , Greg KH , Peter Zijlstra , Charles Hsu , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org References: <20250428221420.2077697-1-paweldembicki@gmail.com> <20250428221420.2077697-5-paweldembicki@gmail.com> Content-Language: en-US From: Guenter Roeck Autocrypt: addr=linux@roeck-us.net; keydata= xsFNBE6H1WcBEACu6jIcw5kZ5dGeJ7E7B2uweQR/4FGxH10/H1O1+ApmcQ9i87XdZQiB9cpN RYHA7RCEK2dh6dDccykQk3bC90xXMPg+O3R+C/SkwcnUak1UZaeK/SwQbq/t0tkMzYDRxfJ7 nyFiKxUehbNF3r9qlJgPqONwX5vJy4/GvDHdddSCxV41P/ejsZ8PykxyJs98UWhF54tGRWFl 7i1xvaDB9lN5WTLRKSO7wICuLiSz5WZHXMkyF4d+/O5ll7yz/o/JxK5vO/sduYDIlFTvBZDh gzaEtNf5tQjsjG4io8E0Yq0ViobLkS2RTNZT8ICq/Jmvl0SpbHRvYwa2DhNsK0YjHFQBB0FX IdhdUEzNefcNcYvqigJpdICoP2e4yJSyflHFO4dr0OrdnGLe1Zi/8Xo/2+M1dSSEt196rXaC kwu2KgIgmkRBb3cp2vIBBIIowU8W3qC1+w+RdMUrZxKGWJ3juwcgveJlzMpMZNyM1jobSXZ0 VHGMNJ3MwXlrEFPXaYJgibcg6brM6wGfX/LBvc/haWw4yO24lT5eitm4UBdIy9pKkKmHHh7s jfZJkB5fWKVdoCv/omy6UyH6ykLOPFugl+hVL2Prf8xrXuZe1CMS7ID9Lc8FaL1ROIN/W8Vk BIsJMaWOhks//7d92Uf3EArDlDShwR2+D+AMon8NULuLBHiEUQARAQABzTJHdWVudGVyIFJv ZWNrIChMaW51eCBhY2NvdW50KSA8bGludXhAcm9lY2stdXMubmV0PsLBgQQTAQIAKwIbAwYL CQgHAwIGFQgCCQoLBBYCAwECHgECF4ACGQEFAlVcphcFCRmg06EACgkQyx8mb86fmYFg0RAA nzXJzuPkLJaOmSIzPAqqnutACchT/meCOgMEpS5oLf6xn5ySZkl23OxuhpMZTVX+49c9pvBx hpvl5bCWFu5qC1jC2eWRYU+aZZE4sxMaAGeWenQJsiG9lP8wkfCJP3ockNu0ZXXAXwIbY1O1 c+l11zQkZw89zNgWgKobKzrDMBFOYtAh0pAInZ9TSn7oA4Ctejouo5wUugmk8MrDtUVXmEA9 7f9fgKYSwl/H7dfKKsS1bDOpyJlqhEAH94BHJdK/b1tzwJCFAXFhMlmlbYEk8kWjcxQgDWMu GAthQzSuAyhqyZwFcOlMCNbAcTSQawSo3B9yM9mHJne5RrAbVz4TWLnEaX8gA5xK3uCNCeyI sqYuzA4OzcMwnnTASvzsGZoYHTFP3DQwf2nzxD6yBGCfwNGIYfS0i8YN8XcBgEcDFMWpOQhT Pu3HeztMnF3HXrc0t7e5rDW9zCh3k2PA6D2NV4fews9KDFhLlTfCVzf0PS1dRVVWM+4jVl6l HRIAgWp+2/f8dx5vPc4Ycp4IsZN0l1h9uT7qm1KTwz+sSl1zOqKD/BpfGNZfLRRxrXthvvY8 BltcuZ4+PGFTcRkMytUbMDFMF9Cjd2W9dXD35PEtvj8wnEyzIos8bbgtLrGTv/SYhmPpahJA l8hPhYvmAvpOmusUUyB30StsHIU2LLccUPPOwU0ETofVZwEQALlLbQeBDTDbwQYrj0gbx3bq 7kpKABxN2MqeuqGr02DpS9883d/t7ontxasXoEz2GTioevvRmllJlPQERVxM8gQoNg22twF7 pB/zsrIjxkE9heE4wYfN1AyzT+AxgYN6f8hVQ7Nrc9XgZZe+8IkuW/Nf64KzNJXnSH4u6nJM J2+Dt274YoFcXR1nG76Q259mKwzbCukKbd6piL+VsT/qBrLhZe9Ivbjq5WMdkQKnP7gYKCAi pNVJC4enWfivZsYupMd9qn7Uv/oCZDYoBTdMSBUblaLMwlcjnPpOYK5rfHvC4opxl+P/Vzyz 6WC2TLkPtKvYvXmdsI6rnEI4Uucg0Au/Ulg7aqqKhzGPIbVaL+U0Wk82nz6hz+WP2ggTrY1w ZlPlRt8WM9w6WfLf2j+PuGklj37m+KvaOEfLsF1v464dSpy1tQVHhhp8LFTxh/6RWkRIR2uF I4v3Xu/k5D0LhaZHpQ4C+xKsQxpTGuYh2tnRaRL14YMW1dlI3HfeB2gj7Yc8XdHh9vkpPyuT nY/ZsFbnvBtiw7GchKKri2gDhRb2QNNDyBnQn5mRFw7CyuFclAksOdV/sdpQnYlYcRQWOUGY HhQ5eqTRZjm9z+qQe/T0HQpmiPTqQcIaG/edgKVTUjITfA7AJMKLQHgp04Vylb+G6jocnQQX JqvvP09whbqrABEBAAHCwWUEGAECAA8CGwwFAlVcpi8FCRmg08MACgkQyx8mb86fmYHNRQ/+ J0OZsBYP4leJvQF8lx9zif+v4ZY/6C9tTcUv/KNAE5leyrD4IKbnV4PnbrVhjq861it/zRQW cFpWQszZyWRwNPWUUz7ejmm9lAwPbr8xWT4qMSA43VKQ7ZCeTQJ4TC8kjqtcbw41SjkjrcTG wF52zFO4bOWyovVAPncvV9eGA/vtnd3xEZXQiSt91kBSqK28yjxAqK/c3G6i7IX2rg6pzgqh hiH3/1qM2M/LSuqAv0Rwrt/k+pZXE+B4Ud42hwmMr0TfhNxG+X7YKvjKC+SjPjqp0CaztQ0H nsDLSLElVROxCd9m8CAUuHplgmR3seYCOrT4jriMFBtKNPtj2EE4DNV4s7k0Zy+6iRQ8G8ng QjsSqYJx8iAR8JRB7Gm2rQOMv8lSRdjva++GT0VLXtHULdlzg8VjDnFZ3lfz5PWEOeIMk7Rj trjv82EZtrhLuLjHRCaG50OOm0hwPSk1J64R8O3HjSLdertmw7eyAYOo4RuWJguYMg5DRnBk WkRwrSuCn7UG+qVWZeKEsFKFOkynOs3pVbcbq1pxbhk3TRWCGRU5JolI4ohy/7JV1TVbjiDI HP/aVnm6NC8of26P40Pg8EdAhajZnHHjA7FrJXsy3cyIGqvg9os4rNkUWmrCfLLsZDHD8FnU mDW4+i+XlNFUPUYMrIKi9joBhu18ssf5i5Q= In-Reply-To: <20250428221420.2077697-5-paweldembicki@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 4/28/25 15:13, Pawel Dembicki wrote: > Implement support for setting the VOUT_SCALE_LOOP PMBus register > based on an optional device tree property "voltage-scale-loop". > > This allows the driver to provide the correct VOUT value depending > on the feedback voltage divider configuration for chips where the > bootloader does not configure the voltage scale. > > Signed-off-by: Pawel Dembicki > --- > drivers/hwmon/pmbus/mpq8785.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/hwmon/pmbus/mpq8785.c b/drivers/hwmon/pmbus/mpq8785.c > index e6a643856f08..6e2325d7f37b 100644 > --- a/drivers/hwmon/pmbus/mpq8785.c > +++ b/drivers/hwmon/pmbus/mpq8785.c > @@ -78,6 +78,8 @@ static int mpq8785_probe(struct i2c_client *client) > struct device *dev = &client->dev; > struct pmbus_driver_info *info; > enum chips chip_id; > + u32 voltage_scale; > + int ret; > > info = devm_kmemdup(dev, &mpq8785_info, sizeof(*info), GFP_KERNEL); > if (!info) > @@ -105,6 +107,14 @@ static int mpq8785_probe(struct i2c_client *client) > return -ENODEV; > } > > + if (!of_property_read_u32(dev->of_node, "voltage-scale-loop", > + &voltage_scale)) { > + ret = i2c_smbus_write_word_data(client, PMBUS_VOUT_SCALE_LOOP, > + voltage_scale); Per PMBus specification this value can be in any supported scale. Also, the chips do not support the full 16-bit value range. I see 10 bit for mpq8785 and mpm3695, 7 bit for mp2853, and 12 bit for MPM82504. There will have to be some device specific range check. I don't understand the units. The devicetree document talks about VOUT_SCALE_LOOP = VFB / VOUT * 1000, but I don't see how that translates into chip values. For MPM82504, the datasheet says 1 LSB=2mV. For mpm3695 it is 0.001/LSB. I have no idea how that is supposed to translate to the units suggested in the property patch. Either case, I think the property needs to be something generic that is well defined. Maybe "pmbus,voltage-scale-loop", but I really don't know what would be acceptable for DT maintainers. Guenter