From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 82DA1C83F14 for ; Wed, 9 Jul 2025 15:59:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To: Subject:MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=gqBmmiQ/noa4bl94QYtmV2Q1TIUhxHrRIxLG0dd9C90=; b=46G3AfQ1yDu1c9 UXCDc+UFXaxCZyD3DlE1mKbJC3G3KaZzw6h73YKQCH9qo4nm66ddI99x8iF39qFM29Judg/Xzss0e s/psYq5VZ39m3OUhk1QIKDliPKch5Dc0Blfl04m6jAxzrKOB2xCB0MZvf5xTPhQgz7Ot0l94j0cSV FxnVKjQ4d6S5OIsaOJwv4q6gV5q6nVQJ9SHhPOptZggus0U3SIdYQD+ginGgJhkc6OhjLxy4NNa0e h85EXECE2yfglS7cG+jTempr8NoCXOSq1s4ESDrwq3Lplb5I9C68pIGFDD0nV5Lj5QG7CqxOa5qj6 KXHZYFk6ENgWqXvCP/1Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uZXCH-00000009Eto-0eZ0; Wed, 09 Jul 2025 15:59:01 +0000 Received: from nyc.source.kernel.org ([147.75.193.91]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uZVCf-00000008qFp-11mj for linux-phy@lists.infradead.org; Wed, 09 Jul 2025 13:51:18 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 85DD5A53E46; Wed, 9 Jul 2025 13:51:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 96B24C4CEEF; Wed, 9 Jul 2025 13:51:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1752069076; bh=7fDy/IDtzY+P10jh2FH05bGuxkbANfM+VBCgF1upyb0=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Qvcq9pczvwZs/pgT3fBuh6JlQaf/4U/OlntMStbs5+RnniDq9sAMJ0yG2swfAxW39 y8Ewv6JQ0cKwsYiM5F5CFarb2VMl1A4Zz9KOnwbrN6g4zlxdy8SMvF0tZHkYUBIY9o T49meZ/NxJJH4QX6FgjKQYG/APVEpS2B+Ra3KZvbSBjQ/tupkP1RJ8w7ENyy3dt091 iZc/Xmsg/6I7DASsMa+V8/BbXXEWCcvEKGG0dY9VvrSyEouwfma5wrA0tZQejNbXaY SuOk9fsXN/Ixn+BtgZQnMpWD1yOioXiEdNUuJ9UCjVttI4b7Za77oLNX+nUAh27cLe DJjV2polVNeKQ== Message-ID: Date: Wed, 9 Jul 2025 15:51:10 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/4] dt-bindings: phy: qcom,snps-eusb2-repeater: Document qcom,tune-res-fsdif To: Luca Weiss Cc: Vinod Koul , Kishon Vijay Abraham I , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Abel Vesa , ~postmarketos/upstreaming@lists.sr.ht, phone-devel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-phy@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250625-sm7635-eusb-repeater-v1-0-19d85541eb4c@fairphone.com> <20250625-sm7635-eusb-repeater-v1-1-19d85541eb4c@fairphone.com> <20250708-unicorn-of-ancient-excellence-e8945c@krzk-bin> <20250708-stoic-slim-bison-ac55ee@krzk-bin> <1c7fdeca-d531-4f90-9e4c-4d8bfac67fae@kernel.org> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.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 TNeBxJu5Ex0Izf1NV9CzC3nNaFUYOY8KfN01X5SExAoVTr09ewARAQABzSVLcnp5c3p0b2Yg S296bG93c2tpIDxrcnprQGtlcm5lbC5vcmc+wsGVBBMBCgA/AhsDBgsJCAcDAgYVCAIJCgsE FgIDAQIeAQIXgBYhBJvQfg4MUfjVlne3VBuTQ307QWKbBQJoF1BKBQkWlnSaAAoJEBuTQ307 QWKbHukP/3t4tRp/bvDnxJfmNdNVn0gv9ep3L39IntPalBFwRKytqeQkzAju0whYWg+R/rwp +r2I1Fzwt7+PTjsnMFlh1AZxGDmP5MFkzVsMnfX1lGiXhYSOMP97XL6R1QSXxaWOpGNCDaUl ajorB0lJDcC0q3xAdwzRConxYVhlgmTrRiD8oLlSCD5baEAt5Zw17UTNDnDGmZQKR0fqLpWy 786Lm5OScb7DjEgcA2PRm17st4UQ1kF0rQHokVaotxRM74PPDB8bCsunlghJl1DRK9s1aSuN hL1Pv9VD8b4dFNvCo7b4hfAANPU67W40AaaGZ3UAfmw+1MYyo4QuAZGKzaP2ukbdCD/DYnqi tJy88XqWtyb4UQWKNoQqGKzlYXdKsldYqrLHGoMvj1UN9XcRtXHST/IaLn72o7j7/h/Ac5EL 8lSUVIG4TYn59NyxxAXa07Wi6zjVL1U11fTnFmE29ALYQEXKBI3KUO1A3p4sQWzU7uRmbuxn naUmm8RbpMcOfa9JjlXCLmQ5IP7Rr5tYZUCkZz08LIfF8UMXwH7OOEX87Y++EkAB+pzKZNNd hwoXulTAgjSy+OiaLtuCys9VdXLZ3Zy314azaCU3BoWgaMV0eAW/+gprWMXQM1lrlzvwlD/k whyy9wGf0AEPpLssLVt9VVxNjo6BIkt6d1pMg6mHsUEVzsFNBFVDXDQBEADNkrQYSREUL4D3 Gws46JEoZ9HEQOKtkrwjrzlw/tCmqVzERRPvz2Xg8n7+HRCrgqnodIYoUh5WsU84N03KlLue MNsWLJBvBaubYN4JuJIdRr4dS4oyF1/fQAQPHh8Thpiz0SAZFx6iWKB7Qrz3OrGCjTPcW6ei OMheesVS5hxietSmlin+SilmIAPZHx7n242u6kdHOh+/SyLImKn/dh9RzatVpUKbv34eP1wA GldWsRxbf3WP9pFNObSzI/Bo3kA89Xx2rO2roC+Gq4LeHvo7ptzcLcrqaHUAcZ3CgFG88CnA 6z6lBZn0WyewEcPOPdcUB2Q7D/NiUY+HDiV99rAYPJztjeTrBSTnHeSBPb+qn5ZZGQwIdUW9 YegxWKvXXHTwB5eMzo/RB6vffwqcnHDoe0q7VgzRRZJwpi6aMIXLfeWZ5Wrwaw2zldFuO4Dt 91pFzBSOIpeMtfgb/Pfe/a1WJ/GgaIRIBE+NUqckM+3zJHGmVPqJP/h2Iwv6nw8U+7Yyl6gU BLHFTg2hYnLFJI4Xjg+AX1hHFVKmvl3VBHIsBv0oDcsQWXqY+NaFahT0lRPjYtrTa1v3tem/ JoFzZ4B0p27K+qQCF2R96hVvuEyjzBmdq2esyE6zIqftdo4MOJho8uctOiWbwNNq2U9pPWmu 4vXVFBYIGmpyNPYzRm0QPwARAQABwsF8BBgBCgAmAhsMFiEEm9B+DgxR+NWWd7dUG5NDfTtB YpsFAmgXUF8FCRaWWyoACgkQG5NDfTtBYptO0w//dlXJs5/42hAXKsk+PDg3wyEFb4NpyA1v qmx7SfAzk9Hf6lWwU1O6AbqNMbh6PjEwadKUk1m04S7EjdQLsj/MBSgoQtCT3MDmWUUtHZd5 RYIPnPq3WVB47GtuO6/u375tsxhtf7vt95QSYJwCB+ZUgo4T+FV4hquZ4AsRkbgavtIzQisg Dgv76tnEv3YHV8Jn9mi/Bu0FURF+5kpdMfgo1sq6RXNQ//TVf8yFgRtTUdXxW/qHjlYURrm2 H4kutobVEIxiyu6m05q3e9eZB/TaMMNVORx+1kM3j7f0rwtEYUFzY1ygQfpcMDPl7pRYoJjB dSsm0ZuzDaCwaxg2t8hqQJBzJCezTOIkjHUsWAK+tEbU4Z4SnNpCyM3fBqsgYdJxjyC/tWVT AQ18NRLtPw7tK1rdcwCl0GFQHwSwk5pDpz1NH40e6lU+NcXSeiqkDDRkHlftKPV/dV+lQXiu jWt87ecuHlpL3uuQ0ZZNWqHgZoQLXoqC2ZV5KrtKWb/jyiFX/sxSrodALf0zf+tfHv0FZWT2 zHjUqd0t4njD/UOsuIMOQn4Ig0SdivYPfZukb5cdasKJukG1NOpbW7yRNivaCnfZz6dTawXw XRIV/KDsHQiyVxKvN73bThKhONkcX2LWuD928tAR6XMM2G5ovxLe09vuOzzfTWQDsm++9UKF a/A= In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250709_065117_426221_AAC2CBDE X-CRM114-Status: GOOD ( 26.41 ) X-BeenThere: linux-phy@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux Phy Mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-phy" Errors-To: linux-phy-bounces+linux-phy=archiver.kernel.org@lists.infradead.org On 09/07/2025 14:22, Luca Weiss wrote: > On Wed Jul 9, 2025 at 12:16 PM CEST, Krzysztof Kozlowski wrote: >> On 09/07/2025 11:40, Luca Weiss wrote: >>> Hi Krzysztof, >>> >>> On Tue Jul 8, 2025 at 10:31 AM CEST, Luca Weiss wrote: >>>> On Tue Jul 8, 2025 at 10:21 AM CEST, Krzysztof Kozlowski wrote: >>>>> On Tue, Jul 08, 2025 at 10:13:24AM +0200, Krzysztof Kozlowski wrote: >>>>>> On Wed, Jun 25, 2025 at 11:14:56AM +0200, Luca Weiss wrote: >>>>>>> Document the FS Differential TX Output Resistance Tuning value found on >>>>>>> the eUSB2 repeater on Qualcomm PMICs. >>>>>>> >>>>>>> Signed-off-by: Luca Weiss >>>>>>> --- >>>>>>> Documentation/devicetree/bindings/phy/qcom,snps-eusb2-repeater.yaml | 6 ++++++ >>>>>>> 1 file changed, 6 insertions(+) >>>>>>> >>>>>>> diff --git a/Documentation/devicetree/bindings/phy/qcom,snps-eusb2-repeater.yaml b/Documentation/devicetree/bindings/phy/qcom,snps-eusb2-repeater.yaml >>>>>>> index 27f064a71c9fb8cb60e8333fb285f0510a4af94f..6bfd11657e2992735998063b3ca390e04a03930d 100644 >>>>>>> --- a/Documentation/devicetree/bindings/phy/qcom,snps-eusb2-repeater.yaml >>>>>>> +++ b/Documentation/devicetree/bindings/phy/qcom,snps-eusb2-repeater.yaml >>>>>>> @@ -52,6 +52,12 @@ properties: >>>>>>> minimum: 0 >>>>>>> maximum: 7 >>>>>>> >>>>>>> + qcom,tune-res-fsdif: >>>>>>> + $ref: /schemas/types.yaml#/definitions/uint8 >>>>>>> + description: FS Differential TX Output Resistance Tuning >>>>>> >>>>>> Resistance is in Ohms, tuning could be in dB, so I wonder what are the >>>>>> actual units here. Neither commit msg nor this description helps me to >>>>>> understand that. >>>>> >>>>> I checked and the values are in Ohms. >>>> >>>> Yes it's Ohms but not 0x00 = 0 ohms, and it's also an offset in ohms >>>> from the nominal value according to the Hardware Register Description I >>>> have, e.g. 0x7 = -12.1ohm from the default >>>> >>>> I can try and create bindings using these Ohm offset values, I didn't >>>> worry about it too much since the other tuning values in these bindings >>>> are also just register values, presumably from before Konrad had access >>>> to the docs. >>> >>> I've taken some more looks, and checked how similar tuning is handled in >>> qcom,usb-snps-femto-v2.yaml and phy-qcom-snps-femto-v2.c, and changing up >>> the concept of tuning in the eUSB2-repeater bindings+driver is not a >>> trivial task. >>> >>> Since this is adding just one more property in-line with the already >>> supported properties in the bindings+driver, can we get this in as-is, >>> and deprecate all 4 qcom,tune-* properties later with a replacement that >>> describes the values better? >> >> This is a new property, so other existing properties do not matter here. >> We cannot take new code which you already think should be deprecated. >> >> register-like values are acceptable for vendor properties, but that does >> not make them usually more readable. The question is whether this should >> be more readable for hardware engineers or anyone writing/validating >> DTS. Is the actual resistance important or no one ever cares because you >> paste whatever qcom told you and you do not know what should be actually >> there? >> >> I can imagine the first - that some document explains you should have >> resistance of foo because of bar, which would mean the property should >> be more readable. But I can also imagine the second. Make your claim in >> commit msg. > > Would this text in the commit message work for you? > > --- > Document the FS Differential TX Output Resistance Tuning value found on > the eUSB2 repeater on Qualcomm PMICs. The tuning values have special > meanings, being different offsets of the resistance to the default value > in Ohms but the exact meaning is not relevant here, as the correct > tuning is determined by hardware engineers to make sure the electrical > properties are as expected. > --- > > I'm trying to avoid resending the whole series if we're not yet aligned > on the wording. Sounds fine. Best regards, Krzysztof -- linux-phy mailing list linux-phy@lists.infradead.org https://lists.infradead.org/mailman/listinfo/linux-phy