From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 264C43403F9; Sat, 30 May 2026 17:33:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780162408; cv=none; b=Pu8AFO1jxt9NV4HRw3Ln5AkBrb5QbOgjeiK53d5NHM7u2jBPjYPn1ut6W8bCpaRT7BIExkOJlgM6f42qUy7pZQ+R0mgmPRpJKTdxue3GUTwHHCphs83/ZBwQO/rl0WQUIe/5nOzCFH8/xW8ZgUwuJ6sUi7wQI5ahD7JKq/BdCzg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780162408; c=relaxed/simple; bh=Cwzmcd1bXpq1ItCP3waaFojujM6EvxkPRqBPiv4+6EE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=L02waWwGwSsa5C4hkQCkWEkGMXHFdVnwDWAXbA7q4xyjR9+/Qn/pwA/lzENyJEPU2J8nQ/vNLi0ZXjU6mTxHe6wo8cf/fxxJLa8hImMbm5eLwkOCKUp4oYg6KjGLmFHRU3ypFt14ZOoiah4n+hSM3f2vi5DVYFXjHmj27hDGlx0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DtB1Ks3p; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="DtB1Ks3p" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF4BC1F00893; Sat, 30 May 2026 17:33:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780162406; bh=uAflBWOHLMczVAx0OqWwLrWmJzNPKJqnt7OnFqzNt6g=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=DtB1Ks3pddrvkt5ANvMit/Nr8FN17UEKfuMv2Qi/BtHKQyho9447UtfHZj+UeLCAc 09J6ceCqzucIPNqZtuXbMHDjr4ws45MU4fPPOnF2nMWLDJSi7Xy9YXGzwQDii0YrUS xqSj+RKNT8jbK0/5+wUTEiPeXdH/RHgcHb/m3anLXeuAKrSoPHv4VTSq/6dykdEP47 XdsWrzVjZB1mNd1igVz3RKG4798No2SYhFHLns+U3v1oUPlG9wpK3duXFV/Fc9aZsU 0QIFapivknON4x62Ec46BzEa/orUxdutBwrkh0w/NOxD+N8A3O+hCnrSSx6439d7bj Ob5C2TZg2QF/g== Message-ID: Date: Sat, 30 May 2026 19:33:20 +0200 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: [PATCH v6 1/2] dt-bindings: ufs: Document static TX Equalization settings properties To: Can Guo Cc: bvanassche@acm.org, beanhuo@micron.com, peter.wang@mediatek.com, martin.petersen@oracle.com, mani@kernel.org, linux-scsi@vger.kernel.org, Alim Akhtar , Avri Altman , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Matthias Brugger , AngeloGioacchino Del Regno , Zhaoming Luo , Ram Kumar Dwivedi , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , open list , "moderated list:ARM/Mediatek SoC support:Keyword:mediatek" , "moderated list:ARM/Mediatek SoC support:Keyword:mediatek" References: <20260529113338.984301-1-can.guo@oss.qualcomm.com> <20260529113338.984301-2-can.guo@oss.qualcomm.com> <20260529-neat-bright-shellfish-eab5e8@quoll> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 30/05/2026 14:45, Can Guo wrote: > > > On 5/30/2026 12:58 AM, Krzysztof Kozlowski wrote: >> On Fri, May 29, 2026 at 04:33:37AM -0700, Can Guo wrote: >>> UFS v5.0/UFSHCI v5.0 add HS-G6 support (46.6 Gbps/lane) via UniPro v3.0 >>> and M-PHY v6.0. In these specs, TX Equalization is defined for all High >>> Speed Gears (not only HS-G6) to compensate channel loss and improve signal >>> integrity at high speed operation. >>> >>> For HS-G6, M-PHY uses PAM4 1b1b line coding, Pre-Coding may also be >>> required depending on channel characteristics. >>> >>> Add vendor-neutral DT properties: >>> >>> - patternProperties for txeq-preshoot-g[1-6] and txeq-deemphasis-g[1-6] >>> - fixed property tx-precode-enable-g6 >>> >>> Each property is a uint32 array of per-lane tuples: >>> , [] >>> >>> Accept 2 or 4 values (x1/x2 lane configs). PreShoot and DeEmphasis values >>> are 0..7. Precode enable values are 0/1 and only applicable to HS-G6. >>> >>> Acked-by: Manivannan Sadhasivam >>> Reviewed-by: Bean Huo >>> Reviewed-by: Peter Wang >>> Signed-off-by: Can Guo >>> --- >>> .../devicetree/bindings/ufs/ufs-common.yaml | 45 +++++++++++++++++++ >>> 1 file changed, 45 insertions(+) >>> >>> diff --git a/Documentation/devicetree/bindings/ufs/ufs-common.yaml b/Documentation/devicetree/bindings/ufs/ufs-common.yaml >>> index ed97f5682509..d90cf25adfa5 100644 >>> --- a/Documentation/devicetree/bindings/ufs/ufs-common.yaml >>> +++ b/Documentation/devicetree/bindings/ufs/ufs-common.yaml >>> @@ -105,6 +105,51 @@ properties: >>> Restricts the UFS controller to rate-a or rate-b for both TX and >>> RX directions. >>> >>> + tx-precode-enable-g6: >>> + $ref: /schemas/types.yaml#/definitions/uint32-array >>> + oneOf: >>> + - minItems: 2 >>> + maxItems: 2 >>> + - minItems: 4 >>> + maxItems: 4 >>> + items: >>> + enum: [0, 1] >>> + description: | >>> + Static TX Precode enable values for HS-G6 only. >>> + Values are specified as per-lane tuples: >>> + , []. >> You need to include them in any of applicable examples, otherwise >> nothing here is validated. > Hi Krzysztof, > > Thanks for the review. > > Since no UFS5-capable SoC binding exists upstream yet (the target SoC is I would imagine cover letter or commit msg would briefly mention that. > still pre-CS), there is no vendor-specific YAML to attach the example to. > > Is a synthetic example directly in ufs-common.yaml OK to you? Skip example in such case. >> >> Why values cannot be on or off? Or even better: why you cannot just list >> all the lanes which has it enabled, assuming disabled is by default? > Thanks for the suggestions. > > For the "just list enabled lanes" suggestion: precode must be configured > independently for the Host-side TX and Device-side TX transceivers within > the same physical lane. A lane index list alone cannot capture this > two-dimensional per-lane state. The tuple format > is the minimal encoding that covers both. Again, why do you need to encode '0'? > > For the "on/off" suggestion: the on/off string pattern is used with > single-value properties (e.g. LED default-state) read via > of_property_read_string(). I am not aware of precedent for on/off as a > string array for per-lane tuples. git grep string-array. Plenty of precedents. Best regards, Krzysztof