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Fri, 20 Jun 2025 09:08:05 +0000 (GMT) Received: from nasanex01a.na.qualcomm.com (nasanex01a.na.qualcomm.com [10.52.223.231]) by NASANPPMTA02.qualcomm.com (8.18.1.2/8.18.1.2) with ESMTPS id 55K985Bh014393 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 20 Jun 2025 09:08:05 GMT Received: from [10.217.216.168] (10.80.80.8) by nasanex01a.na.qualcomm.com (10.52.223.231) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.9; Fri, 20 Jun 2025 02:07:59 -0700 Message-ID: <9e345e90-58e6-4755-a0af-8e0b4ccd5d44@quicinc.com> Date: Fri, 20 Jun 2025 14:37:56 +0530 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 V3 2/4] dt-bindings: mmc: controller: Add max-sd-hs-frequency property To: Krzysztof Kozlowski , Ulf Hansson , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Bjorn Andersson , Konrad Dybcio , Adrian Hunter CC: , , , , , , , , , , , References: <20250618072818.1667097-1-quic_sartgarg@quicinc.com> <20250618072818.1667097-3-quic_sartgarg@quicinc.com> <6040afd9-a2a8-49f0-85e9-95257b938156@kernel.org> Content-Language: en-US From: Sarthak Garg In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: nasanex01a.na.qualcomm.com (10.52.223.231) To nasanex01a.na.qualcomm.com (10.52.223.231) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-ORIG-GUID: XTSWE4Sv_90BkLJb9rPSjfcXl0D6EZSz X-Authority-Analysis: v=2.4 cv=YKyfyQGx c=1 sm=1 tr=0 ts=685524f5 cx=c_pps a=JYp8KDb2vCoCEuGobkYCKw==:117 a=JYp8KDb2vCoCEuGobkYCKw==:17 a=GEpy-HfZoHoA:10 a=IkcTkHD0fZMA:10 a=6IFa9wvqVegA:10 a=COk6AnOGAAAA:8 a=fBqTZhuuraqRRh6TpvYA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=TjNXssC_j7lpFel5tvFf:22 X-Proofpoint-GUID: XTSWE4Sv_90BkLJb9rPSjfcXl0D6EZSz X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNjIwMDA2NiBTYWx0ZWRfXy4Gu4uIaBaMU lwAjqpLkzirQKGcuMkU0noOto5ZU3gCNj/NSjNQ97Zm2/i6856vPyPG5CE5/YKZfjLoGU0HtIGg 5+5jA9k8J7Yh2UaW8toGIealWcefe4emBd8fzJqoa0zz9CKwOdpudoGcBpoAmVgtJVIvT8bq2Qb nTLMQxfzdoHTErQ5W5gdK7+wHMcztGeySEC/WTLs1YzT51hsagQyDFz7n3K+ocuPiRk8lBVvIps 8IRJRep8Xjrb3TGyi3xrF9k9c5p1C/xIMjY5w1n2plA+33C8SfsAr+vya8wuWAmczPKg+jWBe72 o7lCEau0rTMETRtNLlvFu3nIr+0zu507vrClcgJdunr+PZYF3Rq+B09LfsDCBrXlbRfJp8rdIIc +iFdrLwtBEfFJ6E6aDUOt8qn+2JUetXoL/Hap29ooVOtrRelXHPFtfBFIdrX5M1cpUV7vMZF X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.0.736,FMLib:17.12.80.40 definitions=2025-06-20_03,2025-06-18_03,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 adultscore=0 impostorscore=0 priorityscore=1501 mlxscore=0 malwarescore=0 mlxlogscore=999 phishscore=0 suspectscore=0 clxscore=1015 lowpriorityscore=0 spamscore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2505280000 definitions=main-2506200066 On 6/18/2025 2:38 PM, Krzysztof Kozlowski wrote: > On 18/06/2025 10:38, Sarthak Garg wrote: >> >> >> On 6/18/2025 1:13 PM, Krzysztof Kozlowski wrote: >>> On 18/06/2025 09:28, Sarthak Garg wrote: >>>> Introduce a new optional device tree property `max-sd-hs-frequency` to >>>> limit the maximum frequency (in Hz) used for SD cards operating in >>>> High-Speed (HS) mode. >>>> >>>> This property is useful for platforms with vendor-specific hardware >>>> constraints, such as the presence of a level shifter that cannot >>>> reliably support the default 50 MHz HS frequency. It allows the host >>>> driver to cap the HS mode frequency accordingly. >>>> >>>> Signed-off-by: Sarthak Garg >>>> --- >>>> .../devicetree/bindings/mmc/mmc-controller-common.yaml | 10 ++++++++++ >>>> 1 file changed, 10 insertions(+) >>>> >>>> diff --git a/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml b/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml >>>> index 9a7235439759..1976f5f8c401 100644 >>>> --- a/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml >>>> +++ b/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml >>>> @@ -93,6 +93,16 @@ properties: >>>> minimum: 400000 >>>> maximum: 384000000 >>>> >>>> + max-sd-hs-frequency: >>>> + $ref: /schemas/types.yaml#/definitions/uint32 >>>> + description: | >>>> + Maximum frequency (in Hz) to be used for SD cards operating in >>>> + High-Speed (HS) mode. This is useful for platforms with vendor-specific >>>> + limitations, such as the presence of a level shifter that cannot support >>>> + the default 50 MHz HS frequency or other. >>>> + minimum: 400000 >>>> + maximum: 50000000 >>> >>> This might be fine, but your DTS suggests clearly this is SoC compatible >>> deducible, which I already said at v1. >>> >>> So now you send v3 which is the same as v1, so you get the same comments. >>> >>> Best regards, >>> Krzysztof >> >> Introducing this flag no longer becomes SoC compatible because as per >> discussions in V2 patchset with Ulf and Konrad this new property can be >> used by any vendor who wants to limit the HS mode frequency due to any >> reason. Thats why moved to this generic approach again in V3 as compared >> to compatible based approach in V2. > > The are no arguments provided in favor, so my review from v1 stays. You > get the same comments. > > Best regards, > Krzysztof @Ulf, @Konrad — since you previously supported the idea of a generic property for HS frequency limitation, could you please share your thoughts on whether this still seems like a valid approach? Best regards, Sarthak