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[78.88.45.245]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-ae0541b6e36sm333295866b.120.2025.06.21.03.20.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 21 Jun 2025 03:20:14 -0700 (PDT) Message-ID: <9627ed6f-2bb8-40b0-b647-5f659d87f2f9@oss.qualcomm.com> Date: Sat, 21 Jun 2025 12:20:11 +0200 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 , Sarthak Garg , Ulf Hansson , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Bjorn Andersson , Konrad Dybcio , Adrian Hunter Cc: linux-mmc@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, quic_cang@quicinc.com, quic_nguyenb@quicinc.com, quic_rampraka@quicinc.com, quic_pragalla@quicinc.com, quic_sayalil@quicinc.com, quic_nitirawa@quicinc.com, quic_bhaskarv@quicinc.com, kernel@oss.qualcomm.com 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: Konrad Dybcio In-Reply-To: <6040afd9-a2a8-49f0-85e9-95257b938156@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNjIxMDA2MCBTYWx0ZWRfXyIZeYy552/2s Obse1MPqHhV1dxwBgh0HUm6JP9BUkxm5jdn5cDpMb01V3sYrZQkwxyKgL0ts3sGxxhgR2oGn+Fi MP53uEQzWi0qESc5WYoz8LM+ClaVAbm6WyRb+divcrjJJTb+rLs2KUXoAhaQkQDam4vAeiC23ds 3GeQxb/OKQkFa+nI2ofSk/KCdYG170UeS1RrNz9yUcWaHp8Dyu7zX5ddNvvz49t966VPlAiheaC ofYWp+3oodb3kt6AJgjf5p/QbJHrdeh/PENQifnvgzV2rQQktDG3AaC0HIOJ+IDnY1DUjpCkAHw tuWPiBbwJMejWFcbtbxrc63RcCTUtDXZMYnwN1ThybstJfBnHAJ6xr/LprLRjAPs0dOQTvh1xXQ h2G9Q2TZjSnkj5w+cIir5xWAOdOxogAvwEgjt0OhD6SQbBj0FcqAqwIccoIpAMCrjdotXBom X-Proofpoint-ORIG-GUID: aibTOPVmpB2nzVpZ7Of9FdE7386AUgoq X-Authority-Analysis: v=2.4 cv=cbPSrmDM c=1 sm=1 tr=0 ts=68568760 cx=c_pps a=7E5Bxpl4vBhpaufnMqZlrw==:117 a=FpWmc02/iXfjRdCD7H54yg==:17 a=IkcTkHD0fZMA:10 a=6IFa9wvqVegA:10 a=COk6AnOGAAAA:8 a=pUFaWy8oF3eVePBgSHwA:9 a=QEXdDO2ut3YA:10 a=pJ04lnu7RYOZP9TFuWaZ:22 a=TjNXssC_j7lpFel5tvFf:22 X-Proofpoint-GUID: aibTOPVmpB2nzVpZ7Of9FdE7386AUgoq 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=2025-06-21_02,2025-06-20_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 clxscore=1015 spamscore=0 lowpriorityscore=0 malwarescore=0 mlxlogscore=999 suspectscore=0 bulkscore=0 priorityscore=1501 phishscore=0 mlxscore=0 adultscore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2505280000 definitions=main-2506210060 On 6/18/25 9:43 AM, 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. I don't understand why you're rejecting a common solution to a problem that surely exists outside this one specific chip from one specific vendor, which may be caused by a multitude of design choices, including erratic board (not SoC) electrical design Konrad