Re: [PATCH] dt-bindings: mmc: Set maximum documented operating frequency as 384MHz

From: Bhupesh Sharma
Date: Mon Jul 25 2022 - 16:33:38 EST


Hi Rob,

On 7/26/22 1:59 AM, Rob Herring wrote:
On Mon, Jul 25, 2022 at 12:09 PM Bhupesh Sharma
<bhupesh.sharma@xxxxxxxxxx> wrote:

As Ulf noted in [1], the maximum operating frequency
documented in the mmc-controller device-tree bindings
should be updated to the maximum frequency supported
by the mmc controller(s).

Please send DT patches to the DT list so checks run and they are in
the review queue.

Oops, will do.

Without this fix in place, the 'make dtbs_check' reports
issues with 'max-frequency' value for ipq8074 sdhci node:

arch/arm64/boot/dts/qcom/ipq8074-hk01.dtb: mmc@7824900:
max-frequency:0:0: 384000000 is greater than the maximum of 200000000

[1]. https://www.spinics.net/lists/kernel/msg4442049.html

Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Cc: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
Cc: Rob Herring <robh@xxxxxxxxxx>
Signed-off-by: Bhupesh Sharma <bhupesh.sharma@xxxxxxxxxx>
---
- Rebased on linux-next/master

.../devicetree/bindings/mmc/mmc-controller.yaml | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/mmc/mmc-controller.yaml b/Documentation/devicetree/bindings/mmc/mmc-controller.yaml
index ff5ce89e5111..c49f3060c24a 100644
--- a/Documentation/devicetree/bindings/mmc/mmc-controller.yaml
+++ b/Documentation/devicetree/bindings/mmc/mmc-controller.yaml
@@ -87,12 +87,19 @@ properties:
enum: [1, 4, 8]
default: 1

+ # Maximum operating frequency:
+ # - for eMMC, the maximum supported frequency is 200MHz,
+ # - for SD/SDIO cards the SDR104 mode has a max supported
+ # frequency of 208MHz,
+ # - some mmc host controllers do support a max frequency
+ # upto 384MHz,
+ # so lets keep the maximum supported value here.

Add to the description instead of a comment.

Ok, will fix in v2.

Thanks,
Bhupesh