Re: [PATCH v3 1/5] i2c: qcom-cci: Switch msm8953 to the CCI v2 timing/rate config

From: Konrad Dybcio

Date: Fri Jul 31 2026 - 10:12:07 EST


On 7/29/26 2:25 PM, Loic Poulain wrote:
> The msm8953 CCI timing table is internally inconsistent. Its Standard
> and Fast timings match v1/v1.5, which are calibrated for a 19.2 MHz CCI
> clock, but its Fast+ timings are essentially the v2 values, which are
> calibrated for 37.5 MHz. Since all masters share a single CCI clock,
> no single rate can satisfy all three modes with the current table, and
> the DT assigns 19.2 MHz, so Fast+ timings are wrong.
>
> The msm8953 CCI is the same hardware version as msm8996/sdm630, which
> already use the cci_v2_data config (37.5 MHz). 37.5 MHz is supported by
> the msm8953 CCI RCG, so reuse cci_v2_data for msm8953 as well and drop
> the redundant, inconsistent standalone table. This makes all three I2C
> modes self-consistent under a single clock rate.
>
> Note this requires the CCI clock to run at 37.5 MHz, the driver selects
> and enforces the proper rate in following patches.
>
> Tested-by: Wenmeng Liu <wenmeng.liu@xxxxxxxxxxxxxxxx>

Wenmeng, have you actually tested this on MSM8953 device?

Konrad