Re: [PATCH 0/3] i2c: qcom-cci: Fix CCI clock rate enforcement
Wenmeng Liu <[email protected]> Thu, 23 Jul 2026 11:04:56 +0800
| Newsgroups | org.kernel.vger.linux-i2c,org.kernel.vger.linux-arm-msm,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
On 7/21/2026 10:58 PM, Loic Poulain wrote: > The CCI hw_params timing values (thigh, tlow, etc.) are expressed in > clock ticks and were calibrated for a specific CCI clock frequency per > hardware variant (19.2 MHz for v1/v1.5/msm8953, 37.5 MHz for v2). > Running at the wrong frequency causes incorrect I2C timings that may > violate the I2C specification. > > A previous series removed the cci_clk_rate field and the associated > warning from the driver on the grounds that the warning was noisy and > the rate was already set via assigned-clock-rates in the DT. However, > enforcing a clock frequency configuration through DT is fragile and not > the right approach, the driver owns the hw_params and should own the > clock rate too. > > This series reverts the removal of cci_clk_rate, fixes the missing rate > for the msm8953 variant (added after the field was removed), and > replaces the passive warn-only approach with an active clk_set_rate() > at probe time, retaining the warning for cases where the rate cannot be > applied. > > Signed-off-by: Loic Poulain <[email protected]> > --- > Loic Poulain (3): > Revert "i2c: qcom-cci: Remove unused struct member cci_clk_rate" > i2c: qcom-cci: Add missing cci_clk_rate for msm8953 > i2c: qcom-cci: Fix CCI clock rate enforcement > > drivers/i2c/busses/i2c-qcom-cci.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > --- > base-commit: fce2dfa773ced15f27dd27cd0b482a7473cdcf2a > change-id: 20260721-cci-clk-fix-fe145b2acfa7 > > Best regards, For this patch series: Tested-by: Wenmeng Liu <[email protected]>