linux-kernel - [PATCH 0/5] Qualcomm CCI I2C clock requirements enforcement

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Message-Id: <20250904-topic-cci_updates-v1-0-d38559692703@oss.qualcomm.com>
Date: Thu, 04 Sep 2025 16:31:19 +0200
From: Konrad Dybcio <konradybcio@...nel.org>
To: Bjorn Andersson <andersson@...nel.org>, 
 Konrad Dybcio <konradybcio@...nel.org>, Rob Herring <robh@...nel.org>, 
 Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, 
 Bryan O'Donoghue <bryan.odonoghue@...aro.org>, 
 Loic Poulain <loic.poulain@....qualcomm.com>, 
 Robert Foss <rfoss@...nel.org>, Andi Shyti <andi.shyti@...nel.org>
Cc: Marijn Suijten <marijn.suijten@...ainline.org>, 
 linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org, 
 linux-kernel@...r.kernel.org, linux-i2c@...r.kernel.org, 
 Konrad Dybcio <konrad.dybcio@....qualcomm.com>
Subject: [PATCH 0/5] Qualcomm CCI I2C clock requirements enforcement

The hardware requires the faster of the two (37.5 MHz as opposed to
19.2 MHz) clock rates to hit the required timings for I2C Fast+ Mode.

Additionally, the magic presets for electrical tuning registers on SoCs
supporting that faster mode ("cci_v2" in the driver) are calculated
based on that faster frequency.

Moreover, while its unlikely that it would ever exhibit as an issue
given CCI is a slow & tiny core, we do need to express a minimal voltage
level for any given clock rate, which is where the (optional -
backwards compat) OPP table addition comes in.

This series helps ensure all these requirements are met.

Patch 1 is a related but independent fix, can be picked right away
Patch 5 can be functionally merged as-is, but depends on patch 2 for
bindings

Signed-off-by: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
---
Konrad Dybcio (5):
      arm64: dts: qcom: sc8280xp: Fix CCI3 interrupt
      dt-bindings: i2c: qcom-cci: Allow operating-points-v2
      i2c: qcom-cci: Drop single-line wrappers
      i2c: qcom-cci: Add OPP table support and enforce FAST_PLUS requirements
      arm64: dts: qcom: sc8280xp: Add OPP table for CCI hosts

 .../devicetree/bindings/i2c/qcom,i2c-cci.yaml      |  2 +
 arch/arm64/boot/dts/qcom/sc8280xp.dtsi             | 16 +++++++-
 drivers/i2c/busses/i2c-qcom-cci.c                  | 45 +++++++++++++++++-----
 3 files changed, 52 insertions(+), 11 deletions(-)
---
base-commit: 4ac65880ebca1b68495bd8704263b26c050ac010
change-id: 20250904-topic-cci_updates-800fdc9bada4

Best regards,
-- 
Konrad Dybcio <konrad.dybcio@....qualcomm.com>