From: Loic Poulain <loic.poulain@oss.qualcomm.com>
To: Robert Foss <rfoss@kernel.org>,
Andi Shyti <andi.shyti@kernel.org>,
Wolfram Sang <wsa+renesas@sang-engineering.com>,
Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>,
Luca Weiss <luca@lucaweiss.eu>
Cc: linux-i2c@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-kernel@vger.kernel.org, vladimir.zapolskiy@linaro.org,
konradybcio@kernel.org, stephan.gerhold@linaro.org,
Loic Poulain <loic.poulain@oss.qualcomm.com>
Subject: [PATCH v4 1/5] i2c: qcom-cci: Switch msm8953 to the CCI v2 timing/rate config
Date: Sat, 01 Aug 2026 22:10:43 +0200 [thread overview]
Message-ID: <20260801-cci-clk-fix-v4-1-e1d80da54e01@oss.qualcomm.com> (raw)
In-Reply-To: <20260801-cci-clk-fix-v4-0-e1d80da54e01@oss.qualcomm.com>
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.
Signed-off-by: Loic Poulain <loic.poulain@oss.qualcomm.com>
---
drivers/i2c/busses/i2c-qcom-cci.c | 47 +--------------------------------------
1 file changed, 1 insertion(+), 46 deletions(-)
diff --git a/drivers/i2c/busses/i2c-qcom-cci.c b/drivers/i2c/busses/i2c-qcom-cci.c
index bdeda3979c4814b5cdb463734b8361da7fffa879..0a216c4d08114f267c8441925e8811ca64f1a909 100644
--- a/drivers/i2c/busses/i2c-qcom-cci.c
+++ b/drivers/i2c/busses/i2c-qcom-cci.c
@@ -756,54 +756,9 @@ static const struct cci_data cci_v2_data = {
},
};
-static const struct cci_data cci_msm8953_data = {
- .num_masters = 2,
- .queue_size = { 64, 16 },
- .quirks = {
- .max_write_len = 11,
- .max_read_len = 12,
- },
- .params[I2C_MODE_STANDARD] = {
- .thigh = 78,
- .tlow = 114,
- .tsu_sto = 28,
- .tsu_sta = 28,
- .thd_dat = 10,
- .thd_sta = 77,
- .tbuf = 118,
- .scl_stretch_en = 0,
- .trdhld = 6,
- .tsp = 1
- },
- .params[I2C_MODE_FAST] = {
- .thigh = 20,
- .tlow = 28,
- .tsu_sto = 21,
- .tsu_sta = 21,
- .thd_dat = 13,
- .thd_sta = 18,
- .tbuf = 32,
- .scl_stretch_en = 0,
- .trdhld = 6,
- .tsp = 3
- },
- .params[I2C_MODE_FAST_PLUS] = {
- .thigh = 16,
- .tlow = 22,
- .tsu_sto = 17,
- .tsu_sta = 18,
- .thd_dat = 16,
- .thd_sta = 15,
- .tbuf = 19,
- .scl_stretch_en = 1,
- .trdhld = 3,
- .tsp = 3
- },
-};
-
static const struct of_device_id cci_dt_match[] = {
{ .compatible = "qcom,msm8226-cci", .data = &cci_v1_data},
- { .compatible = "qcom,msm8953-cci", .data = &cci_msm8953_data},
+ { .compatible = "qcom,msm8953-cci", .data = &cci_v2_data},
{ .compatible = "qcom,msm8974-cci", .data = &cci_v1_5_data},
{ .compatible = "qcom,msm8996-cci", .data = &cci_v2_data},
--
2.34.1
next prev parent reply other threads:[~2026-08-01 20:10 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-01 20:10 [PATCH v4 0/5] i2c: qcom-cci: Enforce the required CCI clock rate Loic Poulain
2026-08-01 20:10 ` Loic Poulain [this message]
2026-08-01 20:10 ` [PATCH v4 2/5] i2c: qcom-cci: Support per-mode CCI clock rates Loic Poulain
2026-08-01 20:10 ` [PATCH v4 3/5] i2c: qcom-cci: Add 19.2 MHz timings for the v2 CCI Loic Poulain
2026-08-01 20:10 ` [PATCH v4 4/5] i2c: qcom-cci: Share the timing table across CCI revisions Loic Poulain
2026-08-01 20:10 ` [PATCH v4 5/5] i2c: qcom-cci: Enforce the required CCI clock rate Loic Poulain
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260801-cci-clk-fix-v4-1-e1d80da54e01@oss.qualcomm.com \
--to=loic.poulain@oss.qualcomm.com \
--cc=andi.shyti@kernel.org \
--cc=dmitry.baryshkov@oss.qualcomm.com \
--cc=konradybcio@kernel.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-i2c@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=luca@lucaweiss.eu \
--cc=rfoss@kernel.org \
--cc=stephan.gerhold@linaro.org \
--cc=vladimir.zapolskiy@linaro.org \
--cc=wsa+renesas@sang-engineering.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®