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From: Akhil R <akhilrajeev@nvidia.com>
To: Laxman Dewangan <ldewangan@nvidia.com>,
	Dmitry Osipenko <digetx@gmail.com>,
	Andi Shyti <andi.shyti@kernel.org>,
	Thierry Reding <thierry.reding@kernel.org>,
	Jonathan Hunter <jonathanh@nvidia.com>,
	"Wolfram Sang" <wsa+renesas@sang-engineering.com>,
	Kartik Rajput <kkartik@nvidia.com>,
	Akhil R <akhilrajeev@nvidia.com>, <linux-i2c@vger.kernel.org>,
	<linux-tegra@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH] i2c: tegra: Use non-HS timings for clock divisor
Date: Tue, 10 Nov 2026 16:23:00 +0000	[thread overview]
Message-ID: <20261110162300.3834584-1-akhilrajeev@nvidia.com> (raw)

Programming the HS timing registers overwrites the local tlow and thigh
values before they are used to calculate the controller clock rate. On
controllers with HS support, this mixes HS timings with the clock divisor
calculation and sets an incorrect clock rate.

Calculate the clock multiplier before the HS register setup overwrites
the selected non-HS timings.

Fixes: 978b3ccbbac3 ("i2c: tegra: Add HS mode support")
Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
---
 drivers/i2c/busses/i2c-tegra.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 76d21bc51c618..6a98432734d37 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -976,6 +976,8 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 	if (i2c_dev->hw->has_interface_timing_reg && tsu_thd)
 		i2c_writel(i2c_dev, tsu_thd, i2c_dev->hw->regs->interface_timing_1);
 
+	clk_multiplier = (tlow + thigh + 2) * (non_hs_mode + 1);
+
 	/* Write HS mode registers. These will get used only for HS mode*/
 	if (i2c_dev->hw->enable_hs_mode_support) {
 		tlow = i2c_dev->hw->tlow_hs_mode;
@@ -988,8 +990,6 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 		i2c_writel(i2c_dev, tsu_thd, i2c_dev->hw->regs->hs_interface_timing_1);
 	}
 
-	clk_multiplier = (tlow + thigh + 2) * (non_hs_mode + 1);
-
 	err = clk_set_rate(i2c_dev->div_clk,
 			   t->bus_freq_hz * clk_multiplier);
 	if (err) {

base-commit: 7649ba73f9e7e1e04d0b46213e39c79ae09dd55c
-- 
2.43.0


             reply	other threads:[~2026-11-10 16:24 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-11-10 16:23 Akhil R [this message]
2026-11-10 17:06 ` Jon Hunter

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