linux-kernel - [PATCH RESEND v3 3/5] i2c: davinci: calculate bus freq from Hz instead of kHz

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Message-Id: <20251117-i2c-mux-v3-3-696c83e3505a@gmail.com>
Date: Mon, 17 Nov 2025 10:05:00 +0100
From: Marcus Folkesson <marcus.folkesson@...il.com>
To: Wolfram Sang <wsa+renesas@...g-engineering.com>, 
 Peter Rosin <peda@...ntia.se>, 
 Michael Hennerich <michael.hennerich@...log.com>, 
 Bartosz Golaszewski <brgl@...ev.pl>, Andi Shyti <andi.shyti@...nel.org>
Cc: linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-arm-kernel@...ts.infradead.org, 
 Marcus Folkesson <marcus.folkesson@...il.com>, 
 Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: [PATCH RESEND v3 3/5] i2c: davinci: calculate bus freq from Hz
 instead of kHz

The bus frequency is unnecessarily converted between Hz and kHz in
several places.
This is probably an old legacy from the old times (pre-devicetrees)
when the davinci_i2c_platform_data took the bus_freq in kHz.

Stick to Hz.

Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Signed-off-by: Marcus Folkesson <marcus.folkesson@...il.com>
---
 drivers/i2c/busses/i2c-davinci.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 6a3d4e9e07f4..82f295619c4d 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -117,8 +117,6 @@
 /* timeout for pm runtime autosuspend */
 #define DAVINCI_I2C_PM_TIMEOUT	1000	/* ms */
 
-#define DAVINCI_I2C_DEFAULT_BUS_FREQ	100
-
 struct davinci_i2c_dev {
 	struct device           *dev;
 	void __iomem		*base;
@@ -134,8 +132,8 @@ struct davinci_i2c_dev {
 #ifdef CONFIG_CPU_FREQ
 	struct notifier_block	freq_transition;
 #endif
-	/* standard bus frequency (kHz) */
-	unsigned int		bus_freq;
+	/* standard bus frequency */
+	unsigned int		bus_freq_hz;
 	/* Chip has a ICPFUNC register */
 	bool			has_pfunc;
 };
@@ -209,16 +207,16 @@ static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev)
 	if (device_is_compatible(dev->dev, "ti,keystone-i2c"))
 		d = 6;
 
-	clk = ((input_clock / (psc + 1)) / (dev->bus_freq * 1000));
+	clk = ((input_clock / (psc + 1)) / (dev->bus_freq_hz));
 	/* Avoid driving the bus too fast because of rounding errors above */
-	if (input_clock / (psc + 1) / clk > dev->bus_freq * 1000)
+	if (input_clock / (psc + 1) / clk > dev->bus_freq_hz)
 		clk++;
 	/*
 	 * According to I2C-BUS Spec 2.1, in FAST-MODE LOW period should be at
 	 * least 1.3uS, which is not the case with 50% duty cycle. Driving HIGH
 	 * to LOW ratio as 1 to 2 is more safe.
 	 */
-	if (dev->bus_freq > 100)
+	if (dev->bus_freq_hz > 100000)
 		clkl = (clk << 1) / 3;
 	else
 		clkl = (clk >> 1);
@@ -269,7 +267,7 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
 		davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG));
 	dev_dbg(dev->dev, "CLKH = %d\n",
 		davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG));
-	dev_dbg(dev->dev, "bus_freq = %dkHz\n", dev->bus_freq);
+	dev_dbg(dev->dev, "bus_freq_hz = %dHz\n", dev->bus_freq_hz);
 
 
 	/* Take the I2C module out of reset: */
@@ -761,9 +759,9 @@ static int davinci_i2c_probe(struct platform_device *pdev)
 
 	r = device_property_read_u32(&pdev->dev, "clock-frequency", &prop);
 	if (r)
-		prop = DAVINCI_I2C_DEFAULT_BUS_FREQ;
+		prop = I2C_MAX_STANDARD_MODE_FREQ;
 
-	dev->bus_freq = prop / 1000;
+	dev->bus_freq_hz = prop;
 
 	dev->has_pfunc = device_property_present(&pdev->dev, "ti,has-pfunc");
 

-- 
2.51.2