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From: Marcus Folkesson <marcus.folkesson@gmail.com>
To: Wolfram Sang <wsa+renesas@sang-engineering.com>,
	 Peter Rosin <peda@axentia.se>,
	 Michael Hennerich <michael.hennerich@analog.com>,
	 Bartosz Golaszewski <brgl@bgdev.pl>,
	Andi Shyti <andi.shyti@kernel.org>
Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
	 linux-arm-kernel@lists.infradead.org,
	 Marcus Folkesson <marcus.folkesson@gmail.com>
Subject: [PATCH RFC 5/7] i2c: davinci: calculate bus freq from Hz instead of kHz
Date: Mon, 22 Sep 2025 08:21:00 +0200	[thread overview]
Message-ID: <20250922-i2c-mux-v1-5-28c94a610930@gmail.com> (raw)
In-Reply-To: <20250922-i2c-mux-v1-0-28c94a610930@gmail.com>

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.

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
---
 drivers/i2c/busses/i2c-davinci.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 6a3d4e9e07f45ecc228943e877cde1fd9d72e8cb..6b18938457d0c5cabc323c364d9330c2890df107 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;
@@ -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));
 	/* 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)
 		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 > 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 = %dHz\n", dev->bus_freq);
 
 
 	/* 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 = prop;
 
 	dev->has_pfunc = device_property_present(&pdev->dev, "ti,has-pfunc");
 

-- 
2.50.1


  parent reply	other threads:[~2025-09-22  6:21 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-09-22  6:20 [PATCH RFC 0/7] I2C Mux per channel bus speed Marcus Folkesson
2025-09-22  6:20 ` [PATCH RFC 1/7] i2c: core: add callback to change bus frequency Marcus Folkesson
2025-09-22  6:20 ` [PATCH RFC 2/7] i2c: mux: add idle_state property to i2c_mux_core Marcus Folkesson
2025-09-22  6:20 ` [PATCH RFC 3/7] i2c: mux: add support for per channel bus frequency Marcus Folkesson
2025-09-22  6:20 ` [PATCH RFC 4/7] i2c: mux: ltc4306: set correct idle_state in i2c_mux_core Marcus Folkesson
2025-09-22  6:21 ` Marcus Folkesson [this message]
2025-09-22 14:42   ` [PATCH RFC 5/7] i2c: davinci: calculate bus freq from Hz instead of kHz Bartosz Golaszewski
2025-09-22 14:50     ` Marcus Folkesson
2025-09-22  6:21 ` [PATCH RFC 6/7] i2c: davinci: add support for setting bus frequency Marcus Folkesson
2025-09-22 14:43   ` Bartosz Golaszewski
2025-09-22  6:21 ` [PATCH RFC 7/7] docs: i2c: i2c-topology: add section about bus speed Marcus Folkesson
2025-09-23 15:10 ` [PATCH RFC 0/7] I2C Mux per channel " Peter Rosin
2025-09-23 20:37   ` Marcus Folkesson

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