[PATCH v5 03/10] i2c: meson: set clock divider in probe instead of setting it for each transfer

[Heiner Kallweit]

The bus frequency is fixed to what is set DT, therefore we can set
the clock divider in probe already and we don't have to set it for
each transfer.

Signed-off-by: Heiner Kallweit <hkallweit1 at gmail.com>
---
v2:
- no changes
v3:
- change order of patches
v4:
- no changes
v5:
- improved commit message
---
 drivers/i2c/busses/i2c-meson.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-meson.c b/drivers/i2c/busses/i2c-meson.c
index 50059d09..e597764e 100644
--- a/drivers/i2c/busses/i2c-meson.c
+++ b/drivers/i2c/busses/i2c-meson.c
@@ -73,7 +73,6 @@ enum {
  * @error:	Flag set when an error is received
  * @lock:	To avoid race conditions between irq handler and xfer code
  * @done:	Completion used to wait for transfer termination
- * @frequency:	Operating frequency of I2C bus clock
  * @tokens:	Sequence of tokens to be written to the device
  * @num_tokens:	Number of tokens
  */
@@ -92,7 +91,6 @@ struct meson_i2c {
 
 	spinlock_t		lock;
 	struct completion	done;
-	unsigned int		frequency;
 	u32			tokens[2];
 	int			num_tokens;
 };
@@ -131,17 +129,17 @@ static void meson_i2c_write_tokens(struct meson_i2c *i2c)
 	writel(i2c->tokens[1], i2c->regs + REG_TOK_LIST1);
 }
 
-static void meson_i2c_set_clk_div(struct meson_i2c *i2c)
+static void meson_i2c_set_clk_div(struct meson_i2c *i2c, unsigned int freq)
 {
 	unsigned long clk_rate = clk_get_rate(i2c->clk);
 	unsigned int div;
 
-	div = DIV_ROUND_UP(clk_rate, i2c->frequency * 4);
+	div = DIV_ROUND_UP(clk_rate, freq * 4);
 	meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_CLKDIV_MASK,
 			   div << REG_CTRL_CLKDIV_SHIFT);
 
 	dev_dbg(i2c->dev, "%s: clk %lu, freq %u, div %u\n", __func__,
-		clk_rate, i2c->frequency, div);
+		clk_rate, freq, div);
 }
 
 static void meson_i2c_get_data(struct meson_i2c *i2c, char *buf, int len)
@@ -361,7 +359,6 @@ static int meson_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 	int i, ret = 0, count = 0;
 
 	clk_enable(i2c->clk);
-	meson_i2c_set_clk_div(i2c);
 
 	for (i = 0; i < num; i++) {
 		ret = meson_i2c_xfer_msg(i2c, msgs + i, i == num - 1);
@@ -390,15 +387,15 @@ static int meson_i2c_probe(struct platform_device *pdev)
 	struct device_node *np = pdev->dev.of_node;
 	struct meson_i2c *i2c;
 	struct resource *mem;
+	u32 freq;
 	int irq, ret = 0;
 
 	i2c = devm_kzalloc(&pdev->dev, sizeof(struct meson_i2c), GFP_KERNEL);
 	if (!i2c)
 		return -ENOMEM;
 
-	if (of_property_read_u32(pdev->dev.of_node, "clock-frequency",
-				 &i2c->frequency))
-		i2c->frequency = DEFAULT_FREQ;
+	if (of_property_read_u32(pdev->dev.of_node, "clock-frequency", &freq))
+		freq = DEFAULT_FREQ;
 
 	i2c->dev = &pdev->dev;
 	platform_set_drvdata(pdev, i2c);
@@ -456,6 +453,8 @@ static int meson_i2c_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	meson_i2c_set_clk_div(i2c, freq);
+
 	return 0;
 }
 
-- 
2.12.0