[PATCH 05/12] i2c: meson: set clock divider in probe instead of setting it for each transfer

Heiner Kallweit hkallweit1 at gmail.com
Tue Mar 7 22:45:30 PST 2017


The bus frequency won't change, 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>
---
 drivers/i2c/busses/i2c-meson.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/i2c/busses/i2c-meson.c b/drivers/i2c/busses/i2c-meson.c
index a5764be5..594fec22 100644
--- a/drivers/i2c/busses/i2c-meson.c
+++ b/drivers/i2c/busses/i2c-meson.c
@@ -74,7 +74,6 @@ 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
- * @timings:	Struct including the bus frequency
  * @tokens:	Sequence of tokens to be written to the device
  * @num_tokens:	Number of tokens
  */
@@ -93,7 +92,6 @@ struct meson_i2c {
 
 	spinlock_t		lock;
 	struct completion	done;
-	struct i2c_timings	timings;
 	u32			tokens[2];
 	int			num_tokens;
 };
@@ -132,12 +130,12 @@ 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->timings.bus_freq_hz * 4);
+	div = DIV_ROUND_UP(clk_rate, freq * 4);
 
 	/* clock divider has 12 bits */
 	WARN_ON(div >= (1 << 12));
@@ -149,7 +147,7 @@ static void meson_i2c_set_clk_div(struct meson_i2c *i2c)
 			   (div >> 10) << REG_CTRL_CLKDIVEXT_SHIFT);
 
 	dev_dbg(i2c->dev, "%s: clk %lu, freq %u, div %u\n", __func__,
-		clk_rate, i2c->timings.bus_freq_hz, div);
+		clk_rate, freq, div);
 }
 
 static void meson_i2c_get_data(struct meson_i2c *i2c, char *buf, int len)
@@ -369,7 +367,6 @@ 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);
@@ -396,6 +393,7 @@ static const struct i2c_algorithm meson_i2c_algorithm = {
 static int meson_i2c_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
+	struct i2c_timings timings;
 	struct meson_i2c *i2c;
 	struct resource *mem;
 	int irq, ret = 0;
@@ -404,7 +402,7 @@ static int meson_i2c_probe(struct platform_device *pdev)
 	if (!i2c)
 		return -ENOMEM;
 
-	i2c_parse_fw_timings(&pdev->dev, &i2c->timings, true);
+	i2c_parse_fw_timings(&pdev->dev, &timings, true);
 
 	i2c->dev = &pdev->dev;
 	platform_set_drvdata(pdev, i2c);
@@ -462,6 +460,8 @@ static int meson_i2c_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	meson_i2c_set_clk_div(i2c, timings.bus_freq_hz);
+
 	return 0;
 }
 
-- 
2.12.0





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