Dear Shawn Guo,

On Sat, Jun 09, 2012 at 01:45:50PM +0200, Marek Vasut wrote:

quoted

This patch configures the I2C bus timing registers according
to information passed via DT. Currently, 100kHz and 400kHz
modes are supported.

Signed-off-by: Marek Vasut <marex@denx.de>

I gave it a test on imx28-evk board with audio playback.  It seems
the patch makes the first time playback non-functional, but the later
playback is still working.

Any hints what can be the source of this issue? I tested it with i2c eeprom, saw 
no issues in there. I'll poke into it later.

quoted

+static int mxs_i2c_get_ofdata(struct mxs_i2c_dev *i2c)
+{
+	uint32_t speed;
+	struct device *dev = i2c->dev;
+	struct device_node *node = dev->of_node;
+
+	if (!node)
+		return -EINVAL;
+
+	i2c->speed = &mxs_i2c_95kHz_config;
+	ret = of_property_read_u32(node, "clock-frequency", &speed);

"ret" is undeclared.

quoted

+	if (ret)
+		dev_warn(dev, "No I2C speed selected, using 100kHz\n");
+	else if (speed == 400000)
+		i2c->speed = &mxs_i2c_400kHz_config;
+	else if (speed != 100000)
+		dev_warn(dev, "Invalid I2C speed selected, using 100kHz\n");
+
+	return 0;
+}
+

Best regards,
Marek Vasut