This patch modify the s3c2410 i2c driver behaviour to enable the
i2c clock only when needed. I'm not sure if this has a big impact
on power usage but at least it's fixing a bug with the uda1380
codec which needs to be hard reset'ed if the i2c clock is enabled
before it's powered on (at least on h1940).
Signed-off-by: Arnaud Patard <arnaud.patard@xxxxxxxxxxx>
Index: linux-2.6/drivers/i2c/busses/i2c-s3c2410.c
===================================================================
--- linux-2.6.orig/drivers/i2c/busses/i2c-s3c2410.c 2010-07-03 22:47:14.473885834 +0200
+++ linux-2.6/drivers/i2c/busses/i2c-s3c2410.c 2010-07-03 22:48:43.261886656 +0200
@@ -555,18 +555,23 @@ static int s3c24xx_i2c_xfer(struct i2c_a
int retry;
int ret;
+ clk_enable(i2c->clk);
+
for (retry = 0; retry < adap->retries; retry++) {
ret = s3c24xx_i2c_doxfer(i2c, msgs, num);
- if (ret != -EAGAIN)
+ if (ret != -EAGAIN) {
+ clk_disable(i2c->clk);
return ret;
+ }
dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
udelay(100);
}
+ clk_disable(i2c->clk);
return -EREMOTEIO;
}
@@ -911,6 +916,7 @@ static int s3c24xx_i2c_probe(struct plat
platform_set_drvdata(pdev, i2c);
dev_info(&pdev->dev, "%s: S3C I2C adapter\n", dev_name(&i2c->adap.dev));
+ clk_disable(i2c->clk);
return 0;
err_cpufreq:
--
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