i2c-s3c2410: fix calculation of SDA line delay
authorMyungJoo Ham <myungjoo.ham@samsung.com>
Thu, 30 Sep 2010 13:54:46 +0000 (15:54 +0200)
committerBen Dooks <ben-linux@fluff.org>
Thu, 30 Sep 2010 23:00:35 +0000 (00:00 +0100)
S3C2440 style I2C controller uses PCLK to calculate the SDA line delay.
The driver wrongly assumed that this delay is calculated from the
frequency that the controller is operating on. This patch fixes this
issue.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
drivers/i2c/busses/i2c-s3c2410.c

index 72902e0bbfa79a48caaf2193420d4b8712af1e18..bf831bf8158741a9f857eb541afc1f3a48d38e52 100644 (file)
@@ -662,8 +662,8 @@ static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
                unsigned long sda_delay;
 
                if (pdata->sda_delay) {
-                       sda_delay = (freq / 1000) * pdata->sda_delay;
-                       sda_delay /= 1000000;
+                       sda_delay = clkin * pdata->sda_delay;
+                       sda_delay = DIV_ROUND_UP(sda_delay, 1000000);
                        sda_delay = DIV_ROUND_UP(sda_delay, 5);
                        if (sda_delay > 3)
                                sda_delay = 3;