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authorJean Delvare <khali@linux-fr.org>2009-02-24 21:19:49 +0300
committerJean Delvare <khali@linux-fr.org>2009-02-24 21:19:49 +0300
commitcd97f39b7cdf1c8a9c9f52865eec795b7f0c811d (patch)
tree010cd2255376a95120da810a1600bbd8d4d7d1c3 /drivers/i2c
parenta746b578d8406b2db0e9f0d040061bc1f78433cf (diff)
downloadlinux-cd97f39b7cdf1c8a9c9f52865eec795b7f0c811d.tar.xz
i2c-dev: Clarify the unit of ioctl I2C_TIMEOUT
The unit in which user-space can set the bus timeout value is jiffies for historical reasons (back when HZ was always 100.) This is however not good because user-space doesn't know how long a jiffy lasts. The timeout value should instead be set in a fixed time unit. Given the original value of HZ, this unit should be 10 ms, for compatibility. Signed-off-by: Jean Delvare <khali@linux-fr.org> Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/i2c-dev.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index c171988a9f51..7e13d2df9af3 100644
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -35,6 +35,7 @@
#include <linux/i2c.h>
#include <linux/i2c-dev.h>
#include <linux/smp_lock.h>
+#include <linux/jiffies.h>
#include <asm/uaccess.h>
static struct i2c_driver i2cdev_driver;
@@ -422,7 +423,10 @@ static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
client->adapter->retries = arg;
break;
case I2C_TIMEOUT:
- client->adapter->timeout = arg;
+ /* For historical reasons, user-space sets the timeout
+ * value in units of 10 ms.
+ */
+ client->adapter->timeout = msecs_to_jiffies(arg * 10);
break;
default:
/* NOTE: returning a fault code here could cause trouble