From cd97f39b7cdf1c8a9c9f52865eec795b7f0c811d Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Tue, 24 Feb 2009 19:19:49 +0100 Subject: 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 Acked-by: Wolfram Sang --- drivers/i2c/i2c-dev.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'drivers/i2c/i2c-dev.c') 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 #include #include +#include #include 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 -- cgit v1.2.3