On Fri, 20 Feb 2009 13:28:39 +0100, Wolfram Sang wrote:
> On Fri, Feb 20, 2009 at 01:21:37PM +0100, Jean Delvare wrote:
> > 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 <[email protected]>
>
> Acked-by: Wolfram Sang <[email protected]>
Thanks!
>
> (see minor nit below)
>
> > ---
> > drivers/i2c/i2c-dev.c | 6 +++++-
> > include/linux/i2c-dev.h | 2 +-
> > include/linux/i2c.h | 2 +-
> > 3 files changed, 7 insertions(+), 3 deletions(-)
> >
> > --- linux-2.6.29-rc5.orig/drivers/i2c/i2c-dev.c 2009-01-06
> > 20:24:44.000000000 +0100
> > +++ linux-2.6.29-rc5/drivers/i2c/i2c-dev.c 2009-02-20 12:59:38.000000000
> > +0100
> > @@ -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 *fi
> > 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.
>
> Double space after * intended?
Not intended. Fixed, thanks for reporting!
>
> > + */
> > + client->adapter->timeout = msecs_to_jiffies(arg * 10);
> > break;
> > default:
> > /* NOTE: returning a fault code here could cause trouble
> > --- linux-2.6.29-rc5.orig/include/linux/i2c-dev.h 2008-04-17
> > 04:49:44.000000000 +0200
> > +++ linux-2.6.29-rc5/include/linux/i2c-dev.h 2009-02-20
> > 12:48:08.000000000 +0100
> > @@ -33,7 +33,7 @@
> > */
> > #define I2C_RETRIES 0x0701 /* number of times a device address
> > should
> > be polled when not acknowledging */
> > -#define I2C_TIMEOUT 0x0702 /* set timeout in jiffies - call with
> > int */
> > +#define I2C_TIMEOUT 0x0702 /* set timeout in units of 10 ms */
> >
> > /* NOTE: Slave address is 7 or 10 bits, but 10-bit addresses
> > * are NOT supported! (due to code brokenness)
> > --- linux-2.6.29-rc5.orig/include/linux/i2c.h 2009-01-29
> > 08:27:20.000000000 +0100
> > +++ linux-2.6.29-rc5/include/linux/i2c.h 2009-02-20 12:47:39.000000000
> > +0100
> > @@ -361,7 +361,7 @@ struct i2c_adapter {
> > struct mutex bus_lock;
> > struct mutex clist_lock;
> >
> > - int timeout;
> > + int timeout; /* in jiffies */
> > int retries;
> > struct device dev; /* the adapter device */
> >
> >
> >
> > --
> > Jean Delvare
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
> > the body of a message to [email protected]
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
>
--
Jean Delvare
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