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]> (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? > + */ > + 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 -- Pengutronix e.K. | Wolfram Sang | Industrial Linux Solutions | http://www.pengutronix.de/ |
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