On Mon, Feb 09, 2009 at 05:17:20PM +0100, Jean Delvare wrote: > On Fri, 6 Feb 2009 16:23:17 +0100, Rodolfo Giometti wrote: > > It could happen that an i2c adapter may lock the bus due due > > Typo: "due due" -> "due to".
Ok. > > electrical problems, so the user may recover this stale state by using: > > > > $ echo 1 > /sys/class/i2c-adapter/i2c-0/reset > > What is the intended purpose, debugging? I would certainly hope that > drivers know by themselves when they need a reset. Requiring users to > reset themselves doesn't sound terribly friendly :( Unluckely not all adapter does it by themselfes! At least not PXA one. I'm currently work on adding this new feature. > > Signed-off-by: Rodolfo Giometti <[email protected]> > > --- > > drivers/i2c/i2c-core.c | 21 +++++++++++++++++++++ > > include/linux/i2c.h | 2 ++ > > 2 files changed, 23 insertions(+), 0 deletions(-) > > > > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c > > index b1c9abe..b0c4053 100644 > > --- a/drivers/i2c/i2c-core.c > > +++ b/drivers/i2c/i2c-core.c > > @@ -393,8 +393,29 @@ show_adapter_name(struct device *dev, struct > > device_attribute *attr, char *buf) > > return sprintf(buf, "%s\n", adap->name); > > } > > > > +static ssize_t > > +write_adapter_reset(struct device *dev, struct device_attribute *attr, > > + const char *buf, size_t count) > > +{ > > + struct i2c_adapter *adap = to_i2c_adapter(dev); > > + unsigned long val; > > + int ret; > > + > > + if (!adap->reset) > > + return -EINVAL; > > + > > + ret = strict_strtoul(buf, 10, &val); > > + if (ret || val != 1) > > + return -EINVAL; > > + > > + adap->reset(adap); > > I consider it good practice to always test for function pointers > _right_ before dereferencing them. Makes it harder to accidentally > break things later. Ok. > > + > > + return count; > > +} > > + > > static struct device_attribute i2c_adapter_attrs[] = { > > __ATTR(name, S_IRUGO, show_adapter_name, NULL), > > + __ATTR(reset, S_IWUSR, NULL, write_adapter_reset), > > { }, > > }; > > > > diff --git a/include/linux/i2c.h b/include/linux/i2c.h > > index fcfbfea..0f84345 100644 > > --- a/include/linux/i2c.h > > +++ b/include/linux/i2c.h > > @@ -369,6 +369,8 @@ struct i2c_adapter { > > struct list_head clients; /* DEPRECATED */ > > char name[48]; > > struct completion dev_released; > > + > > + void (*reset)(struct i2c_adapter *); /* user request adap reset */ > > }; > > #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev) > > I'll repropose a new patch ASAP. Ciao, Rodolfo -- GNU/Linux Solutions e-mail: [email protected] Linux Device Driver [email protected] Embedded Systems phone: +39 349 2432127 UNIX programming skype: rodolfo.giometti -- 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
