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". > 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 :( > 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. > + > + 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) > -- 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
