It could happen that an i2c adapter may lock the bus due due
electrical problems, so the user may recover this stale state by using:
$ echo 1 > /sys/class/i2c-adapter/i2c-0/reset
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);
+
+ 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)
--
1.5.6.3
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