power_supply_sysfs: Handle -ENODATA in a special way

There are cases when some device can not report any meaningful value,
e.g. TWL4030 charger can report voltage only when charging is
active.

In these cases drivers will return -ENODATA, and we shouldn't flood
kernel log with error messages.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>

diff --git a/drivers/power/power_supply_sysfs.c b/drivers/power/power_supply_sysfs.c
index 08144393d64b72e7b2a54d44929a6d47cbf18036..c790e0c77d4be02c71917fcdea8a2f91d2c9c33e 100644 (file)
--- a/drivers/power/power_supply_sysfs.c
+++ b/drivers/power/power_supply_sysfs.c
@@ -65,7 +65,10 @@ static ssize_t power_supply_show_property(struct device *dev,
        ret = psy->get_property(psy, off, &value);
 
        if (ret < 0) {
-               if (ret != -ENODEV)
+               if (ret == -ENODATA)
+                       dev_dbg(dev, "driver has no data for `%s' property\n",
+                               attr->attr.name);
+               else if (ret != -ENODEV)
                        dev_err(dev, "driver failed to report `%s' property\n",
                                attr->attr.name);
                return ret;