mtd: add a new sys node to show the ecc step size

Add a new sys node to show the ecc step size.
The application then can uses this node to get the ecc step
size.
Signed-off-by: NHuang Shijie <b32955@freescale.com>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/mtdcore.c

@@ -285,6 +285,16 @@ static DEVICE_ATTR(bitflip_threshold, S_IRUGO | S_IWUSR,
 		   mtd_bitflip_threshold_show,
 		   mtd_bitflip_threshold_store);
 
+static ssize_t mtd_ecc_step_size_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct mtd_info *mtd = dev_get_drvdata(dev);
+
+	return snprintf(buf, PAGE_SIZE, "%u\n", mtd->ecc_step_size);
+
+}
+static DEVICE_ATTR(ecc_step_size, S_IRUGO, mtd_ecc_step_size_show, NULL);
+
 static struct attribute *mtd_attrs[] = {
 	&dev_attr_type.attr,
 	&dev_attr_flags.attr,
@@ -296,6 +306,7 @@ static struct attribute *mtd_attrs[] = {
 	&dev_attr_numeraseregions.attr,
 	&dev_attr_name.attr,
 	&dev_attr_ecc_strength.attr,
+	&dev_attr_ecc_step_size.attr,
 	&dev_attr_bitflip_threshold.attr,
 	NULL,
 };