Input: atmel_mxt_ts - add sysfs entries to read fw and hw version

Make firmware and hardware version strings available to userspace.
This is useful, for example, to allow a userspace program to implement
a firwmare update policy.

Change-Id: I1eddb4bbf5f3f9ae6947a8528598973ddead18cf
Signed-off-by: NDaniel Kurtz <djkurtz@chromium.org>
Signed-off-by: NHenrik Rydberg <rydberg@euromail.se>

drivers/input/touchscreen/atmel_mxt_ts.c

@@ -882,6 +882,26 @@ static void mxt_calc_resolution(struct mxt_data *data)
 	}
 }
 
+/* Firmware Version is returned as Major.Minor.Build */
+static ssize_t mxt_fw_version_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct mxt_data *data = dev_get_drvdata(dev);
+	struct mxt_info *info = &data->info;
+	return scnprintf(buf, PAGE_SIZE, "%u.%u.%02X\n",
+			 info->version >> 4, info->version & 0xf, info->build);
+}
+
+/* Hardware Version is returned as FamilyID.VariantID */
+static ssize_t mxt_hw_version_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct mxt_data *data = dev_get_drvdata(dev);
+	struct mxt_info *info = &data->info;
+	return scnprintf(buf, PAGE_SIZE, "%u.%u\n",
+			 info->family_id, info->variant_id);
+}
+
 static ssize_t mxt_show_instance(char *buf, int count,
 				 struct mxt_object *object, int instance,
 				 const u8 *val)
@@ -1047,10 +1067,14 @@ static ssize_t mxt_update_fw_store(struct device *dev,
 	return count;
 }
 
+static DEVICE_ATTR(fw_version, S_IRUGO, mxt_fw_version_show, NULL);
+static DEVICE_ATTR(hw_version, S_IRUGO, mxt_hw_version_show, NULL);
 static DEVICE_ATTR(object, S_IRUGO, mxt_object_show, NULL);
 static DEVICE_ATTR(update_fw, S_IWUSR, NULL, mxt_update_fw_store);
 
 static struct attribute *mxt_attrs[] = {
+	&dev_attr_fw_version.attr,
+	&dev_attr_hw_version.attr,
 	&dev_attr_object.attr,
 	&dev_attr_update_fw.attr,
 	NULL