usb: gadget: configfs: make qw_sign attribute symmetric

Currently qw_sign requires UTF-8 character to set, but returns UTF-16
when read. This isn't obvious when simply using cat since the null
characters are not visible, but hexdump unveils the true string:

  # echo MSFT100 > os_desc/qw_sign
  # hexdump -C os_desc/qw_sign
  00000000  4d 00 53 00 46 00 54 00  31 00 30 00 30 00        |M.S.F.T.1.0.0.|

Make qw_sign symmetric by returning an UTF-8 string too. Also follow
common convention and add a new line at the end.

Reviewed-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index cbff3b02840df901ca0ca03c646b14f5f6085719..863ca4ded1bec8eddd8020170361cb0ac4e89c2e 100644 (file)
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -787,9 +787,13 @@ static ssize_t os_desc_b_vendor_code_store(struct config_item *item,
 static ssize_t os_desc_qw_sign_show(struct config_item *item, char *page)
 {
        struct gadget_info *gi = os_desc_item_to_gadget_info(item);
+       int res;
 
-       memcpy(page, gi->qw_sign, OS_STRING_QW_SIGN_LEN);
-       return OS_STRING_QW_SIGN_LEN;
+       res = utf16s_to_utf8s((wchar_t *) gi->qw_sign, OS_STRING_QW_SIGN_LEN,
+                             UTF16_LITTLE_ENDIAN, page, PAGE_SIZE - 1);
+       page[res++] = '\n';
+
+       return res;
 }
 
 static ssize_t os_desc_qw_sign_store(struct config_item *item, const char *page,