drm/edid: Extract drm_edid_decode_mfg_id()

Make the PNPID decoding available for other users.

Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220510104242.6099-15-ville.syrjala@linux.intel.com

include/drm/drm_edid.h

@@ -497,6 +497,22 @@ static inline u8 drm_eld_get_conn_type(const uint8_t *eld)
 	return eld[DRM_ELD_SAD_COUNT_CONN_TYPE] & DRM_ELD_CONN_TYPE_MASK;
 }
 
+/**
+ * drm_edid_decode_mfg_id - Decode the manufacturer ID
+ * @mfg_id: The manufacturer ID
+ * @vend: A 4-byte buffer to store the 3-letter vendor string plus a '\0'
+ *	  termination
+ */
+static inline const char *drm_edid_decode_mfg_id(u16 mfg_id, char vend[4])
+{
+	vend[0] = '@' + ((mfg_id >> 10) & 0x1f);
+	vend[1] = '@' + ((mfg_id >> 5) & 0x1f);
+	vend[2] = '@' + ((mfg_id >> 0) & 0x1f);
+	vend[3] = '\0';
+
+	return vend;
+}
+
 /**
  * drm_edid_encode_panel_id - Encode an ID for matching against drm_edid_get_panel_id()
  * @vend_chr_0: First character of the vendor string.
@@ -537,10 +553,7 @@ static inline u8 drm_eld_get_conn_type(const uint8_t *eld)
 static inline void drm_edid_decode_panel_id(u32 panel_id, char vend[4], u16 *product_id)
 {
 	*product_id = (u16)(panel_id & 0xffff);
-	vend[0] = '@' + ((panel_id >> 26) & 0x1f);
-	vend[1] = '@' + ((panel_id >> 21) & 0x1f);
-	vend[2] = '@' + ((panel_id >> 16) & 0x1f);
-	vend[3] = '\0';
+	drm_edid_decode_mfg_id(panel_id >> 16, vend);
 }
 
 bool drm_probe_ddc(struct i2c_adapter *adapter);