drm/edid: add drm_edid_get_product_id()

Add a struct drm_edid based function to get the vendor and product ID
from an EDID. Add a separate struct for defining this part of the EDID,
with defined byte order for manufacturer name, product code and serial
number.

v2: Define manufacturer_name as __be16 instead of u8[2] (Ville)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Melissa Wen <mwen@igalia.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/df0e7dedbf7f2c190039d6e6eae3e126eba113c9.1712655867.git.jani.nikula@intel.comSigned-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/drm_edid.c

@@ -2756,6 +2756,21 @@ const struct drm_edid *drm_edid_read(struct drm_connector *connector)
 }
 EXPORT_SYMBOL(drm_edid_read);
 
+/**
+ * drm_edid_get_product_id - Get the vendor and product identification
+ * @drm_edid: EDID
+ * @id: Where to place the product id
+ */
+void drm_edid_get_product_id(const struct drm_edid *drm_edid,
+			     struct drm_edid_product_id *id)
+{
+	if (drm_edid && drm_edid->edid && drm_edid->size >= EDID_LENGTH)
+		memcpy(id, &drm_edid->edid->product_id, sizeof(*id));
+	else
+		memset(id, 0, sizeof(*id));
+}
+EXPORT_SYMBOL(drm_edid_get_product_id);
+
 /**
  * drm_edid_get_panel_id - Get a panel's ID from EDID
  * @drm_edid: EDID that contains panel ID.

include/drm/drm_edid.h

@@ -272,14 +272,27 @@ struct detailed_timing {
 #define DRM_EDID_DSC_MAX_SLICES			0xf
 #define DRM_EDID_DSC_TOTAL_CHUNK_KBYTES		0x3f
 
+struct drm_edid_product_id {
+	__be16 manufacturer_name;
+	__le16 product_code;
+	__le32 serial_number;
+	u8 week_of_manufacture;
+	u8 year_of_manufacture;
+} __packed;
+
 struct edid {
 	u8 header[8];
 	/* Vendor & product info */
+	union {
+		struct drm_edid_product_id product_id;
+		struct {
 			u8 mfg_id[2];
 			u8 prod_code[2];
 			u32 serial; /* FIXME: byte order */
 			u8 mfg_week;
 			u8 mfg_year;
+		} __packed;
+	} __packed;
 	/* EDID version */
 	u8 version;
 	u8 revision;
@@ -466,6 +479,8 @@ int drm_edid_connector_update(struct drm_connector *connector,
 			      const struct drm_edid *edid);
 int drm_edid_connector_add_modes(struct drm_connector *connector);
 bool drm_edid_is_digital(const struct drm_edid *drm_edid);
+void drm_edid_get_product_id(const struct drm_edid *drm_edid,
+			     struct drm_edid_product_id *id);
 
 const u8 *drm_find_edid_extension(const struct drm_edid *drm_edid,
 				  int ext_id, int *ext_index);