mtd: spi-nor: add a helper to find the spi_device_id

Add the spi_nor_match_id() to find the proper spi_device_id with the
NOR flash's name in the spi_nor_ids table.

Signed-off-by: Huang Shijie <b32955@freescale.com>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/spi-nor/spi-nor.c

@@ -1082,6 +1082,18 @@ int spi_nor_scan(struct spi_nor *nor, const struct spi_device_id *id,
 	return 0;
 }
 
+const struct spi_device_id *spi_nor_match_id(char *name)
+{
+	const struct spi_device_id *id = spi_nor_ids;
+
+	while (id->name[0]) {
+		if (!strcmp(name, id->name))
+			return id;
+		id++;
+	}
+	return NULL;
+}
+
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Huang Shijie <shijie8@gmail.com>");
 MODULE_AUTHOR("Mike Lavender");

include/linux/mtd/spi-nor.h

@@ -182,4 +182,16 @@ int spi_nor_scan(struct spi_nor *nor, const struct spi_device_id *id,
 			enum read_mode mode);
 extern const struct spi_device_id spi_nor_ids[];
 
+/**
+ * spi_nor_match_id() - find the spi_device_id by the name
+ * @name:	the name of the spi_device_id
+ *
+ * The drivers use this function to find the spi_device_id
+ * specified by the @name.
+ *
+ * Return: returns the right spi_device_id pointer on success,
+ *         and returns NULL on failure.
+ */
+const struct spi_device_id *spi_nor_match_id(char *name);
+
 #endif