mtd: mchp23k256: Add OF device ID table

This allows registering of this device via a Device Tree.
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

Documentation/devicetree/bindings/mtd/microchip,mchp23k256.txt

+* MTD SPI driver for Microchip 23K256 (and similar) serial SRAM
+
+Required properties:
+- #address-cells, #size-cells : Must be present if the device has sub-nodes
+  representing partitions.
+- compatible : Must be "microchip,mchp23k256"
+- reg : Chip-Select number
+- spi-max-frequency : Maximum frequency of the SPI bus the chip can operate at
+
+Example:
+
+	spi-sram@0 {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		compatible = "microchip,mchp23k256";
+		reg = <0>;
+		spi-max-frequency = <20000000>;
+	};

drivers/mtd/devices/mchp23k256.c

@@ -19,6 +19,7 @@
 #include <linux/sizes.h>
 #include <linux/spi/flash.h>
 #include <linux/spi/spi.h>
+#include <linux/of_device.h>
 
 struct mchp23k256_flash {
 	struct spi_device	*spi;
@@ -166,9 +167,16 @@ static int mchp23k256_remove(struct spi_device *spi)
 	return mtd_device_unregister(&flash->mtd);
 }
 
+static const struct of_device_id mchp23k256_of_table[] = {
+	{ .compatible = "microchip,mchp23k256" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, mchp23k256_of_table);
+
 static struct spi_driver mchp23k256_driver = {
 	.driver = {
 		.name	= "mchp23k256",
+		.of_match_table = of_match_ptr(mchp23k256_of_table),
 	},
 	.probe		= mchp23k256_probe,
 	.remove		= mchp23k256_remove,