dt-bindings: gpio: Add ASPEED constants

These are used to by the device tree to map pin numbers to constants
required by the GPIO bindings.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>

include/dt-bindings/gpio/aspeed-gpio.h

@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * This header provides constants for binding aspeed,*-gpio.
+ *
+ * The first cell in Aspeed's GPIO specifier is the GPIO ID. The macros below
+ * provide names for this.
+ *
+ * The second cell contains standard flag values specified in gpio.h.
+ */
+
+#ifndef _DT_BINDINGS_GPIO_ASPEED_GPIO_H
+#define _DT_BINDINGS_GPIO_ASPEED_GPIO_H
+
+#include <dt-bindings/gpio/gpio.h>
+
+#define ASPEED_GPIO_PORT_A 0
+#define ASPEED_GPIO_PORT_B 1
+#define ASPEED_GPIO_PORT_C 2
+#define ASPEED_GPIO_PORT_D 3
+#define ASPEED_GPIO_PORT_E 4
+#define ASPEED_GPIO_PORT_F 5
+#define ASPEED_GPIO_PORT_G 6
+#define ASPEED_GPIO_PORT_H 7
+#define ASPEED_GPIO_PORT_I 8
+#define ASPEED_GPIO_PORT_J 9
+#define ASPEED_GPIO_PORT_K 10
+#define ASPEED_GPIO_PORT_L 11
+#define ASPEED_GPIO_PORT_M 12
+#define ASPEED_GPIO_PORT_N 13
+#define ASPEED_GPIO_PORT_O 14
+#define ASPEED_GPIO_PORT_P 15
+#define ASPEED_GPIO_PORT_Q 16
+#define ASPEED_GPIO_PORT_R 17
+#define ASPEED_GPIO_PORT_S 18
+#define ASPEED_GPIO_PORT_T 19
+#define ASPEED_GPIO_PORT_U 20
+#define ASPEED_GPIO_PORT_V 21
+#define ASPEED_GPIO_PORT_W 22
+#define ASPEED_GPIO_PORT_X 23
+#define ASPEED_GPIO_PORT_Y 24
+#define ASPEED_GPIO_PORT_Z 25
+#define ASPEED_GPIO_PORT_AA 26
+#define ASPEED_GPIO_PORT_AB 27
+#define ASPEED_GPIO_PORT_AC 28
+
+#define ASPEED_GPIO(port, offset) \
+	((ASPEED_GPIO_PORT_##port * 8) + offset)
+
+#endif