omap3: Introduce function to detect the IGEP v2 hardwarerevision

There are currently two versions of IGEP v2 board, this patch introduces a
function to detect the hardware revision of IGEP board.

  --------------------------
 | Id. | Hw Rev. | GPIO 28  |
  --------------------------
 |  0  |   B/C   |   high   |
 |  1  |   C     |   low    |
  --------------------------
Signed-off-by: Enric Balletbo i Serra <eballetbo@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/board-igep0020.c

@@ -46,6 +46,49 @@
 #define IGEP2_GPIO_WIFI_NPD 	94
 #define IGEP2_GPIO_WIFI_NRESET 	95
 
+/*
+ * IGEP2 Hardware Revision Table
+ *
+ *  --------------------------
+ * | Id. | Hw Rev. | HW0 (28) |
+ *  --------------------------
+ * |  0  |   B/C   |   high   |
+ * |  1  |   C     |   low    |
+ *  --------------------------
+ */
+
+#define IGEP2_BOARD_HWREV_B	0
+#define IGEP2_BOARD_HWREV_C	1
+
+static u8 hwrev;
+
+static void __init igep2_get_revision(void)
+{
+	u8 ret;
+
+	omap_mux_init_gpio(IGEP2_GPIO_LED1_RED, OMAP_PIN_INPUT);
+
+	if ((gpio_request(IGEP2_GPIO_LED1_RED, "GPIO_HW0_REV") == 0) &&
+	    (gpio_direction_input(IGEP2_GPIO_LED1_RED) == 0)) {
+		ret = gpio_get_value(IGEP2_GPIO_LED1_RED);
+		if (ret == 0) {
+			pr_info("IGEP2: Hardware Revision C (B-NON compatible)\n");
+			hwrev = IGEP2_BOARD_HWREV_C;
+		} else if (ret ==  1) {
+			pr_info("IGEP2: Hardware Revision B/C (B compatible)\n");
+			hwrev = IGEP2_BOARD_HWREV_B;
+		} else {
+			pr_err("IGEP2: Unknown Hardware Revision\n");
+			hwrev = -1;
+		}
+	} else {
+		pr_warning("IGEP2: Could not obtain gpio GPIO_HW0_REV\n");
+		pr_err("IGEP2: Unknown Hardware Revision\n");
+	}
+
+	gpio_free(IGEP2_GPIO_LED1_RED);
+}
+
 #if defined(CONFIG_MTD_ONENAND_OMAP2) || \
 	defined(CONFIG_MTD_ONENAND_OMAP2_MODULE)
 
@@ -538,6 +581,10 @@ static struct omap_board_mux board_mux[] __initdata = {
 static void __init igep2_init(void)
 {
 	omap3_mux_init(board_mux, OMAP_PACKAGE_CBB);
+
+	/* Get IGEP2 hardware revision */
+	igep2_get_revision();
+
 	igep2_i2c_init();
 	platform_add_devices(igep2_devices, ARRAY_SIZE(igep2_devices));
 	omap_serial_init();