imx: ventana: disable IMX6 watchdogs on GW51xx RevA and RevB

A board level errata causes the IMX6 watchdog to be unstable on the GW51xx
RevA and RevB boards which can cause the watchdog to trip extremely early
(under 5seconds) under certain operating conditions. Disable the watchdog
node in the device-tree to work around this issue.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>

board/gateworks/gw_ventana/gw_ventana.c

@@ -1515,6 +1515,16 @@ int ft_board_setup(void *blob, bd_t *bd)
 		{ "fsl,imx6q-gpmi-nand",  MTD_DEV_TYPE_NAND, }, /* NAND flash */
 	};
 	const char *model = getenv("model");
+	int i;
+	char rev = 0;
+
+	/* determine board revision */
+	for (i = sizeof(ventana_info.model) - 1; i > 0; i--) {
+		if (ventana_info.model[i] >= 'A') {
+			rev = ventana_info.model[i];
+			break;
+		}
+	}
 
 	if (getenv("fdt_noauto")) {
 		puts("   Skiping ft_board_setup (fdt_noauto defined)\n");
@@ -1539,6 +1549,17 @@ int ft_board_setup(void *blob, bd_t *bd)
 	fdt_setprop(blob, 0, "board", info->model,
 		    strlen((const char *)info->model) + 1);
 
+	/*
+	 * disable wdog1/wdog2 nodes for GW51xx below revC to work around
+	 * errata causing wdog timer to be unreliable.
+	 */
+	if (board_type == GW51xx && rev >= 'A' && rev < 'C') {
+		i = fdt_path_offset(blob,
+				    "/soc/aips-bus@02000000/wdog@020bc000");
+		if (i)
+			fdt_status_disabled(blob, i);
+	}
+
 	/*
 	 * Peripheral Config:
 	 *  remove nodes by alias path if EEPROM config tells us the