db820c: stop autoboot when vol- pressed

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>

arch/arm/dts/dragonboard820c-uboot.dtsi

@@ -0,0 +1,19 @@
+/*
+ * U-Boot addition to handle Dragonboard 820c pins
+ *
+ * (C) Copyright 2017 Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+&pm8994_pon {
+	key_vol_down {
+		gpios = <&pm8994_pon 1 0>;
+		label = "key_vol_down";
+	};
+
+	key_power {
+		gpios = <&pm8994_pon 0 0>;
+		label = "key_power";
+	};
+};

board/qualcomm/dragonboard820c/dragonboard820c.c

@@ -1,7 +1,7 @@
 /*
  * Board init file for Dragonboard 820C
  *
- * (C) Copyright 2017 Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@gmail.com>
+ * (C) Copyright 2017 Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
  *
  * SPDX-License-Identifier:	GPL-2.0+
  */
@@ -14,6 +14,7 @@
 #include <asm/io.h>
 #include <linux/bitops.h>
 #include <asm/psci.h>
+#include <asm/gpio.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -125,3 +126,38 @@ int board_init(void)
 void reset_cpu(ulong addr)
 {
 	psci_system_reset();
+}
+
+/* Check for vol- button - if pressed - stop autoboot */
+int misc_init_r(void)
+{
+	struct udevice *pon;
+	struct gpio_desc resin;
+	int node, ret;
+
+	ret = uclass_get_device_by_name(UCLASS_GPIO, "pm8994_pon@800", &pon);
+	if (ret < 0) {
+		printf("Failed to find PMIC pon node. Check device tree\n");
+		return 0;
+	}
+
+	node = fdt_subnode_offset(gd->fdt_blob, dev_of_offset(pon),
+				  "key_vol_down");
+	if (node < 0) {
+		printf("Failed to find key_vol_down node. Check device tree\n");
+		return 0;
+	}
+
+	if (gpio_request_by_name_nodev(offset_to_ofnode(node), "gpios", 0,
+				       &resin, 0)) {
+		printf("Failed to request key_vol_down button.\n");
+		return 0;
+	}
+
+	if (dm_gpio_get_value(&resin)) {
+		env_set("bootdelay", "-1");
+		printf("Power button pressed - dropping to console.\n");
+	}
+
+	return 0;
+}

include/configs/dragonboard820c.h

@@ -12,6 +12,8 @@
 #include <linux/sizes.h>
 #include <asm/arch/sysmap-apq8096.h>
 
+#define CONFIG_MISC_INIT_R /* To stop autoboot */
+
 /* Physical Memory Map */
 #define CONFIG_NR_DRAM_BANKS		2