stm32f746: to switch on user LED1 & read user button

All discovery boards have one user button & one user LED. Here we are
just reading the button status & switching ON the user LED.

Signed-off-by: Vikas Manocha <vikas.manocha@st.com>
cc: Christophe KERELLO <christophe.kerello@st.com>

arch/arm/dts/stm32f746-disco.dts

@@ -78,6 +78,16 @@
 		gpio9 = &gpioj;
 		gpio10 = &gpiok;
 	};
+
+	led1 {
+		compatible = "st,led1";
+		led-gpio = <&gpioi 1 0>;
+	};
+
+	button1 {
+		compatible = "st,button1";
+		button-gpio = <&gpioi 11 0>;
+	};
 };
 
 &clk_hse {

board/st/stm32f746-disco/stm32f746-disco.c

@@ -17,6 +17,7 @@
 #include <asm/arch/stm32_periph.h>
 #include <asm/arch/stm32_defs.h>
 #include <asm/arch/syscfg.h>
+#include <asm/gpio.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -72,6 +73,42 @@ u32 get_board_rev(void)
 	return 0;
 }
 
+int board_late_init(void)
+{
+	struct gpio_desc gpio = {};
+	int node;
+
+	node = fdt_node_offset_by_compatible(gd->fdt_blob, 0, "st,led1");
+	if (node < 0)
+		return -1;
+
+	gpio_request_by_name_nodev(gd->fdt_blob, node, "led-gpio", 0, &gpio,
+				   GPIOD_IS_OUT);
+
+	if (dm_gpio_is_valid(&gpio)) {
+		dm_gpio_set_value(&gpio, 0);
+		mdelay(10);
+		dm_gpio_set_value(&gpio, 1);
+	}
+
+	/* read button 1*/
+	node = fdt_node_offset_by_compatible(gd->fdt_blob, 0, "st,button1");
+	if (node < 0)
+		return -1;
+
+	gpio_request_by_name_nodev(gd->fdt_blob, node, "button-gpio", 0, &gpio,
+				   GPIOD_IS_IN);
+
+	if (dm_gpio_is_valid(&gpio)) {
+		if (dm_gpio_get_value(&gpio))
+			puts("usr button is at HIGH LEVEL\n");
+		else
+			puts("usr button is at LOW LEVEL\n");
+	}
+
+	return 0;
+}
+
 int board_init(void)
 {
 	gd->bd->bi_boot_params = CONFIG_SYS_SDRAM_BASE + 0x100;

include/configs/stm32f746-disco.h

@@ -75,4 +75,5 @@
 
 #define CONFIG_CMD_MEM
 #define CONFIG_CMD_CACHE
+#define CONFIG_BOARD_LATE_INIT
 #endif /* __CONFIG_H */