From 0d1d441aec9e37c5b6c138f73ce041761d188405 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mart=C3=AD=20Bol=C3=ADvar?= <marti.bolivar@nordicsemi.no>
Date: Tue, 10 Mar 2020 11:44:10 -0700
Subject: [PATCH] samples: convert blinky to new DT API
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This doesn't sacrifice any readability when compiled for boards that
don't support this alias.

Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>
---
 samples/basic/blinky/README.rst | 29 +++++++++++++++--------------
 samples/basic/blinky/src/main.c | 23 ++++++++++++++---------
 2 files changed, 29 insertions(+), 23 deletions(-)

diff --git a/samples/basic/blinky/README.rst b/samples/basic/blinky/README.rst
index 9adb3c69214..674ab1099ea 100644
--- a/samples/basic/blinky/README.rst
+++ b/samples/basic/blinky/README.rst
@@ -6,29 +6,31 @@ Blinky sample
 Overview
 ********
 
-The Blinky example shows how to configure GPIO pins as outputs which can also be
-used to drive LEDs on the hardware usually delivered as "User LEDs" on many of
-the supported boards in Zephyr.
+Blinky is a simple application which blinks an LED forever.
+
+The source code shows how to configure GPIO pins as outputs, then turn them on
+and off.
 
 .. _blinky-sample-requirements:
 
 Requirements
 ************
 
-The demo assumes that an LED is connected to one of GPIO lines. The
-sample code is configured to work on boards that have defined the ``led0``
-alias in their :ref:`board's devicetree description file
-<devicetree-in-out-files>`, :file:`<board>.dts`.
-Doing so will generate these variables:
+The board must have an LED connected via a GPIO pin. These are called "User
+LEDs" on many of Zephyr's :ref:`boards`. The LED must be configured using the
+``led0`` :ref:`dt-guide` alias in the :ref:`BOARD.dts file
+<devicetree-in-out-files>`.
 
-- ``DT_ALIAS_LED0_GPIOS_CONTROLLER``
-- ``DT_ALIAS_LED0_GPIOS_PIN``
+You will see this error if you try to build Blinky for an unsupported board:
+
+.. code-block:: none
+
+   Unsupported board: led0 devicetree alias is not defined
 
 Building and Running
 ********************
 
-This sample does not output anything to the console. It can be built and
-flashed to a board as follows:
+Build and flash Blinky as follows, changing ``reel_board`` for your board:
 
 .. zephyr-app-commands::
    :zephyr-app: samples/basic/blinky
@@ -36,5 +38,4 @@ flashed to a board as follows:
    :goals: build flash
    :compact:
 
-After flashing the image to the board, the user LED on the board should start to
-blink.
+After flashing, the LED starts to blink. Blinky does not print to the console.
diff --git a/samples/basic/blinky/src/main.c b/samples/basic/blinky/src/main.c
index 21f33309194..198ad58ddf4 100644
--- a/samples/basic/blinky/src/main.c
+++ b/samples/basic/blinky/src/main.c
@@ -6,27 +6,32 @@
 
 #include <zephyr.h>
 #include <device.h>
+#include <devicetree.h>
 #include <drivers/gpio.h>
 
 /* 1000 msec = 1 sec */
 #define SLEEP_TIME_MS   1000
 
-#ifndef DT_ALIAS_LED0_GPIOS_FLAGS
-#define FLAGS 0
-#else
-#define FLAGS DT_ALIAS_LED0_GPIOS_FLAGS
-#endif
+/* The devicetree node identifier for the "led0" alias. */
+#define LED0_NODE DT_ALIAS(led0)
 
-/* Make sure the board's devicetree declares led0 in its /aliases. */
-#ifdef DT_ALIAS_LED0_GPIOS_CONTROLLER
-#define LED0	DT_ALIAS_LED0_GPIOS_CONTROLLER
-#define PIN	DT_ALIAS_LED0_GPIOS_PIN
+#if DT_HAS_NODE(LED0_NODE)
+#define LED0	DT_GPIO_LABEL(LED0_NODE, gpios)
+#define PIN	DT_GPIO_PIN(LED0_NODE, gpios)
+#if DT_PHA_HAS_CELL(LED0_NODE, gpios, flags)
+#define FLAGS	DT_GPIO_FLAGS(LED0_NODE, gpios)
+#endif
 #else
+/* A build error here means your board isn't set up to blink an LED. */
 #error "Unsupported board: led0 devicetree alias is not defined"
 #define LED0	""
 #define PIN	0
 #endif
 
+#ifndef FLAGS
+#define FLAGS	0
+#endif
+
 void main(void)
 {
 	struct device *dev;