samples: led: lp5569: demo write_channels

Add a simple demonstration of the led_write_channels api on the lp5569
driver sample.
The demonstration simply turns on all of the channels with a single call to
led_write_channels. Then the same is done for turning off the channels.
Thus, it doesn't add much visually, but it shows the usage of the api.

Signed-off-by: Emil Dahl Juhl <[email protected]>

Author: Emil Dahl Juhl

doc/releases/release-notes-4.1.rst

@@ -121,6 +121,7 @@ Drivers and Sensors
   * Added a new set of devicetree based LED APIs, see :c:struct:`led_dt_spec`.
   * lp5569: added use of auto-increment functionality.
   * lp5569: implemented ``write_channels`` api.
+  * lp5569: demonstrate ``led_write_channels`` in the sample.
 
 * LED Strip
 

samples/drivers/led/lp5569/README.rst

@@ -8,7 +8,10 @@ Overview
 ********
 
 This sample controls 9 LEDs connected to an LP5569 driver. The sample turns
-all LEDs on and switches all LEDs off again within a one second interval.
+all LEDs on one by one with a 1 second delay between each. Then it fades all
+LEDs until they are off again. Afterwards, it turns them all on at once, waits
+a second, and turns them all back off.
+This pattern then repeats indefinitely.
 
 Building and Running
 ********************

samples/drivers/led/lp5569/src/main.c

@@ -18,6 +18,7 @@ LOG_MODULE_REGISTER(app, CONFIG_LED_LOG_LEVEL);
 int main(void)
 {
 	const struct device *const led_dev = DEVICE_DT_GET_ANY(ti_lp5569);
+	uint8_t ch_buf[9] = {0};
 	int i, ret;
 
 	if (!led_dev) {
@@ -32,7 +33,8 @@ int main(void)
 
 	/*
 	 * Display a continuous pattern that turns on 9 LEDs at 1 s one by
-	 * one until it reaches the end and turns off LEDs in reverse order.
+	 * one until it reaches the end and fades off all LEDs.
+	 * Afterwards, all LEDs get blinked once at the same time.
 	 */
 
 	LOG_INF("Testing 9 LEDs ..");
@@ -59,6 +61,26 @@ int main(void)
 
 			k_sleep(DELAY_TIME_BREATHING);
 		}
+
+		k_sleep(DELAY_TIME_ON);
+
+		/* Turn on all LEDs at once to demonstrate write_channels */
+		memset(ch_buf, 255, ARRAY_SIZE(ch_buf));
+		ret = led_write_channels(led_dev, 0, ARRAY_SIZE(ch_buf), ch_buf);
+		if (ret) {
+			return ret;
+		}
+
+		k_sleep(DELAY_TIME_ON);
+
+		/* Turn off all LEDs at once to demonstrate write_channels */
+		memset(ch_buf, 0, ARRAY_SIZE(ch_buf));
+		ret = led_write_channels(led_dev, 0, ARRAY_SIZE(ch_buf), ch_buf);
+		if (ret) {
+			return ret;
+		}
+
+		k_sleep(DELAY_TIME_ON);
 	}
 	return 0;
 }