Add heartbeat LED

noahp · noahp · commit dfa33796c169 · 2026-04-13T14:17:44.000-04:00
Surprisingly involve TBH, but it works! Tested on ESP32-C6 only for now.
diff --git a/Kconfig b/Kconfig
@@ -35,6 +35,28 @@ config WIFI_WATCHDOG_CHECK_INTERVAL_SECONDS
 	help
 	  Interval in seconds between WiFi watchdog checks.
 
+choice HEARTBEAT_LED_TYPE
+	prompt "Select heartbeat LED variant"
+	default HEARTBEAT_LED_STRIP if $(dt_alias_enabled,led-strip)
+	default HEARTBEAT_LED_GPIO if $(dt_alias_enabled,heartbeat-led)
+
+config HEARTBEAT_LED_STRIP
+	bool "WS2812 RGB LED strip"
+	depends on LED_STRIP
+	help
+	  Enable heartbeat LED using a WS2812 RGB LED strip.
+	  GREEN when WiFi is connected, RED otherwise.
+	  Blinks at a 1-second interval.
+
+config HEARTBEAT_LED_GPIO
+	bool "GPIO LED"
+	depends on GPIO
+	help
+	  Enable heartbeat LED using a simple GPIO-driven LED.
+	  Blinks at a 1-second interval unconditionally.
+
+endchoice
+
 endmenu
 
 config MEMFAULT_BUILTIN_DEVICE_INFO_SOFTWARE_VERSION
diff --git a/boards/esp32c3_devkitm.overlay b/boards/esp32c3_devkitm.overlay
@@ -4,10 +4,48 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include <zephyr/dt-bindings/led/led.h>
+
 &wifi {
 	status = "okay";
 };
 
 &coretemp {
 	status = "okay";
 };
+
+/ {
+	aliases {
+		led-strip = &led_strip;
+	};
+};
+
+/* WS2812 RGB LED on GPIO8 via SPI2 */
+&spi2 {
+	/* Workaround to support WS2812 driver */
+	line-idle-low;
+
+	led_strip: ws2812@0 {
+		compatible = "worldsemi,ws2812-spi";
+
+		/* SPI */
+		reg = <0>;
+		spi-max-frequency = <6400000>;
+
+		/* WS2812 */
+		chain-length = <1>;
+		spi-cpha;
+		spi-one-frame = <0xf0>;
+		spi-zero-frame = <0xc0>;
+		color-mapping = <LED_COLOR_ID_GREEN LED_COLOR_ID_RED LED_COLOR_ID_BLUE>;
+	};
+};
+
+&pinctrl {
+	spim2_default: spim2_default {
+		group2 {
+			/* WS2812 data on GPIO8 */
+			pinmux = <SPIM2_MOSI_GPIO8>;
+		};
+	};
+};
diff --git a/boards/esp32c6_devkitc_esp32c6_hpcore.conf b/boards/esp32c6_devkitc_esp32c6_hpcore.conf
@@ -0,0 +1,3 @@
+# Enable DMA for heartbeat LED
+CONFIG_DMA=y
+CONFIG_LED_STRIP=y
diff --git a/boards/esp32c6_devkitc_esp32c6_hpcore.overlay b/boards/esp32c6_devkitc_esp32c6_hpcore.overlay
@@ -4,10 +4,45 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include <zephyr/dt-bindings/led/led.h>
+
 &wifi {
 	status = "okay";
 };
 
 &coretemp {
 	status = "okay";
 };
+
+/ {
+	aliases {
+		led-strip = &led_strip;
+	};
+};
+
+/* WS2812 RGB LED on GPIO8 via I2S */
+&i2s_default {
+	group1 {
+		pinmux = <I2S_O_SD_GPIO8>;
+	};
+};
+
+i2s_led: &i2s {
+	status = "okay";
+
+	dmas = <&dma 3>;
+	dma-names = "tx";
+
+	led_strip: ws2812@0 {
+		compatible = "worldsemi,ws2812-i2s";
+
+		reg = <0>;
+		chain-length = <1>;
+		color-mapping = <LED_COLOR_ID_GREEN LED_COLOR_ID_RED LED_COLOR_ID_BLUE>;
+		reset-delay = <500>;
+	};
+};
+
+&dma {
+	status = "okay";
+};
diff --git a/boards/esp32s3_devkitc_esp32s3_procpu.conf b/boards/esp32s3_devkitc_esp32s3_procpu.conf
@@ -1,3 +1,7 @@
 # Enable external SPI RAM
 CONFIG_SPI=y
 CONFIG_ESP_SPIRAM=y
+
+# Enable DMA for heartbeat LED
+CONFIG_DMA=y
+CONFIG_LED_STRIP=y
diff --git a/boards/esp32s3_devkitc_esp32s3_procpu.overlay b/boards/esp32s3_devkitc_esp32s3_procpu.overlay
@@ -4,6 +4,8 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include <zephyr/dt-bindings/led/led.h>
+
 &wifi {
 	status = "okay";
 };
@@ -16,3 +18,36 @@
 &psram0 {
 	size = <DT_SIZE_M(2)>;
 };
+
+/ {
+	aliases {
+		led-strip = &led_strip;
+	};
+};
+
+/* WS2812 RGB LED on GPIO38 via I2S0 */
+&i2s0_default {
+	group1 {
+		pinmux = <I2S0_O_SD_GPIO38>;
+	};
+};
+
+i2s_led: &i2s0 {
+	status = "okay";
+
+	dmas = <&dma 3>;
+	dma-names = "tx";
+
+	led_strip: ws2812@0 {
+		compatible = "worldsemi,ws2812-i2s";
+
+		reg = <0>;
+		chain-length = <1>;
+		color-mapping = <LED_COLOR_ID_GREEN LED_COLOR_ID_RED LED_COLOR_ID_BLUE>;
+		reset-delay = <500>;
+	};
+};
+
+&dma {
+	status = "okay";
+};
diff --git a/boards/esp32s3_devkitm_esp32s3_procpu.conf b/boards/esp32s3_devkitm_esp32s3_procpu.conf
@@ -0,0 +1,3 @@
+# Enable DMA + LED_STRIP for heartbeat LED
+CONFIG_DMA=y
+CONFIG_LED_STRIP=y
diff --git a/boards/esp32s3_devkitm_esp32s3_procpu.overlay b/boards/esp32s3_devkitm_esp32s3_procpu.overlay
@@ -4,10 +4,48 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include <zephyr/dt-bindings/led/led.h>
+
 &wifi {
 	status = "okay";
 };
 
 &coretemp {
 	status = "okay";
 };
+
+/ {
+	aliases {
+		led-strip = &led_strip;
+	};
+};
+
+/* WS2812 RGB LED on GPIO48 via SPI3 */
+&spi3 {
+	/* Workaround to support WS2812 driver */
+	line-idle-low;
+
+	led_strip: ws2812@0 {
+		compatible = "worldsemi,ws2812-spi";
+
+		/* SPI */
+		reg = <0>;
+		spi-max-frequency = <6400000>;
+
+		/* WS2812 */
+		chain-length = <1>;
+		spi-cpha;
+		spi-one-frame = <0xf0>;
+		spi-zero-frame = <0xc0>;
+		color-mapping = <LED_COLOR_ID_GREEN LED_COLOR_ID_RED LED_COLOR_ID_BLUE>;
+	};
+};
+
+&pinctrl {
+	spim3_default: spim3_default {
+		group2 {
+			/* WS2812 data on GPIO48 */
+			pinmux = <SPIM3_MOSI_GPIO48>;
+		};
+	};
+};
diff --git a/boards/esp_wrover_kit_procpu.conf b/boards/esp_wrover_kit_procpu.conf
@@ -0,0 +1 @@
+CONFIG_HEARTBEAT_LED_GPIO=y
diff --git a/boards/esp_wrover_kit_procpu.overlay b/boards/esp_wrover_kit_procpu.overlay
@@ -1,3 +1,9 @@
 &wifi {
 	status = "okay";
 };
+
+/ {
+	aliases {
+		heartbeat-led = &red_led;
+	};
+};
diff --git a/src/heartbeat_led.c b/src/heartbeat_led.c
@@ -0,0 +1,130 @@
+//! @file
+//!
+//! @brief Heartbeat LED module.
+//!
+//! Blinks an LED at a 1-second interval to indicate the device is running.
+//!
+//! On boards with a WS2812 RGB LED (CONFIG_HEARTBEAT_LED_STRIP):
+//!   - GREEN when WiFi is connected
+//!   - RED when WiFi is not connected
+//!
+//! On boards with a simple GPIO LED (CONFIG_HEARTBEAT_LED_GPIO):
+//!   - Blinks unconditionally at a 1-second interval
+
+#include <zephyr/kernel.h>
+#include <zephyr/logging/log.h>
+
+LOG_MODULE_REGISTER(heartbeat_led, LOG_LEVEL_DBG);
+
+// Blink half-period: 500ms on + 500ms off = 1 second total
+#define HEARTBEAT_BLINK_HALF_PERIOD_MS 500
+
+#define HEARTBEAT_LED_STACK_SIZE 1024
+#define HEARTBEAT_LED_PRIORITY 7
+
+#if defined(CONFIG_HEARTBEAT_LED_STRIP)
+
+#include <zephyr/drivers/led_strip.h>
+#include <zephyr/net/net_mgmt.h>
+#include <zephyr/net/wifi_mgmt.h>
+
+static const struct device* s_led_strip = DEVICE_DT_GET(DT_ALIAS(led_strip));
+
+static bool s_wifi_connected = false;
+static struct net_mgmt_event_callback s_wifi_led_mgmt_cb;
+
+// WiFi event handler to track connection state
+static void prv_wifi_event_handler(struct net_mgmt_event_callback* cb,
+                                   uint64_t mgmt_event, struct net_if* iface) {
+  ARG_UNUSED(iface);
+  if (mgmt_event == NET_EVENT_WIFI_CONNECT_RESULT) {
+    const struct wifi_status* status = (const struct wifi_status*)cb->info;
+    s_wifi_connected = (status->status == 0);
+    LOG_DBG("Heartbeat LED: WiFi %s",
+            s_wifi_connected ? "connected" : "failed");
+  } else if (mgmt_event == NET_EVENT_WIFI_DISCONNECT_RESULT) {
+    s_wifi_connected = false;
+    LOG_DBG("Heartbeat LED: WiFi disconnected");
+  }
+}
+
+static void prv_heartbeat_led_thread(void* arg1, void* arg2, void* arg3) {
+  ARG_UNUSED(arg1);
+  ARG_UNUSED(arg2);
+  ARG_UNUSED(arg3);
+
+  net_mgmt_init_event_callback(
+      &s_wifi_led_mgmt_cb, prv_wifi_event_handler,
+      NET_EVENT_WIFI_CONNECT_RESULT | NET_EVENT_WIFI_DISCONNECT_RESULT);
+  net_mgmt_add_event_callback(&s_wifi_led_mgmt_cb);
+
+  if (!device_is_ready(s_led_strip)) {
+    LOG_ERR("LED strip device not ready");
+    return;
+  }
+
+  bool led_on = false;
+  while (1) {
+    led_on = !led_on;
+
+    struct led_rgb pixel;
+    if (led_on) {
+      if (s_wifi_connected) {
+        // Green: WiFi connected
+        pixel = (struct led_rgb){.r = 0, .g = 32, .b = 0};
+      } else {
+        // Red: WiFi not connected
+        pixel = (struct led_rgb){.r = 32, .g = 0, .b = 0};
+      }
+    } else {
+      // Off
+      pixel = (struct led_rgb){.r = 0, .g = 0, .b = 0};
+    }
+
+    int rc = led_strip_update_rgb(s_led_strip, &pixel, 1);
+    if (rc != 0) {
+      LOG_ERR("LED strip update failed: %d", rc);
+    }
+
+    k_sleep(K_MSEC(HEARTBEAT_BLINK_HALF_PERIOD_MS));
+  }
+}
+
+#elif defined(CONFIG_HEARTBEAT_LED_GPIO)
+
+#include <zephyr/drivers/gpio.h>
+
+static const struct gpio_dt_spec s_led =
+    GPIO_DT_SPEC_GET(DT_ALIAS(heartbeat_led), gpios);
+
+static void prv_heartbeat_led_thread(void* arg1, void* arg2, void* arg3) {
+  ARG_UNUSED(arg1);
+  ARG_UNUSED(arg2);
+  ARG_UNUSED(arg3);
+
+  if (!gpio_is_ready_dt(&s_led)) {
+    LOG_ERR("Heartbeat LED GPIO not ready");
+    return;
+  }
+
+  int rc = gpio_pin_configure_dt(&s_led, GPIO_OUTPUT_INACTIVE);
+  if (rc != 0) {
+    LOG_ERR("Failed to configure heartbeat LED GPIO: %d", rc);
+    return;
+  }
+
+  while (1) {
+    gpio_pin_toggle_dt(&s_led);
+    k_sleep(K_MSEC(HEARTBEAT_BLINK_HALF_PERIOD_MS));
+  }
+}
+
+#endif /* CONFIG_HEARTBEAT_LED_STRIP / CONFIG_HEARTBEAT_LED_GPIO */
+
+#if defined(CONFIG_HEARTBEAT_LED_STRIP) || defined(CONFIG_HEARTBEAT_LED_GPIO)
+
+K_THREAD_DEFINE(heartbeat_led_thread, HEARTBEAT_LED_STACK_SIZE,
+                prv_heartbeat_led_thread, NULL, NULL, NULL,
+                HEARTBEAT_LED_PRIORITY, 0, 0);
+
+#endif /* CONFIG_HEARTBEAT_LED_STRIP || CONFIG_HEARTBEAT_LED_GPIO */

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+# Enable DMA for heartbeat LED`
	`2`	`+CONFIG_DMA=y`
	`3`	`+CONFIG_LED_STRIP=y`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+# Enable DMA + LED_STRIP for heartbeat LED`
	`2`	`+CONFIG_DMA=y`
	`3`	`+CONFIG_LED_STRIP=y`