boards: esp8684_devkitm: PWM sample and document update

Added sample for ESP32C2/ESP8684 SoC and updated document
indicating LEDC PWM support.

Signed-off-by: Raffael Rostagno <raffael.rostagno@espressif.com>

boards/espressif/esp8684_devkitm/doc/index.rst

@@ -61,6 +61,8 @@ Current Zephyr's ESP8684-Devkitm board supports the following features:
 +------------+------------+-------------------------------------+
 | Wi-Fi      | on-chip    |                                     |
 +------------+------------+-------------------------------------+
+| LEDC       | on-chip    | pwm                                 |
++------------+------------+-------------------------------------+
 
 For a getting started user guide, please check `ESP8684 Devkitm User Guide`_.
 

boards/espressif/esp8684_devkitm/esp8684_devkitm.yaml

@@ -10,6 +10,7 @@ supported:
   - uart
   - counter
   - entropy
+  - pwm
 testing:
   ignore_tags:
     - net

tests/drivers/pwm/pwm_api/socs/esp32c2.overlay

@@ -0,0 +1,34 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Copyright (c) 2024 Espressif Systems (Shanghai) Co., Ltd.
+ */
+
+#include <zephyr/dt-bindings/pwm/pwm.h>
+
+/ {
+	aliases {
+		pwm-0 = &ledc0;
+	};
+};
+
+&pinctrl {
+	ledc0_default: ledc0_default {
+		group1 {
+			pinmux = <LEDC_CH0_GPIO2>;
+			output-enable;
+		};
+	};
+};
+
+&ledc0 {
+	pinctrl-0 = <&ledc0_default>;
+	pinctrl-names = "default";
+	status = "okay";
+	#address-cells = <1>;
+	#size-cells = <0>;
+	channel0@0 {
+		reg = <0x0>;
+		timer = <0>;
+	};
+};