esp32: Add PWM support using the LEDC peripheral

Co-authored-by: Petro Karashchenko <petro.karashchenko@gmail.com>

arch/xtensa/src/esp32/Kconfig

@@ -324,11 +324,12 @@ config ESP32_I2S1
 		No yet implemented
 
 config ESP32_LEDC
-	bool "LED PWM (LEDC)"
+	bool "LEDC (PWM)"
 	default n
-	depends on EXPERIMENTAL
+	select PWM
+	select ARCH_HAVE_PWM_MULTICHAN
 	---help---
-		No yet implemented
+		Enable support to PWM on ESP32 using LEDC peripheral.
 
 config ESP32_PCNT
 	bool "Pulse Count Module (PCNT)"
@@ -1282,6 +1283,91 @@ config ESP32_FREERUN
 endmenu # Timer/counter Configuration
 endif # ESP32_TIMER
 
+menu "LEDC configuration"
+	depends on ESP32_LEDC
+
+menuconfig ESP32_LEDC_TIM0
+	bool "Timer 0"
+	default n
+
+if ESP32_LEDC_TIM0
+
+config ESP32_LEDC_TIM0_CHANNELS
+	int "Number of Timer 0 channels"
+	default 2
+
+endif # ESP32_LEDC_TIM0
+
+menuconfig ESP32_LEDC_TIM1
+	bool "Timer 1"
+	default n
+
+if ESP32_LEDC_TIM1
+
+config ESP32_LEDC_TIM1_CHANNELS
+	int "Number of Timer 1 channels"
+	default 2
+
+endif # ESP32_LEDC_TIM1
+
+menuconfig ESP32_LEDC_TIM2
+	bool "Timer 2"
+	default n
+
+if ESP32_LEDC_TIM2
+
+config ESP32_LEDC_TIM2_CHANNELS
+	int "Number of Timer 2 channels"
+	default 2
+
+endif # ESP32_LEDC_TIM2
+
+menuconfig ESP32_LEDC_TIM3
+	bool "Timer 3"
+	default n
+
+if ESP32_LEDC_TIM3
+
+config ESP32_LEDC_TIM3_CHANNELS
+	int "Number of Timer 3 channels"
+	default 2
+
+endif # ESP32_LEDC_TIM2
+
+config ESP32_LEDC_CHANNEL0_PIN
+	int "Channel 0 pin"
+	default 2
+
+config ESP32_LEDC_CHANNEL1_PIN
+	int "Channel 1 pin"
+	default 3
+
+config ESP32_LEDC_CHANNEL2_PIN
+	int "Channel 2 pin"
+	default 4
+
+config ESP32_LEDC_CHANNEL3_PIN
+	int "Channel 3 pin"
+	default 5
+
+config ESP32_LEDC_CHANNEL4_PIN
+	int "Channel 4 pin"
+	default 6
+
+config ESP32_LEDC_CHANNEL5_PIN
+	int "Channel 5 pin"
+	default 7
+
+config ESP32_LEDC_CHANNEL6_PIN
+	int "Channel 6 pin"
+	default 8
+
+config ESP32_LEDC_CHANNEL7_PIN
+	int "Channel 7 pin"
+	default 9
+
+endmenu # LEDC configuration
+
 config ESP32_HAVE_OTA_PARTITION
 	bool
 	default n

arch/xtensa/src/esp32/Make.defs

@@ -95,6 +95,10 @@ ifeq ($(CONFIG_XTENSA_IMEM_USE_SEPARATE_HEAP),y)
 CHIP_CSRCS += esp32_imm.c
 endif
 
+ifeq ($(CONFIG_ESP32_LEDC),y)
+CHIP_CSRCS += esp32_ledc.c
+endif
+
 ifeq ($(CONFIG_ESP32_I2C),y)
 CHIP_CSRCS += esp32_i2c.c
 endif

arch/xtensa/src/esp32/esp32_ledc.h

@@ -0,0 +1,52 @@
+/****************************************************************************
+ * arch/xtensa/src/esp32/esp32_ledc.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __ARCH_XTENSA_SRC_ESP32_ESP32_LEDC_H
+#define __ARCH_XTENSA_SRC_ESP32_ESP32_LEDC_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/timers/pwm.h>
+
+/****************************************************************************
+ * Public functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: esp32_ledc_init
+ *
+ * Description:
+ *   Initialize one LEDC timer for use with the upper_level PWM driver.
+ *
+ * Input Parameters:
+ *   timer - A number identifying the timer use.
+ *
+ * Returned Value:
+ *   On success, a pointer to the ESP32-C3 LEDC lower half PWM driver is
+ *   returned. NULL is returned on any failure.
+ *
+ ****************************************************************************/
+
+struct pwm_lowerhalf_s *esp32_ledc_init(int timer);
+
+#endif /* __ARCH_RISCV_SRC_ESP32_ESP32_LEDC_H */