risc-v/esp_<rmt|ws2812>: Implement the RMT peripheral for all the supported Risc-V ESP32 devices

Documentation/platforms/risc-v/esp32c3/boards/esp32c3-generic/index.rst

@@ -105,6 +105,35 @@ To test it, just execute the ``pwm`` application::
     pwm_main: starting output with frequency: 10000 duty: 00008000
     pwm_main: stopping output
 
+rmt
+---
+
+This configuration configures the transmitter and the receiver of the
+Remote Control Transceiver (RMT) peripheral on the ESP32-C3 using GPIOs 8
+and 2, respectively. The RMT peripheral is better explained
+`here <https://docs.espressif.com/projects/esp-idf/en/latest/esp32c3/api-reference/peripherals/rmt.html>`__,
+in the ESP-IDF documentation. The minimal data unit in the frame is called the
+RMT symbol, which is represented by ``rmt_item32_t`` in the driver:
+
+.. figure:: rmt_symbol.png
+   :align: center
+
+The example ``rmtchar`` can be used to test the RMT peripheral. Connecting
+these pins externally to each other will make the transmitter send RMT items
+and demonstrates the usage of the RMT peripheral::
+
+    nsh> rmtchar
+
+**WS2812 addressable RGB LEDs**
+
+This same configuration enables the usage of the RMT peripheral and the example
+``ws2812`` to drive addressable RGB LEDs::
+
+    nsh> ws2812
+
+Please note that this board contains an on-board WS2812 LED connected to GPIO8
+and, by default, this config configures the RMT transmitter in the same pin.
+
 rtc
 ---
 

Documentation/platforms/risc-v/esp32c6/boards/esp32c6-devkit/index.rst

@@ -140,6 +140,35 @@ To test it, just execute the ``pwm`` application::
     pwm_main: starting output with frequency: 10000 duty: 00008000
     pwm_main: stopping output
 
+rmt
+---
+
+This configuration configures the transmitter and the receiver of the
+Remote Control Transceiver (RMT) peripheral on the ESP32-C6 using GPIOs 8
+and 2, respectively. The RMT peripheral is better explained
+`here <https://docs.espressif.com/projects/esp-idf/en/latest/esp32c6/api-reference/peripherals/rmt.html>`__,
+in the ESP-IDF documentation. The minimal data unit in the frame is called the
+RMT symbol, which is represented by ``rmt_item32_t`` in the driver:
+
+.. figure:: rmt_symbol.png
+   :align: center
+
+The example ``rmtchar`` can be used to test the RMT peripheral. Connecting
+these pins externally to each other will make the transmitter send RMT items
+and demonstrates the usage of the RMT peripheral::
+
+    nsh> rmtchar
+
+**WS2812 addressable RGB LEDs**
+
+This same configuration enables the usage of the RMT peripheral and the example
+``ws2812`` to drive addressable RGB LEDs::
+
+    nsh> ws2812
+
+Please note that this board contains an on-board WS2812 LED connected to GPIO8
+and, by default, this config configures the RMT transmitter in the same pin.
+
 rtc
 ---
 

Documentation/platforms/risc-v/esp32h2/boards/esp32h2-devkit/index.rst

@@ -139,6 +139,35 @@ To test it, just execute the ``pwm`` application::
     pwm_main: starting output with frequency: 10000 duty: 00008000
     pwm_main: stopping output
 
+rmt
+---
+
+This configuration configures the transmitter and the receiver of the
+Remote Control Transceiver (RMT) peripheral on the ESP32-H2 using GPIOs 8
+and 2, respectively. The RMT peripheral is better explained
+`here <https://docs.espressif.com/projects/esp-idf/en/latest/esp32h2/api-reference/peripherals/rmt.html>`__,
+in the ESP-IDF documentation. The minimal data unit in the frame is called the
+RMT symbol, which is represented by ``rmt_item32_t`` in the driver:
+
+.. figure:: rmt_symbol.png
+   :align: center
+
+The example ``rmtchar`` can be used to test the RMT peripheral. Connecting
+these pins externally to each other will make the transmitter send RMT items
+and demonstrates the usage of the RMT peripheral::
+
+    nsh> rmtchar
+
+**WS2812 addressable RGB LEDs**
+
+This same configuration enables the usage of the RMT peripheral and the example
+``ws2812`` to drive addressable RGB LEDs::
+
+    nsh> ws2812
+
+Please note that this board contains an on-board WS2812 LED connected to GPIO8
+and, by default, this config configures the RMT transmitter in the same pin.
+
 rtc
 ---
 

Documentation/platforms/xtensa/esp32s2/boards/esp32s2-saola-1/index.rst

@@ -335,6 +335,35 @@ To test it, just run ``rand`` to get 32 randomly generated bytes::
     0000  98 b9 66 a2 a2 c0 a2 ae 09 70 93 d1 b5 91 86 c8  ..f......p......
     0010  8f 0e 0b 04 29 64 21 72 01 92 7c a2 27 60 6f 90  ....)d!r..|.'`o.
 
+rmt
+---
+
+This configuration configures the transmitter and the receiver of the
+Remote Control Transceiver (RMT) peripheral on the ESP32-S2 using GPIOs 18
+and 2, respectively. The RMT peripheral is better explained
+`here <https://docs.espressif.com/projects/esp-idf/en/latest/esp32s2/api-reference/peripherals/rmt.html>`__,
+in the ESP-IDF documentation. The minimal data unit in the frame is called the
+RMT symbol, which is represented by ``rmt_item32_t`` in the driver:
+
+.. figure:: rmt_symbol.png
+   :align: center
+
+The example ``rmtchar`` can be used to test the RMT peripheral. Connecting
+these pins externally to each other will make the transmitter send RMT items
+and demonstrates the usage of the RMT peripheral::
+
+    nsh> rmtchar
+
+**WS2812 addressable RGB LEDs**
+
+This same configuration enables the usage of the RMT peripheral and the example
+``ws2812`` to drive addressable RGB LEDs::
+
+    nsh> ws2812
+
+Please note that this board contains an on-board WS2812 LED connected to GPIO18
+and, by default, this config configures the RMT transmitter in the same pin.
+
 rtc
 ---
 

Documentation/platforms/xtensa/esp32s3/boards/esp32s3-devkit/index.rst

@@ -46,6 +46,14 @@ Board LEDs
 
 There are several on-board LEDs for that indicate the presence of power
 and USB activity.  None of these are available for use by software.
+Another WS2812 LED is connected to GPIO48 or GPIO38 depending on the boards
+version.
+
+.. note:: Both the initial and v1.1 versions of ESP32-S3-DevKitC-1 are
+   available on the market. The main difference lies in the GPIO assignment
+   for the RGB LED: the initial version (1.0) uses GPIO48, whereas v1.1 uses
+   GPIO38. The initial version is selected by default, but one can select
+   ``CONFIG_ESP32S3_DEVKITC_1_V11`` through ``make menuconfig``.
 
 I2S
 ===
@@ -372,6 +380,37 @@ To test it, just run ``rand`` to get 32 randomly generated bytes::
     0000  98 b9 66 a2 a2 c0 a2 ae 09 70 93 d1 b5 91 86 c8  ..f......p......
     0010  8f 0e 0b 04 29 64 21 72 01 92 7c a2 27 60 6f 90  ....)d!r..|.'`o.
 
+rmt
+---
+
+This configuration configures the transmitter and the receiver of the
+Remote Control Transceiver (RMT) peripheral on the ESP32-S3 using GPIOs 48
+(or 38, depending on the board version) and 2, respectively.
+The RMT peripheral is better explained
+`here <https://docs.espressif.com/projects/esp-idf/en/latest/esp32s3/api-reference/peripherals/rmt.html>`__,
+in the ESP-IDF documentation. The minimal data unit in the frame is called the
+RMT symbol, which is represented by ``rmt_item32_t`` in the driver:
+
+.. figure:: rmt_symbol.png
+   :align: center
+
+The example ``rmtchar`` can be used to test the RMT peripheral. Connecting
+these pins externally to each other will make the transmitter send RMT items
+and demonstrates the usage of the RMT peripheral::
+
+    nsh> rmtchar
+
+**WS2812 addressable RGB LEDs**
+
+This same configuration enables the usage of the RMT peripheral and the example
+``ws2812`` to drive addressable RGB LEDs::
+
+    nsh> ws2812
+
+Please note that this board contains an on-board WS2812 LED connected to GPIO48
+(or GPIO38, depending on the board version) and, by default, this config
+configures the RMT transmitter in the same pin.
+
 rtc
 ---
 

arch/risc-v/src/Makefile

@@ -130,6 +130,7 @@ endif
 
 VPATH += chip
 VPATH += common
+VPATH += common/espressif
 VPATH += $(SBI_DIR)
 VPATH += $(ARCH_SUBDIR)
 VPATH += $(CHIP_DIR)

arch/risc-v/src/common/espressif/Kconfig

@@ -298,6 +298,16 @@ config ESPRESSIF_BROWNOUT_DET
 		than a specific value. If this happens, it will reset the chip in
 		order to prevent unintended behaviour.
 
+config ESP_RMT
+	bool "Remote Control Module (RMT)"
+	default n
+	depends on RMT
+	---help---
+		The RMT (Remote Control Transceiver) peripheral was designed to act as
+		an infrared transceiver. However, due to the flexibility of its data
+		format, RMT can be extended to a versatile and general-purpose
+		transceiver, transmitting or receiving many other types of signals.
+
 endmenu # Peripheral Support
 
 menu "UART Configuration"

arch/risc-v/src/common/espressif/Make.defs

@@ -73,6 +73,13 @@ ifeq ($(CONFIG_ESPRESSIF_USBSERIAL),y)
   CHIP_CSRCS += esp_usbserial.c
 endif
 
+ifeq ($(CONFIG_ESP_RMT),y)
+  CHIP_CSRCS += esp_rmt.c
+  ifeq ($(CONFIG_WS2812_NON_SPI_DRIVER),y)
+    CHIP_CSRCS += esp_ws2812.c
+  endif
+endif
+
 #############################################################################
 # Espressif HAL for 3rd Party Platforms
 #############################################################################

arch/risc-v/src/common/espressif/esp_gpio.h

@@ -98,6 +98,24 @@
 #define ONLOW             0x04
 #define ONHIGH            0x05
 
+/* Check whether it is a valid GPIO number */
+
+#define GPIO_IS_VALID_GPIO(gpio_num)   ((gpio_num >= 0) && \
+                                        (((1ULL << (gpio_num)) & \
+                                         SOC_GPIO_VALID_GPIO_MASK) != 0))
+
+/* Check whether it can be a valid GPIO number of output mode */
+
+#define GPIO_IS_VALID_OUTPUT_GPIO(gpio_num) \
+  ((gpio_num >= 0) && \
+      (((1ULL << (gpio_num)) & SOC_GPIO_VALID_OUTPUT_GPIO_MASK) != 0))
+
+/* Check whether it can be a valid digital I/O pad */
+
+#define GPIO_IS_VALID_DIGITAL_IO_PAD(gpio_num) \
+  ((gpio_num >= 0) && \
+    (((1ULL << (gpio_num)) & SOC_GPIO_VALID_DIGITAL_IO_PAD_MASK) != 0))
+
 /****************************************************************************
  * Public Types
  ****************************************************************************/