add ws2812 example

components/ws2812/component.mk

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+COMPONENT_ADD_INCLUDEDIRS := .
+COMPONENT_SRCDIRS := .
+

components/ws2812/ws2812_control.c

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+#include "ws2812_control.h"
+#include "driver/rmt.h"
+
+// Configure these based on your project needs ********
+#define LED_RMT_TX_CHANNEL RMT_CHANNEL_0
+#define LED_RMT_TX_GPIO 18
+// ****************************************************
+
+#define BITS_PER_LED_CMD 24 
+#define LED_BUFFER_ITEMS ((NUM_LEDS * BITS_PER_LED_CMD))
+
+// These values are determined by measuring pulse timing with logic analyzer and adjusting to match datasheet. 
+#define T0H 14  // 0 bit high time
+#define T1H 52  // 1 bit high time
+#define TL  52  // low time for either bit
+
+// This is the buffer which the hw peripheral will access while pulsing the output pin
+rmt_item32_t led_data_buffer[LED_BUFFER_ITEMS];
+
+void setup_rmt_data_buffer(struct led_state new_state);
+
+void ws2812_control_init(void)
+{
+  rmt_config_t config;
+  config.rmt_mode = RMT_MODE_TX;
+  config.channel = LED_RMT_TX_CHANNEL;
+  config.gpio_num = LED_RMT_TX_GPIO;
+  config.mem_block_num = 3;
+  config.tx_config.loop_en = false;
+  config.tx_config.carrier_en = false;
+  config.tx_config.idle_output_en = true;
+  config.tx_config.idle_level = 0;
+  config.clk_div = 2;
+
+  ESP_ERROR_CHECK(rmt_config(&config));
+  ESP_ERROR_CHECK(rmt_driver_install(config.channel, 0, 0));
+}
+
+void ws2812_write_leds(struct led_state new_state) {
+  setup_rmt_data_buffer(new_state);
+  ESP_ERROR_CHECK(rmt_write_items(LED_RMT_TX_CHANNEL, led_data_buffer, LED_BUFFER_ITEMS, false));
+  ESP_ERROR_CHECK(rmt_wait_tx_done(LED_RMT_TX_CHANNEL, portMAX_DELAY));
+}
+
+void setup_rmt_data_buffer(struct led_state new_state) 
+{
+  for (uint32_t led = 0; led < NUM_LEDS; led++) {
+    uint32_t bits_to_send = new_state.leds[led];
+    uint32_t mask = 1 << (BITS_PER_LED_CMD - 1);
+    for (uint32_t bit = 0; bit < BITS_PER_LED_CMD; bit++) {
+      uint32_t bit_is_set = bits_to_send & mask;
+      led_data_buffer[led * BITS_PER_LED_CMD + bit] = bit_is_set ?
+                                                      (rmt_item32_t){{{T1H, 1, TL, 0}}} : 
+                                                      (rmt_item32_t){{{T0H, 1, TL, 0}}};
+      mask >>= 1;
+    }
+  }
+}

components/ws2812/ws2812_control.h

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+#ifndef WS2812_CONTROL_H
+#define WS2812_CONTROL_H
+#include <stdint.h>
+
+#ifndef NUM_LEDS
+#define NUM_LEDS 30
+#endif
+
+// This structure is used for indicating what the colors of each LED should be set to.
+// There is a 32bit value for each LED. Only the lower 3 bytes are used and they hold the
+// Red (byte 2), Green (byte 1), and Blue (byte 0) values to be set.
+struct led_state {
+    uint32_t leds[NUM_LEDS];
+};
+
+// Setup the hardware peripheral. Only call this once.
+void ws2812_control_init(void);
+
+// Update the LEDs to the new state. Call as needed.
+// This function will block the current task until the RMT peripheral is finished sending 
+// the entire sequence.
+void ws2812_write_leds(struct led_state new_state);
+
+#endif

examples/led-strip/Makefile

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+#
+# This is a project Makefile. It is assumed the directory this Makefile resides in is a
+# project subdirectory.
+#
+
+EXTRA_COMPONENT_DIRS += \
+    $(abspath ../../components/wolfssl)\
+    $(abspath ../../components/homekit)\
+    $(abspath ../../components/ws2812)
+
+PROJECT_NAME := homekit-esp32-ledstrip
+include $(IDF_PATH)/make/project.mk

examples/led-strip/components/ledrgb/component.mk

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+COMPONENT_ADD_INCLUDEDIRS := ./
+COMPONENT_SRCDIRS := ./