Initial commit.

examples/common/ws2812_led/ws2812_led.c

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+/*  WS2812 RGB LED helper functions
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+*/
+
+/* It is recommended to copy this code in your example so that you can modify as
+ * per your application's needs.
+ */
+
+
+#include <stdint.h>
+#include <esp_err.h>
+#include <esp_log.h>
+
+static const char *TAG = "ws2812_led";
+
+#ifdef CONFIG_WS2812_LED_ENABLE
+#include <driver/rmt.h>
+#include "led_strip.h"
+#define RMT_TX_CHANNEL RMT_CHANNEL_0
+
+static led_strip_t *g_strip;
+
+/**
+ * @brief Simple helper function, converting HSV color space to RGB color space
+ *
+ * Wiki: https://en.wikipedia.org/wiki/HSL_and_HSV
+ *
+ */
+static void ws2812_led_hsv2rgb(uint32_t h, uint32_t s, uint32_t v, uint32_t *r, uint32_t *g, uint32_t *b)
+{
+    h %= 360; // h -> [0,360]
+    uint32_t rgb_max = v * 2.55f;
+    uint32_t rgb_min = rgb_max * (100 - s) / 100.0f;
+
+    uint32_t i = h / 60;
+    uint32_t diff = h % 60;
+
+    // RGB adjustment amount by hue
+    uint32_t rgb_adj = (rgb_max - rgb_min) * diff / 60;
+
+    switch (i) {
+    case 0:
+        *r = rgb_max;
+        *g = rgb_min + rgb_adj;
+        *b = rgb_min;
+        break;
+    case 1:
+        *r = rgb_max - rgb_adj;
+        *g = rgb_max;
+        *b = rgb_min;
+        break;
+    case 2:
+        *r = rgb_min;
+        *g = rgb_max;
+        *b = rgb_min + rgb_adj;
+        break;
+    case 3:
+        *r = rgb_min;
+        *g = rgb_max - rgb_adj;
+        *b = rgb_max;
+        break;
+    case 4:
+        *r = rgb_min + rgb_adj;
+        *g = rgb_min;
+        *b = rgb_max;
+        break;
+    default:
+        *r = rgb_max;
+        *g = rgb_min;
+        *b = rgb_max - rgb_adj;
+        break;
+    }
+}
+
+esp_err_t ws2812_led_set_rgb(uint32_t red, uint32_t green, uint32_t blue)
+{
+    if (!g_strip) {
+        return ESP_ERR_INVALID_STATE;
+    }
+    g_strip->set_pixel(g_strip, 0, red, green, blue);
+    g_strip->refresh(g_strip, 100);
+    return ESP_OK;
+}
+
+esp_err_t ws2812_led_set_hsv(uint32_t hue, uint32_t saturation, uint32_t value)
+{
+    if (!g_strip) {
+        return ESP_ERR_INVALID_STATE;
+    }
+    uint32_t red = 0;
+    uint32_t green = 0;
+    uint32_t blue = 0;
+    ws2812_led_hsv2rgb(hue, saturation, value, &red, &green, &blue);
+    return ws2812_led_set_rgb(red, green, blue);
+}
+
+esp_err_t ws2812_led_clear(void)
+{
+    if (!g_strip) {
+        return ESP_ERR_INVALID_STATE;
+    }
+    g_strip->clear(g_strip, 100);
+    return ESP_OK;
+}
+
+esp_err_t ws2812_led_init(void)
+{
+    rmt_config_t config = RMT_DEFAULT_CONFIG_TX(CONFIG_WS2812_LED_GPIO, RMT_TX_CHANNEL);
+    // set counter clock to 40MHz
+    config.clk_div = 2;
+
+    if (rmt_config(&config) != ESP_OK) {
+        ESP_LOGE(TAG, "RMT Config failed.");
+        return ESP_FAIL;
+    }
+    if (rmt_driver_install(config.channel, 0, 0) != ESP_OK) {
+        ESP_LOGE(TAG, "RMT Driver install failed.");
+        return ESP_FAIL;
+    }
+
+    // install ws2812 driver
+    led_strip_config_t strip_config = LED_STRIP_DEFAULT_CONFIG(1, (led_strip_dev_t)config.channel);
+    g_strip = led_strip_new_rmt_ws2812(&strip_config);
+    if (!g_strip) {
+        ESP_LOGE(TAG, "Install WS2812 driver failed.");
+        return ESP_FAIL;
+    }
+    return ESP_OK;
+}
+#else /* !CONFIG_WS2812_LED_ENABLE */
+esp_err_t ws2812_led_set_rgb(uint32_t red, uint32_t green, uint32_t blue)
+{
+    /* Empty function, since WS2812 RGB LED has been disabled.  */
+    return ESP_OK;
+}
+
+esp_err_t ws2812_led_set_hsv(uint32_t hue, uint32_t saturation, uint32_t value)
+{
+    /* Empty function, since WS2812 RGB LED has been disabled.  */
+    return ESP_OK;
+}
+
+esp_err_t ws2812_led_clear(void)
+{
+    /* Empty function, since WS2812 RGB LED has been disabled.  */
+    return ESP_OK;
+}
+
+esp_err_t ws2812_led_init(void)
+{
+    ESP_LOGW(TAG, "WS2812 LED is disabled");
+    return ESP_OK;
+}
+#endif /* !CONFIG_WS2812_LED_ENABLE */