Add crude ws2812b driver.

This driver can run lights! However it is very crude and does not
provide a great API. It does work though! Currently lights up 5 leds of
different colors.

Right now this does synchronous writes, which is not the best. It would
be better to be async, but I think that sholud not be a problem and will
shortly be done.

1 files changed, 42 insertions, 0 deletions

diff --git a/include/drv/ws2812b.h b/include/drv/ws2812b.h
new file mode 100644
index 0000000..9cf35e4
--- /dev/null
+++ b/include/drv/ws2812b.h
@@ -0,0 +1,42 @@
+#pragma once
+#ifndef INCLUDE_DRV_WS2812B_H_
+#define INCLUDE_DRV_WS2812B_H_
+
+#include <stdint.h>
+#include "driver/spi_master.h"
+
+typedef struct {
+  uint8_t r;
+  uint8_t g;
+  uint8_t b;
+} ws2812b_rgb_t;
+
+typedef struct {
+  uint8_t* buf_;       /* Buffer to hold the value to spi. */
+
+  uint32_t n_rgb;      /* Number of rgb values which exist. */
+  ws2812b_rgb_t rgb[]; /* Colors to write. */
+} ws2812b_buffer_t;
+
+struct WS2812B;
+typedef struct WS2812B ws2812b_t;
+
+ws2812b_buffer_t* ws2812b_new_buffer(uint32_t size);
+
+ws2812b_t* ws2812b_init(spi_device_handle_t spi);
+
+esp_err_t ws2812b_write_sync(ws2812b_t* drv, ws2812b_buffer_t* buffer);
+
+static inline void ws2812b_buffer_set_rgb(
+    ws2812b_buffer_t* buf, size_t idx, uint8_t r, uint8_t g, uint8_t b)
+{
+  if (idx >= buf->n_rgb) {
+    return;
+  }
+
+  buf->rgb[idx].r = r;
+  buf->rgb[idx].g = g;
+  buf->rgb[idx].b = b;
+}
+
+#endif /* INCLUDE_DRV_WS2812B_H_ */