drivers/arm/ws2812_spi.c

   1 #include "quantum.h"
   2 #include "ws2812.h"
   3
   4 /* Adapted from https://github.com/gamazeps/ws2812b-chibios-SPIDMA/ */
   5
   6 #ifdef RGBW
   7 #    error "RGBW not supported"
   8 #endif
   9
  10 // Define the spi your LEDs are plugged to here
  11 #ifndef WS2812_SPI
  12 #    define WS2812_SPI SPID1
  13 #endif
  14
  15 #ifndef WS2812_SPI_MOSI_PAL_MODE
  16 #    define WS2812_SPI_MOSI_PAL_MODE 5
  17 #endif
  18
  19 #define BYTES_FOR_LED_BYTE 4
  20 #define NB_COLORS 3
  21 #define BYTES_FOR_LED (BYTES_FOR_LED_BYTE * NB_COLORS)
  22 #define DATA_SIZE (BYTES_FOR_LED * RGBLED_NUM)
  23 #define RESET_SIZE 200
  24 #define PREAMBLE_SIZE 4
  25
  26 static uint8_t txbuf[PREAMBLE_SIZE + DATA_SIZE + RESET_SIZE] = {0};
  27
  28 /*
  29  * As the trick here is to use the SPI to send a huge pattern of 0 and 1 to
  30  * the ws2812b protocol, we use this helper function to translate bytes into
  31  * 0s and 1s for the LED (with the appropriate timing).
  32  */
  33 static uint8_t get_protocol_eq(uint8_t data, int pos) {
  34     uint8_t eq = 0;
  35     if (data & (1 << (2 * (3 - pos))))
  36         eq = 0b1110;
  37     else
  38         eq = 0b1000;
  39     if (data & (2 << (2 * (3 - pos))))
  40         eq += 0b11100000;
  41     else
  42         eq += 0b10000000;
  43     return eq;
  44 }
  45
  46 static void set_led_color_rgb(LED_TYPE color, int pos) {
  47     uint8_t* tx_start = &txbuf[PREAMBLE_SIZE];
  48
  49     for (int j = 0; j < 4; j++) tx_start[BYTES_FOR_LED * pos + j] = get_protocol_eq(color.g, j);
  50     for (int j = 0; j < 4; j++) tx_start[BYTES_FOR_LED * pos + BYTES_FOR_LED_BYTE + j] = get_protocol_eq(color.r, j);
  51     for (int j = 0; j < 4; j++) tx_start[BYTES_FOR_LED * pos + BYTES_FOR_LED_BYTE * 2 + j] = get_protocol_eq(color.b, j);
  52 }
  53
  54 void ws2812_init(void) {
  55 #if defined(USE_GPIOV1)
  56     palSetLineMode(RGB_DI_PIN, PAL_MODE_STM32_ALTERNATE_PUSHPULL);
  57 #else
  58     palSetLineMode(RGB_DI_PIN, PAL_MODE_ALTERNATE(WS2812_SPI_MOSI_PAL_MODE) | PAL_STM32_OTYPE_PUSHPULL);
  59 #endif
  60
  61     // TODO: more dynamic baudrate
  62     static const SPIConfig spicfg = {
  63         0, NULL, PAL_PORT(RGB_DI_PIN), PAL_PAD(RGB_DI_PIN),
  64         SPI_CR1_BR_1 | SPI_CR1_BR_0  // baudrate : fpclk / 8 => 1tick is 0.32us (2.25 MHz)
  65     };
  66
  67     spiAcquireBus(&WS2812_SPI);     /* Acquire ownership of the bus.    */
  68     spiStart(&WS2812_SPI, &spicfg); /* Setup transfer parameters.       */
  69     spiSelect(&WS2812_SPI);         /* Slave Select assertion.          */
  70 }
  71
  72 void ws2812_setleds(LED_TYPE* ledarray, uint16_t leds) {
  73     static bool s_init = false;
  74     if (!s_init) {
  75         ws2812_init();
  76         s_init = true;
  77     }
  78
  79     for (uint8_t i = 0; i < leds; i++) {
  80         set_led_color_rgb(ledarray[i], i);
  81     }
  82
  83     // Send async - each led takes ~0.03ms, 50 leds ~1.5ms, animations flushing faster than send will cause issues.
  84     // Instead spiSend can be used to send synchronously (or the thread logic can be added back).
  85 #ifdef WS2812_SPI_SYNC
  86     spiSend(&WS2812_SPI, sizeof(txbuf) / sizeof(txbuf[0]), txbuf);
  87 #else
  88     spiStartSend(&WS2812_SPI, sizeof(txbuf) / sizeof(txbuf[0]), txbuf);
  89 #endif
  90 }