From 680ebef0869b7860017a80bd601faac61227cd28 Mon Sep 17 00:00:00 2001
From: Joel Challis <git@zvecr.com>
Date: Tue, 31 Dec 2019 17:26:40 +0000
Subject: SPI DMA based RGB Underglow for STM32 (#7674)

* Initial stash of ws2812 spi driver

* Update comment, add sync backup plan

* Add testing notes to spi ws2812 driver

* Align RGBW error messages
---
 drivers/arm/ws2812_spi.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 90 insertions(+), 1 deletion(-)

(limited to 'drivers')

diff --git a/drivers/arm/ws2812_spi.c b/drivers/arm/ws2812_spi.c
index 2094e50098..0e954ec506 100644
--- a/drivers/arm/ws2812_spi.c
+++ b/drivers/arm/ws2812_spi.c
@@ -1 +1,90 @@
-#error("NOT SUPPORTED")
\ No newline at end of file
+#include "quantum.h"
+#include "ws2812.h"
+
+/* Adapted from https://github.com/gamazeps/ws2812b-chibios-SPIDMA/ */
+
+#ifdef RGBW
+#    error "RGBW not supported"
+#endif
+
+// Define the spi your LEDs are plugged to here
+#ifndef WS2812_SPI
+#    define WS2812_SPI SPID1
+#endif
+
+#ifndef WS2812_SPI_MOSI_PAL_MODE
+#    define WS2812_SPI_MOSI_PAL_MODE 5
+#endif
+
+#define BYTES_FOR_LED_BYTE 4
+#define NB_COLORS 3
+#define BYTES_FOR_LED (BYTES_FOR_LED_BYTE * NB_COLORS)
+#define DATA_SIZE (BYTES_FOR_LED * RGBLED_NUM)
+#define RESET_SIZE 200
+#define PREAMBLE_SIZE 4
+
+static uint8_t txbuf[PREAMBLE_SIZE + DATA_SIZE + RESET_SIZE] = {0};
+
+/*
+ * As the trick here is to use the SPI to send a huge pattern of 0 and 1 to
+ * the ws2812b protocol, we use this helper function to translate bytes into
+ * 0s and 1s for the LED (with the appropriate timing).
+ */
+static uint8_t get_protocol_eq(uint8_t data, int pos) {
+    uint8_t eq = 0;
+    if (data & (1 << (2 * (3 - pos))))
+        eq = 0b1110;
+    else
+        eq = 0b1000;
+    if (data & (2 << (2 * (3 - pos))))
+        eq += 0b11100000;
+    else
+        eq += 0b10000000;
+    return eq;
+}
+
+static void set_led_color_rgb(LED_TYPE color, int pos) {
+    uint8_t* tx_start = &txbuf[PREAMBLE_SIZE];
+
+    for (int j = 0; j < 4; j++) tx_start[BYTES_FOR_LED * pos + j] = get_protocol_eq(color.g, j);
+    for (int j = 0; j < 4; j++) tx_start[BYTES_FOR_LED * pos + BYTES_FOR_LED_BYTE + j] = get_protocol_eq(color.r, j);
+    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);
+}
+
+void ws2812_init(void) {
+#if defined(USE_GPIOV1)
+    palSetLineMode(RGB_DI_PIN, PAL_MODE_STM32_ALTERNATE_PUSHPULL);
+#else
+    palSetLineMode(RGB_DI_PIN, PAL_MODE_ALTERNATE(WS2812_SPI_MOSI_PAL_MODE) | PAL_STM32_OTYPE_PUSHPULL);
+#endif
+
+    // TODO: more dynamic baudrate
+    static const SPIConfig spicfg = {
+        NULL, PAL_PORT(RGB_DI_PIN), PAL_PAD(RGB_DI_PIN),
+        SPI_CR1_BR_1 | SPI_CR1_BR_0  // baudrate : fpclk / 8 => 1tick is 0.32us (2.25 MHz)
+    };
+
+    spiAcquireBus(&WS2812_SPI);     /* Acquire ownership of the bus.    */
+    spiStart(&WS2812_SPI, &spicfg); /* Setup transfer parameters.       */
+    spiSelect(&WS2812_SPI);         /* Slave Select assertion.          */
+}
+
+void ws2812_setleds(LED_TYPE* ledarray, uint16_t leds) {
+    static bool s_init = false;
+    if (!s_init) {
+        ws2812_init();
+        s_init = true;
+    }
+
+    for (uint8_t i = 0; i < leds; i++) {
+        set_led_color_rgb(ledarray[i], i);
+    }
+
+    // Send async - each led takes ~0.03ms, 50 leds ~1.5ms, animations flushing faster than send will cause issues.
+    // Instead spiSend can be used to send synchronously (or the thread logic can be added back).
+#ifdef WS2812_SPI_SYNC
+    spiSend(&WS2812_SPI, sizeof(txbuf) / sizeof(txbuf[0]), txbuf);
+#else
+    spiStartSend(&WS2812_SPI, sizeof(txbuf) / sizeof(txbuf[0]), txbuf);
+#endif
+}
-- 
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