// Copyright 2022 Stefan Kerkmann (@KarlK90) // SPDX-License-Identifier: GPL-2.0-or-later #include "ws2812.h" // Keep this exact include order otherwise we run into naming conflicts between // pico-sdk and rp2040.h which we don't control. #include "hardware/timer.h" #include "hardware/clocks.h" #include #include "hardware/pio.h" #include "gpio.h" #include "debug.h" #include "wait.h" #include "util.h" #if !defined(MCU_RP) # error PIO Driver is only available for Raspberry Pi 2040 MCUs! #endif #if defined(WS2812_PIO_USE_PIO1) static const PIO pio = pio1; #else static const PIO pio = pio0; #endif #if !defined(RP_DMA_PRIORITY_WS2812) # define RP_DMA_PRIORITY_WS2812 3 #endif #if defined(WS2812_EXTERNAL_PULLUP) # pragma message "The GPIOs of the RP2040 are NOT 5V tolerant! Make sure to NOT apply any voltage over 3.3V to the RGB data pin." #endif /*================== WS2812 PIO TIMINGS =================*/ // WS2812_T1L rounded to 50ns intervals and split into two wait timings #define PIO_T1L (WS2812_T1L / 50) #define PIO_T1L_A (MAX(CEILING(PIO_T1L, 2) - 1, 0)) #define PIO_T1L_B (MAX(PIO_T1L / 2 - 1, 0)) // WS2812_T0L rounded to 50ns intervals #define PIO_T0L (MAX(WS2812_T0L / 50 - PIO_T1L, 0)) #define PIO_T0L_A (MAX(PIO_T0L - 1, 0)) // WS2812_T0H rounded to 50ns intervals #define PIO_T0H (WS2812_T0H / 50) #define PIO_T0H_A MAX(PIO_T0H - 1, 0) // WS2812_T1H rounded to 50ns intervals and split into two wait timings #define PIO_T1H (MAX(WS2812_T1H / 50 - PIO_T0H, 0)) #define PIO_T1H_A (MAX((CEILING(PIO_T1H, 2) - 1), 0)) #define PIO_T1H_B (MAX((PIO_T1H / 2) - 1, 0)) #if (WS2812_T0L % 50) != 0 # pragma message "WS2812_T0L is not given in an 50ns interval, it will be rounded to the next 50ns" #endif #if (WS2812_T0H % 50) != 0 # pragma message "WS2812_T0H is not given in an 50ns interval, it will be rounded to the next 50ns" #endif #if (WS2812_T1L % 50) != 0 # pragma message "WS2812_T0L is not given in an 50ns interval, it will be rounded to the next 50ns" #endif #if (WS2812_T1H % 50) != 0 # pragma message "WS2812_T0H is not given in an 50ns interval, it will be rounded to the next 50ns" #endif #if WS2812_T0L < WS2812_T1L # error WS2812_T0L is shorter than WS2812_T1L, this is impossible to express in the RP2040 PIO driver. Please correct your timings. #endif #if WS2812_T1H < WS2812_T0H # error WS2812_T1H is shorter than WS2812_T0H, this is impossible to express in the RP2040 PIO driver. Please correct your timings. #endif #if WS2812_T0L > (850 + WS2812_T1L) # error WS2812_T0L is longer than 850ns + WS2812_T1L, this is impossible to express in the RP2040 PIO driver. Please correct your timings. #endif #if WS2812_T0H > 850 # error WS2812_T0H is longer than 850ns, this is impossible to express in the RP2040 PIO driver. Please correct your timings. #endif #if WS2812_T1H > (1700 + WS2812_T0H) # error WS2812_T1H is longer than 1700ns + WS2812_T0H, this is impossible to express in the RP2040 PIO driver. Please correct your timings. #endif #if WS2812_T1L > 1700 # error WS2812_T1L is longer than 1700ns, this is impossible to express in the RP2040 PIO driver. Please correct your timings. #endif #if WS2812_T0L < (50 + WS2812_T1L) # error WS2812_T0L is shorter than 50ns + WS2812_T1L, this is impossible to express in the RP2040 PIO driver. Please correct your timings. #endif #if WS2812_T0H < 50 # error WS2812_T0H is shorter than 50ns, this is impossible to express in the RP2040 PIO driver. Please correct your timings. #endif #if WS2812_T1H < (100 + WS2812_T0H) # error WS2812_T1H is longer than 100ns + WS2812_T0H, this is impossible to express in the RP2040 PIO driver. Please correct your timings. #endif #if WS2812_T1L < 100 # error WS2812_T1L is longer than 1700ns, this is impossible to express in the RP2040 PIO driver. Please correct your timings. #endif /** * @brief Helper macro to binary patch the delay part of an per-compiled PIO * opcode. */ #define PIO_DELAY(delay, opcode) (((delay & 0xF) << 8U) | opcode) #define WS2812_WRAP_TARGET 0 #define WS2812_WRAP 5 static const uint16_t ws2812_program_instructions[] = { // .wrap_target PIO_DELAY(PIO_T1L_A, 0x6021), // 0: out x, 1 side 0 // T1L (max. 1700ns) PIO_DELAY(PIO_T1L_B, 0xa042), // 1: nop side 0 // T1L PIO_DELAY(PIO_T0H_A, 0x1025), // 2: jmp !x, 5 side 1 // T0H (max. 850ns) PIO_DELAY(PIO_T1H_A, 0xb042), // 3: nop side 1 // T1H (max. 1700ns + T0H) PIO_DELAY(PIO_T1H_B, 0x1000), // 4: jmp 0 side 1 // T1H PIO_DELAY(PIO_T0L_A, 0xa042), // 5: nop side 0 // T0L (max. 850ns + T1L) // .wrap }; static const pio_program_t ws2812_program = { .instructions = ws2812_program_instructions, .length = ARRAY_SIZE(ws2812_program_instructions), .origin = -1, }; static uint32_t WS2812_BUFFER[WS2812_LED_COUNT]; static const rp_dma_channel_t* WS2812_DMA_CHANNEL; static uint32_t RP_DMA_MODE_WS2812; static int STATE_MACHINE = -1; static SEMAPHORE_DECL(TRANSFER_COUNTER, 1); static absolute_time_t LAST_TRANSFER; /** * @brief Convert RGBW value into WS2812 compatible 32-bit data word. */ __always_inline static uint32_t rgbw8888_to_u32(uint8_t red, uint8_t green, uint8_t blue, uint8_t white) { #if (WS2812_BYTE_ORDER == WS2812_BYTE_ORDER_GRB) return ((uint32_t)green << 24) | ((uint32_t)red << 16) | ((uint32_t)blue << 8) | ((uint32_t)white); #elif (WS2812_BYTE_ORDER == WS2812_BYTE_ORDER_RGB) return ((uint32_t)red << 24) | ((uint32_t)green << 16) | ((uint32_t)blue << 8) | ((uint32_t)white); #elif (WS2812_BYTE_ORDER == WS2812_BYTE_ORDER_BGR) return ((uint32_t)blue << 24) | ((uint32_t)green << 16) | ((uint32_t)red << 8) | ((uint32_t)white); #endif } static void ws2812_dma_callback(void* p, uint32_t ct) { // We assume that there is at least one frame left in the OSR even if the TX // FIFO is already empty. rtcnt_t time_to_completion = (pio_sm_get_tx_fifo_level(pio, STATE_MACHINE) + 1) * MAX(WS2812_T1H + WS2812_T1L, WS2812_T0H + WS2812_T0L); #if defined(RGBW) time_to_completion *= 32; #else time_to_completion *= 24; #endif // Convert from ns to us time_to_completion /= 1000; update_us_since_boot(&LAST_TRANSFER, time_us_64() + time_to_completion + WS2812_TRST_US); osalSysLockFromISR(); chSemSignalI(&TRANSFER_COUNTER); osalSysUnlockFromISR(); } bool ws2812_init(void) { uint pio_idx = pio_get_index(pio); /* Get PIOx peripheral out of reset state. */ hal_lld_peripheral_unreset(pio_idx == 0 ? RESETS_ALLREG_PIO0 : RESETS_ALLREG_PIO1); // clang-format off iomode_t rgb_pin_mode = PAL_RP_PAD_SLEWFAST | PAL_RP_GPIO_OE | #if defined(WS2812_EXTERNAL_PULLUP) PAL_RP_IOCTRL_OEOVER_DRVINVPERI | #endif (pio_idx == 0 ? PAL_MODE_ALTERNATE_PIO0 : PAL_MODE_ALTERNATE_PIO1); // clang-format on palSetLineMode(WS2812_DI_PIN, rgb_pin_mode); STATE_MACHINE = pio_claim_unused_sm(pio, true); if (STATE_MACHINE < 0) { dprintln("ERROR: Failed to acquire state machine for WS2812 output!"); return false; } uint offset = pio_add_program(pio, &ws2812_program); pio_sm_set_consecutive_pindirs(pio, STATE_MACHINE, WS2812_DI_PIN, 1, true); pio_sm_config config = pio_get_default_sm_config(); sm_config_set_wrap(&config, offset + WS2812_WRAP_TARGET, offset + WS2812_WRAP); sm_config_set_sideset_pins(&config, WS2812_DI_PIN); sm_config_set_fifo_join(&config, PIO_FIFO_JOIN_TX); #if defined(WS2812_EXTERNAL_PULLUP) /* Instruct side-set to change the pin-directions instead of outputting * a logic level. We generate our levels the following way: * * 1: Set RGB data pin to high impedance input and let the pull-up drive the * signal high. * * 0: Set RGB data pin to low impedance output and drive the pin low. */ sm_config_set_sideset(&config, 1, false, true); #else sm_config_set_sideset(&config, 1, false, false); #endif #if defined(RGBW) sm_config_set_out_shift(&config, false, true, 32); #else sm_config_set_out_shift(&config, false, true, 24); #endif // Every instruction takes 50ns to execute with a clock speed of 20 MHz, // giving the WS2812 PIO driver its time resolution float div = clock_get_hz(clk_sys) / (20.0f * MHZ); sm_config_set_clkdiv(&config, div); pio_sm_init(pio, STATE_MACHINE, offset, &config); pio_sm_set_enabled(pio, STATE_MACHINE, true); WS2812_DMA_CHANNEL = dmaChannelAlloc(RP_DMA_CHANNEL_ID_ANY, RP_DMA_PRIORITY_WS2812, (rp_dmaisr_t)ws2812_dma_callback, NULL); dmaChannelEnableInterruptX(WS2812_DMA_CHANNEL); dmaChannelSetDestinationX(WS2812_DMA_CHANNEL, (uint32_t)&pio->txf[STATE_MACHINE]); // clang-format off RP_DMA_MODE_WS2812 = DMA_CTRL_TRIG_INCR_READ | DMA_CTRL_TRIG_DATA_SIZE_WORD | DMA_CTRL_TRIG_TREQ_SEL(pio == pio0 ? STATE_MACHINE : STATE_MACHINE + 8) | DMA_CTRL_TRIG_PRIORITY(RP_DMA_PRIORITY_WS2812); // clang-format on return true; } static inline void sync_ws2812_transfer(void) { if (chSemWaitTimeout(&TRANSFER_COUNTER, TIME_MS2I(WS2812_LED_COUNT)) == MSG_TIMEOUT) { // Abort the synchronization if we have to wait longer than the total // count of LEDs in milliseconds. This is safely much longer than it // would take to push all the data out. dprintln("ERROR: WS2812 DMA transfer has stalled, aborting!"); dmaChannelDisableX(WS2812_DMA_CHANNEL); pio_sm_clear_fifos(pio, STATE_MACHINE); pio_sm_restart(pio, STATE_MACHINE); chSemReset(&TRANSFER_COUNTER, 0); wait_us(WS2812_TRST_US); return; } // Busy wait until last transfer has finished busy_wait_until(LAST_TRANSFER); } void ws2812_setleds(LED_TYPE* ledarray, uint16_t leds) { static bool is_initialized = false; if (unlikely(!is_initialized)) { is_initialized = ws2812_init(); } sync_ws2812_transfer(); for (int i = 0; i < leds; i++) { #if defined(RGBW) WS2812_BUFFER[i] = rgbw8888_to_u32(ledarray[i].r, ledarray[i].g, ledarray[i].b, ledarray[i].w); #else WS2812_BUFFER[i] = rgbw8888_to_u32(ledarray[i].r, ledarray[i].g, ledarray[i].b, 0); #endif } dmaChannelSetSourceX(WS2812_DMA_CHANNEL, (uint32_t)WS2812_BUFFER); dmaChannelSetCounterX(WS2812_DMA_CHANNEL, leds); dmaChannelSetModeX(WS2812_DMA_CHANNEL, RP_DMA_MODE_WS2812); dmaChannelEnableX(WS2812_DMA_CHANNEL); }