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