/**************************************************************************** * drivers/leds/ws2812.c * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance with the * License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include #ifndef CONFIG_WS2812_NON_SPI_DRIVER #include #endif /* CONFIG_WS2812_NON_SPI_DRIVER */ #ifdef CONFIG_WS2812 /**************************************************************************** * ######## ATTENTION ####### * This file contains code that supports two separate ws2812 upper-half * models: * * If CONFIG_WS2812_NON_SPI_DRIVER is NOT defined the older upper-half * code that uses SPI to send the serial data will be built. * * If WS2812_NEW_MODEL_DRIVER is defined the upper-half code that does * not relay on SPI will be built. ****************************************************************************/ /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #ifdef WS2812_HAS_WHITE # define WS2812_RW_PIXEL_SIZE 4 #else # define WS2812_RW_PIXEL_SIZE 3 #endif #ifdef CONFIG_WS2812_NON_SPI_DRIVER #else /* CONFIG_WS2812_NON_SPI_DRIVER */ /* In order to meet the signaling timing requirements, the waveforms required * to represent a 0/1 symbol are created by specific SPI bytes defined here. * * Only two target frequencies: 4 MHz and 8 MHz. However, given the tolerance * allowed in the WS2812 timing specs, two ranges around those target * frequencies can be used for better flexibility. Extreme frequencies * rounded to the nearest multiple of 100 kHz which meets the specs. * Try to avoid using the extreme frequencies. * * If using an LED different to the WS2812 (e.g. WS2812B) check its timing * specs, which may vary slightly, to decide which frequency is safe to use. * * WS2812 specs: * T0H range: 200ns - 500ns * T1H range: 550ns - 850ns * Reset: low signal >50us */ #if CONFIG_WS2812_FREQUENCY >= 3600000 && CONFIG_WS2812_FREQUENCY <= 5000000 # define WS2812_ZERO_BYTE 0b01000000 /* 200ns at 5 MHz, 278ns at 3.6 MHz */ # define WS2812_ONE_BYTE 0b01110000 /* 600ns at 5 MHz, 833ns at 3.6 MHz */ #elif CONFIG_WS2812_FREQUENCY >= 5900000 && CONFIG_WS2812_FREQUENCY <= 9000000 # define WS2812_ZERO_BYTE 0b01100000 /* 222ns at 9 MHz, 339ns at 5.9 MHz */ # define WS2812_ONE_BYTE 0b01111100 /* 556ns at 9 MHz, 847ns at 5.9 MHz */ #else # error "Unsupported SPI Frequency" #endif /* Reset bytes * Number of empty bytes to create the reset low pulse * Aiming for 60 us, safely above the 50us required. */ #define WS2812_RST_CYCLES (CONFIG_WS2812_FREQUENCY * 60 / 1000000 / 8) #define WS2812_BYTES_PER_LED (8 * 3) /* Transmit buffer looks like: * [<----N reset bytes---->|<-RGBn->...<-RGB0->|<----1 reset byte---->] * * It is important that this is shipped as close to one chunk as possible * in order to meet timing requirements and to keep MOSI from going high * between transactions. Some chips will leave MOSI at the state of the * MSB of the last byte for this reason it is recommended to shift the * bits that represents the zero or one waveform so that the MSB is 0. * The reset byte after the RGB data will pad the shortened low at the end. */ #define TXBUFF_SIZE(n) (WS2812_RST_CYCLES + n * WS2812_BYTES_PER_LED + 1) #endif /* CONFIG_WS2812_NON_SPI_DRIVER */ /**************************************************************************** * Private Types ****************************************************************************/ #ifndef CONFIG_WS2812_NON_SPI_DRIVER struct ws2812_dev_s { FAR struct spi_dev_s *spi; /* SPI interface */ uint16_t nleds; /* Number of addressable LEDs */ FAR uint8_t *tx_buf; /* Buffer for write transaction and state */ mutex_t lock; /* Assures exclusive access to the driver */ }; #endif /* CONFIG_WS2812_NON_SPI_DRIVER */ /**************************************************************************** * Private Function Prototypes ****************************************************************************/ #ifndef CONFIG_WS2812_NON_SPI_DRIVER static inline void ws2812_configspi(FAR struct spi_dev_s *spi); static void ws2812_pack(FAR uint8_t *buf, uint32_t rgb); #endif /* CONFIG_WS2812_NON_SPI_DRIVER */ /* Character driver methods */ #ifdef CONFIG_WS2812_NON_SPI_DRIVER static ssize_t ws2812_open(FAR struct file *filep); static ssize_t ws2812_close(FAR struct file *filep); #endif /* CONFIG_WS2812_NON_SPI_DRIVER */ static ssize_t ws2812_read(FAR struct file *filep, FAR char *buffer, size_t buflen); static ssize_t ws2812_write(FAR struct file *filep, FAR const char *buffer, size_t buflen); static off_t ws2812_seek(FAR struct file *filep, off_t offset, int whence); /**************************************************************************** * Private Data ****************************************************************************/ static const struct file_operations g_ws2812fops = { #ifdef CONFIG_WS2812_NON_SPI_DRIVER ws2812_open, /* open */ ws2812_close, /* close */ #else /* CONFIG_WS2812_NON_SPI_DRIVER */ NULL, /* open */ NULL, /* close */ #endif /* CONFIG_WS2812_NON_SPI_DRIVER */ ws2812_read, /* read */ ws2812_write, /* write */ ws2812_seek, /* seek */ }; /**************************************************************************** * #### TODO #### * * Consider supporting mmap by returning memory buffer using file_operations' * mmap * Code using this would be non-portable across architectures as the format * of the buffer can be different. * * Consider supporting rectangular arrays of ws2812s as a video output * device. * ****************************************************************************/ /**************************************************************************** * Table of Gamma Correction Values * * This table is based on: * y = 255 * (x / 255)^2.6 ****************************************************************************/ static const uint8_t ws2812_gamma[256] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 10, 11, 11, 11, 12, 12, 13, 13, 13, 14, 14, 15, 15, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 22, 22, 23, 24, 24, 25, 25, 26, 27, 27, 28, 29, 29, 30, 31, 31, 32, 33, 34, 34, 35, 36, 37, 38, 38, 39, 40, 41, 42, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 68, 69, 70, 71, 72, 73, 75, 76, 77, 78, 80, 81, 82, 84, 85, 86, 88, 89, 90, 92, 93, 94, 96, 97, 99, 100, 102, 103, 105, 106, 108, 109, 111, 112, 114, 115, 117, 119, 120, 122, 124, 125, 127, 129, 130, 132, 134, 136, 137, 139, 141, 143, 145, 146, 148, 150, 152, 154, 156, 158, 160, 162, 164, 166, 168, 170, 172, 174, 176, 178, 180, 182, 184, 186, 188, 191, 193, 195, 197, 199, 202, 204, 206, 209, 211, 213, 215, 218, 220, 223, 225, 227, 230, 232, 235, 237, 240, 242, 245, 247, 250, 252, 255 }; /**************************************************************************** * Table for HSV to RGB conversion ****************************************************************************/ static const uint8_t hsv_rgb[43] = { 0, 6, 12, 18, 24, 30, 36, 43, 49, 55, 61, 67, 73, 79, 85, 91, 97, 103, 109, 115, 121, 128, 134, 140, 146, 152, 158, 164, 170, 176, 182, 188, 194, 200, 206, 213, 219, 225, 231, 237, 243, 249, 255 }; /**************************************************************************** * Private Functions ****************************************************************************/ #ifdef CONFIG_WS2812_NON_SPI_DRIVER /**************************************************************************** * Name: ws2812_open * * Description: * Prepare the ws2812 for use. This method just calls the lower-half * open routine if one exists. * * Input Parameters: * filep - Pointer system file data * * Returned Value: * A pointer to an internal structure used by rp2040_ws2812 * ****************************************************************************/ ssize_t ws2812_open(FAR struct file *filep) { FAR struct inode *inode = filep->f_inode; FAR struct ws2812_dev_s *priv = inode->i_private; int res; res = priv->open(filep); return res; } /**************************************************************************** * Name: ws2812_close * * Description: * Cleanup after use. This method just calls the lower-half * open routine if one exists. * * Input Parameters: * filep - Pointer system file data * * Returned Value: * OK if successful, or an error code on failure. * ****************************************************************************/ static int ws2812_close(FAR struct file *filep) { FAR struct inode *inode = filep->f_inode; FAR struct ws2812_dev_s *priv = inode->i_private; int res = OK; if (priv != NULL && priv->close != NULL) { res = priv->close(filep); } return res; } /**************************************************************************** * Name: ws2812_write * Description: * Updates the data buffer with the supplied data any then sends the data * to the LEDs. A write length of zero does not update data but will * re-send the data to the leds. * * Input Parameter: * filep - Pointer system file data * data - Data to send. * len - Length of data in bytes. * * Returned Value: * number of bytes written on success, ERROR if write fails. * ****************************************************************************/ ssize_t ws2812_write(FAR struct file *filep, FAR const char *data, size_t len) { FAR struct inode *inode = filep->f_inode; FAR struct ws2812_dev_s *priv = inode->i_private; ssize_t res; if ((len % WS2812_RW_PIXEL_SIZE) != 0) { lederr("ERROR: LED values must be 24bit packed in 32bit\n"); return -EINVAL; } res = priv->write(filep, data, len); return res; } /**************************************************************************** * Name: ws2812_read * Description: * Fetches data from the pixel buffer. * * Input Parameter: * filep - Pointer system file data * data - pointer to receive buffer. * len - Length to read in bytes. * * Returned Value: * number of bytes read on success, ERROR if read fails. * ****************************************************************************/ ssize_t ws2812_read(FAR struct file *filep, FAR char *data, size_t len) { FAR struct inode *inode = filep->f_inode; FAR struct ws2812_dev_s *priv = inode->i_private; ssize_t res; if (priv == NULL || priv->read == NULL) { return -ENOSYS; } if ((len % WS2812_RW_PIXEL_SIZE) != 0) { lederr("ERROR: LED values must be packed in 32bit words.\n"); return -EINVAL; } res = priv->read(filep, data, len); return res; } #else /* CONFIG_WS2812_NON_SPI_DRIVER */ /**************************************************************************** * Name: ws2812_configspi * * Description: * Set the SPI bus configuration * ****************************************************************************/ static inline void ws2812_configspi(FAR struct spi_dev_s *spi) { /* Configure SPI for the WS2812 * There is no CS on this device we just use MOSI and it is exclusive */ SPI_LOCK(spi, true); /* Exclusive use of the bus */ SPI_SETMODE(spi, SPIDEV_MODE3); SPI_SETBITS(spi, 8); SPI_HWFEATURES(spi, 0); SPI_SETFREQUENCY(spi, CONFIG_WS2812_FREQUENCY); } /**************************************************************************** * Name: ws2812_pack * * Description: * This writes the expanded SPI transaction to the transaction buffer * for a given 24bit RGB value. * * Input Parameters: * buf - The location in the transmit buffer to write. * rgb - A 24bit RGB color 8bit red, 8-bit green, 8-bit blue * ****************************************************************************/ static void ws2812_pack(FAR uint8_t *buf, uint32_t rgb) { uint8_t bit_idx; uint8_t byte_idx; uint8_t offset = 0; uint8_t color; uint32_t grb; grb = (rgb & 0x00ff00) << 8; grb |= (rgb & 0xff0000) >> 8; grb |= rgb & 0x0000ff; for (byte_idx = 0; byte_idx < 3; byte_idx++) { color = (uint8_t)(grb >> (8 * (2 - byte_idx))); for (bit_idx = 0; bit_idx < 8; bit_idx++) { if (color & (1 << (7 - bit_idx))) { buf[offset] = WS2812_ONE_BYTE; } else { buf[offset] = WS2812_ZERO_BYTE; } offset++; } } } /**************************************************************************** * Name: ws2812_read ****************************************************************************/ static ssize_t ws2812_read(FAR struct file *filep, FAR char *buffer, size_t buflen) { return -ENOSYS; } /**************************************************************************** * Name: ws2812_write * * Description: * This routine is called when writing to the WS2812 device. Data buffer * should be an array of 32bit values holding 24bits of color information * in host byte ordering 0x**rrggbb. * ****************************************************************************/ static ssize_t ws2812_write(FAR struct file *filep, FAR const char *buffer, size_t buflen) { FAR struct inode *inode = filep->f_inode; FAR struct ws2812_dev_s *priv = inode->i_private; FAR uint8_t *tx_pixel; FAR uint32_t *pixel_buf = (FAR uint32_t *)buffer; size_t cur_led; size_t start_led; size_t end_led; size_t written = 0; if (buffer == NULL) { lederr("ERROR: Buffer is null\n"); return -EINVAL; } /* We need at least one LED, so 1 byte */ if (buflen < 1) { lederr("ERROR: You need to control at least 1 LED!\n"); return -EINVAL; } if ((buflen % WS2812_RW_PIXEL_SIZE) != 0) { lederr("ERROR: LED values must be 24bit packed in 32bit\n"); return -EINVAL; } nxmutex_lock(&priv->lock); start_led = filep->f_pos / WS2812_RW_PIXEL_SIZE; tx_pixel = priv->tx_buf + WS2812_RST_CYCLES + \ start_led * WS2812_BYTES_PER_LED; end_led = start_led + (buflen / WS2812_RW_PIXEL_SIZE) - 1; ledinfo("Start: %d End: %d\n", start_led, end_led); if (end_led > (priv->nleds -1)) { end_led = priv->nleds - 1; } for (cur_led = start_led; cur_led <= end_led; cur_led++) { ws2812_pack(tx_pixel, *pixel_buf & 0xffffff); pixel_buf++; tx_pixel += WS2812_BYTES_PER_LED; written += WS2812_RW_PIXEL_SIZE; } SPI_SNDBLOCK(priv->spi, priv->tx_buf, TXBUFF_SIZE(priv->nleds)); /* Update LED position and handle case were we wrote the last LED */ filep->f_pos += written; if (end_led == (priv->nleds - 1)) { filep->f_pos -= WS2812_RW_PIXEL_SIZE; } nxmutex_unlock(&priv->lock); return written; } #endif /* CONFIG_WS2812_NON_SPI_DRIVER */ /**************************************************************************** * Name: ws2812_seek * * Description: * This routine is called when seeking the WS2812 device. This can be used * to address the starting LED to write. This should be done on a full * color boundary which is 32bits. e.g. LED0 - offset 0, LED 8 - offset 32 * ****************************************************************************/ static off_t ws2812_seek(FAR struct file *filep, off_t offset, int whence) { FAR struct inode *inode = filep->f_inode; FAR struct ws2812_dev_s *priv = inode->i_private; off_t maxpos; off_t pos; if ((offset % WS2812_RW_PIXEL_SIZE) != 0) { return (off_t)-EINVAL; } nxmutex_lock(&priv->lock); maxpos = (priv->nleds - 1) * WS2812_RW_PIXEL_SIZE; pos = filep->f_pos; switch (whence) { case SEEK_CUR: pos += offset; filep->f_pos = pos; break; case SEEK_SET: pos = offset; break; case SEEK_END: pos = maxpos + offset + 4; break; default: /* Return EINVAL if the whence argument is invalid */ nxmutex_unlock(&priv->lock); return (off_t)-EINVAL; } if (pos > maxpos) { pos = maxpos; } else if (pos < 0) { pos = 0; } filep->f_pos = pos; nxmutex_unlock(&priv->lock); return pos; } /**************************************************************************** * Public Functions ****************************************************************************/ #ifdef CONFIG_WS2812_NON_SPI_DRIVER /**************************************************************************** * Name: ws2812_register * * Description: * Initialize a ws2812 device as a LEDs interface. * * Input Parameters: * dev_path - The full path to the driver to register. E.g., "/dev/leds0" * count - The number of ws2812s in the chain * has_white - Set true if the ws2812s in the chain have while LEDs * slow_leds - Set true to support older 400 kHz leds. * * Returned Value: * Zero (OK) on success; a negated errno value on failure. * ****************************************************************************/ int ws2812_register(FAR const char *dev_path, FAR struct ws2812_dev_s *dev_data) { /* Register the character driver */ int ret = register_driver(dev_path, &g_ws2812fops, 0666, dev_data); if (ret < 0) { lederr("ERROR: Failed to register ws2812 driver: %d\n", ret); } return ret; } #else /* CONFIG_WS2812_NON_SPI_DRIVER */ /**************************************************************************** * Name: ws2812_leds_register * * Description: * Register the WS2812 character device as 'devpath' * * Input Parameters: * devpath - The full path to the driver to register. E.g., "/dev/leds0" * spi - An instance of the SPI interface to use to communicate with * WS2812 * nleds - Number of addressable LEDs * * Returned Value: * Zero (OK) on success; a negated errno value on failure. * ****************************************************************************/ int ws2812_leds_register(FAR const char *devpath, FAR struct spi_dev_s *spi, uint16_t nleds) { FAR struct ws2812_dev_s *priv; int ret; int led; /* Initialize the WS2812 device structure */ priv = (FAR struct ws2812_dev_s *)kmm_malloc(sizeof(struct ws2812_dev_s)); if (!priv) { lederr("ERROR: Failed to allocate instance\n"); return -ENOMEM; } priv->nleds = nleds; priv->tx_buf = (FAR uint8_t *)kmm_zalloc(TXBUFF_SIZE(priv->nleds)); if (!priv->tx_buf) { lederr("ERROR: Failed to allocate tx buffer\n"); kmm_free(priv); return -ENOMEM; } /* Mark LED section of TX buffer as off */ for (led = 0; led < priv->nleds; led++) { ws2812_pack( priv->tx_buf + WS2812_RST_CYCLES + led * WS2812_BYTES_PER_LED, 0); } priv->spi = spi; ws2812_configspi(priv->spi); nxmutex_init(&priv->lock); SPI_SNDBLOCK(priv->spi, priv->tx_buf, TXBUFF_SIZE(priv->nleds)); /* Register the character driver */ ret = register_driver(devpath, &g_ws2812fops, 0666, priv); if (ret < 0) { lederr("ERROR: Failed to register driver: %d\n", ret); nxmutex_destroy(&priv->lock); kmm_free(priv->tx_buf); kmm_free(priv); } return ret; } #endif /* CONFIG_WS2812_NON_SPI_DRIVER */ /**************************************************************************** * Name: ws2812_hsv_to_rgb * * Description: * Convert a set of hue, saturation and value numbers to an RGB pixel. * * Representative "hue" values: * Red 0 * Yellow 42 * Green 86 * Cyan 128 * Blue 170 * Magenta 212 * * "Saturation" values run from 0 (gray) to 255 (pure color) * * "Value" values run from 0 (black) to 255 (full brightness) * * Input Parameters: * hue in range (0-255) (red -> 0, green -> 85, blue -> 170) * saturation in range (0-255) * value in range (0-255) * * Returned Value: * A 32-bit pixel in 0x00RRGGBB format. * ****************************************************************************/ uint32_t ws2812_hsv_to_rgb(uint8_t hue, uint8_t saturation, uint8_t value) { uint32_t val = value + 1; /* move value to range 1...256 */ uint32_t sat = saturation + 1; /* move value to range 1...256 */ uint16_t r; uint16_t g; uint16_t b; /* ===== Compute full saturation R,G,B based on hue ===== * * These computed values are inverted from the normal * sense. (0 -> full color 255 -> black) in preparation * for the saturation adjustment. */ if (hue < 86) { /* Color between Red and Green */ b = 255; if (hue < 43) { /* 0 - 42 Color between Red and Yellow */ r = 0; g = 255 - hsv_rgb[hue]; } else { /* 43 - 85 Color between Yellow and Green */ r = hsv_rgb[hue - 43]; g = 0; } } else if (hue < 171) { /* Color between Green and Blue */ r = 255; if (hue < 128) { /* 86 - 127 Color between Green and Cyan */ g = 0; b = 255 - hsv_rgb[hue - 86]; } else { /* 128 - 170 Color between Cyan and Blue */ g = hsv_rgb[hue - 128]; b = 0; } } else { /* Color between Blue and Red */ g = 255; if (hue < 214) { /* 171 - 213 Color between Blue and Magenta */ b = 0; r = 255 - hsv_rgb[hue - 171]; } else { /* 214 - 255 Color between Magenta and Red */ b = hsv_rgb[hue - 214]; r = 0; } } /* This step scales the color for saturation and inverts * back to 255 -> bright and 0 -> black. */ r = 255 - ((r * sat) >> 8); g = 255 - ((g * sat) >> 8); b = 255 - ((b * sat) >> 8); /* compute the return value using the r, g, and b values scaled * by the value parameter */ return (((r * val) << 8) & 0xff0000) | (((g * val) << 0) & 0x00ff00) | (((b * val) >> 8) & 0x0000ff); } /**************************************************************************** * Name: ws2812_gamma_correct * * Description: * Applies a gamma correction to the supplied pixel. * * Input Parameters: * a 32-bit pixel with 8-bit color components. * * Returned Value: * A 32-bit gamma corrected pixel. * ****************************************************************************/ uint32_t ws2812_gamma_correct(uint32_t pixel) { uint32_t res; FAR uint8_t *in = (FAR uint8_t *)&pixel; FAR uint8_t *out = (FAR uint8_t *)&res; *out++ = ws2812_gamma[*in++]; *out++ = ws2812_gamma[*in++]; *out++ = ws2812_gamma[*in++]; *out = ws2812_gamma[*in]; return res; } #endif /* CONFIG_WS2812 */