/**************************************************************************** * drivers/sensors/apa102.c * Character driver to control LED strips with APA102. * * Copyright (C) 2017 Gregory Nutt. All rights reserved. * Copyright (C) 2017 Alan Carvalho de Assis * Author: Alan Carvalho de Assis * * More info: * https://cpldcpu.com/2014/11/30/understanding-the-apa102-superled/ * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name NuttX nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include #if defined(CONFIG_SPI) && defined(CONFIG_LEDS_APA102) /**************************************************************************** * Private Types ****************************************************************************/ struct apa102_dev_s { FAR struct spi_dev_s *spi; /* SPI interface */ }; /**************************************************************************** * Private Function Prototypes ****************************************************************************/ static inline void apa102_configspi(FAR struct spi_dev_s *spi); static inline void apa102_write32(FAR struct apa102_dev_s *priv, FAR uint32_t value); /* Character driver methods */ static int apa102_open(FAR struct file *filep); static int apa102_close(FAR struct file *filep); static ssize_t apa102_read(FAR struct file *filep, FAR char *buffer, size_t buflen); static ssize_t apa102_write(FAR struct file *filep, FAR const char *buffer, size_t buflen); /**************************************************************************** * Private Data ****************************************************************************/ static const struct file_operations g_apa102fops = { apa102_open, /* open */ apa102_close, /* close */ apa102_read, /* read */ apa102_write, /* write */ 0, /* seek */ 0, /* ioctl */ #ifndef CONFIG_DISABLE_POLL 0, /* poll */ #endif #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS , NULL /* unlink */ #endif }; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: apa102_configspi * * Description: * Set the SPI bus configuration * ****************************************************************************/ static inline void apa102_configspi(FAR struct spi_dev_s *spi) { /* Configure SPI for the APA102 */ SPI_SETMODE(spi, SPIDEV_MODE0); SPI_SETBITS(spi, 8); (void)SPI_HWFEATURES(spi, 0); (void)SPI_SETFREQUENCY(spi, APA102_SPI_MAXFREQUENCY); } /**************************************************************************** * Name: apa102_write32 * * Description: * Write 32-bit to APA102 * ****************************************************************************/ static inline void apa102_write32(FAR struct apa102_dev_s *priv, FAR uint32_t value) { /* If SPI bus is shared then lock and configure it */ (void)SPI_LOCK(priv->spi, true); apa102_configspi(priv->spi); /* Note: APA102 doesn't use chip select */ /* Send 32 bits (4 bytes) */ (void)SPI_SEND(priv->spi, (value & 0xff)); (void)SPI_SEND(priv->spi, ((value & 0xff00) >> 8)); (void)SPI_SEND(priv->spi, ((value & 0xff0000) >> 16)); (void)SPI_SEND(priv->spi, ((value & 0xff000000) >> 24)); /* Unlock bus */ (void)SPI_LOCK(priv->spi, false); } /**************************************************************************** * Name: apa102_open * * Description: * This function is called whenever the APA102 device is opened. * ****************************************************************************/ static int apa102_open(FAR struct file *filep) { return OK; } /**************************************************************************** * Name: apa102_close * * Description: * This routine is called when the LM-75 device is closed. * ****************************************************************************/ static int apa102_close(FAR struct file *filep) { return OK; } /**************************************************************************** * Name: apa102_read ****************************************************************************/ static ssize_t apa102_read(FAR struct file *filep, FAR char *buffer, size_t buflen) { return -ENOSYS; } /**************************************************************************** * Name: apa102_write ****************************************************************************/ static ssize_t apa102_write(FAR struct file *filep, FAR const char *buffer, size_t buflen) { FAR struct inode *inode = filep->f_inode; FAR struct apa102_dev_s *priv = inode->i_private; FAR uint32_t *leds = (FAR uint32_t *) buffer; uint16_t nleds; uint16_t i; if (!leds) { snerr("ERROR: Buffer is null\n"); return -1; } /* At least one LED, so 4 bytes */ if (buflen < 4) { snerr("ERROR: You need to control at least 1 LED!\n"); return -1; } /* It needs to be multiple of 4 */ if ((buflen % 4) != 0) { snerr("ERROR: Each LED uses 4 bytes, so (buflen % 4) needs to be 0!\n"); return -1; } nleds = buflen / 4; /* Send a start of frame */ apa102_write32(priv, APA102_START_FRAME); /* Write all LEDs */ for (i = 0; i < nleds; i++) { /* Send the LED color, the LSB is the Bright and Header */ apa102_write32(priv, (uint32_t) (leds[i] | APA102_HEADER_FRAME)); } /* Send an end of frame */ apa102_write32(priv, APA102_END_FRAME); for (i = 0; i < (1 + nleds/32); i++) { apa102_write32(priv, 0); } /* All bytes were written */ return buflen; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: apa102_register * * Description: * Register the APA102 character device as 'devpath' * * Input Parameters: * devpath - The full path to the driver to register. E.g., "/dev/temp0" * i2c - An instance of the I2C interface to use to communicate with * APA102 * addr - The I2C address of the LM-75. The base I2C address of the * APA102 is 0x48. Bits 0-3 can be controlled to get 8 unique * addresses from 0x48 through 0x4f. * * Returned Value: * Zero (OK) on success; a negated errno value on failure. * ****************************************************************************/ int apa102_register(FAR const char *devpath, FAR struct spi_dev_s *spi) { FAR struct apa102_dev_s *priv; int ret; /* Initialize the APA102 device structure */ priv = (FAR struct apa102_dev_s *)kmm_malloc(sizeof(struct apa102_dev_s)); if (!priv) { snerr("ERROR: Failed to allocate instance\n"); return -ENOMEM; } priv->spi = spi; /* Configure SPI for the APA102 */ apa102_configspi(spi); /* Register the character driver */ ret = register_driver(devpath, &g_apa102fops, 0666, priv); if (ret < 0) { snerr("ERROR: Failed to register driver: %d\n", ret); kmm_free(priv); } return ret; } #endif /* CONFIG_SPI && CONFIG_APA102 */