/**************************************************************************** * drivers/rgbled.c * * Copyright (C) 2016-2018 Gregory Nutt. All rights reserved. * Author: Alan Carvalho de Assis * * 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 #include #include #include #include #include #include #include #include #include #include #include #ifdef CONFIG_RGBLED /**************************************************************************** * Private Type Definitions ****************************************************************************/ /* This structure describes the state of the upper half driver */ struct rgbled_upperhalf_s { uint8_t crefs; /* The number of times the device has been opened */ volatile bool started; /* True: pulsed output is being generated */ sem_t exclsem; /* Supports mutual exclusion */ FAR struct pwm_lowerhalf_s *devledr; FAR struct pwm_lowerhalf_s *devledg; FAR struct pwm_lowerhalf_s *devledb; #ifdef CONFIG_PWM_MULTICHAN int chanr; /* Red PWM channel */ int chang; /* Green PWM channel */ int chanb; /* Blue PWM channel */ #endif }; /**************************************************************************** * Private Function Prototypes ****************************************************************************/ static int rgbled_open(FAR struct file *filep); static int rgbled_close(FAR struct file *filep); static ssize_t rgbled_read(FAR struct file *filep, FAR char *buffer, size_t buflen); static ssize_t rgbled_write(FAR struct file *filep, FAR const char *buffer, size_t buflen); /**************************************************************************** * Private Data ****************************************************************************/ static const struct file_operations g_rgbledops = { rgbled_open, /* open */ rgbled_close, /* close */ rgbled_read, /* read */ rgbled_write, /* write */ NULL, /* seek */ NULL, /* ioctl */ NULL /* poll */ #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS , NULL /* unlink */ #endif }; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: rgbled_open * * Description: * This function is called whenever the PWM device is opened. * ****************************************************************************/ static int rgbled_open(FAR struct file *filep) { FAR struct inode *inode = filep->f_inode; FAR struct rgbled_upperhalf_s *upper = inode->i_private; uint8_t tmp; int ret; lcdinfo("crefs: %d\n", upper->crefs); /* Get exclusive access to the device structures */ ret = nxsem_wait(&upper->exclsem); if (ret < 0) { lcderr("ERROR: nxsem_wait failed: %d\n", ret); goto errout; } /* Increment the count of references to the device. If this the first * time that the driver has been opened for this device, then initialize * the device. */ tmp = upper->crefs + 1; if (tmp == 0) { /* More than 255 opens; uint8_t overflows to zero */ ret = -EMFILE; goto errout_with_sem; } /* Save the new open count on success */ upper->crefs = tmp; ret = OK; errout_with_sem: nxsem_post(&upper->exclsem); errout: return ret; } /**************************************************************************** * Name: rgbled_close * * Description: * This function is called when the PWM device is closed. * ****************************************************************************/ static int rgbled_close(FAR struct file *filep) { FAR struct inode *inode = filep->f_inode; FAR struct rgbled_upperhalf_s *upper = inode->i_private; int ret; lcdinfo("crefs: %d\n", upper->crefs); /* Get exclusive access to the device structures */ ret = nxsem_wait(&upper->exclsem); if (ret < 0) { lcderr("ERROR: nxsem_wait failed: %d\n", ret); goto errout; } /* Decrement the references to the driver. If the reference count will * decrement to 0, then uninitialize the driver. */ if (upper->crefs > 1) { upper->crefs--; } nxsem_post(&upper->exclsem); ret = OK; errout: return ret; } /**************************************************************************** * Name: rgbled_read * * Description: * A dummy read method. This is provided only to satisfy the VFS layer. * ****************************************************************************/ static ssize_t rgbled_read(FAR struct file *filep, FAR char *buffer, size_t buflen) { /* Return zero -- usually meaning end-of-file */ return 0; } /**************************************************************************** * Name: rgbled_lightness * * Description: * Convert an 8-bit color level to a 16-bit PWM command, using a * piecewise linear approximation of the CIE 1931 lightness formula. * ****************************************************************************/ #ifdef CONFIG_RGBLED_LIGHTNESS_CORRECTION static unsigned short rgbled_lightness(unsigned char color_level) { unsigned int lut_index; unsigned short pwm_cmd = 0; static const unsigned char lut_color_in[9] = { 0x00, 0x20, 0x40, 0x60, 0x80, 0xa0, 0xc0, 0xe0, 0xff }; static const unsigned short lut_pwm_out[9] = { 0x0000, 0x03d1, 0x0b62, 0x1952, 0x2f93, 0x5015, 0x7ccb, 0xb7a7, 0xffff }; for (lut_index = 0; lut_index < sizeof(lut_color_in); ++lut_index) { if (lut_color_in[lut_index] >= color_level) { break; } } if (lut_index < sizeof(lut_color_in)) { if (lut_color_in[lut_index] == color_level) { pwm_cmd = lut_pwm_out[lut_index]; } else { pwm_cmd = (unsigned short)(lut_pwm_out[lut_index - 1] + (int)(lut_pwm_out[lut_index] - lut_pwm_out[lut_index - 1]) * (int)(color_level - lut_color_in[lut_index - 1]) / (int)(lut_color_in[lut_index] - lut_color_in[lut_index - 1])); } } return pwm_cmd; } #endif /* CONFIG_RGBLED_LIGHTNESS_CORRECTION */ /**************************************************************************** * Name: rgbled_write * * Description: * A write method which parses an HTML-style RGB string like "#FF8833" * into color values, and sends them to the lower-half PWM drivers. * ****************************************************************************/ static ssize_t rgbled_write(FAR struct file *filep, FAR const char *buffer, size_t buflen) { FAR struct inode *inode = filep->f_inode; FAR struct rgbled_upperhalf_s *upper = inode->i_private; FAR struct pwm_lowerhalf_s *ledr = upper->devledr; FAR struct pwm_lowerhalf_s *ledg = upper->devledg; FAR struct pwm_lowerhalf_s *ledb = upper->devledb; struct pwm_info_s pwm; unsigned int red; unsigned int green; unsigned int blue; char color[3]; #ifdef CONFIG_PWM_MULTICHAN int i; #endif /* We need to receive a string #RRGGBB = 7 bytes */ if (buffer == NULL || buflen < 7) { /* Well... nothing to do */ return -EINVAL; } /* Check if it is a color format */ if (buffer[0] != '#') { /* The color code needs to start with # */ return -EINVAL; } /* Move buffer to next character */ buffer++; color[0] = buffer[0]; color[1] = buffer[1]; color[2] = '\0'; red = strtol(color, NULL, 16); color[0] = buffer[2]; color[1] = buffer[3]; color[2] = '\0'; green = strtol(color, NULL, 16); color[0] = buffer[4]; color[1] = buffer[5]; color[2] = '\0'; blue = strtol(color, NULL, 16); /* Sane check */ if (red > 255) { red = 255; } if (green > 255) { green = 255; } if (blue > 255) { blue = 255; } /* Convert 8bit to 16bits */ #ifdef CONFIG_RGBLED_LIGHTNESS_CORRECTION red = rgbled_lightness((unsigned char)red); green = rgbled_lightness((unsigned char)green); blue = rgbled_lightness((unsigned char)blue); #else red = (red << 8) | red; green = (green << 8) | green; blue = (blue << 8) | blue; #endif #ifdef CONFIG_RGBLED_INVERT red ^= 0xffff; green ^= 0xffff; blue ^= 0xffff; #endif #ifdef CONFIG_PWM_MULTICHAN memset(&pwm, 0, sizeof(struct pwm_info_s)); pwm.frequency = 100; i = 0; pwm.channels[i].duty = red; pwm.channels[i++].channel = upper->chanr; /* If the green pwm source is on the same timer as the red, * set that up now too. */ if (ledr == ledg) { pwm.channels[i].duty = green; pwm.channels[i++].channel = upper->chang; } /* If the blue pwm source is on the same timer as the red, * set that up now too. */ if (ledr == ledb) { pwm.channels[i].duty = blue; pwm.channels[i++].channel = upper->chanb; } ledr->ops->start(ledr, &pwm); for (i = 0; i < CONFIG_PWM_NCHANNELS; i++) { pwm.channels[i].channel = 0; } /* If the green timer is not the same as the red timer, update it * separately. */ if (ledg != ledr) { i = 0; pwm.channels[i].duty = green; pwm.channels[i++].channel = upper->chang; /* If the blue pwm source is on the same timer as the green, * set that up now too. */ if (ledg == ledb) { pwm.channels[i].duty = blue; pwm.channels[i++].channel = upper->chanb; } ledg->ops->start(ledg, &pwm); for (i = 0; i < CONFIG_PWM_NCHANNELS; i++) { pwm.channels[i].channel = 0; } } /* If the blue timer is not the same as the red or green timer, update it * separately. */ if (ledb != ledr && ledb != ledg) { pwm.channels[0].duty = green; pwm.channels[0].channel = upper->chanb; ledb->ops->start(ledb, &pwm); } #else pwm.frequency = 100; pwm.duty = red; ledr->ops->start(ledr, &pwm); pwm.duty = green; ledg->ops->start(ledg, &pwm); pwm.duty = blue; ledb->ops->start(ledb, &pwm); #endif return buflen; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: rgbled_register * * Description: * This function binds three instances of a "lower half" PWM driver with * the "upper half" RGB LED device and registers that device so that can * be used by application code. * * * Input Parameters: * path - The full path to the driver to be registers in the NuttX pseudo- * filesystem. The recommended convention is to name all PWM drivers * as "/dev/rgdbled0", "/dev/rgbled1", etc. where the driver path * differs only in the "minor" number at the end of the device name. * ledr, ledg, and ledb - A pointer to an instance of lower half PWM * drivers for the red, green, and blue LEDs, respectively. These * instances will be bound to the RGB LED driver and must persists as * long as that driver persists. * chanr, chang, chanb -Red/Green/Blue PWM channels (only if * CONFIG_PWM_MULTICHAN is defined) * * Returned Value: * Zero on success; a negated errno value on failure. * ****************************************************************************/ int rgbled_register(FAR const char *path, FAR struct pwm_lowerhalf_s *ledr, FAR struct pwm_lowerhalf_s *ledg, FAR struct pwm_lowerhalf_s *ledb #ifdef CONFIG_PWM_MULTICHAN , int chanr, int chang, int chanb #endif ) { FAR struct rgbled_upperhalf_s *upper; /* Allocate the upper-half data structure */ upper = (FAR struct rgbled_upperhalf_s *) kmm_zalloc(sizeof(struct rgbled_upperhalf_s)); if (!upper) { lcderr("ERROR: Allocation failed\n"); return -ENOMEM; } /* Initialize the PWM device structure (it was already zeroed by * kmm_zalloc()) */ nxsem_init(&upper->exclsem, 0, 1); upper->devledr = ledr; upper->devledg = ledg; upper->devledb = ledb; #ifdef CONFIG_PWM_MULTICHAN upper->chanr = chanr; upper->chang = chang; upper->chanb = chanb; #endif /* Register the PWM device */ lcdinfo("Registering %s\n", path); return register_driver(path, &g_rgbledops, 0666, upper); } #endif /* CONFIG_RGBLED */