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incubator-nuttx/drivers/leds/rgbled.c

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/****************************************************************************
* drivers/leds/rgbled.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 <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/fs/fs.h>
#include <nuttx/arch.h>
#include <nuttx/timers/pwm.h>
#include <nuttx/leds/rgbled.h>
#include <nuttx/mutex.h>
#include <arch/irq.h>
#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 */
mutex_t lock; /* 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 */
};
/****************************************************************************
* 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 = nxmutex_lock(&upper->lock);
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_lock;
}
/* Save the new open count on success */
upper->crefs = tmp;
ret = OK;
errout_with_lock:
nxmutex_unlock(&upper->lock);
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 = nxmutex_lock(&upper->lock);
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--;
}
nxmutex_unlock(&upper->lock);
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 = CONFIG_RGBLED_PWM_FREQ;
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 = CONFIG_RGBLED_PWM_FREQ;
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())
*/
nxmutex_init(&upper->lock);
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 */
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