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nuttx/drivers/ioexpander/gpio.c

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/****************************************************************************
* drivers/ioexpander/gpio.c
*
* Copyright (C) 2016 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 <nuttx/config.h>
#include <sys/types.h>
#include <stdio.h>
#include <signal.h>
#include <assert.h>
#include <errno.h>
#include <nuttx/fs/fs.h>
#include <nuttx/ioexpander/gpio.h>
#ifdef CONFIG_DEV_GPIO
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static int gpio_handler(FAR struct gpio_dev_s *dev);
static int gpio_open(FAR struct file *filep);
static int gpio_close(FAR struct file *filep);
static ssize_t gpio_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static ssize_t gpio_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen);
static int gpio_ioctl(FAR struct file *filep, int cmd,
unsigned long arg);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_gpio_drvrops =
{
gpio_open, /* open */
gpio_close, /* close */
gpio_read, /* read */
gpio_write, /* write */
NULL, /* seek */
gpio_ioctl /* ioctl */
#ifndef CONFIG_DISABLE_POLL
, NULL /* poll */
#endif
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
, NULL /* unlink */
#endif
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: gpio_handler
*
* Description:
* GPIO interrupt callback function.
*
****************************************************************************/
static int gpio_handler(FAR struct gpio_dev_s *dev)
{
DEBUGASSERT(dev != NULL);
(void)kill(dev->gp_pid, dev->gp_signo);
return OK;
}
/****************************************************************************
* Name: gpio_open
*
* Description:
* Standard character driver open method.
*
****************************************************************************/
static int gpio_open(FAR struct file *filep)
{
return OK;
}
/****************************************************************************
* Name: gpio_close
*
* Description:
* Standard character driver close method.
*
****************************************************************************/
static int gpio_close(FAR struct file *filep)
{
return OK;
}
/****************************************************************************
* Name: gpio_read
*
* Description:
* Standard character driver read method.
*
****************************************************************************/
static ssize_t gpio_read(FAR struct file *filep, FAR char *buffer,
size_t buflen)
{
return 0;
}
/****************************************************************************
* Name: gpio_write
*
* Description:
* Standard character driver write method.
*
****************************************************************************/
static ssize_t gpio_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen)
{
return (ssize_t)buflen;
}
/****************************************************************************
* Name: gpio_ioctl
*
* Description:
* Standard character driver ioctl method.
*
****************************************************************************/
static int gpio_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
FAR struct inode *inode;
FAR struct gpio_dev_s *dev;
int ret;
DEBUGASSERT(filep != NULL && filep->f_inode != NULL);
inode = filep->f_inode;
DEBUGASSERT(inode->i_private != NULL);
dev = inode->i_private;
switch (cmd)
{
/* Command: GPIOC_WRITE
* Description: Set the value of an output GPIO
* Argument: 0=output a low value; 1=outut a high value
*/
case GPIOC_WRITE:
if (dev->gp_pintype == GPIO_OUTPUT_PIN)
{
DEBUGASSERT(arg == 0ul || arg == 1ul);
ret = dev->gp_ops->go_write(dev, (bool)arg);
}
else
{
ret = -EACCES;
}
break;
/* Command: GPIOC_READ
* Description: Read the value of an input or output GPIO
* Argument: A pointer to an bool value to receive the result:
* false=low value; true=high value.
*/
case GPIOC_READ:
{
FAR bool *ptr = (FAR bool *)((uintptr_t)arg);
DEBUGASSERT(ptr != NULL);
ret = dev->gp_ops->go_read(dev, ptr);
DEBUGASSERT(ret < 0 || *ptr == 0 || *ptr == 1);
}
break;
/* Command: GPIOC_PINTYPE
* Description: Return the GPIO pin type.
* Argument: A pointer to an instance of type enum gpio_pintype_e
*/
case GPIOC_PINTYPE:
{
FAR enum gpio_pintype_e *ptr = (FAR enum gpio_pintype_e *)((uintptr_t)arg);
DEBUGASSERT(ptr != NULL);
*ptr = dev->gp_pintype;
ret = OK;
}
break;
/* Command: GPIOC_REGISTER
* Description: Register to receive a signal whenever there an
* interrupt is received on an input gpio pin. This
* feature, of course, depends upon interrupt GPIO
* support from the platform.
* Argument: The number of signal to be generated when the
* interrupt occurs.
*/
case GPIOC_REGISTER:
if (dev->gp_pintype == GPIO_INTERRUPT_PIN)
{
/* Make sure that the pin interrupt is disabled */
ret = dev->gp_ops->go_enable(dev, false);
if (ret >= 0)
{
/* Save signal information */
DEBUGASSERT(GOOD_SIGNO(arg));
dev->gp_pid = getpid();
dev->gp_signo = (uint8_t)arg;
/* Register our handler */
ret = dev->gp_ops->go_attach(dev,
(pin_interrupt_t)gpio_handler);
if (ret >= 0)
{
/* Enable pin interrupts */
ret = dev->gp_ops->go_enable(dev, true);
}
}
}
else
{
ret = -EACCES;
}
break;
/* Command: GPIOC_UNREGISTER
* Description: Stop receiving signals for pin interrupts.
* Argument: None.
*/
case GPIOC_UNREGISTER:
if (dev->gp_pintype == GPIO_INTERRUPT_PIN)
{
/* Make sure that the pin interrupt is disabled */
ret = dev->gp_ops->go_enable(dev, false);
if (ret >= 0)
{
/* Detach the handler */
ret = dev->gp_ops->go_attach(dev, NULL);
dev->gp_pid = 0;
dev->gp_signo = 0;
}
}
else
{
ret = -EACCES;
}
break;
/* Unrecognized command */
default:
ret = -ENOTTY;
break;
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: gpio_pin_register
*
* Description:
* Register GPIO pin device driver.
*
* - Input pin types will be registered at /dev/gpinN
* - Output pin types will be registered at /dev/gpoutN
* - Interrupt pin types will be registered at /dev/gpintN
*
* Where N is the provided minor number in the range of 0-99.
*
****************************************************************************/
int gpio_pin_register(FAR struct gpio_dev_s *dev, int minor)
{
FAR const char *fmt;
char devname[16];
int ret;
DEBUGASSERT(dev != NULL && dev->gp_ops != NULL && (unsigned int)minor < 100);
switch (dev->gp_pintype)
{
case GPIO_INPUT_PIN:
{
DEBUGASSERT(dev->gp_ops->go_read != NULL);
fmt = "/dev/gpin%u";
}
break;
case GPIO_OUTPUT_PIN:
{
DEBUGASSERT(dev->gp_ops->go_read != NULL &&
dev->gp_ops->go_write != NULL);
fmt = "/dev/gpout%u";
}
break;
case GPIO_INTERRUPT_PIN:
{
DEBUGASSERT(dev->gp_ops->go_read != NULL &&
dev->gp_ops->go_attach != NULL &&
dev->gp_ops->go_enable != NULL);
/* Make sure that the pin interrupt is disabled */
ret = dev->gp_ops->go_enable(dev, false);
if (ret < 0)
{
return ret;
}
fmt = "/dev/gpint%u";
}
break;
default:
return -EINVAL;
}
snprintf(devname, 16, fmt, (unsigned int)minor);
return register_driver(devname, &g_gpio_drvrops, 0666, dev);
}
#endif /* CONFIG_DEV_GPIO */
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