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- /****************************************************************************
- * drivers/i2c/i2c_driver.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 <stdbool.h>
- #include <stdio.h>
- #include <semaphore.h>
- #include <string.h>
- #include <errno.h>
- #include <debug.h>
- #include <nuttx/kmalloc.h>
- #include <nuttx/fs/fs.h>
- #include <nuttx/i2c/i2c_master.h>
- #ifdef CONFIG_I2C_DRIVER
- /****************************************************************************
- * Pre-processor Definitions
- ****************************************************************************/
- /* Device naming ************************************************************/
- #define DEVNAME_FMT "/dev/i2c%d"
- #define DEVNAME_FMTLEN (8 + 3 + 1)
- /****************************************************************************
- * Private Types
- ****************************************************************************/
- /* Driver state structure */
- struct i2c_driver_s
- {
- FAR struct i2c_master_s *i2c; /* Contained I2C lower half driver */
- #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
- sem_t exclsem; /* Mutual exclusion */
- int16_t crefs; /* Number of open references */
- bool unlinked; /* True, driver has been unlinked */
- #endif
- };
- /****************************************************************************
- * Private Function Prototypes
- ****************************************************************************/
- #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
- static int i2cdrvr_open(FAR struct file *filep);
- static int i2cdrvr_close(FAR struct file *filep);
- #endif
- static ssize_t i2cdrvr_read(FAR struct file *filep, FAR char *buffer,
- size_t buflen);
- static ssize_t i2cdrvr_write(FAR struct file *filep, FAR const char *buffer,
- size_t buflen);
- static int i2cdrvr_ioctl(FAR struct file *filep, int cmd,
- unsigned long arg);
- #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
- static int i2cdrvr_unlink(FAR struct inode *inode);
- #endif
- /****************************************************************************
- * Private Data
- ****************************************************************************/
- static const struct file_operations i2cdrvr_fops =
- {
- #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
- i2cdrvr_open, /* open */
- i2cdrvr_close, /* close */
- #else
- 0, /* open */
- 0, /* close */
- #endif
- i2cdrvr_read, /* read */
- i2cdrvr_write, /* write */
- 0, /* seek */
- i2cdrvr_ioctl /* ioctl */
- #ifndef CONFIG_DISABLE_POLL
- , 0 /* poll */
- #endif
- #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
- , i2cdrvr_unlink /* unlink */
- #endif
- };
- /****************************************************************************
- * Private Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: i2cdrvr_open
- ****************************************************************************/
- #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
- static int i2cdrvr_open(FAR struct file *filep)
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct i2c_driver_s *priv;
- int ret;
- /* Get our private data structure */
- DEBUGASSERT(filep != NULL && filep->f_inode != NULL);
- inode = filep->f_inode;
- priv = (FAR struct i2c_driver_s *)inode->i_private;
- DEBUGASSERT(priv);
- /* Get exclusive access to the I2C driver state structure */
- ret = sem_wait(&priv->exclsem);
- if (ret < 0)
- {
- int errcode = errno;
- DEBUGASSERT(errcode < 0);
- return -errcode;
- }
- /* Increment the count of open references on the RTC driver */
- priv->crefs++;
- DEBUGASSERT(priv->crefs > 0);
- sem_post(&priv->exclsem);
- return OK;
- }
- #endif
- /****************************************************************************
- * Name: i2cdrvr_close
- ****************************************************************************/
- #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
- static int i2cdrvr_close(FAR struct file *filep)
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct i2c_driver_s *priv;
- int ret;
- /* Get our private data structure */
- DEBUGASSERT(filep != NULL && filep->f_inode != NULL);
- inode = filep->f_inode;
- priv = (FAR struct i2c_driver_s *)inode->i_private;
- DEBUGASSERT(priv);
- /* Get exclusive access to the I2C driver state structure */
- ret = sem_wait(&priv->exclsem);
- if (ret < 0)
- {
- int errcode = errno;
- DEBUGASSERT(errcode < 0);
- return -errcode;
- }
- /* Decrement the count of open references on the RTC driver */
- DEBUGASSERT(priv->crefs > 0);
- priv->crefs--;
- /* If the count has decremented to zero and the driver has been unlinked,
- * then commit Hara-Kiri now.
- */
- if (priv->crefs <= 0 && priv->unlinked)
- {
- sem_destroy(&priv->exclsem);
- kmm_free(priv);
- return OK;
- }
- sem_post(&priv->exclsem);
- return OK;
- }
- #endif
- /****************************************************************************
- * Name: i2cdrvr_read
- ****************************************************************************/
- static ssize_t i2cdrvr_read(FAR struct file *filep, FAR char *buffer,
- size_t len)
- {
- return 0; /* Return EOF */
- }
- /****************************************************************************
- * Name: i2cdrvr_write
- ****************************************************************************/
- static ssize_t i2cdrvr_write(FAR struct file *filep, FAR const char *buffer,
- size_t len)
- {
- return len; /* Say that everything was written */
- }
- /****************************************************************************
- * Name: i2cdrvr_ioctl
- ****************************************************************************/
- static int i2cdrvr_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct i2c_driver_s *priv;
- FAR struct i2c_transfer_s *transfer;
- int ret;
- i2cinfo("cmd=%d arg=%lu\n", cmd, arg);
- /* Get our private data structure */
- DEBUGASSERT(filep != NULL && filep->f_inode != NULL);
- inode = filep->f_inode;
- priv = (FAR struct i2c_driver_s *)inode->i_private;
- DEBUGASSERT(priv);
- #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
- /* Get exclusive access to the I2C driver state structure */
- ret = sem_wait(&priv->exclsem);
- if (ret < 0)
- {
- int errcode = errno;
- DEBUGASSERT(errcode < 0);
- return -errcode;
- }
- #endif
- /* Process the IOCTL command */
- switch (cmd)
- {
- /* Command: I2CIOC_TRANSFER
- * Description: Perform an I2C transfer
- * Argument: A reference to an instance of struct i2c_transfer_s.
- * Dependencies: CONFIG_I2C_DRIVER
- */
- case I2CIOC_TRANSFER:
- {
- /* Get the reference to the i2c_transfer_s structure */
- transfer = (FAR struct i2c_transfer_s *)((uintptr_t)arg);
- DEBUGASSERT(transfer != NULL);
- /* Perform the transfer */
- ret = I2C_TRANSFER(priv->i2c, transfer->msgv, transfer->msgc);
- }
- break;
- #ifdef CONFIG_I2C_RESET
- /* Command: I2CIOC_RESET
- * Description: Perform an I2C bus reset in an attempt to break loose
- * stuck I2C devices.
- * Argument: None
- * Dependencies: CONFIG_I2C_DRIVER && CONFIG_I2C_RESET
- */
- case I2CIOC_RESET:
- {
- ret = I2C_RESET(priv->i2c);
- }
- break;
- #endif
- default:
- ret = -ENOTTY;
- break;
- }
- #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
- sem_post(&priv->exclsem);
- #endif
- return ret;
- }
- /****************************************************************************
- * Name: i2cdrvr_unlink
- ****************************************************************************/
- #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
- static int i2cdrvr_unlink(FAR struct inode *inode)
- {
- FAR struct i2c_driver_s *priv;
- int ret;
- /* Get our private data structure */
- DEBUGASSERT(inode != NULL && inode->i_private != NULL);
- priv = (FAR struct i2c_driver_s *)inode->i_private;
- /* Get exclusive access to the I2C driver state structure */
- ret = sem_wait(&priv->exclsem);
- if (ret < 0)
- {
- int errcode = errno;
- DEBUGASSERT(errcode < 0);
- return -errcode;
- }
- /* Are there open references to the driver data structure? */
- if (priv->crefs <= 0)
- {
- sem_destroy(&priv->exclsem);
- kmm_free(priv);
- return OK;
- }
- /* No... just mark the driver as unlinked and free the resouces when the
- * last client closes their reference to the driver.
- */
- priv->unlinked = true;
- sem_post(&priv->exclsem);
- return ret;
- }
- #endif
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: i2c_register
- *
- * Description:
- * Create and register the I2C character driver.
- *
- * The I2C character driver is a simple character driver that supports I2C
- * transfers. The intent of this driver is to support I2C testing. It is
- * not suitable for use in any real driver application.
- *
- * Input Parameters:
- * i2c - An instance of the lower half I2C driver
- * bus - The I2C bus number. This will be used as the I2C device minor
- * number. The I2C character device will be registered as /dev/i2cN
- * where N is the minor number
- *
- * Returned Value:
- * OK if the driver was successfully register; A negated errno value is
- * returned on any failure.
- *
- ****************************************************************************/
- int i2c_register(FAR struct i2c_master_s *i2c, int bus)
- {
- FAR struct i2c_driver_s *priv;
- char devname[DEVNAME_FMTLEN];
- int ret;
- /* Sanity check */
- DEBUGASSERT(i2c != NULL && (unsigned)bus < 1000);
- /* Allocate a I2C character device structure */
- priv = (FAR struct i2c_driver_s *)kmm_zalloc(sizeof(struct i2c_driver_s));
- if (priv)
- {
- /* Initialize the I2C character device structure */
- priv->i2c = i2c;
- #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
- sem_init(&priv->exclsem, 0, 1);
- #endif
- /* Create the character device name */
- snprintf(devname, DEVNAME_FMTLEN, DEVNAME_FMT, bus);
- ret = register_driver(devname, &i2cdrvr_fops, 0666, priv);
- if (ret < 0)
- {
- /* Free the device structure if we failed to create the character
- * device.
- */
- kmm_free(priv);
- }
- /* Return the result of the registration */
- return OK;
- }
- return -ENOMEM;
- }
- #endif /* CONFIG_I2C_DRIVER */
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