nuttx/drivers/ioexpander/pcf8574.h

/********************************************************************************************
 * drivers/ioexpander/pcf8574.h
 *
 *   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.
 *
 ********************************************************************************************/

#ifndef __DRIVERS_IOEXPANDER_PCF8574_H
#define __DRIVERS_IOEXPANDER_PCF8574_H

/********************************************************************************************
 * Included Files
 ********************************************************************************************/

#include <nuttx/config.h>

#include <nuttx/wdog.h>
#include <nuttx/clock.h>
#include <nuttx/semaphore.h>
#include <nuttx/wqueue.h>
#include <nuttx/ioexpander/ioexpander.h>
#include <nuttx/ioexpander/pcf8574.h>

#include <nuttx/i2c/i2c_master.h>
#include <nuttx/irq.h>

#if defined(CONFIG_IOEXPANDER) && defined(CONFIG_IOEXPANDER_PCF8574)

/********************************************************************************************
 * Pre-processor Definitions
 ********************************************************************************************/

/* Configuration ****************************************************************************/
/* Prerequisites:
 *   CONFIG_I2C
 *     I2C support is required
 *   CONFIG_IOEXPANDER
 *     Enables I/O expander support
 *
 * CONFIG_IOEXPANDER_PCF8574
 *   Enables support for the PCF8574 driver (Needs CONFIG_INPUT)
 * CONFIG_PCF8574_MULTIPLE
 *   Can be defined to support multiple PCF8574 devices on board.
 * CONFIG_PCF8574_INT_NCALLBACKS
 *   Maximum number of supported pin interrupt callbacks.
 * CONFIG_PCF8574_INT_POLL
 *   Enables a poll for missed interrupts
 * CONFIG_PCF8574_INT_POLLDELAY
 *   If CONFIG_PCF8574_INT_POLL=y, then this is the delay in microseconds
 *   between polls for missed interrupts.
 */

#ifndef CONFIG_I2C
#  error "CONFIG_I2C is required by PCF8574"
#endif

#ifdef CONFIG_IOEXPANDER_INT_ENABLE
#  ifndef CONFIG_PCF8574_INT_NCALLBACKS
#    define CONFIG_PCF8574_INT_NCALLBACKS 4
#  endif
#endif

#ifdef CONFIG_IOEXPANDER_INT_ENABLE
#  ifndef CONFIG_SCHED_WORKQUEUE
#    error Work queue support required.  CONFIG_SCHED_WORKQUEUE must be selected.
#  endif
#endif

#ifndef CONFIG_PCF8574_INT_POLLDELAY
#  define CONFIG_PCF8574_INT_POLLDELAY 500000
#endif

/* PCF8574 Definitions **********************************************************************/

#define PCF8574_I2C_MAXFREQUENCY  400000       /* 400KHz */
#define PCF8574_POLLDELAY         (CONFIG_PCF8574_INT_POLLDELAY / USEC_PER_TICK)

#define PCF8574_LEVEL_SENSITIVE(d,p) \
  (((d)->trigger  & ((ioe_pinset_t)1 << (p))) == 0)
#define PCF8574_LEVEL_HIGH(d,p) \
  (((d)->level[0] & ((ioe_pinset_t)1 << (p))) != 0)
#define PCF8574_LEVEL_LOW(d,p) \
  (((d)->level[1] & ((ioe_pinset_t)1 << (p))) != 0)

#define PCF8574_EDGE_SENSITIVE(d,p) \
  (((d)->trigger  & ((ioe_pinset_t)1 << (p))) != 0)
#define PCF8574_EDGE_RISING(d,p) \
  (((d)->level[0] & ((ioe_pinset_t)1 << (p))) != 0)
#define PCF8574_EDGE_FALLING(d,p) \
  (((d)->level[1] & ((ioe_pinset_t)1 << (p))) != 0)
#define PCF8574_EDGE_BOTH(d,p) \
  (PCF8574_LEVEL_RISING(d,p) && PCF8574_LEVEL_FALLING(d,p))

/********************************************************************************************
 * Public Types
 ********************************************************************************************/

#ifdef CONFIG_IOEXPANDER_INT_ENABLE
/* This type represents on registered pin interrupt callback */

struct pcf8574_callback_s
{
  ioe_pinset_t pinset;                 /* Set of pin interrupts that will generate
                                        * the callback. */
  ioe_callback_t cbfunc;               /* The saved callback function pointer */
  FAR void *cbarg;                     /* Callback argument */
};
#endif

/* This structure represents the state of the PCF8574 driver */

struct pcf8574_dev_s
{
  struct ioexpander_dev_s dev;         /* Nested structure to allow casting as public gpio
                                        * expander. */
  FAR struct pcf8574_config_s *config; /* Board configuration data */
  FAR struct i2c_master_s *i2c;        /* Saved I2C driver instance */
  sem_t exclsem;                       /* Mutual exclusion */
  uint8_t inpins;                      /* Set of input pins */
  uint8_t outstate;                    /* State of all output pins */

#ifdef CONFIG_IOEXPANDER_INT_ENABLE
#ifdef CONFIG_PCF8574_INT_POLL
  WDOG_ID wdog;                        /* Timer used to poll for missed interrupts */
#endif

  uint8_t input;                       /* Last input registeres */
  uint8_t intstat;                     /* Pending interrupts */
  uint8_t trigger;                     /* Bit encoded: 0=level 1=edge */
  uint8_t level[2];                    /* Bit encoded: 01=high/rising, 10 low/falling, 11 both */
  struct work_s work;                  /* Supports the interrupt handling "bottom half" */

  /* Saved callback information for each I/O expander client */

  struct pcf8574_callback_s cb[CONFIG_PCF8574_INT_NCALLBACKS];
#endif
};

#endif /* CONFIG_IOEXPANDER && CONFIG_IOEXPANDER_PCF8574 */
#endif /* __DRIVERS_IOEXPANDER_PCF8574_H */