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incubator-nuttx/drivers/ioexpander/pcf8574.c

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/****************************************************************************
* drivers/ioexpander/pcf8574.h
*
* Copyright (C) 2016-2017 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 <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/wdog.h>
#include <nuttx/ioexpander/ioexpander.h>
#include <nuttx/ioexpander/pcf8574.h>
#include "pcf8574.h"
#ifdef CONFIG_IOEXPANDER_PCF8574
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#ifndef MAX
# define MAX(a,b) (((a) > (b)) ? (a) : (b))
#endif
#ifndef MIN
# define MIN(a,b) (((a) < (b)) ? (a) : (b))
#endif
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* PCF8574xx Helpers */
static void pcf8574_lock(FAR struct pcf8574_dev_s *priv);
static int pcf8574_read(FAR struct pcf8574_dev_s *priv, FAR uint8_t *portval);
static int pcf8574_write(struct pcf8574_dev_s *priv, uint8_t portval);
/* I/O Expander Methods */
static int pcf8574_direction(FAR struct ioexpander_dev_s *dev, uint8_t pin,
int dir);
static int pcf8574_option(FAR struct ioexpander_dev_s *dev, uint8_t pin,
int opt, void *regval);
static int pcf8574_writepin(FAR struct ioexpander_dev_s *dev, uint8_t pin,
bool value);
static int pcf8574_readpin(FAR struct ioexpander_dev_s *dev, uint8_t pin,
FAR bool *value);
#ifdef CONFIG_IOEXPANDER_MULTIPIN
static int pcf8574_multiwritepin(FAR struct ioexpander_dev_s *dev,
FAR uint8_t *pins, FAR bool *values, int count);
static int pcf8574_multireadpin(FAR struct ioexpander_dev_s *dev,
FAR uint8_t *pins, FAR bool *values, int count);
#endif
#ifdef CONFIG_IOEXPANDER_INT_ENABLE
static FAR void *pcf8574_attach(FAR struct ioexpander_dev_s *dev,
ioe_pinset_t pinset, ioe_callback_t callback, FAR void *arg);
static int pcf8574_detach(FAR struct ioexpander_dev_s *dev, FAR void *handle);
#endif
#ifdef CONFIG_PCF8574_INT_ENABLE
static void pcf8574_int_update(void *handle, uint8_t input);
static void pcf8574_register_update(FAR struct pcf8574_dev_s *priv);
static void pcf8574_irqworker(void *arg);
static void pcf8574_interrupt(FAR void *arg);
#ifdef CONFIG_PCF8574_INT_POLL
static void pcf8574_poll_expiry(int argc, wdparm_t arg1, ...);
#endif
#endif
/****************************************************************************
* Private Data
****************************************************************************/
#ifndef CONFIG_PCF8574_MULTIPLE
/* If only a single device is supported, then the driver state structure may
* as well be pre-allocated.
*/
static struct pcf8574_dev_s g_pcf8574;
#endif
/* I/O expander vtable */
static const struct ioexpander_ops_s g_pcf8574_ops =
{
pcf8574_direction,
pcf8574_option,
pcf8574_writepin,
pcf8574_readpin,
pcf8574_readpin
#ifdef CONFIG_IOEXPANDER_MULTIPIN
, pcf8574_multiwritepin
, pcf8574_multireadpin
, pcf8574_multireadpin
#endif
#ifdef CONFIG_IOEXPANDER_INT_ENABLE
, pcf8574_attach
, pcf8574_detach
#endif
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: pcf8574_lock
*
* Description:
* Get exclusive access to the I/O Expander
*
****************************************************************************/
static void pcf8574_lock(FAR struct pcf8574_dev_s *priv)
{
nxsem_wait_uninterruptible(&priv->exclsem);
}
#define pcf8574_unlock(p) nxsem_post(&(p)->exclsem)
/****************************************************************************
* Name: pcf8574_read
*
* Description:
* Read the PCF8574 8-bit value from a PCF8574xx port
*
* Primitive I2C read operation for the PCA8574. The PCF8574 is
* 'interesting' in that it doesn't really have a data direction register,
* but instead the outputs are current-limited when high, so by setting an
* IO line high, you are also making it an input. Consequently, before
* using this method, you'll need to perform a pca8574_write() setting the
* bits you are interested in reading to 1's, then call this method.
*
****************************************************************************/
static int pcf8574_read(FAR struct pcf8574_dev_s *priv, FAR uint8_t *portval)
{
struct i2c_msg_s msg;
int ret;
DEBUGASSERT(priv != NULL && priv->i2c != NULL && priv->config != NULL);
/* Setup for the transfer */
msg.frequency = priv->config->frequency,
msg.addr = priv->config->address,
msg.flags = I2C_M_READ;
msg.buffer = portval;
msg.length = 1;
/* Then perform the transfer. */
ret = I2C_TRANSFER(priv->i2c, &msg, 1);
return (ret >= 0) ? OK : ret;
}
/****************************************************************************
* Name: pcf8574_write
*
* Description:
* Write an 8-bit value to a PCF8574xx port
*
* Primitive I2C write operation for the PCA8574. The I2C interface
* simply sets the state of the 8 IO lines in the PCA8574 port.
*
****************************************************************************/
static int pcf8574_write(struct pcf8574_dev_s *priv, uint8_t portval)
{
struct i2c_msg_s msg;
int ret;
DEBUGASSERT(priv != NULL && priv->i2c != NULL && priv->config != NULL);
/* Setup for the transfer */
msg.frequency = priv->config->frequency,
msg.addr = priv->config->address;
msg.flags = 0;
msg.buffer = (FAR uint8_t *)&portval;
msg.length = 1;
/* Then perform the transfer. */
ret = I2C_TRANSFER(priv->i2c, &msg, 1);
return (ret >= 0) ? OK : ret;
}
/****************************************************************************
* Name: pcf8574_direction
*
* Description:
* Set the direction of an ioexpander pin. Required.
*
* The PCF8574 is 'interesting' in that it doesn't really have a data
* direction register, but instead the outputs are current-limited when
* high, so by setting an IO line high, you are also making it an input.
* Consequently, before using this method, you'll need to perform a
* pca8574_write() setting the bits you are interested in reading to 1's,
* before calling pca8574_read().
*
* Input Parameters:
* dev - Device-specific state data
* pin - The index of the pin to alter in this call
* dir - One of the IOEXPANDER_DIRECTION_ macros
*
* Returned Value:
* 0 on success, else a negative error code
*
****************************************************************************/
static int pcf8574_direction(FAR struct ioexpander_dev_s *dev, uint8_t pin,
int direction)
{
FAR struct pcf8574_dev_s *priv = (FAR struct pcf8574_dev_s *)dev;
int ret;
DEBUGASSERT(priv != NULL && priv->config != NULL && pin < 8 &&
(direction == IOEXPANDER_DIRECTION_IN ||
direction == IOEXPANDER_DIRECTION_OUT));
gpioinfo("I2C addr=%02x pin=%u direction=%s\n",
priv->config->address, pin,
(direction == IOEXPANDER_DIRECTION_IN) ? "IN" : "OUT");
/* Get exclusive access to the I/O Expander */
pcf8574_lock(priv);
/* Set a bit in inpins if the pin is an input. Clear the bit in
* inpins if the pin is an output.
*/
if (direction == IOEXPANDER_DIRECTION_IN)
{
priv->inpins |= (1 << pin);
priv->outstate &= ~(1 << pin);
}
else
{
priv->inpins &= ~(1 << pin);
}
/* Write the OR of the set of input pins and the set of output pins.
* In order to read input pins, we have to write a '1' to putt he
* pin in the current limiting state.
*/
ret = pcf8574_write(priv, priv->inpins | priv->outstate);
pcf8574_unlock(priv);
return ret;
}
/****************************************************************************
* Name: pcf8574_option
*
* Description:
* Set pin options. Required.
* Since all IO expanders have various pin options, this API allows setting
* pin options in a flexible way.
*
* Input Parameters:
* dev - Device-specific state data
* pin - The index of the pin to alter in this call
* opt - One of the IOEXPANDER_OPTION_ macros
* val - The option's value
*
* Returned Value:
* 0 on success, else a negative error code
*
****************************************************************************/
static int pcf8574_option(FAR struct ioexpander_dev_s *dev, uint8_t pin,
int opt, FAR void *value)
{
FAR struct pcf8574_dev_s *priv = (FAR struct pcf8574_dev_s *)dev;
int ret = -ENOSYS;
DEBUGASSERT(priv != NULL && priv->config != NULL);
gpioinfo("I2C addr=%02x pin=%u option=%u\n",
priv->config->address, pin, opt);
#ifdef CONFIG_PCF8574_INT_ENABLE
/* Interrupt configuration */
if (opt == IOEXPANDER_OPTION_INTCFG)
{
unsigned int ival = (unsigned int)((uintptr_t)value);
ioe_pinset_t bit = ((ioe_pinset_t)1 << pin);
ret = OK;
pcf8574_lock(priv);
switch (ival)
{
case IOEXPANDER_VAL_HIGH: /* Interrupt on high level */
priv->trigger &= ~bit;
priv->level[0] |= bit;
priv->level[1] &= ~bit;
break;
case IOEXPANDER_VAL_LOW: /* Interrupt on low level */
priv->trigger &= ~bit;
priv->level[0] &= ~bit;
priv->level[1] |= bit;
break;
case IOEXPANDER_VAL_RISING: /* Interrupt on rising edge */
priv->trigger |= bit;
priv->level[0] |= bit;
priv->level[1] &= ~bit;
break;
case IOEXPANDER_VAL_FALLING: /* Interrupt on falling edge */
priv->trigger |= bit;
priv->level[0] &= ~bit;
priv->level[1] |= bit;
break;
case IOEXPANDER_VAL_BOTH: /* Interrupt on both edges */
priv->trigger |= bit;
priv->level[0] |= bit;
priv->level[1] |= bit;
break;
case IOEXPANDER_VAL_DISABLE:
break;
default:
ret = -EINVAL;
}
pcf8574_unlock(priv);
}
#endif
return ret;
}
/****************************************************************************
* Name: pcf8574_writepin
*
* Description:
* Set the pin level. Required.
*
* Input Parameters:
* dev - Device-specific state data
* pin - The index of the pin to alter in this call
* val - The pin level. Usually TRUE will set the pin high,
* except if OPTION_INVERT has been set on this pin.
*
* Returned Value:
* 0 on success, else a negative error code
*
****************************************************************************/
static int pcf8574_writepin(FAR struct ioexpander_dev_s *dev, uint8_t pin,
bool value)
{
FAR struct pcf8574_dev_s *priv = (FAR struct pcf8574_dev_s *)dev;
int ret;
DEBUGASSERT(priv != NULL && priv->config != NULL && pin < 8);
gpioinfo("I2C addr=%02x pin=%u value=%u\n",
priv->config->address, pin, value);
/* Get exclusive access to the I/O Expander */
pcf8574_lock(priv);
/* Make sure that this is an output pin */
if ((priv->inpins & (1 << pin)) != 0)
{
gpioerr("ERROR: pin%u is an input\n", pin);
pcf8574_unlock(priv);
return -EINVAL;
}
/* Set/clear a bit in outstate. */
if (value)
{
priv->outstate |= (1 << pin);
}
else
{
priv->outstate &= ~(1 << pin);
}
/* Write the OR of the set of input pins and the set of output pins.
* In order to set the new output value.
*/
ret = pcf8574_write(priv, priv->inpins | priv->outstate);
pcf8574_unlock(priv);
return ret;
}
/****************************************************************************
* Name: pcf8574_readpin
*
* Description:
* Read the actual PIN level. This can be different from the last value written
* to this pin. Required.
*
* The PCF8574 is 'interesting' in that it doesn't really have a data
* direction register, but instead the outputs are current-limited when
* high, so by setting an IO line high, you are also making it an input.
* Consequently, before using this method, you'll need to perform a
* pca8574_write() setting the bits you are interested in reading to 1's,
* before calling pca8574_read().
*
* Input Parameters:
* dev - Device-specific state data
* pin - The index of the pin
* valptr - Pointer to a buffer where the pin level is stored. Usually TRUE
* if the pin is high, except if OPTION_INVERT has been set on this pin.
*
* Returned Value:
* 0 on success, else a negative error code
*
****************************************************************************/
static int pcf8574_readpin(FAR struct ioexpander_dev_s *dev, uint8_t pin,
FAR bool *value)
{
FAR struct pcf8574_dev_s *priv = (FAR struct pcf8574_dev_s *)dev;
uint8_t regval;
int ret;
DEBUGASSERT(priv != NULL && priv->config != NULL && pin < 8 && value != NULL);
gpioinfo("I2C addr=%02x, pin=%u\n", priv->config->address, pin);
/* Get exclusive access to the I/O Expander */
pcf8574_lock(priv);
/* Is the pin an output? */
if ((priv->inpins & (1 << pin)) == 0)
{
/* We cannot read the value on pin directly. Just Return the last
* value that we wrote to the pin.
*/
*value = ((priv->outstate & (1 << pin)) != 0);
pcf8574_unlock(priv);
return OK;
}
/* It is an input pin. Read the input register for this pin
*
* The Input Port Register reflects the incoming logic levels of the pins,
* regardless of whether the pin is defined as an input or an output by
* the Configuration Register. They act only on read operation.
*/
ret = pcf8574_read(priv, &regval);
if (ret < 0)
{
gpioerr("ERROR: Failed to read port register: %d\n", ret);
goto errout_with_lock;
}
#ifdef CONFIG_PCF8574_INT_ENABLE
/* Update the input status with the 8 bits read from the expander */
pcf8574_int_update(priv, regval);
#endif
/* Return 0 or 1 to indicate the state of pin */
*value = (bool)((regval >> (pin & 7)) & 1);
ret = OK;
errout_with_lock:
pcf8574_unlock(priv);
return ret;
}
/****************************************************************************
* Name: pcf8574_multiwritepin
*
* Description:
* Set the pin level for multiple pins. This routine may be faster than
* individual pin accesses. Optional.
*
* Input Parameters:
* dev - Device-specific state data
* pins - The list of pin indexes to alter in this call
* val - The list of pin levels.
*
* Returned Value:
* 0 on success, else a negative error code
*
****************************************************************************/
#ifdef CONFIG_IOEXPANDER_MULTIPIN
static int pcf8574_multiwritepin(FAR struct ioexpander_dev_s *dev,
FAR uint8_t *pins, FAR bool *values,
int count)
{
FAR struct pcf8574_dev_s *priv = (FAR struct pcf8574_dev_s *)dev;
uint8_t pin;
int ret;
int i;
DEBUGASSERT(priv != NULL && priv->config != NULL &&
pins != NULL && values != NULL);
gpioinfo("I2C addr=%02x count=%d\n", priv->config->address, count);
/* Get exclusive access to the I/O Expander */
pcf8574_lock(priv);
/* Process each pin setting */
for (i = 0; i < count; i++)
{
/* Make sure that this is an output pin */
pin = pins[i];
DEBUGASSERT(pin < 8);
gpioinfo("%d. pin=%u value=%u\n", pin, values[i]);
if ((priv->inpins & (1 << pin)) != 0)
{
gpioerr("ERROR: pin%u is an input\n", pin);
continue;
}
/* Set/clear a bit in outstate. */
if (values[i])
{
priv->outstate |= (1 << pin);
}
else
{
priv->outstate &= ~(1 << pin);
}
}
/* Write the OR of the set of input pins and the set of output pins.
* In order to set the new output value.
*/
ret = pcf8574_write(priv, priv->inpins | priv->outstate);
pcf8574_unlock(priv);
return ret;
}
#endif
/****************************************************************************
* Name: pcf8574_multireadpin
*
* Description:
* Read the actual level for multiple pins. This routine may be faster than
* individual pin accesses. Optional.
*
* Input Parameters:
* dev - Device-specific state data
* pin - The list of pin indexes to read
* valptr - Pointer to a buffer where the pin levels are stored.
*
* Returned Value:
* 0 on success, else a negative error code
*
****************************************************************************/
#ifdef CONFIG_IOEXPANDER_MULTIPIN
static int pcf8574_multireadpin(FAR struct ioexpander_dev_s *dev,
FAR uint8_t *pins, FAR bool *values,
int count)
{
FAR struct pcf8574_dev_s *priv = (FAR struct pcf8574_dev_s *)dev;
uint8_t regval;
uint8_t pin;
int ret;
int i;
DEBUGASSERT(priv != NULL && priv->config != NULL &&
pins != NULL && values != NULL);
gpioinfo("I2C addr=%02x, count=%d\n", priv->config->address, count);
/* Get exclusive access to the I/O Expander */
pcf8574_lock(priv);
/* Read the input register for this pin
*
* The Input Port Register reflects the incoming logic levels of the pins,
* regardless of whether the pin is defined as an input or an output by
* the Configuration Register. They act only on read operation.
*/
ret = pcf8574_read(priv, &regval);
if (ret < 0)
{
gpioerr("ERROR: Failed to read port register: %d\n", ret);
goto errout_with_lock;
}
#ifdef CONFIG_PCF8574_INT_ENABLE
/* Update the input status with the 8 bits read from the expander */
pcf8574_int_update(priv, regval);
#endif
/* Return the requested pin values */
for (i = 0; i < count; i++)
{
/* Make sure that this is an output pin */
pin = pins[i];
DEBUGASSERT(pin < 8);
/* Is the pin an output? */
if ((priv->inpins & (1 << pin)) == 0)
{
/* We cannot read the value on pin directly. Just Return the last
* value that we wrote to the pin.
*/
values[i] = ((priv->outstate & (1 << pin)) != 0);
}
else
{
values[i] = ((regval & (1 << pin)) != 0);
}
gpioinfo("%d. pin=%u value=%u\n", pin, values[i]);
}
ret = OK;
errout_with_lock:
pcf8574_unlock(priv);
return ret;
}
#endif
/****************************************************************************
* Name: pcf8574_attach
*
* Description:
* Attach and enable a pin interrupt callback function.
*
* Input Parameters:
* dev - Device-specific state data
* pinset - The set of pin events that will generate the callback
* callback - The pointer to callback function. NULL will detach the
* callback.
* arg - User-provided callback argument
*
* Returned Value:
* A non-NULL handle value is returned on success. This handle may be
* used later to detach and disable the pin interrupt.
*
****************************************************************************/
#ifdef CONFIG_PCF8574_INT_ENABLE
static FAR void *pcf8574_attach(FAR struct ioexpander_dev_s *dev,
ioe_pinset_t pinset, ioe_callback_t callback,
FAR void *arg)
{
FAR struct pcf8574_dev_s *priv = (FAR struct pcf8574_dev_s *)dev;
FAR void *handle = NULL;
int i;
/* Get exclusive access to the I/O Expander */
pcf8574_lock(priv);
/* Find and available in entry in the callback table */
for (i = 0; i < CONFIG_PCF8574_INT_NCALLBACKS; i++)
{
/* Is this entry available (i.e., no callback attached) */
if (priv->cb[i].cbfunc == NULL)
{
/* Yes.. use this entry */
priv->cb[i].pinset = pinset;
priv->cb[i].cbfunc = callback;
priv->cb[i].cbarg = arg;
handle = &priv->cb[i];
break;
}
}
pcf8574_unlock(priv);
return handle;
}
#endif
/****************************************************************************
* Name: pcf8574_detach
*
* Description:
* Detach and disable a pin interrupt callback function.
*
* Input Parameters:
* dev - Device-specific state data
* handle - The non-NULL opaque value return by pcf8574_attch()
*
* Returned Value:
* 0 on success, else a negative error code
*
****************************************************************************/
#ifdef CONFIG_PCF8574_INT_ENABLE
static int pcf8574_detach(FAR struct ioexpander_dev_s *dev, FAR void *handle)
{
FAR struct pcf8574_dev_s *priv = (FAR struct pcf8574_dev_s *)dev;
FAR struct pcf8574_callback_s *cb = (FAR struct pcf8574_callback_s *)handle;
DEBUGASSERT(priv != NULL && cb != NULL);
DEBUGASSERT((uintptr_t)cb >= (uintptr_t)&priv->cb[0] &&
(uintptr_t)cb <= (uintptr_t)&priv->cb[CONFIG_PCF8574_INT_NCALLBACKS-1]);
UNUSED(priv);
cb->pinset = 0;
cb->cbfunc = NULL;
cb->cbarg = NULL;
return OK;
}
#endif
/****************************************************************************
* Name: pcf8574_int_update
*
* Description:
* Check for pending interrupts.
*
****************************************************************************/
#ifdef CONFIG_PCF8574_INT_ENABLE
static void pcf8574_int_update(void *handle, uint8_t input)
{
struct pcf8574_dev_s *priv = handle;
irqstate_t flags;
uint8_t diff;
int pin;
flags = enter_critical_section();
/* Check the changed bits from last read */
diff = priv->input ^ input;
priv->input = input;
/* PCF8574 doesn't support irq trigger, we have to do this in software. */
for (pin = 0; pin < 8; pin++)
{
if (PCF8574_EDGE_SENSITIVE(priv, pin))
{
/* Edge triggered. Was there a change in the level? */
if ((diff & 1) != 0)
{
/* Set interrupt as a function of edge type */
if (((input & 1) == 0 && PCF8574_EDGE_FALLING(priv, pin)) ||
((input & 1) != 0 && PCF8574_EDGE_RISING(priv, pin)))
{
priv->intstat |= 1 << pin;
}
}
}
else /* if (PCF8574_LEVEL_SENSITIVE(priv, pin)) */
{
/* Level triggered. Set intstat if match in level type. */
if (((input & 1) != 0 && PCF8574_LEVEL_HIGH(priv, pin)) ||
((input & 1) == 0 && PCF8574_LEVEL_LOW(priv, pin)))
{
priv->intstat |= 1 << pin;
}
}
diff >>= 1;
input >>= 1;
}
leave_critical_section(flags);
}
#endif
/****************************************************************************
* Name: tc64_update_registers
*
* Description:
* Read all pin states and update pending interrupts.
*
* Input Parameters:
* dev - Device-specific state data
* pins - The list of pin indexes to alter in this call
* val - The list of pin levels.
*
* Returned Value:
* 0 on success, else a negative error code
*
****************************************************************************/
#ifdef CONFIG_PCF8574_INT_ENABLE
static void pcf8574_register_update(FAR struct pcf8574_dev_s *priv)
{
uint8_t regval;
int ret;
/* Read from the PCF8574 port.
*
* The Input Port Register reflects the incoming logic levels of the pins,
* regardless of whether the pin is defined as an input or an output by
* the Configuration Register. They act only on read operation.
*/
ret = pcf8574_read(priv, &regval);
if (ret < 0)
{
gpioerr("ERROR: Failed to read port register: %d\n", ret);
}
else
{
/* Update the input status with the 8 bits read from the expander */
pcf8574_int_update(priv, regval);
}
}
#endif
/****************************************************************************
* Name: pcf8574_irqworker
*
* Description:
* Handle GPIO interrupt events (this function actually executes in the
* context of the worker thread).
*
****************************************************************************/
#ifdef CONFIG_PCF8574_INT_ENABLE
static void pcf8574_irqworker(void *arg)
{
FAR struct pcf8574_dev_s *priv = (FAR struct pcf8574_dev_s *)arg;
uint8_t pinset;
int ret;
int i;
DEBUGASSERT(priv != NULL && priv->config != NULL);
/* Check for pending interrupts */
pcf8574_lock(priv);
pcf8574_register_update(priv);
/* Sample and clear the pending interrupts. */
pinset = priv->intstat;
priv->intstat = 0;
pcf8574_unlock(priv);
/* Perform pin interrupt callbacks */
for (i = 0; i < CONFIG_PCF8574_INT_NCALLBACKS; i++)
{
/* Is this entry valid (i.e., callback attached)? */
if (priv->cb[i].cbfunc != NULL)
{
/* Did any of the requested pin interrupts occur? */
ioe_pinset_t match = pinset & priv->cb[i].pinset;
if (match != 0)
{
/* Yes.. perform the callback */
priv->cb[i].cbfunc(&priv->dev, match,
priv->cb[i].cbarg);
}
}
}
#ifdef CONFIG_PCF8574_INT_POLL
/* Check for pending interrupts */
pcf8574_register_update(priv);
/* Re-start the poll timer */
sched_lock();
ret = wd_start(priv->wdog, PCF8574_POLLDELAY, (wdentry_t)pcf8574_poll_expiry,
1, (wdparm_t)priv);
if (ret < 0)
{
gpioerr("ERROR: Failed to start poll timer\n");
}
#endif
/* Re-enable interrupts */
priv->config->enable(priv->config, true);
#ifdef CONFIG_PCF8574_INT_POLL
sched_unlock();
#endif
}
#endif
/****************************************************************************
* Name: pcf8574_interrupt
*
* Description:
* Handle GPIO interrupt events (this function executes in the
* context of the interrupt).
*
****************************************************************************/
#ifdef CONFIG_PCF8574_INT_ENABLE
static void pcf8574_interrupt(FAR void *arg)
{
FAR struct pcf8574_dev_s *priv = (FAR struct pcf8574_dev_s *)arg;
DEBUGASSERT(priv != NULL && priv->config != NULL);
/* Defer interrupt processing to the worker thread. This is not only
* much kinder in the use of system resources but is probably necessary
* to access the I/O expander device.
*
* Notice that further GPIO interrupts are disabled until the work is
* actually performed. This is to prevent overrun of the worker thread.
* Interrupts are re-enabled in pcf8574_irqworker() when the work is
* completed.
*/
if (work_available(&priv->work))
{
#ifdef CONFIG_PCF8574_INT_POLL
/* Cancel the poll timer */
wd_cancel(priv->wdog);
#endif
/* Disable interrupts */
priv->config->enable(priv->config, false);
/* Schedule interrupt related work on the high priority worker thread. */
work_queue(HPWORK, &priv->work, pcf8574_irqworker,
(FAR void *)priv, 0);
}
}
#endif
/****************************************************************************
* Name: pcf8574_poll_expiry
*
* Description:
* The poll timer has expired; check for missed interrupts
*
* Input Parameters:
* Standard wdog expiration arguments.
*
****************************************************************************/
#if defined(CONFIG_PCF8574_INT_ENABLE) && defined(CONFIG_PCF8574_INT_POLL)
static void pcf8574_poll_expiry(int argc, wdparm_t arg1, ...)
{
FAR struct pcf8574_dev_s *priv;
DEBUGASSERT(argc == 1);
priv = (FAR struct pcf8574_dev_s *)arg1;
DEBUGASSERT(priv != NULL && priv->config != NULL);
/* Defer interrupt processing to the worker thread. This is not only
* much kinder in the use of system resources but is probably necessary
* to access the I/O expander device.
*
* Notice that further GPIO interrupts are disabled until the work is
* actually performed. This is to prevent overrun of the worker thread.
* Interrupts are re-enabled in pcf8574_irqworker() when the work is
* completed.
*/
if (work_available(&priv->work))
{
/* Disable interrupts */
priv->config->enable(priv->config, false);
/* Schedule interrupt related work on the high priority worker thread. */
work_queue(HPWORK, &priv->work, pcf8574_irqworker,
(FAR void *)priv, 0);
}
}
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: pcf8574_initialize
*
* Description:
* Instantiate and configure the PCF8574xx device driver to use the provided
* I2C device instance.
*
* Input Parameters:
* i2c - An I2C driver instance
* minor - The device i2c address
* config - Persistent board configuration data
*
* Returned Value:
* an ioexpander_dev_s instance on success, NULL on failure.
*
****************************************************************************/
FAR struct ioexpander_dev_s *pcf8574_initialize(FAR struct i2c_master_s *i2c,
FAR struct pcf8574_config_s *config)
{
FAR struct pcf8574_dev_s *priv;
int ret;
#ifdef CONFIG_PCF8574_MULTIPLE
/* Allocate the device state structure */
priv = (FAR struct pcf8574_dev_s *)kmm_zalloc(sizeof(struct pcf8574_dev_s));
if (!priv)
{
gpioerr("ERROR: Failed to allocate driver instance\n");
return NULL;
}
#else
/* Use the one-and-only I/O Expander driver instance */
priv = &g_pcf8574;
#endif
/* Initialize the device state structure */
priv->dev.ops = &g_pcf8574_ops;
priv->i2c = i2c;
priv->config = config;
#ifdef CONFIG_PCF8574_INT_ENABLE
/* Initial interrupt state: Edge triggered on both edges */
priv->trigger = 0xff; /* All edge triggered */
priv->level[0] = 0xff; /* All rising edge */
priv->level[1] = 0xff; /* All falling edge */
#ifdef CONFIG_PCF8574_INT_POLL
/* Set up a timer to poll for missed interrupts */
priv->wdog = wd_create();
DEBUGASSERT(priv->wdog != NULL);
ret = wd_start(priv->wdog, PCF8574_POLLDELAY, (wdentry_t)pcf8574_poll_expiry,
1, (wdparm_t)priv);
if (ret < 0)
{
gpioerr("ERROR: Failed to start poll timer\n");
}
#endif
/* Attach the I/O expander interrupt handler and enable interrupts */
priv->config->attach(config, pcf8574_interrupt, priv);
priv->config->enable(config, true);
#endif
nxsem_init(&priv->exclsem, 0, 1);
return &priv->dev;
}
#endif /* CONFIG_IOEXPANDER_PCF8574 */
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