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px4-firmware/nuttx/drivers/input/stmpe811_adc.c

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/****************************************************************************
* drivers/input/stmpe811_adc.c
*
* Copyright (C) 2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* References:
* "STMPE811 S-Touch® advanced resistive touchscreen controller with 8-bit
* GPIO expander," Doc ID 14489 Rev 6, CD00186725, STMicroelectronics"
*
* 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 <unistd.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <nuttx/input/stmpe811.h>
#include "stmpe811.h"
#if defined(CONFIG_INPUT) && defined(CONFIG_INPUT_STMPE811) && !defined(CONFIG_STMPE811_ADC_DISABLE)
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: stmpe811_adcinitialize
*
* Description:
* Configure for ADC mode operation. Set overall ADC ADC timing that
* applies to all pins.
*
* Input Parameters:
* handle - The handle previously returned by stmpe811_instantiate
*
* Returned Value:
* Zero is returned on success. Otherwise, a negated errno value is
* returned to indicate the nature of the failure.
*
****************************************************************************/
int stmpe811_adcinitialize(STMPE811_HANDLE handle)
{
FAR struct stmpe811_dev_s *priv = (FAR struct stmpe811_dev_s *)handle;
uint8_t regval;
int ret;
DEBUGASSERT(handle);
/* Get exclusive access to the device structure */
ret = sem_wait(&priv->exclsem);
if (ret < 0)
{
int errval = errno;
idbg("sem_wait failed: %d\n", errval);
return -errval;
}
/* Enable Clocking for ADC */
regval = stmpe811_getreg8(priv, STMPE811_SYS_CTRL2);
regval &= ~SYS_CTRL2_ADC_OFF;
stmpe811_putreg8(priv, STMPE811_SYS_CTRL2, regval);
/* Select Sample Time, bit number and ADC Reference */
stmpe811_putreg8(priv, STMPE811_ADC_CTRL1, priv->config->ctrl1);
/* Wait for 20 ms */
up_mdelay(20);
/* Select the ADC clock speed */
stmpe811_putreg8(priv, STMPE811_ADC_CTRL2, priv->config->ctrl2);
/* Mark ADC initialized */
priv->flags |= STMPE811_FLAGS_ADC_INITIALIZED;
sem_post(&priv->exclsem);
return OK;
}
/****************************************************************************
* Name: stmpe811_adcconfig
*
* Description:
* Configure a pin for ADC input.
*
* Input Parameters:
* handle - The handle previously returned by stmpe811_instantiate
* pin - The ADC pin number
*
* Returned Value:
* Zero is returned on success. Otherwise, a negated errno value is
* returned to indicate the nature of the failure.
*
****************************************************************************/
int stmpe811_adcconfig(STMPE811_HANDLE handle, int pin)
{
FAR struct stmpe811_dev_s *priv = (FAR struct stmpe811_dev_s *)handle;
uint8_t pinmask = GPIO_PIN(pin);
uint8_t regval;
int ret;
DEBUGASSERT(handle && (unsigned)pin < STMPE811_ADC_NPINS);
/* Get exclusive access to the device structure */
ret = sem_wait(&priv->exclsem);
if (ret < 0)
{
int errval = errno;
idbg("sem_wait failed: %d\n", errval);
return -errval;
}
/* Make sure that the pin is not already in use */
if ((priv->inuse & pinmask) != 0)
{
idbg("PIN%d is already in-use\n", pin);
sem_post(&priv->exclsem);
return -EBUSY;
}
/* Clear the alternate function bit for the pin, making it an ADC input
* (or perhaps an an external reference, depending on the state of the
* ADC_CTRL1_REF_SEL bit).
*/
regval = stmpe811_getreg8(priv, STMPE811_GPIO_AF);
regval &= ~pinmask;
stmpe811_putreg8(priv, STMPE811_GPIO_AF, regval);
/* Mark the pin as 'in use' */
priv->inuse |= pinmask;
sem_post(&priv->exclsem);
return OK;
}
/****************************************************************************
* Name: stmpe811_adcread
*
* Description:
* Read the converted analog input value from the select pin.
*
* Input Parameters:
* handle - The handle previously returned by stmpe811_instantiate
* pin - The ADC pin number
*
* Returned Value:
* The converted value (there is no error reporting mechanism).
*
****************************************************************************/
uint16_t stmpe811_adcread(STMPE811_HANDLE handle, int pin)
{
FAR struct stmpe811_dev_s *priv = (FAR struct stmpe811_dev_s *)handle;
uint8_t pinmask = GPIO_PIN(pin);
uint8_t regval;
int i;
int ret;
DEBUGASSERT(handle && (unsigned)pin < 8);
/* Get exclusive access to the device structure */
ret = sem_wait(&priv->exclsem);
if (ret < 0)
{
int errval = errno;
idbg("sem_wait failed: %d\n", errval);
return -errval;
}
/* Request AD conversion by setting the bit corresponding the pin in the
* ADC CAPT register.
*/
stmpe811_putreg8(priv, STMPE811_ADC_CAPT, pinmask);
/* Wait for the conversion to complete. The ADC CAPT register reads '1'
* if conversion is completed. Reads '0' if conversion is in progress.
* Try three times before giving up.
*/
for (i = 0; i < 3; i++)
{
/* The worst case ADC conversion time is (nominally) 56.4 uS. The
* following usleep() looks nice but in reality, the usleep()
* does not have that kind of precision (it will probably end up
* waiting 10 MS).
*/
usleep(57);
/* Check if the conversion is complete */
regval = stmpe811_getreg8(priv, STMPE811_ADC_CAPT);
if ((regval & pinmask) != 0)
{
break;
}
}
/* At the completion of the conversion, return whatever we read from
* from the channel register associated with the pin.
*/
return stmpe811_getreg16(priv, STMPE811_ADC_DATACH(pin));
}
#endif /* CONFIG_INPUT && CONFIG_INPUT_STMPE811 && !CONFIG_STMPE811_ADC_DISABLE */
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