Raspberries/mraa
Private
Public Access
2
0
Fork 0
Code Activity

aio: add initial analog input support

Browse Source 
Signed-off-by: Nandkishor Sonar <nandkishor.sonar@intel.com>
Reviewed-by: Brendan Le Foll <brendan.le.foll@intel.com>
This commit is contained in:
Nandkishor Sonar
2014-05-01 16:36:11 +01:00
committed by Brendan Le Foll
parent 8c016318a6
commit 207c54a5e7
5 changed files with 333 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

82
api/aio.h Normal file
View File

@@ -0,0 +1,82 @@
/*
* Author: Nandkishor Sonar
* Copyright (c) 2014 Intel Corporation.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#pragma once
#include <stdio.h>
#include <fcntl.h>
#include "maa.h"
#include "gpio.h"
#define TOTAL_ANALOG_INPUTS_ON_BOARD (6)
static const unsigned int A0 = 0;
static const unsigned int A1 = 1;
static const unsigned int A2 = 2;
static const unsigned int A3 = 3;
static const unsigned int A4 = 4;
static const unsigned int A5 = 5;
#define ADC_RAW_RESOLUTION_BITS (12)
#define ADC_SUPPORTED_RESOLUTION_BITS (10)
#define ADC_COMMON_GATE_A4_A5 (29)
static const unsigned int
adc_gate_pins[TOTAL_ANALOG_INPUTS_ON_BOARD] = {37, 36, 23, 22, 21, 20};
typedef struct {
unsigned int channel;
FILE *adc_in_fp;
} maa_aio_context;
/** Initialise an Analog input device, connected to the specified pin
*
* @param aio_channel channel number to read ADC inputs
*
* @returns pointer to maa_aio_context structure after initialisation of Analog
* input pin successfully, else returns null.
*/
maa_aio_context* maa_aio_init(unsigned int aio_channel);
/** Read the input voltage, represented as an unsigned short in the range [0x0,
* 0xFFFF]
*
* @param dev - pointer to maa_aio_context structure initialised by
* maa_aio_init()
*
* @returns 16-bit unsigned integer representing the current input voltage,
* normalised to a 16-bit value
*/
unsigned int maa_aio_read_u16(maa_aio_context* dev);
/** Close the analog input context
* - Will free the memory for the context.
*
* @param dev - pointer to maa_aio_context structure initialised by
* maa_aio_init()
*
* @return maa_result_t - result type.
*/
maa_result_t maa_aio_close(maa_aio_context* dev);

2
examples/CMakeLists.txt
View File

@@ -2,6 +2,7 @@ add_executable (i2c_HMC5883L i2c_HMC5883L.c)
add_executable (hellomaa hellomaa.c)
add_executable (cycle-pwm3 cycle-pwm3.c)
add_executable (blink-io8 blink-io8.c)
add_executable (analogin_a0 analogin_a0.c)
include_directories(${PROJECT_SOURCE_DIR}/api ${PROJECT_SOURCE_DIR}/include)
@@ -9,3 +10,4 @@ target_link_libraries (hellomaa maa)
target_link_libraries (i2c_HMC5883L maa m)
target_link_libraries (cycle-pwm3 maa)
target_link_libraries (blink-io8 maa)
target_link_libraries (analogin_a0 maa)

48
examples/analogin_a0.c Normal file
View File

@@ -0,0 +1,48 @@
/*
* Author: Nandkishor Sonar
* Copyright (c) 2014 Intel Corporation.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include <unistd.h>
#include "aio.h"
int main ()
{
maa_aio_context* adc_a0;
unsigned int adc_value = 0;
int i = 0;
adc_a0 = maa_aio_init(A0);
if (adc_a0 == NULL) {
return 1;
}
for(i = 0; i < 10; i++) {
adc_value = maa_aio_read_u16(adc_a0);
fprintf(stdout, "ADC A0 read %X\n", adc_value);
}
maa_aio_close(adc_a0);
return MAA_SUCCESS;
}

2
src/CMakeLists.txt
View File

@@ -9,6 +9,7 @@ set (maa_LIB_HEADERS
${PROJECT_SOURCE_DIR}/api/i2c.h
${PROJECT_SOURCE_DIR}/api/pwm.h
${PROJECT_SOURCE_DIR}/api/spi.h
${PROJECT_SOURCE_DIR}/api/aio.h
${PROJECT_SOURCE_DIR}/include/smbus.h
${PROJECT_SOURCE_DIR}/include/version.h
)
@@ -27,6 +28,7 @@ set (maa_LIB_SRCS
${PROJECT_SOURCE_DIR}/src/i2c/smbus.c
${PROJECT_SOURCE_DIR}/src/pwm/pwm.c
${PROJECT_SOURCE_DIR}/src/spi/spi.c
${PROJECT_SOURCE_DIR}/src/aio/aio.c
# autogenerated version file
${CMAKE_CURRENT_BINARY_DIR}/version.c
)

199
src/aio/aio.c Normal file
View File

@@ -0,0 +1,199 @@
/*
* Author: Nandkishor Sonar
* Copyright (c) 2014 Intel Corporation.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include <stdlib.h>
#include "aio.h"
static maa_result_t aio_get_valid_fp(maa_aio_context* dev)
{
char file_path[64]= "";
//Open file Analog device input channel raw voltage file for reading.
snprintf(file_path, 64, "/sys/bus/iio/devices/iio:device0/in_voltage%d_raw",
dev->channel );
if (NULL == (dev->adc_in_fp = fopen(file_path, "r"))) {
fprintf(stderr, "Failed to open Analog input raw file %s for "
"reading!\n", file_path); return( MAA_ERROR_INVALID_RESOURCE);
}
return MAA_SUCCESS;
}
/** Configure multiplexer for Analog Input
*
* @param aio_channel = Analog input channel to read
*
* @return maa_result_t - result type.
*
*/
static maa_result_t maa_aio_set_mux(unsigned int aio_channel)
{
maa_result_t result;
maa_gpio_context* aio_gate;
//Initialise VINx multiplexer gate pins
aio_gate = maa_gpio_init(adc_gate_pins[aio_channel]);
if (NULL == aio_gate) {
fprintf(stderr, "Failed to initialise first gate pin %d for ADC "
"channel %d !\n", adc_gate_pins[aio_channel], aio_channel);
return MAA_ERROR_INVALID_RESOURCE;
}
//Set direction to output for the ADC input gate
result = maa_gpio_dir(aio_gate, MAA_GPIO_OUT);
if (MAA_SUCCESS == result) {
// Write gate configuration output value
result = maa_gpio_write(aio_gate, 0);
if (MAA_SUCCESS == result) {
//For A4 and A5 Analog common gate pin should be high for the
// Galileo board revision D
if (A4 == aio_channel || A5 == aio_channel) {
aio_gate = maa_gpio_init(ADC_COMMON_GATE_A4_A5);
//Set direction to output for the gate
if (NULL == aio_gate) {
fprintf(stderr, "Failed to initialise second gate pin %d "
"for ADC channel %d !\n", ADC_COMMON_GATE_A4_A5,
aio_channel);
return(MAA_ERROR_INVALID_RESOURCE);
}
result = maa_gpio_dir(aio_gate, MAA_GPIO_OUT);
if (MAA_SUCCESS == result)
// Write gate configuration output value
result = maa_gpio_write(aio_gate, 1);
}
}
}
if (NULL != aio_gate)
free(aio_gate);
return (result);
}
/** Initialise an Analog input, connected to the specified channel
*
* @param aio_channel Analog input channel to read
*
* @returns pointer to maa_aio_context structure after initialisation of
* Analog input pin connected to the device successfully, else returns NULL.
*/
maa_aio_context* maa_aio_init(unsigned int aio_channel)
{
maa_aio_context* dev;
// Validate input pins 0-5
if (aio_channel > TOTAL_ANALOG_INPUTS_ON_BOARD) {
fprintf(stderr, "Invalid Analog input channel %d specified!\n",
aio_channel);
return NULL;
}
//Set-up multiplexer for the Analog input channel
if (MAA_SUCCESS != maa_aio_set_mux(aio_channel)) {
fprintf(stderr, "Failed to set-up Analog input channel %d "
"multiplexer!\n", aio_channel); return NULL;
}
//Create ADC device connected to specified channel
dev = (maa_aio_context*) malloc(sizeof(maa_aio_context));
if (NULL == dev) {
fprintf(stderr, "Insufficient memory for specified Analog input channel "
"%d !\n", aio_channel);
return NULL;
}
dev->channel = aio_channel;
//Open valid analog input file and get the pointer.
if (MAA_SUCCESS != aio_get_valid_fp(dev)) {
free(dev);
return NULL;
}
return dev;
}
/** Read the input voltage, represented as an unsigned short in the range [0x0,
* 0xFFFF]
*
* @param pointer to maa_aio_context structure initialised by
* maa_aio_init()
*
* @returns
* 16-bit unsigned int representing the current input voltage, normalised to
* a 16-bit value
*/
unsigned int maa_aio_read_u16(maa_aio_context* dev)
{
char buffer[16] = "";
unsigned int raw_value=0;
unsigned int analog_value=0;
unsigned int shifter_value=0;
if (NULL == dev->adc_in_fp) {
aio_get_valid_fp(dev);
}
fseek(dev->adc_in_fp, SEEK_SET, 0);
fread(buffer, sizeof(buffer), 1, dev->adc_in_fp);
fseek(dev->adc_in_fp, SEEK_SET, 0);
raw_value = atoi(buffer);
/* Adjust the raw analog input reading to supported resolution value*/
if (ADC_RAW_RESOLUTION_BITS == ADC_SUPPORTED_RESOLUTION_BITS) {
analog_value = raw_value;
}
else {
if (ADC_RAW_RESOLUTION_BITS > ADC_SUPPORTED_RESOLUTION_BITS) {
shifter_value = ADC_RAW_RESOLUTION_BITS - ADC_SUPPORTED_RESOLUTION_BITS;
analog_value = raw_value >> shifter_value;
} else {
shifter_value = ADC_SUPPORTED_RESOLUTION_BITS - ADC_RAW_RESOLUTION_BITS;
analog_value = raw_value << shifter_value;
}
}
return analog_value;
}
/** Close the analog input and free context memory
*
* @param dev - the analog input context
*
* @return maa result type.
*/
maa_result_t maa_aio_close(maa_aio_context* dev)
{
if (NULL != dev)
free(dev);
return(MAA_SUCCESS);
}