upm/src/abp/abp.c
Abhishek Malik 8d43c431f2 ABP: Making driver generic
Signed-off-by: Abhishek Malik <abhishek.malik@intel.com>
2017-04-04 14:34:11 -07:00

145 lines
4.5 KiB
C

/*
* Author: Abhishek Malik <abhishek.malik@intel.com>
* Copyright (c) 2017 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 "abp.h"
abp_context abp_init(uint8_t bus, uint8_t dev_address){
// make sure MRAA is initialized
int mraa_rv;
if ((mraa_rv = mraa_init()) != MRAA_SUCCESS)
{
printf("%s: mraa_init() failed (%d).\n", __FUNCTION__, mraa_rv);
return NULL;
}
abp_context dev =
(abp_context) malloc(sizeof(struct _abp_context));
if (!dev)
{
return NULL;
}
// initialize the I2C bus
dev->i2c_bus_number = bus;
dev->address = dev_address;
dev->i2c = mraa_i2c_init(dev->i2c_bus_number);
if (dev->i2c == NULL){
free(dev);
return NULL;
}
if (mraa_i2c_address(dev->i2c, dev->address) != MRAA_SUCCESS)
{
mraa_i2c_stop(dev->i2c);
free(dev);
return NULL;
}
// setting up defaults
dev->abp_pressure_max = 5;
dev->abp_pressure_min = 0;
return dev;
}
void abp_close(abp_context dev){
free(dev);
}
void abp_set_max_pressure(abp_context dev, int max) {
dev->abp_pressure_max = max;
}
void abp_set_min_pressure(abp_context dev, int min) {
dev->abp_pressure_min = min;
}
upm_result_t abp_update(abp_context dev) {
int ret;
// the first 4 bytes are of interest to us
ret = mraa_i2c_read(dev->i2c, dev->readings, 4);
if (ret == -1)
return UPM_ERROR_OPERATION_FAILED;
// the two MSBs are status bits
// S1 S0 Status
// 0 0 Normal operation, valid data
// 0 1 Device in command mode
// 1 0 Stale Data
// 1 1 Diagnostic condition
uint8_t status = (dev->readings[0] >> 6) & 0x03;
if(status == 1) {
dev->status = COMMAND_MODE;
return UPM_ERROR_UNSPECIFIED;
} else if(status == 2) {
dev->status = STALE_DATA;
return UPM_ERROR_UNSPECIFIED;
} else if(status == 3) {
dev->status = DIAGNOSTIC;
return UPM_ERROR_UNSPECIFIED;
} else
dev->status = NORMAL_OPERATION;
return UPM_SUCCESS;
}
float abp_get_pressure(abp_context dev) {
float pressure_comp;
if(dev->status != NORMAL_OPERATION) {
printf("Error: Data might not be correct\n");
}
int output = (dev->readings[0]&ABP_PRESSURE_HIGH_BYTE_MASK)*256 + dev->readings[1];
// Formula as per the data sheet
// output(% of 2^14 counts) = (((output(90% counts) - output(10% counts))/Pmax - Pmin)*(Papplied - Pmin)) + output(10% count)
// based on the formula we can calculate the pressure
// Papplied = ((output(counts) - output(10% count))*(Pmax - Pmin))/(output(90% counts) - output(10% counts)) + Pmin
pressure_comp = ((((float)output - OUTPUT_10_PERCENT_COUNT)*
(dev->abp_pressure_max - dev->abp_pressure_min))/
(OUTPUT_90_PERCENT_COUNT - OUTPUT_10_PERCENT_COUNT)) +
dev->abp_pressure_min;
return pressure_comp;
}
float abp_get_temperature(abp_context dev) {
float temp_comp;
if(dev->status != NORMAL_OPERATION) {
printf("Error: Data might not be correct\n");
}
int output = (((dev->readings[2] << 8)|(dev->readings[3])) >>
ABP_TEMPERATURE_LOW_BYTE_SHIFT)&ABP_TEMPERATURE_MASK;
// Formula as per datasheet:
// Temperature(C) = ((Output(decimal)/2047)*200) - 50
temp_comp = (((float)output/2047)*200) - 50;
return temp_comp;
}