ABP: Making driver generic

Signed-off-by: Abhishek Malik <abhishek.malik@intel.com>

src/abp/abp.c

@@ -0,0 +1,144 @@
+/*
+ * 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;
+}