--- /dev/null
+/**
+ * @file bbb_pin.c
+ * @purpose Implementation of BBB pin control functions and structures
+ * THIS CODE IS NOT THREADSAFE
+ */
+
+#include "bbb_pin.h"
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+/**
+ * Structure to represent a GPIO pin
+ * Note: Only accessable to this file; to use the functions pass a GPIOId
+ */
+typedef struct
+{
+ int fd_value;
+ int fd_direction;
+} GPIO_Pin;
+
+/**
+ * Structure to represent an ADC pin
+ * Note: Only accessable to this file; to use the functions pass a ADCId
+ */
+typedef struct
+{
+ FILE * file_value;
+} ADC_Pin;
+
+/**
+ * Structure to represent a PWM pin
+ * Note: Only accessable to this file; to use the functions pass a PWMId
+ */
+typedef struct
+{
+ int fd_run;
+ FILE * file_duty;
+ FILE * file_period;
+ int fd_polarity;
+} PWM_Pin;
+
+/** Array of GPIO pins **/
+static GPIO_Pin g_gpio[GPIO_NUM_PINS] = {{0}};
+/** Array of ADC pins **/
+static ADC_Pin g_adc[ADC_NUM_PINS] = {{0}};
+/** Array of PWM pins **/
+static PWM_Pin g_pwm[PWM_NUM_PINS] = {{0}};
+
+static char g_buffer[BUFSIZ] = "";
+
+
+
+
+/**
+ * Export a GPIO pin and open the file descriptors
+ */
+void GPIO_Export(int pin)
+{
+ if (pin < 0 || pin > GPIO_NUM_PINS)
+ Fatal("Invalid pin number %d", pin);
+
+
+
+ // Export the pin
+ sprintf(g_buffer, "%s/export", GPIO_DEVICE_PATH);
+ FILE * export = fopen(g_buffer, "w");
+ if (export == NULL)
+ Fatal("Couldn't open %s to export GPIO pin %d - %s", g_buffer, pin, strerror(errno));
+
+ fprintf(export, "%d", pin);
+ fclose(export);
+
+ // Setup direction file descriptor
+ sprintf(g_buffer, "%s/gpio%d/direction", GPIO_DEVICE_PATH, pin);
+ g_gpio[pin].fd_direction = open(g_buffer, O_RDWR);
+ if (g_gpio[pin].fd_direction < 0)
+ Fatal("Couldn't open %s for GPIO pin %d - %s", g_buffer, pin, strerror(errno));
+
+
+ // Setup value file descriptor
+ sprintf(g_buffer, "%s/gpio%d/value", GPIO_DEVICE_PATH, pin);
+ g_gpio[pin].fd_value = open(g_buffer, O_RDWR);
+ if (g_gpio[pin].fd_value < 0)
+ Fatal("Couldn't open %s for GPIO pin %d - %s", g_buffer, pin, strerror(errno));
+}
+
+/**
+ * Unexport a GPIO pin and close its' file descriptors
+ */
+void GPIO_Unexport(int pin)
+{
+
+ if (pin < 0 || pin > GPIO_NUM_PINS)
+ Fatal("Invalid pin number %d", pin);
+
+ // Close file descriptors
+ close(g_gpio[pin].fd_value);
+ close(g_gpio[pin].fd_direction);
+
+ // Unexport the pin
+
+ if (g_buffer[0] == '\0')
+ sprintf(g_buffer, "%s/unexport", GPIO_DEVICE_PATH);
+ FILE * export = fopen(g_buffer, "w");
+ if (export == NULL)
+ Fatal("Couldn't open %s to export GPIO pin %d - %s", g_buffer, pin, strerror(errno));
+
+ fprintf(export, "%d", pin);
+ fclose(export);
+}
+
+
+
+
+/**
+ * Export all PWM pins and open file descriptors
+ * @param pin - The pin number
+ */
+void PWM_Export(int pin)
+{
+ if (pin < 0 || pin > PWM_NUM_PINS)
+ Fatal("Invalid pin number %d", pin);
+
+ // Export the pin
+ sprintf(g_buffer, "%s/export", PWM_DEVICE_PATH);
+ FILE * export = fopen(g_buffer, "w");
+ if (export == NULL)
+ Fatal("Couldn't open %s to export PWM pin %d - %s", g_buffer, pin, strerror(errno));
+
+ fprintf(export, "%d", pin);
+ fclose(export);
+
+ // Open file descriptors
+ sprintf(g_buffer, "%s/pwm%d/run", PWM_DEVICE_PATH, pin);
+ g_pwm[pin].fd_run = open(g_buffer, O_WRONLY);
+ if (g_pwm[pin].fd_run < 0)
+ Fatal("Couldn't open %s for PWM pin %d - %s", g_buffer, pin, strerror(errno));
+
+ sprintf(g_buffer, "%s/pwm%d/polarity",PWM_DEVICE_PATH, pin);
+ g_pwm[pin].fd_polarity = open(g_buffer, O_WRONLY);
+ if (g_pwm[pin].fd_polarity < 0)
+ Fatal("Couldn't open %s for PWM pin %d - %s", g_buffer, pin, strerror(errno));
+
+ sprintf(g_buffer, "%s/pwm%d/period_ns",PWM_DEVICE_PATH, pin);
+ g_pwm[pin].file_period = fopen(g_buffer, "w");
+ if (g_pwm[pin].file_period == NULL)
+ Fatal("Couldn't open %s for PWM pin %d - %s", g_buffer, pin, strerror(errno));
+
+ sprintf(g_buffer, "%s/pwm%d/duty_ns",PWM_DEVICE_PATH, pin);
+ g_pwm[pin].file_duty = fopen(g_buffer, "w");
+ if (g_pwm[pin].file_duty == NULL)
+ Fatal("Couldn't open %s for PWM pin %d - %s", g_buffer, pin, strerror(errno));
+
+ // Don't buffer the streams
+ setbuf(g_pwm[pin].file_period, NULL);
+ setbuf(g_pwm[pin].file_duty, NULL);
+
+
+}
+
+/**
+ * Unexport a PWM pin and close its file descriptors
+ * @param pin - The pin number
+ */
+void PWM_Unexport(int pin)
+{
+ if (pin < 0 || pin > PWM_NUM_PINS)
+ Fatal("Invalid pin number %d", pin);
+
+ // Close the file descriptors
+ close(g_pwm[pin].fd_polarity);
+ close(g_pwm[pin].fd_run);
+ fclose(g_pwm[pin].file_period);
+ fclose(g_pwm[pin].file_duty);
+
+ //Unexport the pin
+ sprintf(g_buffer, "%s/unexport", PWM_DEVICE_PATH);
+ FILE * export = fopen(g_buffer, "w");
+ if (export == NULL)
+ Fatal("Couldn't open %s to unexport PWM pin %d - %s", g_buffer, pin, strerror(errno));
+
+ fprintf(export, "%d", pin);
+ fclose(export);
+
+
+}
+
+/**
+ * Export ADC pins; http://beaglebone.cameon.net/home/reading-the-analog-inputs-adc
+ * Can't use sysfs like GPIO or PWM pins
+ * Bloody annoying how inconsistent stuff is on the Beaglebone
+ */
+void ADC_Export()
+{
+
+ FILE * export = fopen(ADC_EXPORT_PATH, "w");
+ if (export == NULL)
+ Fatal("Couldn't open %s to export ADCs - %s", ADC_EXPORT_PATH, strerror(errno));
+
+ fprintf(export, "cape-bone-iio");
+ fclose(export);
+
+ for (int i = 0; i < ADC_NUM_PINS; ++i)
+ {
+ sprintf(g_buffer, "%s/AIN%d", ADC_DEVICE_PATH, i);
+ g_adc[i].file_value = fopen(g_buffer, "r");
+ if (g_adc[i].file_value == NULL)
+ Fatal("Couldn't open ADC %d device file %s - %s", i, g_buffer, strerror(errno));
+
+ setbuf(g_adc[i].file_value, NULL);
+
+ }
+}
+
+/**
+ * Unexport ADC pins
+ */
+void ADC_Unexport()
+{
+ for (int i = 0; i < ADC_NUM_PINS; ++i)
+ fclose(g_adc[i].file_value);
+}
+
+/**
+ * Set a GPIO pin
+ * @param pin - The pin to set. MUST have been exported before calling this function.
+ */
+void GPIO_Set(int pin, bool value)
+{
+ if (pwrite(g_gpio[pin].fd_direction, "out", 3*sizeof(char), 0) != 3)
+ Fatal("Couldn't set GPIO %d direction - %s", pin, strerror(errno));
+
+ char c = '0' + (value);
+ if (pwrite(g_gpio[pin].fd_value, &c, 1*sizeof(char), 0) != 1)
+ Fatal("Couldn't read GPIO %d value - %s", pin, strerror(errno));
+
+}
+
+/**
+ * Read from a GPIO Pin
+ * @param pin - The pin to read
+ */
+bool GPIO_Read(int pin)
+{
+ if (pwrite(g_gpio[pin].fd_direction, "in", 2*sizeof(char), 0) != 2)
+ Fatal("Couldn't set GPIO %d direction - %s", pin, strerror(errno));
+ char c = '0';
+ if (pread(g_gpio[pin].fd_value, &c, 1*sizeof(char), 0) != 1)
+ Fatal("Couldn't read GPIO %d value - %s", pin, strerror(errno));
+
+ return (c == '1');
+
+}
+
+/**
+ * Activate a PWM pin
+ * @param pin - The pin to activate
+ * @param polarity - if true, pin is active high, else active low
+ * @param period - The period in ns
+ * @param duty - The time the pin is active in ns
+ */
+void PWM_Set(int pin, bool polarity, long period, long duty)
+{
+ // Have to stop PWM before changing it
+ if (pwrite(g_pwm[pin].fd_run, "0", 1*sizeof(char), 0) != 1)
+ Fatal("Couldn't stop PWM %d - %s", pin, strerror(errno));
+
+ char c = '0' + polarity;
+ if (pwrite(g_pwm[pin].fd_polarity, &c, 1*sizeof(char), 0) != 1)
+ Fatal("Couldn't set PWM %d polarity - %s", pin, strerror(errno));
+
+
+ rewind(g_pwm[pin].file_period);
+ rewind(g_pwm[pin].file_duty);
+
+ if (fprintf(g_pwm[pin].file_duty, "%lu", duty) == 0)
+ Fatal("Couldn't set duty cycle for PWM %d - %s", pin, strerror(errno));
+
+ if (fprintf(g_pwm[pin].file_period, "%lu", period) == 0)
+ Fatal("Couldn't set period for PWM %d - %s", pin, strerror(errno));
+
+ if (pwrite(g_pwm[pin].fd_run, "1", 1*sizeof(char), 0) != 1)
+ Fatal("Couldn't start PWM %d - %s", pin, strerror(errno));
+
+}
+
+/**
+ * Deactivate a PWM pin
+ * @param pin - The pin to turn off
+ */
+void PWM_Stop(int pin)
+{
+ if (pwrite(g_pwm[pin].fd_run, "0", 1*sizeof(char), 0) != 1)
+ Fatal("Couldn't stop PWM %d - %s", pin, strerror(errno));
+
+}
+
+/**
+ * Read an ADC value
+ * @param id - The ID of the ADC pin to read
+ * @returns - The reading of the ADC channel
+ */
+long ADC_Read(int id)
+{
+
+ //Log(LOGDEBUG, "Called for pin %d", id);
+ char adc_val[ADC_DIGITS] = "";
+ rewind(g_adc[id].file_value);
+ fgets(adc_val, sizeof(adc_val)/sizeof(char), g_adc[id].file_value);
+ for(int i = ADC_DIGITS-1; i > 0; --i)
+ {
+ if (adc_val[i] == '\n')
+ adc_val[i] = '\0';
+ }
+
+ char * end;
+ long val = strtol(adc_val, &end, 10);
+ if (*end != '\0')
+ {
+ Log(LOGERR, "Reading ADC%d gives %s - invalid!", id, adc_val);
+ }
+ //Log(LOGDEBUG, "Returns %lu", val);
+ return val;
+}
git.ucc.asn.au / matches / MCTX3420.git / blobdiff
UCC git Repository :: git.ucc.asn.au