common.c

/*
Copyright (c) 2013 Adafruit

Original RPi.GPIO Author Ben Croston
Modified for BBIO Author Justin Cooper
Modified for 4.1+ kernels by Grizmio
Unified for 3.8 and 4.1+ kernels by Peter Lawler <relwalretep@gmail.com>

This file incorporates work covered by the following copyright and 
permission notice, all modified code adopts the original license:

Copyright (c) 2013 Ben Croston

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.
*/

#ifndef NO_PYTHON
#  include "Python.h"
#endif // !NO_PYTHON

#include <dirent.h>
#include <errno.h>
#include <glob.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <time.h>

#include "common.h"

#include <linux/version.h>
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,1,0)
#  ifndef BBBVERSION41
#    define BBBVERSION41
#  endif
#endif

int gpio_mode;
int gpio_direction[120];

char ctrl_dir[CTRL_DIR_MAX];
char ocp_dir[OCP_DIR_MAX];

int setup_error = 0;
int module_setup = 0;

typedef struct pins_t { 
    const char *name; 
    const char *key; 
    int gpio;
    int pwm_mux_mode;
    int ain;
} pins_t;

//Table generated based on https://github.com/jadonk/bonescript/blob/master/src/bone.js
pins_t table[] = {
  { "USR0", "USR0", 53, -1, -1},
  { "USR1", "USR1", 54, -1, -1},
  { "USR2", "USR2", 55, -1, -1},
  { "USR3", "USR3", 56, -1, -1},
  { "DGND", "P8_1", 0, -1, -1},
  { "DGND", "P8_2", 0, -1, -1},
  { "GPIO1_6", "P8_3", 38, -1, -1},
  { "GPIO1_7", "P8_4", 39, -1, -1},
  { "GPIO1_2", "P8_5", 34, -1, -1},
  { "GPIO1_3", "P8_6", 35, -1, -1},
  { "TIMER4", "P8_7", 66, 2, -1},
  { "TIMER7", "P8_8", 67, 2, -1},
  { "TIMER5", "P8_9", 69, 2, -1},
  { "TIMER6", "P8_10", 68, 2, -1},
  { "GPIO1_13", "P8_11", 45, -1, -1},
  { "GPIO1_12", "P8_12", 44, -1, -1},
  { "EHRPWM2B", "P8_13", 23, 4, -1},
  { "GPIO0_26", "P8_14", 26, -1, -1},
  { "GPIO1_15", "P8_15", 47, -1, -1},
  { "GPIO1_14", "P8_16", 46, -1, -1},
  { "GPIO0_27", "P8_17", 27, -1, -1},
  { "GPIO2_1", "P8_18", 65, -1, -1},
  { "EHRPWM2A", "P8_19", 22, 4, -1},
  { "GPIO1_31", "P8_20", 63, -1, -1},
  { "GPIO1_30", "P8_21", 62, -1, -1},
  { "GPIO1_5", "P8_22", 37, -1, -1},
  { "GPIO1_4", "P8_23", 36, -1, -1},
  { "GPIO1_1", "P8_24", 33, -1, -1},
  { "GPIO1_0", "P8_25", 32, -1, -1},
  { "GPIO1_29", "P8_26", 61, -1, -1},
  { "GPIO2_22", "P8_27", 86, -1, -1},
  { "GPIO2_24", "P8_28", 88, -1, -1},
  { "GPIO2_23", "P8_29", 87, -1, -1},
  { "GPIO2_25", "P8_30", 89, -1, -1},
  { "UART5_CTSN", "P8_31", 10, -1, -1},
  { "UART5_RTSN", "P8_32", 11, -1, -1},
  { "UART4_RTSN", "P8_33", 9, -1, -1},
  { "UART3_RTSN", "P8_34", 81, 2, -1},
  { "UART4_CTSN", "P8_35", 8, -1, -1},
  { "UART3_CTSN", "P8_36", 80, 2, -1},
  { "UART5_TXD", "P8_37", 78, -1, -1},
  { "UART5_RXD", "P8_38", 79, -1, -1},
  { "GPIO2_12", "P8_39", 76, -1, -1},
  { "GPIO2_13", "P8_40", 77, -1, -1},
  { "GPIO2_10", "P8_41", 74, -1, -1},
  { "GPIO2_11", "P8_42", 75, -1, -1},
  { "GPIO2_8", "P8_43", 72, -1, -1},
  { "GPIO2_9", "P8_44", 73, -1, -1},
  { "GPIO2_6", "P8_45", 70, 3, -1},
  { "GPIO2_7", "P8_46", 71, 3, -1},
  { "DGND", "P9_1", 0, -1, -1},
  { "DGND", "P9_2", 0, -1, -1},
  { "VDD_3V3", "P9_3", 0, -1, -1},
  { "VDD_3V3", "P9_4", 0, -1, -1},
  { "VDD_5V", "P9_5", 0, -1, -1},
  { "VDD_5V", "P9_6", 0, -1, -1},
  { "SYS_5V", "P9_7", 0, -1, -1},
  { "SYS_5V", "P9_8", 0, -1, -1},
  { "PWR_BUT", "P9_9", 0, -1, -1},
  { "SYS_RESETn", "P9_10", 0, -1, -1},
  { "UART4_RXD", "P9_11", 30, -1, -1},
  { "GPIO1_28", "P9_12", 60, -1, -1},
  { "UART4_TXD", "P9_13", 31, -1, -1},
  { "EHRPWM1A", "P9_14", 50, 6, -1},
  { "GPIO1_16", "P9_15", 48, -1, -1},
  { "EHRPWM1B", "P9_16", 51, 6, -1},
  { "I2C1_SCL", "P9_17", 5, -1, -1},
  { "I2C1_SDA", "P9_18", 4, -1, -1},
  { "I2C2_SCL", "P9_19", 13, -1, -1},
  { "I2C2_SDA", "P9_20", 12, -1, -1},
  { "UART2_TXD", "P9_21", 3, 3, -1},
  { "UART2_RXD", "P9_22", 2, 3, -1},
  { "GPIO1_17", "P9_23", 49, -1, -1},
  { "UART1_TXD", "P9_24", 15, -1, -1},
  { "GPIO3_21", "P9_25", 117, -1, -1},
  { "UART1_RXD", "P9_26", 14, -1, -1},
  { "GPIO3_19", "P9_27", 115, -1, -1},
  { "SPI1_CS0", "P9_28", 113, 4, -1},
  { "SPI1_D0", "P9_29", 111, 1, -1},
  { "SPI1_D1", "P9_30", 112, -1, -1},
  { "SPI1_SCLK", "P9_31", 110, 1, -1},
  { "VDD_ADC", "P9_32", 0, -1, -1},
  { "AIN4", "P9_33", 0, -1, 4},
  { "GNDA_ADC", "P9_34", 0, -1, -1},
  { "AIN6", "P9_35", 0, -1, 6},
  { "AIN5", "P9_36", 0, -1, 5},
  { "AIN2", "P9_37", 0, -1, 2},
  { "AIN3", "P9_38", 0, -1, 3},
  { "AIN0", "P9_39", 0, -1, 0},
  { "AIN1", "P9_40", 0, -1, 1},
  { "CLKOUT2", "P9_41", 20, -1, -1},
  { "GPIO0_7", "P9_42", 7, 0, -1},
  { "DGND", "P9_43", 0, -1, -1},
  { "DGND", "P9_44", 0, -1, -1},
  { "DGND", "P9_45", 0, -1, -1},
  { "DGND", "P9_46", 0, -1, -1},
  
  // These are for the Blue
    { "GP0_3", "GP0_3",  57, -1, -1},
    { "GP0_4", "GP0_4",  49, -1, -1},
    { "GP0_5", "GP0_5", 116, -1, -1},
    { "GP0_6", "GP0_6", 113, -1, -1},
    { "GP1_3", "GP1_3",  98, -1, -1},
    { "GP1_4", "GP1_4",  97, -1, -1},
    { "RED_LED",   "RED",    66, -1, -1},   // LEDs
    { "GREEN_LED", "GREEN",  67, -1, -1},
    { "BAT25", "BAT25",  27, -1, -1},
    { "BAT50", "BAT50",  11, -1, -1},
    { "BAT75", "BAT75",  61, -1, -1},
    { "BAT100", "BAT100",  10000, -1, -1}, // Placeholder
    { "WIFI", "WIFI",  10001, -1, -1}, // Placeholder
  
    { "PAUSE", "P8_9",  69, 1, -1},
    { "MODE",  "P8_10", 68, 1, -1},
  
  // These are for the PocketBeagle
  { "VIN_AC", "P1_1", 0, -1, -1},
  { "GPIO2_23", "P1_2", 87, -1, -1},
  { "USB1_DRVVBUS", "P1_3", 0, -1, -1},
  { "GPIO2_25", "P1_4", 89, -1, -1},
  { "USB1_VBUS_IN", "P1_5", 0, -1, -1},
  { "SPI0_CS0", "P1_6", 5, -1, -1},
  { "VIN-USB", "P1_7", 0, -1, -1},
  { "SPI0_SCLK", "P1_8", 2, 3, -1},
  { "USB1-DN", "P1_9", 0, -1, -1},
  { "SPI0_D0", "P1_10", 3, 3, -1},
  { "USB1-DP", "P1_11", 0, -1, -1},
  { "SPI0_D1", "P1_12", 4, -1, -1},
  { "USB1-ID", "P1_13", 0, -1, -1},
  { "VOUT-3.3V", "P1_14", 0, -1, -1},
  { "GND", "P1_15", 0, -1, -1},
  { "GND", "P1_16", 0, -1, -1},
  { "VREFN", "P1_17", 0, -1, -1},
  { "VREFP", "P1_18", 0, -1, -1},
  { "AIN0", "P1_19", 0, -1, 0},
  { "GPIO0_20", "P1_20", 20, 4, -1},
  { "AIN1", "P1_21", 0, -1, 1},
  { "GND", "P1_22", 0, -1, -1},
  { "AIN2", "P1_23", 0, -1, 2},
  { "VOUT-5V", "P1_24", 0, -1, -1},
  { "AIN3", "P1_25", 0, -1, 3},
  { "I2C2_SDA", "P1_26", 12, 1, -1},
  { "AIN4", "P1_27", 0, -1, 4},
  { "I2C2_SCL", "P1_28", 13, 1, -1},
  { "GPIO3_21", "P1_29", 117, -1, -1},
  { "UART0_TXD", "P1_30", 43, -1, -1},
  { "GPIO3_18", "P1_31", 114, -1, -1},
  { "UART0_RXD", "P1_32", 42, -1, -1},
  { "GPIO3_15", "P1_33", 111, 1, -1},
  { "GPIO0_26", "P1_34", 26, -1, -1},
  { "GPIO2_24", "P1_35", 88, -1, -1},
  { "EHRPWM0A", "P1_36", 110, 1, -1},
  { "EHRPWM1A", "P2_1", 50, 6, -1},
  { "GPIO1_27", "P2_2", 59, -1, -1},
  { "GPIO0_23", "P2_3", 23, 4, -1},
  { "GPIO1_26", "P2_4", 58, -1, -1},
  { "UART4_RXD", "P2_5", 30, -1, -1},
  { "GPIO1_25", "P2_6", 57, -1, -1},
  { "UART4_TXD", "P2_7", 31, -1, -1},
  { "GPIO1_28", "P2_8", 60, -1, -1},
  { "I2C1_SCL", "P2_9", 15, -1, -1},
  { "GPIO1_20", "P2_10", 52, -1, -1},
  { "I2C1_SDA", "P2_11", 14, -1, -1},
  { "POWER_BUTTON", "P2_12", 0, -1, -1},
  { "VOUT-5V", "P2_13", 0, -1, -1},
  { "BAT-VIN", "P2_14", 0, -1, -1},
  { "GND", "P2_15", 0, -1, -1},
  { "BAT-TEMP", "P2_16", 0, -1, -1},
  { "GPIO2_1", "P2_17", 65, -1, -1},
  { "GPIO1_15", "P2_18", 47, -1, -1},
  { "GPIO0_27", "P2_19", 27, -1, -1},
  { "GPIO2_0", "P2_20", 64, -1, -1},
  { "GND", "P2_21", 0, -1, -1},
  { "GPIO1_14", "P2_22", 46, -1, -1},
  { "VOUT-3.3V", "P2_23", 0, -1, -1},
  { "GPIO1_12", "P2_24", 44, -1, -1},
  { "SPI1_CS0", "P2_25", 41, -1, -1},
  { "RESET#", "P2_26", 0, -1, -1},
  { "SPI1_D0", "P2_27", 40, 5, -1},
  { "GPIO3_20", "P2_28", 116, -1, -1},
  { "SPI1_SCLK", "P2_29", 7, -1, -1},
  { "GPIO3_17", "P2_30", 113, -1, -1},
  { "SPI1_CS1", "P2_31", 19, 2, -1},
  { "GPIO3_16", "P2_32", 112, -1, -1},
  { "GPIO1_13", "P2_33", 45, -1, -1},
  { "GPIO3_19", "P2_34", 115, -1, -1},
  { "GPIO2_22", "P2_35", 86, -1, -1},
  { "AIN7", "P2_36", 0, -1, 7},
  
  { NULL, NULL, 0, 0, 0 }
};

// Issue #243: UART setup not working for pocket beagle pins
// Add UART entries for the PocketBeagle:
//   P1_30 uart0_txd
//   P1_32 uart0_rxd
//   P2_11 uart1_rxd
//   P2_09 uart1_txd
//   P1_08 uart2_rxd
//   P1_10 uart2_txd
//   P2_05 uart4_rxd
//   P2_07 uart4_txd 

uart_t uart_table[] = {
  { "UART1", "/dev/ttyO1", "ADAFRUIT-UART1", "P9_26", "P9_24"},
  { "UART2", "/dev/ttyO2", "ADAFRUIT-UART2", "P9_22", "P9_21"},
  { "UART3", "/dev/ttyO3", "ADAFRUIT-UART3", "P9_42", ""},
  { "UART4", "/dev/ttyO4", "ADAFRUIT-UART4", "P9_11", "P9_13"},
  { "UART5", "/dev/ttyO5", "ADAFRUIT-UART5", "P8_38", "P8_37"},
  { "PB-UART0", "/dev/ttyO0", "ADAFRUIT-UART0", "P1_30", "P1_32"},
  { "PB-UART1", "/dev/ttyO1", "ADAFRUIT-UART1", "P2_11", "P2_09"},
  { "PB-UART2", "/dev/ttyO2", "ADAFRUIT-UART2", "P1_08", "P1_10"},
  { "PB-UART4", "/dev/ttyO4", "ADAFRUIT-UART4", "P2_05", "P2_07"},
  { NULL, NULL, 0, 0, 0 }
};

// Copied from https://github.com/jadonk/bonescript/blob/master/src/bone.js
// See am335x technical manual, p. 183, for more info:
// https://www.ti.com/lit/ug/spruh73q/spruh73q.pdf
pwm_t pwm_table[] = {
  { "ehrpwm2", 6, 1, 4, "ehrpwm.2:1", "EHRPWM2B", "48304000", "48304200", "P8_13"},
  { "ehrpwm2", 5, 0, 4, "ehrpwm.2:0", "EHRPWM2A", "48304000", "48304200", "P8_19"},
  { "ehrpwm1", 4, 1, 2, "ehrpwm.1:1", "EHRPWM1B", "48302000", "48302200", "P8_34"},
  { "ehrpwm1", 3, 0, 2, "ehrpwm.1:0", "EHRPWM1A", "48302000", "48302200", "P8_36"},
  { "ehrpwm2", 5, 0, 3, "ehrpwm.2:0", "EHRPWM2A", "48304000", "48304200", "P8_45"},
  { "ehrpwm2", 6, 1, 3, "ehrpwm.2:1", "EHRPWM2B", "48304000", "48304200", "P8_46"},
  { "ehrpwm1", 3, 0, 6, "ehrpwm.1:0", "EHRPWM1A", "48302000", "48302200", "P9_14"},
  { "ehrpwm1", 4, 1, 6, "ehrpwm.1:1", "EHRPWM1B", "48302000", "48302200", "P9_16"},
  { "ehrpwm0", 1, 1, 3, "ehrpwm.0:1", "EHRPWM0B", "48300000", "48300200", "P9_21"},
  { "ehrpwm0", 0, 0, 3, "ehrpwm.0:0", "EHRPWM0A", "48300000", "48300200", "P9_22"},
  {   "ecap2", 7, 0, 4, "ecap.2",     "ECAPPWM2", "48304000", "48304100", "P9_28"},
  { "ehrpwm0", 1, 1, 1, "ehrpwm.0:1", "EHRPWM0B", "48300000", "48300200", "P9_29"},
  { "ehrpwm0", 0, 0, 1, "ehrpwm.0:0", "EHRPWM0A", "48300000", "48300200", "P9_31"},
  {   "ecap0", 2, 0, 0, "ecap.0",     "ECAPPWM0", "48300000", "48300100", "P9_42"},
  { "timer4", 0, 0, 2, "", "", "", "dmtimer-pwm-4", "P8_7" },
  { "timer7", 0, 0, 2, "", "", "", "dmtimer-pwm-7", "P8_8" },
  { "timer5", 0, 0, 2, "", "", "", "dmtimer-pwm-5", "P8_9" },
  { "timer6", 0, 0, 2, "", "", "", "dmtimer-pwm-6", "P8_10" },
  { "ehrpwm0", 0, 0, 1, "ehrpwm.0:0", "EHRPWM0A", "48300000", "48300200", "P1_8"},
  { "ehrpwm0", 0, 0, 1, "ehrpwm.0:0", "EHRPWM0A", "48300000", "48300200", "P1_36"},
  { "ehrpwm0", 1, 1, 1, "ehrpwm.0:1", "EHRPWM0B", "48300000", "48300200", "P1_10"},
  { "ehrpwm0", 1, 1, 1, "ehrpwm.0:1", "EHRPWM0B", "48300000", "48300200", "P1_33"},
  { "ehrpwm1", 3, 0, 6, "ehrpwm.1:0", "EHRPWM1A", "48302000", "48302200", "P2_1"},
  { "ehrpwm2", 6, 1, 3, "ehrpwm.2:1", "EHRPWM2B", "48304000", "48304200", "P2_3"},
  { "timer7", 0, 0, 4, "", "", "", "dmtimer-pwm-7", "P1_20" },
  { "timer6", 0, 0, 1, "", "", "", "dmtimer-pwm-6", "P1_26" },
  { "timer5", 0, 0, 1, "", "", "", "dmtimer-pwm-5", "P1_28" },
  { "timer7", 0, 0, 5, "", "", "", "dmtimer-pwm-7", "P2_27" },
  { "timer4", 0, 0, 2, "", "", "", "dmtimer-pwm-4", "P2_31" },
  { NULL, 0, 0, 0, NULL, NULL, NULL, NULL, NULL }
};

int lookup_gpio_by_key(const char *key)
{
  pins_t *p;
  for (p = table; p->key != NULL; ++p) {
      if (strcmp(p->key, key) == 0) {
          return p->gpio;
      }
  }
  return 0;
}

int lookup_gpio_by_name(const char *name)
{
  pins_t *p;
  for (p = table; p->name != NULL; ++p) {
      if (strcmp(p->name, name) == 0) {
          return p->gpio;
      }
  }
  return 0;
}

int lookup_ain_by_key(const char *key)
{
  pins_t *p;
  for (p = table; p->key != NULL; ++p) {
      if (strcmp(p->key, key) == 0) {
        if (p->ain == -1) {
          return -1;
        } else {
          return p->ain;
        }
      }
  }
  return -1;
}

int lookup_ain_by_name(const char *name)
{
  pins_t *p;
  for (p = table; p->name != NULL; ++p) {
      if (strcmp(p->name, name) == 0) {
        if (p->ain == -1) {
          return -1;
        } else {
          return p->ain;
        }
      }
  }
  return -1;
}

BBIO_err lookup_uart_by_name(const char *input_name, char *dt)
{
    uart_t *p;
    for (p = uart_table; p->name != NULL; ++p) {
        if (strcmp(p->name, input_name) == 0) {
            strncpy(dt, p->dt, FILENAME_BUFFER_SIZE);
            dt[FILENAME_BUFFER_SIZE - 1] = '\0';
            return BBIO_OK;
        }
    }
    return BBIO_INVARG;
}

BBIO_err copy_pwm_key_by_key(const char *input_key, char *key)
{
    pins_t *p;
    for (p = table; p->key != NULL; ++p) {
        if (strcmp(p->key, input_key) == 0) {
            //validate it's a valid pwm pin
            if (p->pwm_mux_mode == -1)
                return BBIO_INVARG;

            strncpy(key, p->key, 7);
            key[7] = '\0';
            return BBIO_OK;                
        }
    }
    return BBIO_INVARG;
}

BBIO_err get_pwm_key_by_name(const char *name, char *key)
{
    pins_t *p;
    for (p = table; p->name != NULL; ++p) {
        if (strcmp(p->name, name) == 0) {
            //validate it's a valid pwm pin
            if (p->pwm_mux_mode == -1)
                return BBIO_INVARG;

            strncpy(key, p->key, 7);
            key[7] = '\0';
            return BBIO_OK;
        }
    }
    return BBIO_INVARG;
}

BBIO_err get_gpio_number(const char *key, unsigned int *gpio)
{
    *gpio = lookup_gpio_by_key(key);
    
    if (!*gpio) {
        *gpio = lookup_gpio_by_name(key);
    }

    if (!*gpio) {
        return BBIO_INVARG;
    }

    return BBIO_OK;
}

BBIO_err get_pwm_by_key(const char *key, pwm_t **pwm)
{
    pwm_t *p;
    // Loop through the table
    for (p = pwm_table; p->key != NULL; ++p) {
        if (strcmp(p->key, key) == 0) {
            // Return the pwm_t struct
            *pwm = p;
            return BBIO_OK;
        }
    }
    return BBIO_INVARG;
}

BBIO_err get_pwm_key(const char *input, char *key)
{
    BBIO_err err = copy_pwm_key_by_key(input, key);
    if (err == BBIO_OK) {
        return err;
    }

    err = get_pwm_key_by_name(input, key);
    if (err == BBIO_OK) {
        return err;
    }

    return BBIO_INVARG;
}

// TODO: fix warning
// source/common.c:344:14: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
BBIO_err get_adc_ain(const char *key, int *ain)
{
    *ain = lookup_ain_by_key(key);
    
    if (*ain == -1) {
        *ain = lookup_ain_by_name(key);

        if (*ain == -1) {
          return BBIO_INVARG;
        }
    }

    return BBIO_OK;
}

BBIO_err get_uart_device_tree_name(const char *name, char *dt)
{
    BBIO_err err;
    err = lookup_uart_by_name(name, dt);
    if (err != BBIO_OK) {
        return err;
    }

    return BBIO_OK;
}

BBIO_err build_path(const char *partial_path, const char *prefix, char *full_path, size_t full_path_len)
{
    glob_t results;
    size_t len = strlen(partial_path) + strlen(prefix) + 5;
    char *pattern = malloc(len);
    snprintf(pattern, len, "%s/%s*", partial_path, prefix);

/*  int glob(const char *pattern, int flags,
                int (*errfunc) (const char *epath, int eerrno),
                glob_t *pglob); */
    int err = glob(pattern, 0, NULL, &results);
    free(pattern);
    if (err != BBIO_OK) {
        globfree(&results);
        if (err == GLOB_NOSPACE)
            return BBIO_MEM;
        else
            return BBIO_GEN;
    }

    // We will return the first match
    strncpy(full_path, results.gl_pathv[0], full_path_len);

    // Free memory
    globfree(&results);

    return BBIO_OK;
}

int get_spi_bus_path_number(unsigned int spi)
{
  char path[MAX_PATH];

#ifdef BBBVERSION41
  strncpy(ocp_dir, "/sys/devices/platform/ocp", sizeof(ocp_dir));
#else
  build_path("/sys/devices", "ocp", ocp_dir, sizeof(ocp_dir));
#endif

  if (spi == 0) {
      snprintf(path, sizeof(path), "%s/48030000.spi/spi_master/spi1", ocp_dir);
  } else {
      snprintf(path, sizeof(path), "%s/481a0000.spi/spi_master/spi1", ocp_dir);
  }
  
  DIR* dir = opendir(path);
  if (dir) {
      closedir(dir);
      //device is using /dev/spidev1.x
      return 1;
  } else if (ENOENT == errno) {
      //device is using /dev/spidev2.x
      return 2;
  } else {
      return -1;
  }
}

/*
   Refer to: http://elinux.org/Beagleboard:BeagleBoneBlack_Debian#U-Boot_Overlays
   Robert C. Nelson maintains the BeagleBoard.org Debian images and
   suggested adding this check to see if u-boot overlays are enabled.

   If u-boot overlays are enabled, then device tree overlays should not
   be loaded with the cape manager by writing to the slots file.  There
   is currently a kernel bug that causes the write to hang.
*/
int uboot_overlay_enabled(void) {
    const char *cmd = "/bin/grep -c bone_capemgr.uboot_capemgr_enabled=1 /proc/cmdline";
    char uboot_overlay;
    FILE *file = NULL;

    file = popen(cmd, "r");
    if (file == NULL) {
       fprintf(stderr, "error: uboot_overlay_enabled() failed to run cmd=%s\n", cmd);
       syslog(LOG_ERR, "Adafruit_BBIO: error: uboot_overlay_enabled() failed to run cmd=%s\n", cmd);
       return -1;
    }
    uboot_overlay = fgetc(file);
    pclose(file);

    if(uboot_overlay == '1') {
      syslog(LOG_DEBUG, "Adafruit_BBIO: uboot_overlay_enabled() is true\n");
      return 1;
    } else {
      syslog(LOG_DEBUG, "Adafruit_BBIO: uboot_overlay_enabled() is false\n");
      return 0;
    }
}

/*
   PocketBeagle has everything built-in to the main dtb
*/
int pocketbeagle(void) {
    const char *cmd = "/bin/grep -c 'TI AM335x PocketBeagle' /proc/device-tree/model";
    char pocketbeagle;
    FILE *file = NULL;

    file = popen(cmd, "r");
    if (file == NULL) {
       fprintf(stderr, "error: pocketbeagle() failed to run cmd=%s\n", cmd);
       syslog(LOG_ERR, "Adafruit_BBIO: error: pocketbeagle() failed to run cmd=%s\n", cmd);
       return -1;
    }
    pocketbeagle = fgetc(file);
    pclose(file);

    if(pocketbeagle == '1') {
      return 1;
    } else {
      return 0;
    }
}


/*
   Check if board is a BeagleBone Blue

   Refer to GitHub issue for more information:
   https://github.com/adafruit/adafruit-beaglebone-io-python/issues/178
*/
int beaglebone_blue(void) {
    const char *cmd = "/bin/grep -c 'TI AM335x BeagleBone Blue' /proc/device-tree/model";
    // cache the value to avoid poor performance
    // in functions that are called frequently like
    // gpio_set_value() in source/event_gpio.c
    static int initialized = 0;
    static int retval = 0;
    FILE *file = NULL;

    //fprintf(stderr, "beaglebone_blue(): initialized=[%d] retval=[%d]\n", initialized, retval);
    if(!initialized) {
      initialized = 1;
      //fprintf(stderr, "beaglebone_blue(): not initialized\n");
      file = popen(cmd, "r");
      if (file == NULL) {
         fprintf(stderr, "Adafruit_BBIO: error in beaglebone_blue(): failed to run cmd=%s\n", cmd);
         syslog(LOG_ERR, "Adafruit_BBIO: error in beaglebone_blue(): failed to run cmd=%s\n", cmd);
         return -1;
      }
      if( fgetc(file) == '1' ) {
         retval = 1;
      }
      pclose(file);
    }

    return retval;
}


BBIO_err load_device_tree(const char *name)
{
    char line[256];
    FILE *file = NULL;
    char slots[100];
#ifdef BBBVERSION41
    snprintf(ctrl_dir, sizeof(ctrl_dir), "/sys/devices/platform/bone_capemgr");
#else
    build_path("/sys/devices", "bone_capemgr", ctrl_dir, sizeof(ctrl_dir));
#endif

    /* Check if the Linux kernel booted with u-boot overlays enabled.
       If enabled, do not load overlays via slots file as the write
       will hang due to kernel bug in cape manager driver. Just return
       BBIO_OK in order to avoid cape manager bug. */
    if(uboot_overlay_enabled()) {
      return BBIO_OK;
    }

    /* beaglebone blue has complete dtb file and does not need overlays */
    if(beaglebone_blue()) {
      //fprintf(stderr, "common.c: load_device_tree(): beaglebone_blue(): TRUE\n");
      return BBIO_OK;
    }

    /* pocketbeagle has complete dtb file and does not need overlays */
    if(pocketbeagle()) {
      //fprintf(stderr, "common.c: load_device_tree(): pocketbeagle(): TRUE\n");
      return BBIO_OK;
    }

    snprintf(slots, sizeof(slots), "%s/slots", ctrl_dir);

    file = fopen(slots, "r+");
    if (!file) {
#ifndef NO_PYTHON
        PyErr_SetFromErrnoWithFilename(PyExc_IOError, slots);
#endif // !NO_PYTHON
        return BBIO_CAPE;
    }

    while (fgets(line, sizeof(line), file)) {
        //the device is already loaded, return 1
        if (strstr(line, name)) {
            fclose(file);
            return BBIO_OK;
        }
    }

    //if the device isn't already loaded, load it, and return
    fprintf(file, "%s", name);
    fclose(file);

    //0.2 second delay
    nanosleep((struct timespec[]){{0, 200000000}}, NULL);

    return BBIO_OK;
}

// Find whether a device tree is loaded.
// Returns 1 if so, 0 if not, and <0 if error
int device_tree_loaded(const char *name)
{
    FILE *file = NULL;
    char slots[100];
#ifdef BBBVERSION41
    snprintf(ctrl_dir, sizeof(ctrl_dir), "/sys/devices/platform/bone_capemgr");
#else
    build_path("/sys/devices", "bone_capemgr", ctrl_dir, sizeof(ctrl_dir));
#endif
    char line[256];

    /* Check if the Linux kernel booted with u-boot overlays enabled.
       If enabled, do not load overlays via slots file as the write
       will hang due to kernel bug in cape manager driver. Return 1
       to fake the device tree is loaded to avoid cape manager bug */
    if(uboot_overlay_enabled()) {
      return 1;
    }

    /* beaglebone blue has complete dtb file and does not need overlays */
    if(beaglebone_blue()) {
      //fprintf(stderr, "common.c: device_tree_loaded(): beaglebone_blue(): TRUE\n");
      return BBIO_OK;
    }

    /* pocketbeagle has complete dtb file and does not need overlays */
    if(pocketbeagle()) {
      //fprintf(stderr, "common.c: device_tree_loaded(): pocketbeagle(): TRUE\n");
      return BBIO_OK;
    }

    snprintf(slots, sizeof(slots), "%s/slots", ctrl_dir);


    file = fopen(slots, "r+");
    if (!file) {
#ifndef NO_PYTHON
        PyErr_SetFromErrnoWithFilename(PyExc_IOError, slots);
#endif // !NO_PYTHON
        return -1;
    }

    while (fgets(line, sizeof(line), file)) {
        //the device is loaded, close file and return true
        if (strstr(line, name)) {
            fclose(file);
            return 1;
        }
    }

    //not loaded, close file
    fclose(file);

    return 0;
}

BBIO_err unload_device_tree(const char *name)
{
    FILE *file = NULL;
    char slots[100];
#ifdef BBBVERSION41
    snprintf(ctrl_dir, sizeof(ctrl_dir), "/sys/devices/platform/bone_capemgr");
#else
    build_path("/sys/devices", "bone_capemgr", ctrl_dir, sizeof(ctrl_dir));
#endif
    char line[256];
    char *slot_line;

    /* beaglebone blue has complete dtb file and does not need overlays */
    if(beaglebone_blue()) {
      //fprintf(stderr, "common.c: unload_device_tree(): beaglebone_blue(): TRUE\n");
      return BBIO_OK;
    }

    /* pocketbeagle has complete dtb file and does not need overlays */
    if(pocketbeagle()) {
      //fprintf(stderr, "common.c: unload_device_tree(): pocketbeagle(): TRUE\n");
      return BBIO_OK;
    }

    snprintf(slots, sizeof(slots), "%s/slots", ctrl_dir);
    file = fopen(slots, "r+");
    if (!file) {
#ifndef NO_PYTHON
        PyErr_SetFromErrnoWithFilename(PyExc_IOError, slots);
#endif // !NO_PYTHON
        return BBIO_SYSFS;
    }

    while (fgets(line, sizeof(line), file)) {
        //the device is loaded, let's unload it
        if (strstr(line, name)) {
            slot_line = strtok(line, ":");
            //remove leading spaces
            while(*slot_line == ' ')
                slot_line++;

            fprintf(file, "-%s", slot_line);
            fclose(file);
            return BBIO_OK;
        }
    }

    //not loaded, close file
    fclose(file);

    return BBIO_OK;
}

void initlog(int level, const char* ident, int option)
{
  static int initialized = 0;
  if (initialized) return;

  setlogmask(LOG_UPTO(level));
  if (option == -1) {
    option = BBIO_LOG_OPTION;
  }
  openlog(ident, option, LOG_LOCAL1);
  syslog(LOG_NOTICE, "Adafruit_BBIO: version %s initialized", "<unknown>");

  initialized = 1;
}