bbb_sysutil.c

/*
 * bbb_sysutil.c  Beaglebone Black System Utility
 *
 * Compile with:
 *     cc bbb_sysutil.c -o bbb_sysutil
 *
 * Winston Smith <smith.winston.101@gmail.com>
 */

#include <sys/cdefs.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <errno.h>
#include <unistd.h>
#include <dev/iicbus/iic.h>

#define MIN(a,b) ((a) < (b) ? (a) : (b))

/*
 * Read data from an i2c device
 */
int i2c_read(int fd, int slave, uint8_t* buffer, uint16_t offset, uint16_t offsetlen, uint16_t max)
{
    struct iic_msg msg[2];
    struct iic_rdwr_data rdwr;


    msg[0].slave = slave;
    msg[0].flags = IIC_M_WR;
    msg[0].len = offsetlen;
    msg[0].buf = (uint8_t*)&offset;

    msg[1].slave = slave;
    msg[1].flags = IIC_M_RD;
    msg[1].len = max;
    msg[1].buf = buffer;


    rdwr.nmsgs = 2;
    rdwr.msgs = msg;

    if (ioctl(fd, I2CRDWR, &rdwr) < 0) {
        return errno;
    }

    return 0;
}

/*
 * BeagleBone Black system EEPROM signature
 */
uint8_t signature[] = { 0xAA, 0x55, 0x33, 0xEE };

/*
 * Read data from the Beaglebone system EEPROM
 */
int read_eeprom(int fd)
{
    int     addr = 0x50;
    uint8_t buffer[28];
    char    work[32];
    int     err;


    // For sanity checking!
    memset((void*)buffer, '@', sizeof(buffer));

    if ((err = i2c_read(fd, addr, buffer, 0, sizeof(uint16_t), sizeof(buffer))) != 0) {
        printf("i2c_read() failed with: %s (%d)\n", strerror(err), err);
        return 1;
    }

    printf("EEPROM @ address %02X: signature=%02X:%02X:%02X:%02X\n",
           addr,
           buffer[0], buffer[1], buffer[2], buffer[3]);

    if (memcmp((void*)buffer, (void*)signature, sizeof(signature)) != 0) {
        printf("ERROR: EEPROM signature mismatched\n");
        return 1;
    }

    // Extract the 12 bytes allocated to the model
    strncpy(work, (char*)&buffer[4], 12);
    work[12] = 0;
    printf("Model:\t%s\n", work);

    // Extract the 12 bytes allocated to the serial number
    strncpy(work, (char*)&buffer[16], 12);
    work[12] = 0;
    printf("Serial:\t%s\n", work);


    return 0;
}

typedef struct {
    int value;
    char* name;
} KV;

static KV TPS65217_ID[] = {
    { 0b01100000, "TPS65217D"  },
    { 0b01110000, "TPS65217A"  },
    { 0b11100000, "TPS65217C"  },
    { 0b11110000, "TPS65217B"  },
    { 0, 0 }
};

static KV TPS65217_STATUS[] = {
    { 0b1000, "ACPWR"   },
    { 0b0100, "USBPWR"  },
    { 0, 0 }
};

size_t KV_lookup_value(int val, KV* table, char* buffer, size_t max)
{
    int i;

    for (i = 0; table[i].name; i++) {
        if (val == table[i].value) {
            size_t sz = MIN(max-1, strlen(table[i].name));
            strncpy(buffer, table[i].name, sz);
            buffer[sz] = 0;

            return sz;
        }
    }

    return 0;
}

size_t KV_lookup_mask(int mask, KV* table, char* buffer, size_t max)
{
    int    i;
    size_t used = 0;


    buffer[0] = 0;

    for (i = 0; table[i].name; i++) {
        if ((mask & table[i].value) != 0) {

            size_t sz = MIN(max - used - 1, strlen(table[i].name) + (used > 0 ? 1 : 0));

            if ((used > 0) && (sz > 0)) {
                strcat(buffer, ",");
                used++;
                sz--;
            }

            strncat(buffer, table[i].name, sz);

            used += sz;
        }
    }

    return used;
}

/*
 * Read data from the Beaglebone system PMIC
 */
int read_pmic(int fd)
{
    int     addr = 0x24;
    int     err;
    uint8_t chipid;
    uint8_t status;
    char    work[32];


    printf("TPS65217 PMIC @ address %02X:\n", addr);

    if ((err = i2c_read(fd, addr, &chipid, 0, sizeof(uint8_t), sizeof(chipid))) != 0) {
        printf("i2c_read() failed with: %s (%d)\n", strerror(err), err);
        return 1;
    }

    if ((err = i2c_read(fd, addr, &status, 0x0A, sizeof(uint8_t), sizeof(status))) != 0) {
        printf("i2c_read() failed with: %s (%d)\n", strerror(err), err);
        return 1;
    }

    KV_lookup_value(chipid & 0xF0, TPS65217_ID, work, sizeof(work));
    printf("ChipID:\t%02X %s rev 1.%d\n", chipid, work, chipid & 0xF);

    KV_lookup_mask(status, TPS65217_STATUS, work, sizeof(work));
    printf("Status:\t%02X %s\n", status, work);

    return 0;
}

int main(int argc, char **argv)
{
    int     fd  = -1;
    char*   dev = "/dev/iic0";
    int     err = 0;


    if (argc > 1) {
        dev = argv[1];
    }

    if ((fd = open(dev, O_RDWR)) < 0 )  {
        perror("open failed");
        err = 1;
        goto exit;
    }

    if ((err = read_pmic(fd)) != 0) {
        goto exit;
    }

    if ((err = read_eeprom(fd)) != 0) {
        goto exit;
    }

exit:
    if (fd != -1) {
        close(fd);
    }

    exit(err);
}