Simple utility to test tuneable SFP modules implementing SFF-8690

tuneable.c

#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdint.h>
#include <stdio.h>

int main(int argc, char *argv[]) {
        int fd = open(argv[1], O_RDWR);
        if (fd < 0) {
                perror("open");
                return 1;
        }
        uint8_t ident = 0x0;
        pread(fd, &ident, 1, 65);
        if (((ident >> 6) & 0x1) == 0) {
                printf("Not tuneable\n");
                return 1;
        }
        uint8_t page = 0x2;
        pwrite(fd, &page, 1, 0x100 + 127);
        pread(fd, &ident, 1, 0x180);
        printf("Tunable features: (raw: 0x%x)\n", ident);
        if ((ident & 0x1) != 0) {
                printf(" - Tunable DWDM (selection in 50pm steps)\n");
        }
        if ((ident & 0x2) != 0) {
                printf(" - Tunable DWDM (selection by channel number)\n");
        }
        if ((ident & 0x4) != 0) {
                printf(" - Tx Dither Supported\n");
        }
        if ((ident & 0x8) != 0) {
                printf(" - Self Tuning via Smart Tunable MSA Supported\n");
        }
        if ((ident & 0x10) != 0) {
                printf(" - Tuning support via other methods supported\n");
        }

        uint8_t status = 0;
        pread(fd, &status, 1, 0x100 + 168);
        printf("Current status: 0x%x\n", status);
        if ((status & (1 << 4)) != 0) {
                printf(" - TX not ready, tuning ...\n");
        }
        if ((status & (1 << 5)) != 0) {
                printf(" - Wavelength unlocked\n");
        }
        if ((status & (1 << 6)) != 0) {
                // What is TEC?
                printf(" - TEC fault\n");
        }

        uint16_t channel = 0;
        uint16_t channel_set = 0;
        pread(fd, &channel, 2, 0x100 + 144);

        uint16_t laser_first_freq = 0;
        uint16_t laser_first_freq_sub = 0;
        pread(fd, &laser_first_freq, 2, 0x100 + 132);
        pread(fd, &laser_first_freq_sub, 2, 0x100 + 134);
        laser_first_freq = ((laser_first_freq & 0xff) << 8) | (laser_first_freq >> 8);
        laser_first_freq_sub = ((laser_first_freq_sub & 0xff) << 8) | (laser_first_freq_sub >> 8);

        uint16_t laser_last_freq = 0;
        uint16_t laser_last_freq_sub = 0;
        pread(fd, &laser_last_freq, 2, 0x100 + 136);
        pread(fd, &laser_last_freq_sub, 2, 0x100 + 138);
        laser_last_freq = ((laser_last_freq & 0xff) << 8) | (laser_last_freq >> 8);
        laser_last_freq_sub = ((laser_last_freq_sub & 0xff) << 8) | (laser_last_freq_sub >> 8);

        uint16_t laser_grid_spacing = 0;
        pread(fd, &laser_grid_spacing, 2, 0x100 + 140);
        laser_grid_spacing = ((laser_grid_spacing & 0xff) << 8) | (laser_grid_spacing >> 8);
        printf("Laser first frequency: %d.%d THz\n", laser_first_freq, laser_first_freq_sub);
        printf("Laser last frequency: %d.%d THz\n", laser_last_freq, laser_last_freq_sub);
        printf("Laser grid spacing: %.2f GHz\n", (double)(laser_grid_spacing) / 10.0f);

        channel = ((channel & 0xff) << 8) | (channel >> 8);
        printf("Current channel: %d\n", channel);
        printf("Offset: %.2f THz\n", laser_first_freq + (double)(laser_first_freq_sub) / 10000.0f +((channel-1) * ((double)(laser_grid_spacing) / 10.0f / 1000.0f)));

        // Try to re-activate the channel
        channel_set = channel;
        if (argc == 3) {
                channel_set = atoi(argv[2]);
        }
        printf("Activating channel %d ...\n", channel_set);
        channel_set = ((channel_set & 0xff) << 8) | (channel_set >> 8);
        pwrite(fd, &channel_set, 2, 0x100 + 144);

        pread(fd, &channel, 2, 0x100 + 146);
        channel = ((channel & 0xff) << 8) | (channel >> 8);
        printf("Current wavelength: %.2f nm\n", channel * 0.05f);

        pread(fd, &status, 1, 0x100 + 110);
        printf("Current operational status: 0x%x\n", status);
        if ((status & (1 << 0)) != 0) {
                printf(" - Data_not_ready\n");
        }
        if ((status & (1 << 1)) != 0) {
                printf(" - Rx_LOS State\n");
        }
        if ((status & (1 << 2)) != 0) {
                printf(" - TX Fault State\n");
        }
        if ((status & (1 << 7)) != 0) {
                printf(" - TX disable state\n");
        }
        if ((status & (1 << 6)) != 0) {
                printf(" - Soft TX disable state\n");
        }
}

usage.txt

cumulus@ixp-lab-sw1:mgmt:~$ sudo ./a.out /sys/devices/platform/cel_fpga_i2c.9/i2c-19/i2c-68/68-0050/eeprom 100
Tunable features: (raw: 0x7)
 - Tunable DWDM (selection in 50pm steps)
 - Tunable DWDM (selection by channel number)
 - Tx Dither Supported
Current status: 0x0
Current channel: 102
Activating channel 100 ...
Current wavelength: 1529.15 nm
Current operational status: 0x4
 - TX Fault State