DMAC/internal/pkg/I2C/wrappers.go

package I2C

import (
    "fmt"
    "os/exec"
    "bytes"
    "strings"
    "time"
    "sync"
    "strconv"
    pb "FRMS/internal/pkg/grpc"
)

type I2Cdev struct {
    Addr int
    Active bool
    Bus int             // may be redundant but need to see if I can get around central struct
    LastSeen time.Time
}

type I2CMonitor struct {        // used in RLC to synchronize accesses
    Bus int                 // bus to use {0,1,2}
    Devices map[int]I2Cdev     // mapping to quickly index addresses to their device structs
    Id string  //ip for gRPC
    Port int
    mu sync.Mutex
    pb.UnimplementedMonitoringServer
}

func I2Cconnected(bus int) map[int]bool {
    /*
    I2CConnect takes an integer specifying the bus to search as input
    Returns a slice of type I2Cdev
    */
    b := strconv.Itoa(bus)
    cmd := exec.Command("i2cdetect", "-y", "-r", b)
    var out bytes.Buffer
    cmd.Stdout = &out
    err:= cmd.Run()
    
    if err != nil {
        fmt.Println(err)
    }
    outString := out.String()
    // could split by \n too
    split := strings.SplitAfter(outString,":")
    // 1st entry is garbage headers and ending is always \n##:
    split = split[1:]
    // create empty slice for all the devices
    //var devices []i2cdev
    devices := map[int]bool{} //maps device addresses to active bool
    for i,v := range split {
        lst := strings.Index(v,"\n")
        trimmed := v[:lst]
        trimmed = strings.Trim(trimmed," ")
        // trimmed now holds just possible sensor addresses
        count := strings.Split(trimmed," ")
        for j,d := range count {
            // the first row has to be offset by 3 but after its just i*16 + j
            offset := 0
            if i == 0 {
                offset = 3
            }
            addr := i*16 + j + offset
            if strings.Contains(d,"--") || strings.Contains(d,"UU") {
                // address is unconnected or reserved
                //devices = append(devices, I2Cdev{Addr:addr,Active:false})
                devices[addr] = false
            } else {
                //devices = append(devices, I2Cdev{Addr:addr,Active:true,LastSeen:now})
                devices[addr] = true
            }
        }
    }
    return devices
}