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115 lines
2.4 KiB
Go
115 lines
2.4 KiB
Go
// package i2c wraps the [i2c package] to interact with the i2c
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// with devices on the bus
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//
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// [i2c package]: https://pkg.go.dev/periph.io/x/conn/v3/i2c#pkg-overview
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package i2c
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import (
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"FRMS/internal/pkg/logging"
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"bytes"
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"fmt"
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_ "log"
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"os/exec"
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"strconv"
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"strings"
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)
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// GetConnected returns a map of each device address and its current
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// connection status.
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func GetConnected(b int) (map[int]bool, error) {
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bus := strconv.Itoa(b)
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devices := make(map[int]bool) // only keys
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cmd := exec.Command("i2cdetect", "-y", "-r", bus)
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var out bytes.Buffer
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var errs bytes.Buffer
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cmd.Stderr = &errs
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cmd.Stdout = &out
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if err := cmd.Run(); err != nil {
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logging.Debug(
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logging.DError,
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"I2C scan error %v",
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errs.String(),
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)
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return devices, err
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}
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// parsing the command output
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outString := out.String()
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split := strings.SplitAfter(outString, ":")
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// 1st entry is reserved and ending is always \n##:
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split = split[1:]
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// create empty slice for all the devices
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for i, v := range split {
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lastDevice := strings.Index(v, "\n")
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trimmed := v[:lastDevice]
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trimmed = strings.Trim(trimmed, " ")
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count := strings.Split(trimmed, " ")
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for j, d := range count {
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// the first row has to be offset by 3 but after its just i*16 + j
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offset := j
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if i == 0 {
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offset += 3
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}
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addr := i*16 + offset
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if !strings.Contains(d, "--") && !strings.Contains(d, "UU") {
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devices[addr] = true
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}
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}
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}
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return devices, nil
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}
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// SendCmd sends an arbitrary command string to the device at addr on i2c bus b.
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// Command will be converted from a string to bytes before
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// attempting to be sent.
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func SendCmd(b, addr int, command string) (string, error) {
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var cmd *exec.Cmd
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bus := strconv.Itoa(b)
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// default to an empty read
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operation := "r20"
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frmt_cmd := ""
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if command != "" {
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// command, do write
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operation = fmt.Sprintf("w%d", len(command)) // write
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// formatting cmd
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for _, char := range command {
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// loop over string
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frmt_cmd += fmt.Sprintf("0x%x", char)
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}
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cmd = exec.Command("i2ctransfer", "-y", bus, fmt.Sprintf("%s@0x%x", operation, addr), frmt_cmd)
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} else {
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// reading
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cmd = exec.Command("i2ctransfer", "-y", bus, fmt.Sprintf("%s@0x%x", operation, addr))
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}
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// execute command
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var out bytes.Buffer
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var errs bytes.Buffer
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cmd.Stderr = &errs
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cmd.Stdout = &out
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if err := cmd.Run(); err != nil {
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logging.Debug(logging.DError, "I2C command error %v", err)
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return "", err
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}
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return out.String(), nil
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}
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