mirror of
https://github.com/kidoman/embd
synced 2025-07-03 11:57:38 +02:00
host specific drivers can now be loaded separately
this ensures cleaner abstractions/code and will ensure that the produced binary is as small as possible. a convenience package is provided to easily load all hosts easily: "github.com/kidoman/embd/host/all"
This commit is contained in:
Karan Misra
parent
57328c979d
commit
c35deeb17c
44 changed files with 1184 additions and 1018 deletions
288
host/generic/i2cbus.go
Normal file
288
host/generic/i2cbus.go
Normal file
|
|
@ -0,0 +1,288 @@
|
|||
// I²C support.
|
||||
|
||||
package generic
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"os"
|
||||
"reflect"
|
||||
"sync"
|
||||
"syscall"
|
||||
"time"
|
||||
"unsafe"
|
||||
|
||||
"github.com/kidoman/embd"
|
||||
)
|
||||
|
||||
const (
|
||||
delay = 20
|
||||
|
||||
slaveCmd = 0x0703 // Cmd to set slave address
|
||||
rdrwCmd = 0x0707 // Cmd to read/write data together
|
||||
|
||||
rd = 0x0001
|
||||
)
|
||||
|
||||
type i2c_msg struct {
|
||||
addr uint16
|
||||
flags uint16
|
||||
len uint16
|
||||
buf uintptr
|
||||
}
|
||||
|
||||
type i2c_rdwr_ioctl_data struct {
|
||||
msgs uintptr
|
||||
nmsg uint32
|
||||
}
|
||||
|
||||
type i2cBus struct {
|
||||
l byte
|
||||
file *os.File
|
||||
addr byte
|
||||
mu sync.Mutex
|
||||
|
||||
initialized bool
|
||||
}
|
||||
|
||||
func NewI2CBus(l byte) embd.I2CBus {
|
||||
return &i2cBus{l: l}
|
||||
}
|
||||
|
||||
func (b *i2cBus) init() error {
|
||||
if b.initialized {
|
||||
return nil
|
||||
}
|
||||
|
||||
var err error
|
||||
if b.file, err = os.OpenFile(fmt.Sprintf("/dev/i2c-%v", b.l), os.O_RDWR, os.ModeExclusive); err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
b.initialized = true
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
func (b *i2cBus) setAddress(addr byte) error {
|
||||
if addr != b.addr {
|
||||
if _, _, errno := syscall.Syscall(syscall.SYS_IOCTL, b.file.Fd(), slaveCmd, uintptr(addr)); errno != 0 {
|
||||
return syscall.Errno(errno)
|
||||
}
|
||||
|
||||
b.addr = addr
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
func (b *i2cBus) ReadByte(addr byte) (byte, error) {
|
||||
b.mu.Lock()
|
||||
defer b.mu.Unlock()
|
||||
|
||||
if err := b.setAddress(addr); err != nil {
|
||||
return 0, err
|
||||
}
|
||||
|
||||
bytes := make([]byte, 1)
|
||||
n, _ := b.file.Read(bytes)
|
||||
|
||||
if n != 1 {
|
||||
return 0, fmt.Errorf("i2c: Unexpected number (%v) of bytes read", n)
|
||||
}
|
||||
|
||||
return bytes[0], nil
|
||||
}
|
||||
|
||||
func (b *i2cBus) WriteByte(addr, value byte) error {
|
||||
b.mu.Lock()
|
||||
defer b.mu.Unlock()
|
||||
|
||||
if err := b.setAddress(addr); err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
n, err := b.file.Write([]byte{value})
|
||||
|
||||
if n != 1 {
|
||||
err = fmt.Errorf("i2c: Unexpected number (%v) of bytes written in WriteByte", n)
|
||||
}
|
||||
|
||||
return err
|
||||
}
|
||||
|
||||
func (b *i2cBus) WriteBytes(addr byte, value []byte) error {
|
||||
b.mu.Lock()
|
||||
defer b.mu.Unlock()
|
||||
|
||||
if err := b.setAddress(addr); err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
for i := range value {
|
||||
n, err := b.file.Write([]byte{value[i]})
|
||||
|
||||
if n != 1 {
|
||||
return fmt.Errorf("i2c: Unexpected number (%v) of bytes written in WriteBytes", n)
|
||||
}
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
time.Sleep(delay * time.Millisecond)
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
func (b *i2cBus) ReadFromReg(addr, reg byte, value []byte) error {
|
||||
b.mu.Lock()
|
||||
defer b.mu.Unlock()
|
||||
|
||||
if err := b.setAddress(addr); err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
hdrp := (*reflect.SliceHeader)(unsafe.Pointer(&value))
|
||||
|
||||
var messages [2]i2c_msg
|
||||
messages[0].addr = uint16(addr)
|
||||
messages[0].flags = 0
|
||||
messages[0].len = 1
|
||||
messages[0].buf = uintptr(unsafe.Pointer(®))
|
||||
|
||||
messages[1].addr = uint16(addr)
|
||||
messages[1].flags = rd
|
||||
messages[1].len = uint16(len(value))
|
||||
messages[1].buf = uintptr(unsafe.Pointer(hdrp.Data))
|
||||
|
||||
var packets i2c_rdwr_ioctl_data
|
||||
|
||||
packets.msgs = uintptr(unsafe.Pointer(&messages))
|
||||
packets.nmsg = 2
|
||||
|
||||
if _, _, errno := syscall.Syscall(syscall.SYS_IOCTL, b.file.Fd(), rdrwCmd, uintptr(unsafe.Pointer(&packets))); errno != 0 {
|
||||
return syscall.Errno(errno)
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
func (b *i2cBus) ReadByteFromReg(addr, reg byte) (byte, error) {
|
||||
buf := make([]byte, 1)
|
||||
if err := b.ReadFromReg(addr, reg, buf); err != nil {
|
||||
return 0, err
|
||||
}
|
||||
return buf[0], nil
|
||||
}
|
||||
|
||||
func (b *i2cBus) ReadWordFromReg(addr, reg byte) (uint16, error) {
|
||||
buf := make([]byte, 2)
|
||||
if err := b.ReadFromReg(addr, reg, buf); err != nil {
|
||||
return 0, err
|
||||
}
|
||||
return uint16((uint16(buf[0]) << 8) | uint16(buf[1])), nil
|
||||
}
|
||||
|
||||
func (b *i2cBus) WriteToReg(addr, reg byte, value []byte) error {
|
||||
b.mu.Lock()
|
||||
defer b.mu.Unlock()
|
||||
|
||||
if err := b.setAddress(addr); err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
outbuf := append([]byte{reg}, value...)
|
||||
|
||||
hdrp := (*reflect.SliceHeader)(unsafe.Pointer(&outbuf))
|
||||
|
||||
var message i2c_msg
|
||||
message.addr = uint16(addr)
|
||||
message.flags = 0
|
||||
message.len = uint16(len(outbuf))
|
||||
message.buf = uintptr(unsafe.Pointer(&hdrp.Data))
|
||||
|
||||
var packets i2c_rdwr_ioctl_data
|
||||
|
||||
packets.msgs = uintptr(unsafe.Pointer(&message))
|
||||
packets.nmsg = 1
|
||||
|
||||
if _, _, errno := syscall.Syscall(syscall.SYS_IOCTL, b.file.Fd(), rdrwCmd, uintptr(unsafe.Pointer(&packets))); errno != 0 {
|
||||
return syscall.Errno(errno)
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
func (b *i2cBus) WriteByteToReg(addr, reg, value byte) error {
|
||||
b.mu.Lock()
|
||||
defer b.mu.Unlock()
|
||||
|
||||
if err := b.setAddress(addr); err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
outbuf := [...]byte{
|
||||
reg,
|
||||
value,
|
||||
}
|
||||
|
||||
var message i2c_msg
|
||||
message.addr = uint16(addr)
|
||||
message.flags = 0
|
||||
message.len = uint16(len(outbuf))
|
||||
message.buf = uintptr(unsafe.Pointer(&outbuf))
|
||||
|
||||
var packets i2c_rdwr_ioctl_data
|
||||
|
||||
packets.msgs = uintptr(unsafe.Pointer(&message))
|
||||
packets.nmsg = 1
|
||||
|
||||
if _, _, errno := syscall.Syscall(syscall.SYS_IOCTL, b.file.Fd(), rdrwCmd, uintptr(unsafe.Pointer(&packets))); errno != 0 {
|
||||
return syscall.Errno(errno)
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
func (b *i2cBus) WriteWordToReg(addr, reg byte, value uint16) error {
|
||||
b.mu.Lock()
|
||||
defer b.mu.Unlock()
|
||||
|
||||
if err := b.setAddress(addr); err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
outbuf := [...]byte{
|
||||
reg,
|
||||
byte(value >> 8),
|
||||
byte(value),
|
||||
}
|
||||
|
||||
var messages i2c_msg
|
||||
messages.addr = uint16(addr)
|
||||
messages.flags = 0
|
||||
messages.len = uint16(len(outbuf))
|
||||
messages.buf = uintptr(unsafe.Pointer(&outbuf))
|
||||
|
||||
var packets i2c_rdwr_ioctl_data
|
||||
|
||||
packets.msgs = uintptr(unsafe.Pointer(&messages))
|
||||
packets.nmsg = 1
|
||||
|
||||
if _, _, errno := syscall.Syscall(syscall.SYS_IOCTL, b.file.Fd(), rdrwCmd, uintptr(unsafe.Pointer(&packets))); errno != 0 {
|
||||
return syscall.Errno(errno)
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
func (b *i2cBus) Close() error {
|
||||
b.mu.Lock()
|
||||
defer b.mu.Unlock()
|
||||
|
||||
if !b.initialized {
|
||||
return nil
|
||||
}
|
||||
|
||||
return b.file.Close()
|
||||
}
|
||||
Loading…
Add table
Add a link
Reference in a new issue