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mirror of https://github.com/kidoman/embd synced 2024-10-31 23:38:44 +01:00

gpio: digital pin is responsible for exporting/unexporting itself

This commit is contained in:
Karan Misra 2014-03-22 10:24:29 +05:30
parent df15190e33
commit 6d3b3ae571
2 changed files with 82 additions and 71 deletions

View File

@ -5,6 +5,7 @@ import (
"fmt"
"os"
"path"
"strconv"
)
type digitalPin struct {
@ -14,18 +15,23 @@ type digitalPin struct {
val *os.File
activeLow *os.File
edge *os.File
initialized bool
}
func newDigitalPin(n int) (*digitalPin, error) {
p := &digitalPin{n: n}
if err := p.init(); err != nil {
return nil, err
}
return p, nil
func newDigitalPin(n int) *digitalPin {
return &digitalPin{n: n}
}
func (p *digitalPin) init() error {
if p.initialized {
return nil
}
var err error
if err = p.export(); err != nil {
return err
}
if p.dir, err = p.directionFile(); err != nil {
return err
}
@ -36,9 +42,31 @@ func (p *digitalPin) init() error {
return err
}
p.initialized = true
return nil
}
func (p *digitalPin) export() error {
exporter, err := os.OpenFile("/sys/class/gpio/export", os.O_WRONLY, os.ModeExclusive)
if err != nil {
return err
}
defer exporter.Close()
_, err = exporter.WriteString(strconv.Itoa(p.n))
return err
}
func (p *digitalPin) unexport() error {
unexporter, err := os.OpenFile("/sys/class/gpio/unexport", os.O_WRONLY, os.ModeExclusive)
if err != nil {
return err
}
defer unexporter.Close()
_, err = unexporter.WriteString(strconv.Itoa(p.n))
return err
}
func (p *digitalPin) basePath() string {
return fmt.Sprintf("/sys/class/gpio/gpio%v", p.n)
}
@ -60,6 +88,10 @@ func (p *digitalPin) activeLowFile() (*os.File, error) {
}
func (p *digitalPin) SetDirection(dir Direction) error {
if err := p.init(); err != nil {
return err
}
str := "in"
if dir == Out {
str = "out"
@ -69,6 +101,10 @@ func (p *digitalPin) SetDirection(dir Direction) error {
}
func (p *digitalPin) Read() (int, error) {
if err := p.init(); err != nil {
return 0, err
}
buf := make([]byte, 1)
if _, err := p.val.Read(buf); err != nil {
return 0, err
@ -81,6 +117,10 @@ func (p *digitalPin) Read() (int, error) {
}
func (p *digitalPin) Write(val int) error {
if err := p.init(); err != nil {
return err
}
str := "0"
if val == High {
str = "1"
@ -90,6 +130,10 @@ func (p *digitalPin) Write(val int) error {
}
func (p *digitalPin) ActiveLow(b bool) error {
if err := p.init(); err != nil {
return err
}
str := "0"
if b {
str = "1"
@ -99,14 +143,18 @@ func (p *digitalPin) ActiveLow(b bool) error {
}
func (p *digitalPin) PullUp() error {
return errors.New("not implemented")
return errors.New("gpio: not implemented")
}
func (p *digitalPin) PullDown() error {
return errors.New("not implemented")
return errors.New("gpio: not implemented")
}
func (p *digitalPin) Close() error {
if !p.initialized {
return nil
}
if err := p.dir.Close(); err != nil {
return err
}
@ -119,6 +167,11 @@ func (p *digitalPin) Close() error {
if err := p.edge.Close(); err != nil {
return err
}
if err := p.unexport(); err != nil {
return err
}
p.initialized = false
return nil
}

View File

@ -2,8 +2,6 @@ package embd
import (
"fmt"
"os"
"strconv"
"github.com/golang/glog"
)
@ -47,107 +45,67 @@ func (m PinMap) Lookup(k interface{}) (*PinDesc, bool) {
return nil, false
}
type pin interface {
Close() error
}
type gpioDriver struct {
exporter, unexporter *os.File
initialized bool
pinMap PinMap
initializedPins map[int]*digitalPin
initializedPins map[int]pin
}
func newGPIODriver(pinMap PinMap) *gpioDriver {
return &gpioDriver{
pinMap: pinMap,
initializedPins: map[int]*digitalPin{},
initializedPins: map[int]pin{},
}
}
func (io *gpioDriver) init() error {
if io.initialized {
return nil
}
var err error
if io.exporter, err = os.OpenFile("/sys/class/gpio/export", os.O_WRONLY, os.ModeExclusive); err != nil {
return err
}
if io.unexporter, err = os.OpenFile("/sys/class/gpio/unexport", os.O_WRONLY, os.ModeExclusive); err != nil {
return err
}
io.initialized = true
return nil
}
func (io *gpioDriver) lookupKey(key interface{}) (*PinDesc, bool) {
return io.pinMap.Lookup(key)
}
func (io *gpioDriver) export(n int) error {
_, err := io.exporter.WriteString(strconv.Itoa(n))
return err
}
func (io *gpioDriver) unexport(n int) error {
_, err := io.unexporter.WriteString(strconv.Itoa(n))
return err
}
func (io *gpioDriver) digitalPin(key interface{}) (*digitalPin, error) {
pd, found := io.lookupKey(key)
if !found {
err := fmt.Errorf("gpio: could not find pin matching %q", key)
return nil, err
return nil, fmt.Errorf("gpio: could not find pin matching %q", key)
}
n := pd.N
p, ok := io.initializedPins[n]
if ok {
return p, nil
dp, ok := p.(*digitalPin)
if !ok {
return nil, fmt.Errorf("gpio: sorry, pin %q is already initialized for a different mode", key)
}
return dp, nil
}
if pd.Caps&CapNormal == 0 {
err := fmt.Errorf("gpio: sorry, pin %q cannot be used for GPIO", key)
return nil, err
return nil, fmt.Errorf("gpio: sorry, pin %q cannot be used for digital io", key)
}
if pd.Caps != CapNormal {
glog.Infof("gpio: pin %q is not a dedicated GPIO pin. please refer to the system reference manual for more details", key)
glog.Infof("gpio: pin %q is not a dedicated digital io pin. please refer to the system reference manual for more details", key)
}
if err := io.export(n); err != nil {
return nil, err
}
dp := newDigitalPin(n)
io.initializedPins[n] = dp
p, err := newDigitalPin(n)
if err != nil {
io.unexport(n)
return nil, err
}
io.initializedPins[n] = p
return p, nil
return dp, nil
}
func (io *gpioDriver) DigitalPin(key interface{}) (DigitalPin, error) {
if err := io.init(); err != nil {
return nil, err
}
return io.digitalPin(key)
}
func (io *gpioDriver) Close() error {
for n := range io.initializedPins {
io.unexport(n)
for _, p := range io.initializedPins {
if err := p.Close(); err != nil {
return err
}
}
io.exporter.Close()
io.unexporter.Close()
return nil
}