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87 lines
1.4 KiB
Go
87 lines
1.4 KiB
Go
package firmata
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import (
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"errors"
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"fmt"
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"math"
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"sync"
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"periph.io/x/conn/v3/physic"
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)
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var (
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Err10BitAddressingNotSupported = errors.New("10-bit addressing not supported")
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)
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type I2CBus struct {
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c ClientI
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mu sync.Mutex
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}
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func newI2CBus(c ClientI) (*I2CBus, error) {
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b := &I2CBus{
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c: c,
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}
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err := c.SendI2CConfig(0)
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if err != nil {
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return nil, err
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}
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return b, nil
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}
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func (b *I2CBus) Close() error {
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panic("implement me")
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}
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func (b *I2CBus) String() string {
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panic("implement me")
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}
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func (b *I2CBus) Tx(addr uint16, w, r []byte) error {
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if addr >= 0b11111111 {
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return fmt.Errorf("%w: 0x%04X", Err10BitAddressingNotSupported, addr)
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}
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if len(r) > math.MaxUint16 {
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return fmt.Errorf("%w: cannot reach more than %d bytes", ErrValueOutOfRange, math.MaxUint16)
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}
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b.mu.Lock()
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defer b.mu.Unlock()
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ch := make(chan I2CPacket)
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defer close(ch)
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address := uint8(addr)
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release, err := b.c.SetI2CAddressListener(address, ch)
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if err != nil {
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return err
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}
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defer release()
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if len(w) > 0 {
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if err := b.c.WriteI2CData(address, false, w); err != nil {
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return err
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}
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}
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if len(r) > 0 {
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if err := b.c.ReadI2CData(address, false, uint16(len(r))); err != nil {
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return err
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}
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pck := <-ch
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copy(r, pck.Data)
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}
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return nil
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}
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func (b *I2CBus) SetSpeed(f physic.Frequency) error {
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return fmt.Errorf("%w: firmata does not support setting bus frequency", ErrUnsupportedFeature)
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}
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