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130 lines
2.6 KiB
Go
130 lines
2.6 KiB
Go
// Copyright 2018 The Periph Authors. All rights reserved.
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// Use of this source code is governed under the Apache License, Version 2.0
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// that can be found in the LICENSE file.
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package ep0099
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import (
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"errors"
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"periph.io/x/conn/v3/i2c"
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)
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var InvalidAddressError = errors.New("Invalid EP-0099 address")
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var InvalidChannelError = errors.New("Invalid EP-0099 channel")
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type State byte
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const (
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StateOff State = 0x00
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StateOn State = 0x01
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)
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type Dev struct {
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i2c i2c.Dev
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state map[uint8]State
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}
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func New(bus i2c.Bus, address uint16) (*Dev, error) {
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if err := isValidAddress(address); err != nil {
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return nil, err
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}
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d := &Dev{
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i2c: i2c.Dev{Bus: bus, Addr: address},
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state: buildChannelsList(),
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}
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if err := d.reset(); err != nil {
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return nil, err
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}
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return d, nil
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}
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func (d *Dev) Halt() error {
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return d.reset()
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}
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func (d *Dev) On(channel uint8) error {
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if err := d.isValidChannel(channel); err != nil {
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return err
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}
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_, err := d.i2c.Write([]byte{channel, byte(StateOn)})
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d.state[channel] = StateOn
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return err
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}
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func (d *Dev) Off(channel uint8) error {
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if err := d.isValidChannel(channel); err != nil {
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return err
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}
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_, err := d.i2c.Write([]byte{channel, byte(StateOff)})
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d.state[channel] = StateOff
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return err
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}
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func (d *Dev) State(channel uint8) (State, error) {
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if err := d.isValidChannel(channel); err != nil {
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return 0, err
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}
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return d.state[channel], nil
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}
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func (d *Dev) AvailableChannels() []uint8 {
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return []uint8{0x01, 0x02, 0x03, 0x04}
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}
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func (s State) String() string {
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if s == StateOff {
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return "off"
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}
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return "on"
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}
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// Reset resets the registers to the default values.
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func (d *Dev) reset() error {
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for channel := range d.state {
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d.Off(channel)
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}
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return nil
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}
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// Addresses in EP0099 are configured via DIP Switches on the board.
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// Up to 4 HATs can be stacked and each one need a different address to
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// work.
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func isValidAddress(address uint16) error {
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validAddresses := [...]uint16{0x10, 0x11, 0x12, 0x13}
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for _, addr := range validAddresses {
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if address == addr {
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return nil
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}
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}
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return InvalidAddressError
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}
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func (d *Dev) isValidChannel(channel uint8) error {
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if _, exists := d.state[channel]; !exists {
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return InvalidChannelError
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}
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return nil
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}
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// EP-0099 offers 4 channels per board
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func buildChannelsList() map[uint8]State {
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// Using a map instead of list since indexes of channels are not zero-based
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// values. That would cause loops to have to correct channel ids while
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// looping through items or reading/setting values.
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// With maps, keys correspond to actual channels on the board.
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return map[uint8]State{
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1: StateOff,
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2: StateOff,
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3: StateOff,
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4: StateOff,
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}
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}
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