embd/pin.go

106 lines
2.8 KiB
Go

/*
* Copyright (c) Karan Misra 2014
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
* associated documentation files (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge, publish, distribute,
* sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all copies or
* substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
* NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
// Pin mapping support.
package embd
import (
"fmt"
"strconv"
)
const (
// CapDigital represents the digital IO capability.
CapDigital int = 1 << iota
// CapI2C represents pins with the I2C capability.
CapI2C
// CapUART represents pins with the UART capability.
CapUART
// CapSPI represents pins with the SPI capability.
CapSPI
// CapGPMS represents pins with the GPMC capability.
CapGPMC
// CapLCD represents pins used to carry LCD data.
CapLCD
// CapPWM represents pins with PWM capability.
CapPWM
// CapAnalog represents pins with analog IO capability.
CapAnalog
)
// PinDesc represents a pin descriptor.
type PinDesc struct {
ID string
Aliases []string
Caps int
DigitalLogical int
AnalogLogical int
}
// PinMap type represents a collection of pin descriptors.
type PinMap []*PinDesc
// Lookup returns a pin descriptor matching the provided key and capability
// combination. This allows the same keys to be used across pins with differing
// capabilities. For example, it is perfectly fine to have:
//
// pin1: {Aliases: [10, GPIO10], Cap: CapDigital}
// pin2: {Aliases: [10, AIN0], Cap: CapAnalog}
//
// Searching for 10 with CapDigital will return pin1 and searching for
// 10 with CapAnalog will return pin2. This makes for a very pleasant to use API.
func (m PinMap) Lookup(k interface{}, cap int) (*PinDesc, bool) {
var ks string
switch key := k.(type) {
case int:
ks = strconv.Itoa(key)
case string:
ks = key
case fmt.Stringer:
ks = key.String()
default:
return nil, false
}
for i := range m {
pd := m[i]
if pd.ID == ks {
return pd, true
}
for j := range pd.Aliases {
if pd.Aliases[j] == ks && pd.Caps&cap != 0 {
return pd, true
}
}
}
return nil, false
}