[Inky] autodetect board opts and pHAT v2 support (#12)

* Added support for Inky pHAT v2
* Added support for detecting Inky board. Detect Inky board opts from eeprom, and detect new inky dev with sane default from opts

inky/doc.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
-// Package inky drives an Inky pHAT or wHAT E ink display.
+// Package inky drives an Inky pHAT, pHAT v2 or wHAT E ink display.
 //
 // Datasheet
 //

inky/inky.go

@@ -14,6 +14,7 @@ import (
 	"periph.io/x/conn/v3"
 	"periph.io/x/conn/v3/display"
 	"periph.io/x/conn/v3/gpio"
+	"periph.io/x/conn/v3/i2c"
 	"periph.io/x/conn/v3/physic"
 	"periph.io/x/conn/v3/spi"
 )
@@ -69,12 +70,15 @@ type Model int
 const (
 	PHAT Model = iota
 	WHAT
+	PHAT2
 )
 
 func (m *Model) String() string {
 	switch *m {
 	case PHAT:
 		return "PHAT"
+	case PHAT2:
+		return "PHAT2"
 	case WHAT:
 		return "WHAT"
 	default:
@@ -87,6 +91,8 @@ func (m *Model) Set(s string) error {
 	switch s {
 	case "PHAT":
 		*m = PHAT
+	case "PHAT2":
+		*m = PHAT2
 	case "WHAT":
 		*m = WHAT
 	default:
@@ -106,6 +112,44 @@ type Opts struct {
 	BorderColor Color
 }
 
+// DetectOpts tries to read the device opts from EEPROM.
+func DetectOpts(bus i2c.Bus) (*Opts, error) {
+	// Read data from EEPROM
+	data, err := readEep(bus)
+	if err != nil {
+		return nil, fmt.Errorf("failed to detect Inky board: %v", err)
+	}
+
+	options := new(Opts)
+
+	switch data[6] {
+	case 1, 4, 5:
+		options.Model = PHAT
+	case 10, 11, 12:
+		options.Model = PHAT2
+	case 2, 3, 6, 7, 8:
+		options.Model = WHAT
+	default:
+		return nil, fmt.Errorf("failed to get ops: display type not supported")
+	}
+
+	switch data[4] {
+	case 1:
+		options.ModelColor = Black
+		options.BorderColor = Black
+	case 2:
+		options.ModelColor = Red
+		options.BorderColor = Red
+	case 3:
+		options.ModelColor = Yellow
+		options.BorderColor = Yellow
+	default:
+		return nil, fmt.Errorf("failed to get ops: color not supported")
+	}
+
+	return options, nil
+}
+
 var borderColor = map[Color]byte{
 	Black:  0x00,
 	Red:    0x73,
@@ -148,6 +192,9 @@ func New(p spi.Port, dc gpio.PinOut, reset gpio.PinOut, busy gpio.PinIn, o *Opts
 	case PHAT:
 		d.bounds = image.Rect(0, 0, 104, 212)
 		d.flipVertically = true
+	case PHAT2:
+		d.bounds = image.Rect(0, 0, 122, 250)
+		d.flipVertically = true
 	case WHAT:
 		d.bounds = image.Rect(0, 0, 400, 300)
 	}
@@ -420,5 +467,18 @@ func pack(bits []bool) ([]byte, error) {
 	return ret, nil
 }
 
+func readEep(bus i2c.Bus) ([]byte, error) {
+	// Inky uses SMBus, specify read registry with data
+	write := []byte{0x00, 0x00}
+
+	data := make([]byte, 29)
+
+	if err := bus.Tx(0x50, write, data); err != nil {
+		return nil, err
+	}
+
+	return data, nil
+}
+
 var _ display.Drawer = &Dev{}
 var _ conn.Resource = &Dev{}