inky: Fix Impression Driver

go.mod

@@ -12,7 +12,7 @@ require (
 	github.com/mattn/go-colorable v0.1.13
 	golang.org/x/image v0.23.0
 	periph.io/x/conn/v3 v3.7.2
-	periph.io/x/host/v3 v3.8.4
+	periph.io/x/host/v3 v3.8.5
 )
 
 require (

go.sum

@@ -17,5 +17,5 @@ golang.org/x/sys v0.29.0 h1:TPYlXGxvx1MGTn2GiZDhnjPA9wZzZeGKHHmKhHYvgaU=
 golang.org/x/sys v0.29.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 periph.io/x/conn/v3 v3.7.2 h1:qt9dE6XGP5ljbFnCKRJ9OOCoiOyBGlw7JZgoi72zZ1s=
 periph.io/x/conn/v3 v3.7.2/go.mod h1:Ao0b4sFRo4QOx6c1tROJU1fLJN1hUIYggjOrkIVnpGg=
-periph.io/x/host/v3 v3.8.4 h1:QNleTythDd0k6Chu0n+ISrJFlf3LFig9oNbtOIkxoCc=
-periph.io/x/host/v3 v3.8.4/go.mod h1:hPq8dISZIc+UNfWoRj+bPH3XEBQqJPdFdx218W92mdc=
+periph.io/x/host/v3 v3.8.5 h1:g4g5xE1XZtDiGl1UAJaUur1aT7uNiFLMkyMEiZ7IHII=
+periph.io/x/host/v3 v3.8.5/go.mod h1:hPq8dISZIc+UNfWoRj+bPH3XEBQqJPdFdx218W92mdc=

inky/impression.go

@@ -17,6 +17,7 @@
 	"periph.io/x/conn/v3"
 	"periph.io/x/conn/v3/display"
 	"periph.io/x/conn/v3/gpio"
+	"periph.io/x/conn/v3/gpio/gpioreg"
 	"periph.io/x/conn/v3/physic"
 	"periph.io/x/conn/v3/spi"
 )
@@ -28,36 +29,36 @@
 var (
 	// For more: https://github.com/pimoroni/inky/issues/115#issuecomment-887453065
 	dsc = []color.NRGBA{
-		{0, 0, 0, 0},         // Black
+		{0, 0, 0, 255},       // Black
 		{255, 255, 255, 255}, // White
 		{0, 255, 0, 255},     // Green
 		{0, 0, 255, 255},     // Blue
 		{255, 0, 0, 255},     // Red
 		{255, 255, 0, 255},   // Yellow
 		{255, 140, 0, 255},   // Orange
-		{255, 255, 255, 255},
+		{255, 255, 255, 0},   // Clear
 	}
 
 	sc = []color.NRGBA{
-		{57, 48, 57, 0},      // Black
+		{57, 48, 57, 255},    // Black
 		{255, 255, 255, 255}, // White
 		{58, 91, 70, 255},    // Green
 		{61, 59, 94, 255},    // Blue
 		{156, 72, 75, 255},   // Red
 		{208, 190, 71, 255},  // Yellow
 		{177, 106, 73, 255},  // Orange
-		{255, 255, 255, 255},
+		{255, 255, 255, 0},   // Clear
 	}
 
 	sc7 = []color.NRGBA{
-		{0, 0, 0, 0},         // Black
+		{0, 0, 0, 255},       // Black
 		{217, 242, 255, 255}, // White
 		{3, 124, 76, 255},    // Green
 		{27, 46, 198, 255},   // Blue
 		{245, 80, 34, 255},   // Red
 		{255, 255, 68, 255},  // Yellow
 		{239, 121, 44, 255},  // Orange
-		{255, 255, 255, 255},
+		{255, 255, 255, 0},   // Clear
 	}
 )
 
@@ -155,7 +156,7 @@
 	if o.Model == IMPRESSION73 {
 		cSpeed = acSpeed
 	}
-	c, err := p.Connect(cSpeed, spi.Mode0, cs0Pin)
+	c, err := p.Connect(cSpeed, spi.Mode0, 8)
 	if err != nil {
 		return nil, fmt.Errorf("failed to connect to inky over spi: %v", err)
 	}
@@ -173,6 +174,11 @@
 			maxTxSize = 4096 // Use a conservative default.
 		}
 	}
+	// If possible, grab the CS pin.
+	cs := gpioreg.ByName(cs0Pin)
+	if cs != nil && cs.Out(csDisabled) != nil {
+		cs = nil
+	}
 
 	d := &DevImpression{
 		Dev: Dev{
@@ -186,6 +192,7 @@
 			model:      o.Model,
 			variant:    o.DisplayVariant,
 			pcbVariant: o.PCBVariant,
+			cs:         cs,
 		},
 		saturation: 50, // Looks good enough for most of the images.
 	}
@@ -217,10 +224,10 @@
 }
 
 // blend recalculates the palette based on the saturation level.
-func (d *DevImpression) blend() []color.Color {
-	sat := float64(d.saturation / 100)
+func (d *DevImpression) blend() color.Palette {
+	sat := float64(d.saturation) / 100.0
 
-	pr := []color.Color{}
+	pr := make([]color.Color, 0)
 	for i := 0; i < 7; i++ {
 		var rs, gs, bs uint8
 		if d.Dev.model == IMPRESSION73 {
@@ -288,7 +295,7 @@
 
 	merged := make([]uint8, len(d.Pix)/2)
 	for i, offset := 0, 0; i < len(d.Pix)-1; i, offset = i+2, offset+1 {
-		merged[offset] = (d.Pix[i]<<4)&0xF0 | d.Pix[i+1]&0x0F
+		merged[offset] = ((d.Pix[i] << 4) & 0xF0) | (d.Pix[i+1] & 0x0F)
 	}
 
 	return d.update(merged)
@@ -519,17 +526,16 @@
 	}
 
 	// TODO there has to be a better way to force the white colour to be used instead of clear...
-	buf := make([]byte, len(pix))
 	for i := range pix {
 		if pix[i]&0xF == 7 {
-			buf[i] = (pix[i] & 0xF0) + 1
+			pix[i] = (pix[i] & 0xF0) + 1
 		}
 		if pix[i]&0xF0 == 0x70 {
-			buf[i] = (pix[i] & 0xF) + 0x10
+			pix[i] = (pix[i] & 0xF) + 0x10
 		}
 	}
 
-	if err := d.sendCommand(ac073TC1DTM, buf); err != nil {
+	if err := d.sendCommand(ac073TC1DTM, pix); err != nil {
 		return err
 	}
 
@@ -558,8 +564,28 @@
 		log.Printf("Err: %s", err)
 		return
 	}
+	if d.busy.Read() == gpio.High {
+		time.Sleep(dur)
+		return
+	}
 	// Wait for rising edges (Low -> High) or the timeout.
-	d.busy.WaitForEdge(dur)
+	tEnd := time.Now().Add(dur)
+	edgeDur := dur
+	for tEnd.After(time.Now()) {
+		// Debounce the edge
+		edge := d.busy.WaitForEdge(edgeDur)
+		if edge {
+			// The python driver is using 10ms debounce period
+			time.Sleep(10 * time.Millisecond)
+			l := d.busy.Read()
+			if l {
+				// It's still high. Return
+				return
+			}
+			// It was a bounce. Recalculate the duration to wait for the edge.
+			edgeDur = time.Until(tEnd)
+		}
+	}
 }
 
 // ColorModel returns the device native color model.
@@ -589,7 +615,7 @@
 // Draw updates the display with the image.
 func (d *DevImpression) Draw(r image.Rectangle, src image.Image, sp image.Point) error {
 	if r != d.Bounds() {
-		return fmt.Errorf("partial updates are not supported")
+		return fmt.Errorf("partial updates are not supported r=%#v bounds=%#v", r, d.Bounds())
 	}
 
 	if src.Bounds() != d.Bounds() {
@@ -598,6 +624,7 @@
 
 	// Dither the image using Floyd–Steinberg dithering algorithm otherwise it won't look as good on the screen.
 	draw.FloydSteinberg.Draw(d, r, src, image.Point{})
+
 	return d.Render()
 }
 

inky/inky.go

@@ -14,24 +14,27 @@
 	"periph.io/x/conn/v3"
 	"periph.io/x/conn/v3/display"
 	"periph.io/x/conn/v3/gpio"
+	"periph.io/x/conn/v3/gpio/gpioreg"
 	"periph.io/x/conn/v3/physic"
 	"periph.io/x/conn/v3/spi"
 )
 
 var _ display.Drawer = &Dev{}
 var _ conn.Resource = &Dev{}
 
-const (
-	cs0Pin = 8
-)
-
 var borderColor = map[Color]byte{
 	Black:  0x00,
 	Red:    0x73,
 	Yellow: 0x33,
 	White:  0x31,
 }
 
+const (
+	cs0Pin     = "GPIO8"
+	csEnabled  = gpio.Low
+	csDisabled = gpio.High
+)
+
 // Dev is a handle to an Inky.
 type Dev struct {
 	c conn.Conn
@@ -65,6 +68,8 @@
 	variant uint
 	// PCB Variant of the panel. Represents a version string as a number (12 -> 1.2).
 	pcbVariant uint
+	// cs is the chip-select pin for SPI. Refer to setCSPin() for information.
+	cs gpio.PinOut
 }
 
 // New opens a handle to an Inky pHAT or wHAT.
@@ -73,7 +78,7 @@
 		return nil, fmt.Errorf("unsupported color: %v", o.ModelColor)
 	}
 
-	c, err := p.Connect(488*physic.KiloHertz, spi.Mode0, cs0Pin)
+	c, err := p.Connect(488*physic.KiloHertz, spi.Mode0, 8)
 	if err != nil {
 		return nil, fmt.Errorf("failed to connect to inky over spi: %v", err)
 	}
@@ -87,7 +92,11 @@
 	if maxTxSize == 0 {
 		maxTxSize = 4096 // Use a conservative default.
 	}
-
+	// If possible, grab the CS pin.
+	cs := gpioreg.ByName(cs0Pin)
+	if cs != nil && cs.Out(csDisabled) != nil {
+		cs = nil
+	}
 	d := &Dev{
 		c:          c,
 		maxTxSize:  maxTxSize,
@@ -99,6 +108,7 @@
 		model:      o.Model,
 		variant:    o.DisplayVariant,
 		pcbVariant: o.PCBVariant,
+		cs:         cs,
 	}
 
 	switch o.Model {
@@ -330,43 +340,79 @@
 		}
 	}()
 	if err := d.sendCommand(0x12, nil); err != nil { // Soft Reset
-		return fmt.Errorf("failed to reset inky: %v", err)
+		return fmt.Errorf("inky: failed to reset inky: %v", err)
 	}
 	d.busy.WaitForEdge(-1)
 	return
 }
 
-func (d *Dev) sendCommand(command byte, data []byte) error {
-	if err := d.dc.Out(gpio.Low); err != nil {
-		return err
+// setCSPin sets the ChipSelect pin to the desired mode. The Pimoroni driver
+// uses manual control over the CS pin. To do this, they require the
+// Raspberry Pi /boot/firmware/config.txt to have dtloverlay=spi0-0cs set.
+//
+// So, if we run with automatic CS handling, we won't be compatible with the
+// pimoroni samples. If we run with manual control required, we then require
+// the dtoverlay setting. We really don't want to be incompatible with the
+// Pimoroni driver because that will confuse people. If the CS Pin is
+// not in use, use manual control, and if it is used by the SPI driver, let
+// it handle it.
+func (d *Dev) setCSPin(mode gpio.Level) error {
+	if d.cs != nil {
+		return d.cs.Out(mode)
+	}
+	return nil
+}
+
+func (d *Dev) sendCommand(command byte, data []byte) (err error) {
+	err = d.setCSPin(csEnabled)
+	if err != nil {
+		return
+	}
+
+	if err = d.dc.Out(gpio.Low); err != nil {
+		return
 	}
-	if err := d.c.Tx([]byte{command}, nil); err != nil {
-		return fmt.Errorf("failed to send command %x to inky: %v", command, err)
+	if err = d.c.Tx([]byte{command}, nil); err != nil {
+		err = fmt.Errorf("inky: failed to send command %x to inky: %v", command, err)
+		return
 	}
+	err = d.setCSPin(csDisabled)
+	if err != nil {
+		return
+	}
+
 	if data != nil {
-		if err := d.sendData(data); err != nil {
-			return fmt.Errorf("failed to send data for command %x to inky: %v", command, err)
+		if err = d.sendData(data); err != nil {
+			err = fmt.Errorf("inky: failed to send data for command %x to inky: %v", command, err)
+			return
 		}
 	}
-	return nil
+	return
 }
 
-func (d *Dev) sendData(data []byte) error {
-	if err := d.dc.Out(gpio.High); err != nil {
+func (d *Dev) sendData(data []byte) (err error) {
+	err = d.setCSPin(csEnabled)
+	if err != nil {
+		return
+	}
+	if err = d.dc.Out(gpio.High); err != nil {
 		return err
 	}
+
 	for len(data) != 0 {
 		var chunk []byte
 		if len(data) > d.maxTxSize {
 			chunk, data = data[:d.maxTxSize], data[d.maxTxSize:]
 		} else {
 			chunk, data = data, nil
 		}
-		if err := d.c.Tx(chunk, nil); err != nil {
-			return fmt.Errorf("failed to send data to inky: %v", err)
+		if err = d.c.Tx(chunk, nil); err != nil {
+			err = fmt.Errorf("inky: failed to send data to inky: %v", err)
+			return
 		}
 	}
-	return nil
+	err = d.setCSPin(csDisabled)
+	return
 }
 
 func pack(bits []bool) ([]byte, error) {

inky/types.go

@@ -69,6 +69,8 @@
 		*c = Yellow
 	case "white":
 		*c = White
+	case "multi":
+		*c = Multi
 	default:
 		return fmt.Errorf("unknown color %q: expected either black, red, yellow or white", s)
 	}