From 51561d4eabce53c99a4080c193a8d116e9c1b4a1 Mon Sep 17 00:00:00 2001
From: deadprogram <ron@hybridgroup.com>
Date: Sun, 14 Dec 2025 11:19:41 +0100
Subject: [PATCH] st7789: add Bus interface to accomodate both SPI and parallel
 connections to display

Signed-off-by: deadprogram <ron@hybridgroup.com>
---
 st7789/bus.go    | 8 ++++++++
 st7789/st7789.go | 6 +++---
 2 files changed, 11 insertions(+), 3 deletions(-)
 create mode 100644 st7789/bus.go

diff --git a/st7789/bus.go b/st7789/bus.go
new file mode 100644
index 0000000..44a2ea8
--- /dev/null
+++ b/st7789/bus.go
@@ -0,0 +1,8 @@
+package st7789
+
+// Bus is the interface that wraps the basic Tx and Transfer methods
+// for communication buses like SPI or Parallel.
+type Bus interface {
+	Tx(w, r []byte) error
+	Transfer(w byte) (byte, error)
+}
diff --git a/st7789/st7789.go b/st7789/st7789.go
index 561a559..838f284 100644
--- a/st7789/st7789.go
+++ b/st7789/st7789.go
@@ -46,7 +46,7 @@ type Device = DeviceOf[pixel.RGB565BE]
 // DeviceOf is a generic version of Device. It supports multiple different pixel
 // formats.
 type DeviceOf[T Color] struct {
-	bus             drivers.SPI
+	bus             Bus
 	dcPin           pin.OutputFunc
 	resetPin        pin.OutputFunc
 	csPin           pin.OutputFunc
@@ -84,13 +84,13 @@ type Config struct {
 }
 
 // New creates a new ST7789 connection. The SPI wire must already be configured.
-func New(bus drivers.SPI, resetPin, dcPin, csPin, blPin pin.Output) Device {
+func New(bus Bus, resetPin, dcPin, csPin, blPin pin.Output) Device {
 	return NewOf[pixel.RGB565BE](bus, resetPin, dcPin, csPin, blPin)
 }
 
 // NewOf creates a new ST7789 connection with a particular pixel format. The SPI
 // wire must already be configured.
-func NewOf[T Color](bus drivers.SPI, resetPin, dcPin, csPin, blPin pin.Output) DeviceOf[T] {
+func NewOf[T Color](bus Bus, resetPin, dcPin, csPin, blPin pin.Output) DeviceOf[T] {
 	// IMPORTANT: pin configuration should really be done outside of this
 	// driver, but for backwards compatibility with existing code, we do it
 	// here.