From fa440510ab99af2f42c4dd56e9c4dc569933127a Mon Sep 17 00:00:00 2001
From: Daniel Schaefer <dhs@frame.work>
Date: Mon, 19 Jan 2026 00:50:42 +0800
Subject: [PATCH] Remove chipselect control

SpiDevice actually means that the bus is shared and the chip select
should not be controlled by the driver but by the firmware that manages
the whole bus!

So remove it from here to avoid interfering with the rest of the bus.

Signed-off-by: Daniel Schaefer <dhs@frame.work>
---
 src/lib.rs | 32 ++++++++++++--------------------
 1 file changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 96b1f48..ad151fa 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -97,10 +97,11 @@ impl FpsConfig {
 }
 
 /// ST7306 driver to connect to TFT displays.
-pub struct ST7306<SPI, DC, CS, RST, const COLS: usize, const ROWS: usize>
+///
+/// CS (chip select) is managed by the SpiDevice implementation.
+pub struct ST7306<SPI, DC, RST, const COLS: usize, const ROWS: usize>
 where
     DC: OutputPin,
-    CS: OutputPin,
     RST: OutputPin,
 {
     /// SPI
@@ -109,9 +110,6 @@ where
     /// Data/command pin.
     pub dc: DC,
 
-    /// Chip select pin
-    pub cs: CS,
-
     /// Reset pin.
     pub rst: RST,
 
@@ -155,18 +153,18 @@ pub enum Orientation {
     LandscapeSwapped = 0xA0,
 }
 
-impl<SPI, DC, CS, RST, const COLS: usize, const ROWS: usize> ST7306<SPI, DC, CS, RST, COLS, ROWS>
+impl<SPI, DC, RST, const COLS: usize, const ROWS: usize> ST7306<SPI, DC, RST, COLS, ROWS>
 where
     SPI: SpiDevice,
     DC: OutputPin,
-    CS: OutputPin,
     RST: OutputPin,
 {
     /// Creates a new driver instance that uses hardware SPI.
+    ///
+    /// CS (chip select) is managed by the SpiDevice implementation.
     pub fn new(
         spi: SPI,
         dc: DC,
-        cs: CS,
         rst: RST,
         inverted: bool,
         autopowerdown: bool,
@@ -193,7 +191,6 @@ where
         ST7306 {
             spi,
             dc,
-            cs,
             rst,
             inverted,
             framebuffer: [[[0; 3]; COLS]; ROWS],
@@ -553,25 +550,22 @@ where
 
     /// Write a command with optional parameters
     ///
-    /// This function makes sure CS and DC pins are set correctly
+    /// CS is managed by the SpiDevice, DC is set appropriately for command/data.
     pub fn write_command(&mut self, command: Instruction, params: &[u8]) -> Result<(), ()> {
-        self.cs.set_low().map_err(|_| ())?;
         self.dc.set_low().map_err(|_| ())?;
         self.spi.write(&[command as u8]).map_err(|_| ())?;
         if !params.is_empty() {
             self.start_data()?;
             self.write_command_data(params)?;
         }
-        self.cs.set_high().map_err(|_| ())?;
         Ok(())
     }
 
-    /// Before writing data, the CS and DC pins must be set correctly
+    /// Set DC pin high for data transfer.
     ///
     /// This command can be used if you want to write extra data, in addition
     /// to a command's parameters.
     pub fn start_data(&mut self) -> Result<(), ()> {
-        self.cs.set_low().map_err(|_| ())?;
         self.dc.set_high().map_err(|_| ())
     }
 
@@ -703,12 +697,11 @@ fn col_to_bright(color: Rgb565) -> u8 {
 
 #[cfg(feature = "graphics")]
 // TODO: Remove color support from here
-impl<SPI, DC, CS, RST, const COLS: usize, const ROWS: usize> DrawTarget
-    for ST7306<SPI, DC, CS, RST, COLS, ROWS>
+impl<SPI, DC, RST, const COLS: usize, const ROWS: usize> DrawTarget
+    for ST7306<SPI, DC, RST, COLS, ROWS>
 where
     SPI: SpiDevice,
     DC: OutputPin,
-    CS: OutputPin,
     RST: OutputPin,
 {
     type Error = ();
@@ -778,12 +771,11 @@ where
 }
 
 #[cfg(feature = "graphics")]
-impl<SPI, DC, CS, RST, const COLS: usize, const ROWS: usize> OriginDimensions
-    for ST7306<SPI, DC, CS, RST, COLS, ROWS>
+impl<SPI, DC, RST, const COLS: usize, const ROWS: usize> OriginDimensions
+    for ST7306<SPI, DC, RST, COLS, ROWS>
 where
     SPI: SpiDevice,
     DC: OutputPin,
-    CS: OutputPin,
     RST: OutputPin,
 {
     fn size(&self) -> Size {