From 4d994458f02482a659e0f7580576c92e950321d1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michael=20B=C3=BCchler?= <michael.buechler@posteo.net>
Date: Mon, 25 Sep 2023 05:00:13 +0200
Subject: [PATCH] Document the RP2040-specific PS/2 implementation (#22079)

Co-authored-by: Dasky <32983009+daskygit@users.noreply.github.com>
---
 docs/feature_ps2_mouse.md                     | 23 +++++++++++++++++++
 .../drivers/vendor/RP/RP2040/ps2_vendor.c     |  2 +-
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/docs/feature_ps2_mouse.md b/docs/feature_ps2_mouse.md
index e714d9b867..766fd6fe78 100644
--- a/docs/feature_ps2_mouse.md
+++ b/docs/feature_ps2_mouse.md
@@ -155,6 +155,29 @@ In your keyboard config.h:
 #endif
 ```
 
+### RP2040 PIO Version :id=rp2040-pio-version
+
+The `PIO` subsystem is a Raspberry Pi RP2040 specific implementation, using the integrated PIO peripheral and is therefore only available on this MCU.
+
+There are strict requirements for pin ordering but any pair of GPIO pins can be used. The GPIO used for clock must be directly after data, see the included info.json snippet for an example of correct order.
+
+You may optionally switch the PIO peripheral used with the following define in config.h:
+```c
+#define PS2_PIO_USE_PIO1 // Force the usage of PIO1 peripheral, by default the PS2 implementation uses the PIO0 peripheral
+```
+
+Example info.json content:
+
+```json
+    "ps2": {
+        "clock_pin": "GP1",
+        "data_pin": "GP0",
+        "driver": "vendor",
+        "enabled": true,
+        "mouse_enabled": true
+    }
+```
+
 ## Additional Settings :id=additional-settings
 
 ### PS/2 Mouse Features :id=ps2-mouse-features
diff --git a/platforms/chibios/drivers/vendor/RP/RP2040/ps2_vendor.c b/platforms/chibios/drivers/vendor/RP/RP2040/ps2_vendor.c
index 119c6354b0..1c61f196bd 100644
--- a/platforms/chibios/drivers/vendor/RP/RP2040/ps2_vendor.c
+++ b/platforms/chibios/drivers/vendor/RP/RP2040/ps2_vendor.c
@@ -22,7 +22,7 @@
 #endif
 
 #if PS2_DATA_PIN + 1 != PS2_CLOCK_PIN
-#    error PS/2 Clock pin must be followed by data pin!
+#    error PS/2 clock pin must be data pin + 1!
 #endif
 
 static inline void pio_serve_interrupt(void);