From 40a9f0ed77b720db44b49c6dbc049d0920952d91 Mon Sep 17 00:00:00 2001
From: Florian Brandes <florian.brandes@posteo.de>
Date: Fri, 12 May 2023 17:57:39 +0200
Subject: [PATCH] raspberry-pi."4": add assertion and update some source
 comments

Signed-off-by: Florian Brandes <florian.brandes@posteo.de>
---
 raspberry-pi/4/backlight.nix   |  3 ++-
 raspberry-pi/4/default.nix     | 10 +++++++++-
 raspberry-pi/4/modesetting.nix |  4 ++--
 3 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/raspberry-pi/4/backlight.nix b/raspberry-pi/4/backlight.nix
index f871421..31c0e90 100644
--- a/raspberry-pi/4/backlight.nix
+++ b/raspberry-pi/4/backlight.nix
@@ -16,8 +16,9 @@ in
     hardware.deviceTree = {
       overlays = [
         # This overlay was originally taken from:
-        # https://github.com/raspberrypi/linux/blob/rpi-5.15.y/arch/arm/boot/dts/overlays/rpi-backlight-overlay.dts
+        # https://github.com/raspberrypi/linux/blob/rpi-6.1.y/arch/arm/boot/dts/overlays/rpi-backlight-overlay.dts
         # The only modification made was to change the compatible field to bcm2711
+        # this is the same as for the 5.15.y kernel
         {
           name = "rpi-backlight-overlay";
           dtsText = ''
diff --git a/raspberry-pi/4/default.nix b/raspberry-pi/4/default.nix
index 6101698..acbfcf0 100644
--- a/raspberry-pi/4/default.nix
+++ b/raspberry-pi/4/default.nix
@@ -1,4 +1,4 @@
-{ lib, pkgs, ... }:
+{ lib, pkgs, config, ... }:
 
 {
   imports = [
@@ -34,6 +34,14 @@
 
   hardware.deviceTree.filter = "bcm2711-rpi-*.dtb";
 
+
+  assertions = [
+    {
+      assertion = (lib.versionAtLeast config.boot.kernelPackages.kernel.version "6.1");
+      message = "This version of raspberry pi 4 dts overlays requires a newer kernel version (>=6.1). Please upgrade nixpkgs for this system.";
+    }
+  ];
+
   # Required for the Wireless firmware
   hardware.enableRedistributableFirmware = true;
 }
diff --git a/raspberry-pi/4/modesetting.nix b/raspberry-pi/4/modesetting.nix
index b1f734b..b74e686 100644
--- a/raspberry-pi/4/modesetting.nix
+++ b/raspberry-pi/4/modesetting.nix
@@ -31,7 +31,7 @@ in
     hardware.deviceTree = {
       overlays = [
         # Equivalent to:
-        # https://github.com/raspberrypi/linux/blob/rpi-5.10.y/arch/arm/boot/dts/overlays/cma-overlay.dts
+        # https://github.com/raspberrypi/linux/blob/rpi-6.1.y/arch/arm/boot/dts/overlays/cma-overlay.dts
         {
           name = "rpi4-cma-overlay";
           dtsText = ''
@@ -52,7 +52,7 @@ in
           '';
         }
         # Equivalent to:
-        # https://github.com/raspberrypi/linux/blob/rpi-5.10.y/arch/arm/boot/dts/overlays/vc4-fkms-v3d-overlay.dts
+        # https://github.com/raspberrypi/linux/blob/rpi-6.1.y/arch/arm/boot/dts/overlays/vc4-fkms-v3d-overlay.dts
         {
           name = "rpi4-vc4-fkms-v3d-overlay";
           dtsText = ''