From 496b7da511701c2cd895689554e4869fd23728e2 Mon Sep 17 00:00:00 2001
From: Gavin John <gavinnjohn@gmail.com>
Date: Mon, 6 Jan 2025 14:45:39 -0500
Subject: [PATCH] nixos/hardware/stlink: add ST-Link udev rules

---
 nixos/modules/hardware/stlink.nix | 71 +++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 nixos/modules/hardware/stlink.nix

diff --git a/nixos/modules/hardware/stlink.nix b/nixos/modules/hardware/stlink.nix
new file mode 100644
index 0000000000000..c90c0bef3fa84
--- /dev/null
+++ b/nixos/modules/hardware/stlink.nix
@@ -0,0 +1,71 @@
+{
+  lib,
+  config,
+  options,
+  ...
+}:
+let
+  cfg = config.hardware.stlink;
+  opt = options.hardware.stlink;
+in
+{
+  options.hardware.stlink = {
+    enable = lib.mkEnableOption "udev rules for ST-Link programmer devices";
+    owner = lib.mkOption {
+      type = lib.types.str;
+      default = "root";
+      example = "nobody";
+      description = "Owner of ST-Link devices";
+    };
+    group = lib.mkOption {
+      type = lib.types.str;
+      default = "plugdev";
+      example = "nobody";
+      description = "Group of ST-Link devices";
+    };
+    mode = lib.mkOption {
+      type = lib.types.str;
+      default = "0660";
+      example = "0640";
+      description = "Mode of ST-Link devices";
+    };
+  };
+
+  config = lib.mkMerge [
+    (lib.mkIf cfg.enable {
+      assertions = [
+        {
+          assertion = builtins.hasAttr cfg.owner config.users.users;
+          message = "Owner '${cfg.owner}' set in `${opt.owner}` is not configured via `${options.users.users}.\"${cfg.owner}\"`.";
+        }
+        {
+          assertion = (cfg.group == opt.group.default) || (builtins.hasAttr cfg.group config.users.groups);
+          message = "Group '${cfg.group}' set in `${opt.group}` is not configured via `${options.users.groups}.\"${cfg.group}\"`.";
+        }
+      ];
+      # Source: https://www.linux-usb.org/usb.ids
+      services.udev.extraRules = ''
+        # ST-Link V1
+        SUBSYSTEM=="usb", ATTR{idVendor}=="0483", ATTR{idProduct}=="3744", OWNER="${cfg.owner}", GROUP="${cfg.group}", MODE="${cfg.mode}"
+
+        # ST-Link V2
+        SUBSYSTEM=="usb", ATTR{idVendor}=="0483", ATTR{idProduct}=="3748", OWNER="${cfg.owner}", GROUP="${cfg.group}", MODE="${cfg.mode}"
+        SUBSYSTEM=="usb", ATTR{idVendor}=="0483", ATTR{idProduct}=="3752", OWNER="${cfg.owner}", GROUP="${cfg.group}", MODE="${cfg.mode}"
+
+        # ST-Link V2.1
+        SUBSYSTEM=="usb", ATTR{idVendor}=="0483", ATTR{idProduct}=="374b", OWNER="${cfg.owner}", GROUP="${cfg.group}", MODE="${cfg.mode}"
+        SUBSYSTEM=="usb", ATTR{idVendor}=="0483", ATTR{idProduct}=="3752", OWNER="${cfg.owner}", GROUP="${cfg.group}", MODE="${cfg.mode}"
+
+        # ST-Link V3
+        SUBSYSTEM=="usb", ATTR{idVendor}=="0483", ATTR{idProduct}=="374e", OWNER="${cfg.owner}", GROUP="${cfg.group}", MODE="${cfg.mode}"
+        SUBSYSTEM=="usb", ATTR{idVendor}=="0483", ATTR{idProduct}=="374f", OWNER="${cfg.owner}", GROUP="${cfg.group}", MODE="${cfg.mode}"
+        SUBSYSTEM=="usb", ATTR{idVendor}=="0483", ATTR{idProduct}=="3753", OWNER="${cfg.owner}", GROUP="${cfg.group}", MODE="${cfg.mode}"
+        # ST-Link V3 Loader (what is this?)
+        SUBSYSTEM=="usb", ATTR{idVendor}=="0483", ATTR{idProduct}=="374d", OWNER="${cfg.owner}", GROUP="${cfg.group}", MODE="${cfg.mode}"
+      '';
+      users.groups.plugdev = lib.mkIf (config.group == "plugdev") { };
+    })
+  ];
+
+  meta.maintainers = with lib.maintainers; [ pandapip1 ];
+}