Add simpler way to configure udev rules and ready to use udev rule file

It turns out that we can allow udev access to any USB hub using DRIVER=="hub"
udev filter, this should make it easier for linux ditros to add proper udev rules.

This change adds more documentation to README, and also adds ready to use udev rule
that should work for any USB hub and any Linux kernel version.

Author: mvp

README.md

@@ -222,25 +222,25 @@ This is why there are additional rules for 6.0+ kernels.
 There is no harm in having these rules on systems running older kernel versions.
 
 To fix USB permissions, first run `sudo uhubctl` and note all `vid:pid` for hubs you need to control.
-Then, add one or more udev rules like below to file `/etc/udev/rules.d/52-usb.rules` (replace 2001 with your vendor id):
+Then, add udev rules like below to file `/etc/udev/rules.d/52-usb.rules`
+(replace `2001` with your hub vendor id, or completely remove `ATTR{idVendor}` filter to allow any USB hub access):
 
-    SUBSYSTEM=="usb", ATTR{idVendor}=="2001", MODE="0666"
-
-    # Linux 6.0 or later (its ok to have this block present in older Linux):
+    SUBSYSTEM=="usb", DRIVER=="hub", MODE="0666", ATTR{idVendor}=="2001"
+    # Linux 6.0 or later (its ok to have this block present for older Linux kernels):
     SUBSYSTEM=="usb", DRIVER=="hub", \
       RUN="/bin/sh -c \"chmod -f 666 $sys$devpath/*-port*/disable || true\""
 
 Note that for USB3 hubs, some hubs use different vendor ID for USB2 vs USB3 components of the same chip,
-and both need permissions to make uhubctl work properly. E.g. for Raspberry Pi 4B, you need to add these 2 lines:
+and both need permissions to make uhubctl work properly.
+E.g. for Raspberry Pi 4B, you need to add these 2 lines (or remove idVendor filter):
 
-    SUBSYSTEM=="usb", ATTR{idVendor}=="2109", MODE="0666"
-    SUBSYSTEM=="usb", ATTR{idVendor}=="1d6b", MODE="0666"
+    SUBSYSTEM=="usb", DRIVER=="hub", MODE="0666", ATTR{idVendor}=="2109"
+    SUBSYSTEM=="usb", DRIVER=="hub", MODE="0666", ATTR{idVendor}=="1d6b"
 
 If you don't like wide open mode `0666`, you can restrict access by group like this:
 
-    SUBSYSTEM=="usb", ATTR{idVendor}=="2001", MODE="0664", GROUP="dialout"
-
-    # Linux 6.0 or later (its ok to have this block present in older Linux):
+    SUBSYSTEM=="usb", DRIVER=="hub", MODE="0664", GROUP="dialout"
+    # Linux 6.0 or later (its ok to have this block present for older Linux kernels):
     SUBSYSTEM=="usb", DRIVER=="hub", \
       RUN+="/bin/sh -c \"chown -f root:dialout $sys$devpath/*-port*/disable || true\"" \
       RUN+="/bin/sh -c \"chmod -f 660 $sys$devpath/*-port*/disable || true\""
@@ -253,6 +253,7 @@ For your `udev` rule changes to take effect, reboot or run:
 
     sudo udevadm trigger --attr-match=subsystem=usb
 
+For your convenience, ready to use udev rule is provided [here](https://github.com/mvp/uhubctl/blob/master/udev/rules.d/52-usb.rules).
 
 
 FAQ

udev/rules.d/52-usb.rules

@@ -0,0 +1,24 @@
+# uhubctl – USB hub per-port power control https://github.com/mvp/uhubctl
+#
+# Copyright (c) 2009-2022, Vadim Mikhailov
+#
+# This file can be distributed under the terms and conditions of the
+# GNU General Public License version 2.
+
+# uhubctl udev rules for rootless operation on Linux for users in group `dialout`.
+#
+# Copy this file to /etc/udev/rules.d, then reboot or run:
+#
+#   sudo udevadm trigger --attr-match=subsystem=usb
+#
+# To add yourself to this permission group, run:
+#
+#   sudo usermod -a -G dialout $USER
+
+# This is for Linux before 6.0:
+SUBSYSTEM=="usb", DRIVER=="hub", MODE="0664", GROUP="dialout"
+
+# This is for Linux 6.0 or later (ok to keep this block present for older Linux kernels):
+SUBSYSTEM=="usb", DRIVER=="hub", \
+  RUN+="/bin/sh -c \"chown -f root:dialout $sys$devpath/*-port*/disable || true\"" \
+  RUN+="/bin/sh -c \"chmod -f 660 $sys$devpath/*-port*/disable || true\""