#!/usr/bin/python
"""
Decide numbers for ALSA devices from their sysfs device paths.
Adam Sampson <ats@offog.org>

This is based on the script from <http://alsa.opensrc.org/index.php/Udev>.

Install this script as /etc/udev/alsa-name, and make it executable.
Put the following rules in /etc/udev/rules.d/10-alsa-name.rules (so they run
before whatever your distribution provides):

KERNEL=="controlC*", PROGRAM="/etc/udev/alsa-name %k %p", NAME="snd/%c{1}", MODE="0666"
KERNEL=="hw*",       PROGRAM="/etc/udev/alsa-name %k %p", NAME="snd/%c{1}", MODE="0662"
KERNEL=="pcmC*c",    PROGRAM="/etc/udev/alsa-name %k %p", NAME="snd/%c{1}", MODE="0662"
KERNEL=="pcmC*p",    PROGRAM="/etc/udev/alsa-name %k %p", NAME="snd/%c{1}", MODE="0666"
KERNEL=="midiC*",    PROGRAM="/etc/udev/alsa-name %k %p", NAME="snd/%c{1}", MODE="0666"
KERNEL=="timer",     NAME="snd/%k", MODE="0666"
KERNEL=="seq",       NAME="snd/%k", MODE="0666"
"""

# A list of pairs: (device path regexp to match, card number).
# I'm just matching against PCI device numbers for my machine;
# you'll need to customise this for your own sound devices.
DEVICE_MAP = [
	("0000:02:02.0", 0),  # ice1712
	("0000:02:01.1", 1),  # bt87x
	("0000:00:1f.5", 2),  # Intel onboard
	]

import sys, os, re

alsaname = sys.argv[1]
devpath = sys.argv[2]

num = None
for r, n in DEVICE_MAP:
	if re.search(r, devpath) is not None:
		num = n

if num is not None:
	alsaname = re.sub(r'C([0-9]+)', "C%d" % num, alsaname)

print alsaname
sys.exit(0)