From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from moutng.kundenserver.de (moutng.kundenserver.de [212.227.126.183]) by ozlabs.org (Postfix) with ESMTP id 1961FDDFE6 for ; Tue, 29 Apr 2008 02:17:32 +1000 (EST) Subject: Re: [PATCH 1/2] i2c: Add support for device alias names From: Kay Sievers To: Jean Delvare In-Reply-To: <20080428174010.5a40c2c0@hyperion.delvare> References: <20080428113052.6d024bda@hyperion.delvare> <20080428113901.2772e9d9@hyperion.delvare> <1209395245.3666.9.camel@linux.site> <20080428174010.5a40c2c0@hyperion.delvare> Content-Type: text/plain; charset=utf-8 Date: Mon, 28 Apr 2008 18:16:17 +0200 Message-Id: <1209399377.3666.30.camel@linux.site> Mime-Version: 1.0 Cc: linuxppc-dev list , Paul Mundt , Scott Wood , Linux I2C List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, 2008-04-28 at 17:40 +0200, Jean Delvare wrote: > On Mon, 28 Apr 2008 17:07:25 +0200, Kay Sievers wrote: > > On Mon, 2008-04-28 at 11:39 +0200, Jean Delvare wrote: > > > One thing I am still not happy with is that the aliases created have = a > > > trailing "*": > > >=20 > > > $ /sbin/modinfo lm90 > > > filename: /lib/modules/2.6.25-git11/kernel/drivers/hwmon/lm90.k= o > > > author: Jean Delvare > > > description: LM90/ADM1032 driver > > > license: GPL > > > vermagic: 2.6.25-git11 mod_unload > > > depends: hwmon > > > alias: i2c:lm90* > > > alias: i2c:adm1032* > > > alias: i2c:lm99* > > > alias: i2c:lm86* > > > alias: i2c:max6657* > > > alias: i2c:adt7461* > > > alias: i2c:max6680* > > > $ > > >=20 > > > This would cause trouble if one I2C chip name matches the beginning o= f > > > another I2C chip name and both chips are supported by different > > > drivers. This has yet to be seen, but still, I'd like to see this > > > problem fixed quickly. > >=20 > > =EF=BB=BFRight, the trailing "*" is not nice. > >=20 > > We should terminate the string, so the trailing "*" will not match > > longer strings. The usual thing is to add a ":" to the end, which would > > then show up as > > alias: i2c:max6680:* > >=20 > > See DMI and ACPI: > > alias dmi:*:svnFUJITSU:pnLifeBook*:pvr*:rvnFUJITSU:* apanel > > alias acpi*:ASIM0000:* atlas_btns >=20 > I didn't know about these cases, thanks for the hint. >=20 > >=20 > > If i2c device modaliases could ever contain multiple strings, it should > > be: > > alias: i2c*:max6680:* > > =EF=BB=BFto match the module, regardless of the order of the strings in= the > > modalias: >=20 > Why would i2c device modaliases ever contain multiple strings? A device > can't have multiple names, can it? Like ACPI/PNP devices, which can have several compat id's, which means that a single device can have "multiple names": $ cat /sys/bus/pnp/devices/00:09/id IBM0057 PNP0f13 > Adding a ":" at the end of the i2c device names solves the problem I > was mentioning, sure, but why don't we simply remove the trailing "*", > instead of trying to work around it? A trailing "*" simply makes no > sense for aliases which are simple device names. Sure, if there is only one single string, it's not useful. > This is not only i2c > devices, but also platform devices, acpi, dmi, pnp... ACPI, DMI, PNP (PNP does not do modalias) needs to be able to match only one string in a given list, so the trailing "*" is needed. > Looking at the > various device types handled by file2alias.c, it seems that most of > them don't need the trailing "*", and many of them have the problem I > was mentioning. >=20 > Can't we just stop handle_moddevtable() from adding a tailing "*" > automatically, and just let the device types which need it, add it on > their own? For a lot subsystems it's fine to have it appended, as there is a defined list of identifiers, which must appear in the same order, and new identifiers are appended to the end. So the "*" still matches modules with possibly extended modalias strings. We would also need to review all buses which export modalias, if they need the "*" or not, and add them by hand, if needed. I guess, it's easier to introduce an additional parameter to file2alias::do_table() and suppress the trailing "*" for i2c? Thanks, Kay