From: Olof Johansson <olof@lixom•net>
To: Jon Smirl <jonsmirl@gmail•com>
Cc: linuxppc-dev@ozlabs•org, i2c@lm-sensors•org
Subject: Re: [i2c] [PATCH 3/3] Add device tree compatible aliases to i2c drivers
Date: Thu, 24 Jan 2008 18:32:49 -0600 [thread overview]
Message-ID: <20080125003249.GA30794@lixom.net> (raw)
In-Reply-To: <20080123020916.31675.98481.stgit@terra.home>
On Tue, Jan 22, 2008 at 09:09:16PM -0500, Jon Smirl wrote:
> PowerPC device trees use a different naming convention than the Linux
> kernel. Provide alias names for i2c drivers in order to allow them to
> be loaded by device tree name. The OF_ID macro ensures that the aliases
> are only present in powerpc builds and separated into their own namespace.
Hmm. I just realized that there's yet another twist to the PPC device
bindings that's not yet considered:
Currently the device tree only contains one compatible field for most of
the devices. But it's perfectly legal (actually, recommended) to have more
than one compatible field -- they go from the specific to the generic.
For example, for an eeprom I might have: "MCHP,24lc128est",
"MCHP,24xx128", "24c128". The at24 driver (not in mainline yet :) would
likely match with "24c128", and it would normally not make sense to have
to list all specific vendors and models of the device type in question
in the driver.
I can't register a board_info for each of the compatible fields without
changing the way the i2c drivers are registered, since the creation of
the duplicate entries will start reporting errors. I also shouldn't
(reasonably) have to register every single possible first (i.e. most
specific) compatible-field -- that goes against the whole concept of
having more than one compatible string.
So it seems that the solution would be to make i2c_board_info take a
list of names for the device, and each of them has to be matched with
all drivers, taking the first match.
Sounds reasonable to everyone? I can provide a patch to go on top of
what's already proposed.
-Olof
next prev parent reply other threads:[~2008-01-25 0:21 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-23 2:09 [PATCH 1/3] Rename i2c-mpc to i2c-mpc-drv in preparation for breaking out common code Jon Smirl
2008-01-23 2:09 ` [PATCH 2/3] Convert PowerPC MPC i2c to of_platform_driver from platform_driver Jon Smirl
2008-01-23 3:11 ` Stephen Rothwell
2008-01-23 4:18 ` Jon Smirl
2008-01-23 14:31 ` Jon Loeliger
2008-01-23 14:40 ` Jon Smirl
2008-01-23 2:09 ` [PATCH 3/3] Add device tree compatible aliases to i2c drivers Jon Smirl
2008-01-23 20:18 ` Matt Sealey
2008-01-23 20:30 ` Jon Smirl
2008-02-01 7:32 ` David Gibson
2008-01-25 0:32 ` Olof Johansson [this message]
2008-01-25 0:33 ` [i2c] " Scott Wood
2008-01-25 0:48 ` Jon Smirl
2008-01-25 0:38 ` Jon Smirl
2008-01-23 2:46 ` [PATCH 1/3] Rename i2c-mpc to i2c-mpc-drv in preparation for breaking out common code Stephen Rothwell
2008-01-23 2:50 ` Jon Smirl
2008-01-23 3:02 ` Grant Likely
2008-01-23 3:09 ` Jon Smirl
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