Re: [PATCH 5.15.y] ASoC: cs42l51: fix driver to properly autoload with automatic module loading

[Thomas Petazzoni <thomas.petazzoni@bootlin.com>]

Hello Greg,

On Tue, 1 Aug 2023 10:03:26 +0200
Greg KH <gregkh@linuxfoundation.org> wrote:

> On Thu, Jul 27, 2023 at 02:33:39PM +0200, Thomas Petazzoni wrote:
> > In commit 2cb1e0259f50 ("ASoC: cs42l51: re-hook of_match_table
> > pointer"), 9 years ago, some random guy fixed the cs42l51 after it was
> > split into a core part and an I2C part to properly match based on a
> > Device Tree compatible string.
> > 
> > However, the fix in this commit is wrong: the MODULE_DEVICE_TABLE(of,
> > ....) is in the core part of the driver, not the I2C part. Therefore,
> > automatic module loading based on module.alias, based on matching with
> > the DT compatible string, loads the core part of the driver, but not
> > the I2C part. And threfore, the i2c_driver is not registered, and the
> > codec is not known to the system, nor matched with a DT node with the
> > corresponding compatible string.
> > 
> > In order to fix that, we move the MODULE_DEVICE_TABLE(of, ...) into
> > the I2C part of the driver. The cs42l51_of_match[] array is also moved
> > as well, as it is not possible to have this definition in one file,
> > and the MODULE_DEVICE_TABLE(of, ...) invocation in another file, due
> > to how MODULE_DEVICE_TABLE works.
> > 
> > Thanks to this commit, the I2C part of the driver now properly
> > autoloads, and thanks to its dependency on the core part, the core
> > part gets autoloaded as well, resulting in a functional sound card
> > without having to manually load kernel modules.
> > 
> > Fixes: 2cb1e0259f50 ("ASoC: cs42l51: re-hook of_match_table pointer")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
> > ---
> >  sound/soc/codecs/cs42l51-i2c.c | 6 ++++++
> >  sound/soc/codecs/cs42l51.c     | 7 -------
> >  sound/soc/codecs/cs42l51.h     | 1 -
> >  3 files changed, 6 insertions(+), 8 deletions(-)  
> 
> What is the git commit id of this change in Linus's tree?

Ah, I see I didn't do "git cherry-pick -x
e51df4f81b02bcdd828a04de7c1eb6a92988b61e", so the commit log doesn't
have the reference to the original commit, sorry about this.

The original commit in Linus tree is:

  https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e51df4f81b02bcdd828a04de7c1eb6a92988b61e

Thanks!

Thomas
-- 
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com