[alsa-devel] [PATCH 02/10] ALSA: hda - Bind codecs via standard bus

[Takashi Iwai]

At Sat, 28 Feb 2015 10:55:32 +0100,
Lars-Peter Clausen wrote:
> 
> On 02/26/2015 06:00 PM, Takashi Iwai wrote:
> > Now we create the standard HD-audio bus (/sys/bus/hdaudio), and bind
> > the codec driver with the codec device over there.  This is the first
> > step of the whole transition so that the changes to each codec driver
> > are kept as minimal as possible.
> >
> > Each codec driver needs to register hda_codec_driver struct containing
> > the currently existing preset via the new helper macro
> > module_hda_codec_driver().  The old hda_codec_preset_list is replaced
> > with this infrastructure.  The generic parsers (for HDMI and other)
> > are also included in the preset with the special IDs to bind
> > uniquely.
> >
> > In HD-audio core side, the device binding code is split to
> > hda_bind.c.  It provides the snd_hda_bus_type implementation to match
> > the codec driver with the given codec vendor ID.  It also manages the
> > module auto-loading by itself like before: when the matching isn't
> > found, it tries to probe the corresponding codec modules, and finally
> > falls back to the generic drivers.  (The special ID mentioned above is
> > set at this stage.)
> >
> > The only visible change to outside is that the hdaudio sysfs entry now
> > appears in /sys/bus/devices, not as a sound class device.
> >
> > More works to move the suspend/resume and remove ops will be
> > (hopefully) done in later patches.
> 
> Great stuff. AC'97 is next? ;)

Feel free to join to the club 97! :)

> [...]
> > +	drv->driver.probe = hda_codec_driver_probe;
> > +	drv->driver.remove = hda_codec_driver_remove;
> 
> Small nitpick, in my opinion it would be cleaner to use the snd_hda_bus_type 
> probe/remove callbacks for this.

Correct.  However, this would need more changes.  In this series, I'm
trying a gradual transition without a big surprise.  The merit of this
patch is that you need minimum changes in the codec driver side.

So, yes, I'm going to move to that direction, but in a later stage.


thanks,

Takashi