[alsa-devel] tegra_wm8903 dapm_nc_pins

Stephen Warren swarren at nvidia.com
Thu Oct 20 17:53:54 CEST 2011

Julian Scheel wrote at Wednesday, October 19, 2011 11:27 PM:
> Am 19.10.2011 um 18:12 schrieb Stephen Warren:
> > I believe the idea was to keep as much as possible of the audio related
> > information in the audio drivers rather than in board files. The GPIO
> > IDs are in platform data since the audio driver can't reach into the
> > mach-tegra gpio_names header since it's not public.
> Ok.
> > What I'd like to see in the nc_pins case is the DAPM core automatically
> > perform these calls based on which pins the codec has which aren't
> > mentioned in card->dapm_routes; I haven't investigated whether that's
> > actually possible without breaking unrelated boards though.
> Well actually the current state can break unrelated boards as well.

By "unrelated", I meant boards other than Tegra boards; AFAIK, the current
Tegra driver isn't broken for any board that the current driver expects to

> > Eventually, I see most of these tables moving into device-tree, with
> > the only thing hard-coded into tegra_wm8903.c being all the clock and
> > format setup code.
> I am not aware how much work this would be, as I have not yet worked with
> device tree at all. I would propose to change the init code to auto detection
> based on the dapm routes for now. I should find the time to make up a patch,
> if you agree.

I believe a secretlab employee was working on DT bindings for the Tegra+WM8903
machine driver, although I haven't seen any updates on this front recently.

By all means make the existing driver calculate the nc pins automatically.
I suspect the implementation should probably be in the ASoC core, and Mark
pointed out it should be optional so as not to break any other (non-Tegra
WM8903) boards.


More information about the Alsa-devel mailing list