On Wed, Oct 01, 2014 at 11:28:46AM +0200, Jean-Francois Moine wrote:
> On Tue, 30 Sep 2014 20:25:40 +0100
> Mark Brown <broonie@xxxxxxxxxx> wrote:
>
> > > + request_module("snd-soc-hdmi-codec");
> > > + pdev = platform_device_register_resndata(&priv->hdmi->dev,
> > > + "hdmi-audio-codec",
> > > + PLATFORM_DEVID_NONE,
> > > + NULL, 0,
> > > + &tda998x_hdmi_data,
> > > + sizeof tda998x_hdmi_data);
> >
> > Why is this request_module() needed? If there is a good reason for it
> > we should have some documentation.
>
> The reason is simple: as the HDMI CODEC is not declared in the DT, the
> associated module must be loaded in memory.
Module auto-loading works in non-DT environments too. Unlike the
direction that the arm port is going, the core kernel features, such
as driver autoloading, are coded *not* to require DT (or indeed any
particular firmware.)
There are circumstances where this has been lost sight of (such as
the gpiod stuff), but as a general rule, features do not rely on DT.
Platform drivers will be auto-loaded if they have:
MODULE_ALIAS(PLATFORM_MODULE_PREFIX DRIVER_NAME);
and DRIVER_NAME matches the non-id part of the platform device name.
In the case of platform driver ID tables:
MODULE_DEVICE_TABLE(platform, id-table);
--
FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up
according to speedtest.net.
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