Re: [PATCH v3 10/13] ASoC: tegra: Add audio graph based card driver

[Sameer Pujar]

> > Add Tegra audio machine driver which is based on generic audio graph card
> > driver. It re-uses most of the common stuff from audio graph driver and
> > uses the same DT binding. Required Tegra specific customizations are done
> > in the driver.
> (snip)
> > +static const struct snd_soc_ops tegra_audio_graph_ops = {
> > +     .startup        = asoc_simple_startup,
> > +     .shutdown       = asoc_simple_shutdown,
> > +     .hw_params      = tegra_audio_graph_hw_params,
> > +};
> This is just an idea,
> but can we use hooks here somehow ?
>
>          .ops_hook_pre
>          .ops_hook_func
>          .ops_hook_post
>
>          if (priv->ops_hook_pre->func)
>                  priv->ops_hook_pre->func_pre(...);
>
>          if (priv->ops_hook_func->func)
>                  priv->ops_hook_func->func(...); /* driver's function */
>          else
>                  graph_func(...);        /* audio-graph function */
>
>          if (priv->ops_hook_post->func)
>                  priv->ops_hook_post->func(...);

Right now I just required to populate some flags or structures and do 
not have any specific pre()/post() functions to be called. Can this be 
reserved for later?

> > +static int tegra_audio_graph_probe(struct platform_device *pdev)
> > +{
> > +     struct asoc_simple_priv *priv;
> > +     struct device *dev = &pdev->dev;
> > +     struct snd_soc_card *card;
> > +     struct link_info li;
> > +     int err;
> > +
> > +     /* Allocate the private data and the DAI link array */
> > +     priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> > +     if (!priv)
> > +             return -ENOMEM;
> > +
> > +     priv->data = (struct tegra_audio_graph_data *)
> > +             devm_kzalloc(dev, sizeof(*priv->data), GFP_KERNEL);
> > +     if (!priv->data)
> > +             return -ENOMEM;
> > +
> > +     card = simple_priv_to_card(priv);
> > +
> > +     card->owner = THIS_MODULE;
> > +     card->dev = dev;
> > +     card->component_chaining = true;
> > +     card->probe = tegra_audio_graph_card_probe;
> > +
> > +     priv->ops = &tegra_audio_graph_ops;
> > +     priv->force_dpcm = 1;
> > +
> > +     memset(&li, 0, sizeof(li));
> > +     graph_get_dais_count(priv, &li);
> > +     if (!li.link || !li.dais)
> > +             return -EINVAL;
> > +
> > +     err = asoc_simple_init_priv(priv, &li);
> > +     if (err < 0)
> > +             return err;
> > +
> > +     err = graph_parse_of(priv);
> > +     if (err < 0) {
> > +             if (err != -EPROBE_DEFER)
> > +                     dev_err(dev, "Parse error %d\n", err);
> > +             goto cleanup;
> > +     }
> > +
> > +     snd_soc_card_set_drvdata(card, priv);
> > +
> > +     asoc_simple_debug_info(priv);
> > +
> > +     err = devm_snd_soc_register_card(dev, card);
> > +     if (err < 0)
> > +             goto cleanup;
> > +
> > +     return 0;
> > +
> > +cleanup:
> > +     asoc_simple_clean_reference(card);
> > +
> > +     return err;
> > +}

> These are almost same as graph_probe().
> Maybe we can separate graph_probe() and export function ?

Yes possible, I can move more stuff into graph_parse_of() which is 
already an exported function in the current series. This can be utilized 
by both generic audio graph and Tegra audio graph.

Something like below,

static int tegra_audio_graph_probe(struct platform_device *pdev)
{
        struct tegra_audio_priv *priv;
        struct device *dev = &pdev->dev;
        struct snd_soc_card *card;

        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        card = simple_priv_to_card(&priv->simple);

        card->owner = THIS_MODULE;
        card->dev = dev;
        card->probe = tegra_audio_graph_card_probe;

        /* graph_parse_of() depends on below */
        card->component_chaining = 1;
        priv->simple.ops = &tegra_audio_graph_ops;
        priv->simple.force_dpcm = 1;

        return graph_parse_of(&priv->simple);
}

Does this sound fine?