Re: [PATCH 2/2] ASoC: SOF: Intel: add trigger callback into sdw_callback

[Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>]

>>>> @@ -809,6 +814,10 @@ void hda_set_dai_drv_ops(struct snd_sof_dev *sdev, struct snd_sof_dsp_ops *ops)
>>>>  		if (!hda_use_tplg_nhlt)
>>>>  			ipc4_data->nhlt = intel_nhlt_init(sdev->dev);
>>>>  
>>>> +#if IS_ENABLED(CONFIG_SND_SOC_SOF_INTEL_SOUNDWIRE)
>>>> +		sdw_callback.trigger = ipc4_be_dai_common_trigger;
>>>> +#endif
>>>
>>> #if should not be in .c files if at all possible.  Surely there's a
>>> better way here...
>>
>> we could use
>>
>> if (IS_ENABLED(CONFIG_SND_SOC_SOF_INTEL_SOUNDWIRE))
>>     sdw_callback.trigger = ipc4_be_dai_common_trigger;
>>
>> would that work?
> 
> It's more readable, right?  Also easier to maintain over time.

yes, it's more readable, and that's no problem to update.

There's another #if IS_ENABLED( that we can replace by a if (IS_ENABLED
in the same routine, that would make this routine less of an eyesore. I
am not sure why we added all these #if, we can cleanup.

 	case SOF_INTEL_IPC4:
	{
		struct sof_ipc4_fw_data *ipc4_data = sdev->private;

		for (i = 0; i < ops->num_drv; i++) {
			if (strstr(ops->drv[i].name, "DMIC")) {
				ops->drv[i].ops = &ipc4_dmic_dai_ops;
				continue;
			}
			if (strstr(ops->drv[i].name, "SSP")) {
				ops->drv[i].ops = &ipc4_ssp_dai_ops;
				continue;
			}
#if IS_ENABLED(CONFIG_SND_SOC_SOF_HDA)
			if (strstr(ops->drv[i].name, "iDisp") ||
			    strstr(ops->drv[i].name, "Analog") ||
			    strstr(ops->drv[i].name, "Digital"))
				ops->drv[i].ops = &ipc4_hda_dai_ops;
#endif
		}

		if (!hda_use_tplg_nhlt)
			ipc4_data->nhlt = intel_nhlt_init(sdev->dev);

#if IS_ENABLED(CONFIG_SND_SOC_SOF_INTEL_SOUNDWIRE)
		sdw_callback.trigger = ipc4_be_dai_common_trigger;
#endif

		break;
	}
	default:
		break;
	}
}
>> We try to keep this driver configurable, not all platforms require
>> SoundWire or HDaudio, and that 'sdw_callback' ops structure is
>> conditionally declared.
> 
> Perhaps don't conditionally declare that?  How much does it really save
> to do that?

It would force us to expose additional things that are only relevant for
SoundWire, see the large block of code in hda.c

https://elixir.bootlin.com/linux/latest/source/sound/soc/sof/intel/hda.c#L108

We've been burned in the past by having too many things in a single
configuration, so we try to allow for minimal builds that don't depend
on other modules in sound/soc/codecs/, sound/pci/hda and
drivers/soundwire - it also forces us to get the Kconfig dependencies right.

if (IS_ENABLED()) is less invasive in that case.

Thanks for your feedback
-Pierre