linux-kernel - RE: [PATCH v2] ASoC: Intel: cirrus-common: Use UID to map correct amp to prefix

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Date:   Fri, 29 Jul 2022 15:24:42 +0100
From:   Stefan Binding <sbinding@...nsource.cirrus.com>
To:     'Pierre-Louis Bossart' <pierre-louis.bossart@...ux.intel.com>,
        "'Mark Brown'" <broonie@...nel.org>,
        'Liam Girdwood' <lgirdwood@...il.com>,
        "'Brent Lu'" <brent.lu@...el.com>, 'xliu' <xiang.liu@...rus.com>
CC:     'Vitaly Rodionov' <vitalyr@...nsource.cirrus.com>,
        <patches@...nsource.cirrus.com>, <alsa-devel@...a-project.org>,
        <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v2] ASoC: Intel: cirrus-common: Use UID to map correct amp to prefix

Hi,

> -----Original Message-----
> From: Alsa-devel <alsa-devel-bounces@...a-project.org> On Behalf Of
> Pierre-Louis Bossart
> Sent: 27 July 2022 17:37
> To: Stefan Binding <sbinding@...nsource.cirrus.com>; Mark Brown
> <broonie@...nel.org>; Liam Girdwood <lgirdwood@...il.com>;
> Brent Lu <brent.lu@...el.com>; xliu <xiang.liu@...rus.com>
> Cc: Vitaly Rodionov <vitalyr@...nsource.cirrus.com>;
> patches@...nsource.cirrus.com; alsa-devel@...a-project.org; linux-
> kernel@...r.kernel.org
> Subject: Re: [PATCH v2] ASoC: Intel: cirrus-common: Use UID to map
> correct amp to prefix
> 
> 
> 
> 
> > +/*
> > + * Expected UIDs are integers (stored as strings).
> > + * UID Mapping is fixed:
> > + * UID 0x0 -> WL
> > + * UID 0x1 -> WR
> > + * UID 0x2 -> TL
> > + * UID 0x3 -> TR
> > + * Note: If there are less than 4 Amps, UIDs still map to
> WL/WR/TL/TR. Dynamic code will only create
> > + * dai links for UIDs which exist, and ignore non-existant ones.
> 
> is this intentional to support all variations of 1,2,3 and 4 amplifiers
> being present?
> 
> Or is the intent to really support 2 or 4?

The intent was to support 2 or 4, rather than any number of amps, in
case something was released with 2 amps.

> 
> > + * Return number of codecs found.
> > + */
> > +static int cs35l41_compute_codec_conf(void)
> > +{
> > +	const char * const uid_strings[] = { "0", "1", "2", "3" };
> > +	unsigned int uid, sz = 0;
> > +	struct acpi_device *adev;
> > +	struct device *physdev;
> > +
> > +	for (uid = 0; uid < CS35L41_MAX_AMPS; uid++) {
> > +		adev = acpi_dev_get_first_match_dev(CS35L41_HID,
> uid_strings[uid], -1);
> > +		if (!adev) {
> > +			pr_warn("Cannot find match for HID %s UID
> %u (%s)\n", CS35L41_HID, uid,
> > +				cs35l41_name_prefixes[uid]);
> 
> A warning is a bit strong if some valid configurations don't expose all
> 4 codecs.

I'll change this to a debug message, but also add an error if there is not
2 or 4 amps found.

> 
> > +			continue;
> > +		}
> > +		physdev =
> get_device(acpi_get_first_physical_node(adev));
> > +		cs35l41_components[sz].name = dev_name(physdev);
> > +		cs35l41_components[sz].dai_name =
> CS35L41_CODEC_DAI;
> > +		cs35l41_codec_conf[sz].dlc.name =
> dev_name(physdev);
> > +		cs35l41_codec_conf[sz].name_prefix =
> cs35l41_name_prefixes[uid];
> > +		acpi_dev_put(adev);
> > +		sz++;
> > +	}
> > +	return sz;

Thanks,
Stefan