linux-kernel - Re: [PATCH 2/2] ASoC: max98396: add amplifier driver

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Date:   Wed, 20 Apr 2022 17:17:50 +0100
From:   Mark Brown <broonie@...nel.org>
To:     Ryan Lee <ryan.lee.analog@...il.com>
Cc:     lgirdwood@...il.com, robh+dt@...nel.org, krzk+dt@...nel.org,
        perex@...ex.cz, tiwai@...e.com, srinivas.kandagatla@...aro.org,
        ckeepax@...nsource.cirrus.com, tanureal@...nsource.cirrus.com,
        cy_huang@...htek.com, pierre-louis.bossart@...ux.intel.com,
        drhodes@...nsource.cirrus.com, pbrobinson@...il.com,
        hdegoede@...hat.com, lukas.bulwahn@...il.com, stephan@...hold.net,
        arnd@...db.de, alsa-devel@...a-project.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        ryans.lee@...log.com
Subject: Re: [PATCH 2/2] ASoC: max98396: add amplifier driver

On Fri, Apr 15, 2022 at 05:40:24PM -0700, Ryan Lee wrote:

This looks mostly good - some issues below but nothing structural.

> +	switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
> +	case SND_SOC_DAIFMT_NB_NF:
> +	case SND_SOC_DAIFMT_NB_IF:
> +		break;

One of these must be wrong - the device needs to know if it's handling a
normal or inverted frame clock, otherwise the audio will be corrupted.  

> +static int max98396_mux_put(struct snd_kcontrol *kcontrol,
> +			    struct snd_ctl_elem_value *ucontrol)
> +{
> +	struct snd_soc_component *component =
> +		snd_soc_dapm_kcontrol_component(kcontrol);
> +	struct snd_soc_dapm_context *dapm = snd_soc_dapm_kcontrol_dapm(kcontrol);
> +	struct max98396_priv *max98396 = snd_soc_component_get_drvdata(component);
> +	struct soc_enum *e = (struct soc_enum *)kcontrol->private_value;
> +	unsigned int *item = ucontrol->value.enumerated.item;
> +	int reg, val;
> +
> +	if (item[0] >= e->items)
> +		return -EINVAL;
> +
> +	val = snd_soc_enum_item_to_val(e, item[0]) << e->shift_l;
> +
> +	if (max98396->device_id == CODEC_TYPE_MAX98396)
> +		reg = MAX98396_R2055_PCM_RX_SRC1;
> +	else
> +		reg = MAX98397_R2056_PCM_RX_SRC1;
> +
> +	regmap_update_bits(max98396->regmap, reg,
> +			   MAX98396_PCM_RX_MASK, val);
> +
> +	snd_soc_dapm_mux_update_power(dapm, kcontrol, item[0], e, NULL);
> +
> +	return 0;
> +}

This should return 1 if the value changed - you should get an error
reported by mixer-test from selftests if you run them on a sound card
with the driver.

> +	/* L/R mix configuration */
> +	if (max98396->device_id == CODEC_TYPE_MAX98396) {
> +		regmap_write(max98396->regmap,
> +			     MAX98396_R2055_PCM_RX_SRC1, 0x02);
> +		regmap_write(max98396->regmap,
> +			     MAX98396_R2056_PCM_RX_SRC2, 0x10);
> +	} else {
> +		regmap_write(max98396->regmap,
> +			     MAX98397_R2056_PCM_RX_SRC1, 0x02);
> +		regmap_write(max98396->regmap,
> +			     MAX98397_R2057_PCM_RX_SRC2, 0x10);
> +	}

Shouldn't these be user controllable?  Most of the setup being done here
looks system specific, especially the routing stuff.

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