linux-kernel - Re: [PATCH] [MT6660] Mediatek Smart Amplifier Driver

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Date:   Tue, 3 Sep 2019 17:38:29 +0100
From:   Mark Brown <broonie@...nel.org>
To:     richtek.jeff.chang@...il.com
Cc:     lgirdwood@...il.com, perex@...ex.cz, tiwai@...e.com,
        matthias.bgg@...il.com, alsa-devel@...a-project.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] [MT6660] Mediatek Smart Amplifier Driver

On Tue, Sep 03, 2019 at 03:08:21PM +0800, richtek.jeff.chang@...il.com wrote:

> --- /dev/null
> +++ b/sound/soc/codecs/mt6660.c
> @@ -0,0 +1,802 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2019 MediaTek Inc.
> + */

Please make the entire comment block a C++ comment so things look more
consistent.

> +struct reg_size_table {
> +	u32 addr;
> +	u8 size;
> +};

> +static const struct reg_size_table mt6660_reg_size_table[] = {
> +	{ MT6660_REG_HPF1_COEF, 4 },
> +	{ MT6660_REG_HPF2_COEF, 4 },
> +	{ MT6660_REG_TDM_CFG3, 2 },
> +	{ MT6660_REG_RESV17, 2 },
> +	{ MT6660_REG_RESV23, 2 },
> +	{ MT6660_REG_SIGMAX, 2 },
> +	{ MT6660_REG_DEVID, 2},
> +	{ MT6660_REG_TDM_CFG3, 2},
> +	{ MT6660_REG_HCLIP_CTRL, 2},
> +	{ MT6660_REG_DA_GAIN, 2},
> +};

Please talk to your hardware designers about the benefits of consistent
register sizes :/

> +static int32_t mt6660_i2c_update_bits(struct mt6660_chip *chip,
> +	uint32_t addr, uint32_t mask, uint32_t data)
> +{

It would be good to implement a regmap rather than open coding
*everything* - it'd give you things like this without needing to open
code them.  Providing you don't use the cache code it should cope fine
with variable register sizes.

> +
> +static int mt6660_i2c_init_setting(struct mt6660_chip *chip)
> +{
> +	int i, len, ret;
> +	const struct codec_reg_val *init_table;
> +
> +	init_table = e4_reg_inits;
> +	len = ARRAY_SIZE(e4_reg_inits);
> +
> +	for (i = 0; i < len; i++) {
> +		ret = mt6660_i2c_update_bits(chip, init_table[i].addr,
> +				init_table[i].mask, init_table[i].data);
> +		if (ret < 0)
> +			return ret;

Why are we not using the chip defaults here?

> +static int mt6660_chip_power_on(
> +	struct snd_soc_component *component, int on_off)
> +{
> +	struct mt6660_chip *chip = (struct mt6660_chip *)
> +		snd_soc_component_get_drvdata(component);
> +	int ret = 0;
> +	unsigned int val;
> +
> +	dev_dbg(component->dev, "%s: on_off = %d\n", __func__, on_off);
> +	mutex_lock(&chip->var_lock);
> +	if (on_off) {
> +		if (chip->pwr_cnt == 0) {
> +			ret = mt6660_i2c_update_bits(chip,
> +				MT6660_REG_SYSTEM_CTRL, 0x01, 0x00);
> +			val = mt6660_i2c_read(chip, MT6660_REG_IRQ_STATUS1);
> +			dev_info(chip->dev,
> +				"%s reg0x05 = 0x%x\n", __func__, val);
> +		}
> +		chip->pwr_cnt++;

This looks like you're open coding runtime PM stuff?  AFAICT the issue
is that you need to write to this register to do any I/O.  Just
implement this via the standard runtime PM framework, you'll need to do
something about the register I/O in the controls (ideally in the
framework, it'd be a lot easier if you did have a cache) but you could
cut out this bit.

> +static int mt6660_component_set_bias_level(struct snd_soc_component *component,
> +	enum snd_soc_bias_level level)
> +{
> +	struct snd_soc_dapm_context *dapm =
> +		snd_soc_component_get_dapm(component);
> +	int ret;
> +	unsigned int val;
> +	struct mt6660_chip *chip = snd_soc_component_get_drvdata(component);
> +
> +	if (dapm->bias_level == level) {
> +		dev_warn(component->dev, "%s: repeat level change\n", __func__);

This shouldn't be a warning.

> +static const struct snd_kcontrol_new mt6660_component_snd_controls[] = {
> +	SOC_SINGLE_EXT_TLV("Volume_Ctrl", MT6660_REG_VOL_CTRL, 0, 255,
> +			   1, snd_soc_get_volsw, mt6660_component_put_volsw,
> +			   vol_ctl_tlv),
> +	SOC_SINGLE_EXT("WDT_Enable", MT6660_REG_WDT_CTRL, 7, 1, 0,
> +		       snd_soc_get_volsw, mt6660_component_put_volsw),

These control names should all use standard ALSA control names - on/off
switches should end in Switch, volume controls in Volume.

> +	SOC_SINGLE_EXT("I2SLRS", MT6660_REG_DATAO_SEL, 6, 3, 0,
> +		       snd_soc_get_volsw, mt6660_component_put_volsw),
> +	SOC_SINGLE_EXT("I2SDOLS", MT6660_REG_DATAO_SEL, 3, 7, 0,
> +		       snd_soc_get_volsw, mt6660_component_put_volsw),
> +	SOC_SINGLE_EXT("I2SDORS", MT6660_REG_DATAO_SEL, 0, 7, 0,
> +		       snd_soc_get_volsw, mt6660_component_put_volsw),

What do these controls do?

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