Re: [PATCH v2 1/2] ASoC: tas5720.c: cleanup variant management

[Nikolaus Voss <nv@vosn.de>]

On Mon, 1 Jul 2019, Andrew F. Davis wrote:
> On 7/1/19 9:42 AM, Nikolaus Voss wrote:
>> Replace enum tas572x_type with struct tas5720_variant which aggregates
>> variant specific stuff and can be directly referenced from an id table.
>>
>> Signed-off-by: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
>> ---
>>  sound/soc/codecs/tas5720.c | 98 +++++++++++++-------------------------
>>  1 file changed, 33 insertions(+), 65 deletions(-)
>>
>> diff --git a/sound/soc/codecs/tas5720.c b/sound/soc/codecs/tas5720.c
>> index 37fab8f22800..b2e897f094b4 100644
>> --- a/sound/soc/codecs/tas5720.c
>> +++ b/sound/soc/codecs/tas5720.c
>> @@ -28,9 +28,10 @@
>>  /* Define how often to check (and clear) the fault status register (in ms) */
>>  #define TAS5720_FAULT_CHECK_INTERVAL		200
>>
>> -enum tas572x_type {
>> -	TAS5720,
>> -	TAS5722,
>> +struct tas5720_variant {
>> +	const int device_id;
>> +	const struct regmap_config *reg_config;
>> +	const struct snd_soc_component_driver *comp_drv;
>>  };
>>
>>  static const char * const tas5720_supply_names[] = {
>> @@ -44,7 +45,7 @@ struct tas5720_data {
>>  	struct snd_soc_component *component;
>>  	struct regmap *regmap;
>>  	struct i2c_client *tas5720_client;
>> -	enum tas572x_type devtype;
>> +	const struct tas5720_variant *variant;
>
> Why add a new struct? Actually I don't see the need for this patch at
> all, the commit message only explains the 'what' not the 'why'. We can
> and do already build this info from the tas572x_type.

As the commit message says, the purpose is to aggregate the variant 
specifics and make it accessible via one pointer. This is a standard 
approach for of/acpi_device_id tables and thus makes the code simpler and 
improves readability. This is a maintenance patch to prepare using the 
device match API in a proper way.

>
> Also below are several functional changes, the cover letter says this is
> not a functional change, yet the driver behaves differently now.

Can you be a little bit more specific? The code should behave exactly as 
before.

Niko

>
> Andrew
>
>>  	struct regulator_bulk_data supplies[TAS5720_NUM_SUPPLIES];
>>  	struct delayed_work fault_check_work;
>>  	unsigned int last_fault;
>> @@ -179,17 +180,13 @@ static int tas5720_set_dai_tdm_slot(struct snd_soc_dai *dai,
>>  		goto error_snd_soc_component_update_bits;
>>
>>  	/* Configure TDM slot width. This is only applicable to TAS5722. */
>> -	switch (tas5720->devtype) {
>> -	case TAS5722:
>> +	if (tas5720->variant->device_id == TAS5722_DEVICE_ID) {
>>  		ret = snd_soc_component_update_bits(component, TAS5722_DIGITAL_CTRL2_REG,
>>  						    TAS5722_TDM_SLOT_16B,
>>  						    slot_width == 16 ?
>>  						    TAS5722_TDM_SLOT_16B : 0);
>>  		if (ret < 0)
>>  			goto error_snd_soc_component_update_bits;
>> -		break;
>> -	default:
>> -		break;
>>  	}
>>
>>  	return 0;
>> @@ -277,7 +274,7 @@ static void tas5720_fault_check_work(struct work_struct *work)
>>  static int tas5720_codec_probe(struct snd_soc_component *component)
>>  {
>>  	struct tas5720_data *tas5720 = snd_soc_component_get_drvdata(component);
>> -	unsigned int device_id, expected_device_id;
>> +	unsigned int device_id;
>>  	int ret;
>>
>>  	tas5720->component = component;
>> @@ -301,21 +298,9 @@ static int tas5720_codec_probe(struct snd_soc_component *component)
>>  		goto probe_fail;
>>  	}
>>
>> -	switch (tas5720->devtype) {
>> -	case TAS5720:
>> -		expected_device_id = TAS5720_DEVICE_ID;
>> -		break;
>> -	case TAS5722:
>> -		expected_device_id = TAS5722_DEVICE_ID;
>> -		break;
>> -	default:
>> -		dev_err(component->dev, "unexpected private driver data\n");
>> -		return -EINVAL;
>> -	}
>> -
>> -	if (device_id != expected_device_id)
>> +	if (device_id != tas5720->variant->device_id)
>>  		dev_warn(component->dev, "wrong device ID. expected: %u read: %u\n",
>> -			 expected_device_id, device_id);
>> +			 tas5720->variant->device_id, device_id);
>>
>>  	/* Set device to mute */
>>  	ret = snd_soc_component_update_bits(component, TAS5720_DIGITAL_CTRL2_REG,
>> @@ -637,7 +622,6 @@ static int tas5720_probe(struct i2c_client *client,
>>  {
>>  	struct device *dev = &client->dev;
>>  	struct tas5720_data *data;
>> -	const struct regmap_config *regmap_config;
>>  	int ret;
>>  	int i;
>>
>> @@ -646,20 +630,10 @@ static int tas5720_probe(struct i2c_client *client,
>>  		return -ENOMEM;
>>
>>  	data->tas5720_client = client;
>> -	data->devtype = id->driver_data;
>>
>> -	switch (id->driver_data) {
>> -	case TAS5720:
>> -		regmap_config = &tas5720_regmap_config;
>> -		break;
>> -	case TAS5722:
>> -		regmap_config = &tas5722_regmap_config;
>> -		break;
>> -	default:
>> -		dev_err(dev, "unexpected private driver data\n");
>> -		return -EINVAL;
>> -	}
>> -	data->regmap = devm_regmap_init_i2c(client, regmap_config);
>> +	data->variant = (const struct tas5720_variant *)id->driver_data;
>> +
>> +	data->regmap = devm_regmap_init_i2c(client, data->variant->reg_config);
>>  	if (IS_ERR(data->regmap)) {
>>  		ret = PTR_ERR(data->regmap);
>>  		dev_err(dev, "failed to allocate register map: %d\n", ret);
>> @@ -678,42 +652,36 @@ static int tas5720_probe(struct i2c_client *client,
>>
>>  	dev_set_drvdata(dev, data);
>>
>> -	switch (id->driver_data) {
>> -	case TAS5720:
>> -		ret = devm_snd_soc_register_component(&client->dev,
>> -					&soc_component_dev_tas5720,
>> -					tas5720_dai,
>> -					ARRAY_SIZE(tas5720_dai));
>> -		break;
>> -	case TAS5722:
>> -		ret = devm_snd_soc_register_component(&client->dev,
>> -					&soc_component_dev_tas5722,
>> -					tas5720_dai,
>> -					ARRAY_SIZE(tas5720_dai));
>> -		break;
>> -	default:
>> -		dev_err(dev, "unexpected private driver data\n");
>> -		return -EINVAL;
>> -	}
>> -	if (ret < 0) {
>> -		dev_err(dev, "failed to register component: %d\n", ret);
>> -		return ret;
>> -	}
>> -
>> -	return 0;
>> +	ret = devm_snd_soc_register_component(&client->dev,
>> +					      data->variant->comp_drv,
>> +					      tas5720_dai,
>> +					      ARRAY_SIZE(tas5720_dai));
>> +	return ret;
>>  }
>>
>> +static const struct tas5720_variant tas5720 = {
>> +	.device_id = TAS5720_DEVICE_ID,
>> +	.reg_config = &tas5720_regmap_config,
>> +	.comp_drv = &soc_component_dev_tas5720,
>> +};
>> +
>> +static const struct tas5720_variant tas5722 = {
>> +	.device_id = TAS5722_DEVICE_ID,
>> +	.reg_config = &tas5722_regmap_config,
>> +	.comp_drv = &soc_component_dev_tas5722,
>> +};
>> +
>>  static const struct i2c_device_id tas5720_id[] = {
>> -	{ "tas5720", TAS5720 },
>> -	{ "tas5722", TAS5722 },
>> +	{ "tas5720", (kernel_ulong_t)&tas5720 },
>> +	{ "tas5722", (kernel_ulong_t)&tas5722 },
>>  	{ }
>>  };
>>  MODULE_DEVICE_TABLE(i2c, tas5720_id);
>>
>>  #if IS_ENABLED(CONFIG_OF)
>>  static const struct of_device_id tas5720_of_match[] = {
>> -	{ .compatible = "ti,tas5720", },
>> -	{ .compatible = "ti,tas5722", },
>> +	{ .compatible = "ti,tas5720", .data = &tas5720, },
>> +	{ .compatible = "ti,tas5722", .data = &tas5722, },
>>  	{ },
>>  };
>>  MODULE_DEVICE_TABLE(of, tas5720_of_match);
>>
>