Re: [PATCH v8] ASoc: tas2783: Add tas2783 codec driver

[Pierre-Louis Bossart]

It's starting to look good, but the use of the dev_num is conceptually 
broken. The only way to reliably identify a device is the combination of 
link_id and unique_id. The information is present for both ACPI and DT 
systems. See comments below.
-Pierre

> +static void tas2783_apply_calib(struct tasdevice_priv *tas_dev,
> +	unsigned int *cali_data)
> +{
> +	struct regmap *map = tas_dev->regmap;
> +	u8 *cali_start;
> +	u16 dev_num;
> +	int ret;
> +
> +	if (!tas_dev->sdw_peripheral) {
> +		dev_err(tas_dev->dev, "%s: peripheral doesn't exist.\n",
> +			__func__);
> +		return;
> +	}
> +
> +	dev_num = clamp(tas_dev->sdw_peripheral->dev_num, 1, 4) - 1;

Not following what restrictions you are trying to enforce on the device 
number. That's a value selected by the manager. You absolutely cannot 
assume the value is between 1 and 4, the max value is 11.

> +	/*
> +	 * The area saving tas2783 calibrated data is specified by its
> +	 * dev_num. cali_start is the first address of current tas2783's
> +	 * calibrated data.
> +	 */
> +	cali_start = (u8 *)(cali_data + dev_num * sizeof(tas2783_cali_reg));
> +	for (int i = 0; i < ARRAY_SIZE(tas2783_cali_reg); i++) {
> +		ret = regmap_bulk_write(map, tas2783_cali_reg[i],
> +			&cali_start[4 * i], 4);
> +		if (ret) {
> +			dev_err(tas_dev->dev, "Cali failed %x:%d\n",
> +				tas2783_cali_reg[i], ret);
> +			break;
> +		}
> +	}
> +}
> +
> +/*
> + * Load the calibration data, including speaker impedance, f0, etc.
> + * Calibration is done by the manufacturer in the factory. The calibration
> + * data are used by the algorithm for calculating the speaker temperature,
> + * speaker membrane excursion and f0 in real time during playback.
> + * The DSP will work with default data values if calibrated data are
> + * missing or are invalid.
> + * Layout of calibrated Data in UEFI:
> + *	Calibrated Data of Dev 0 (20 bytes)
> + *	Calibrated Data of Dev 1 (20 bytes)
> + *	Calibrated Data of Dev 2 (20 bytes)
> + *	Calibrated Data of Dev 3 (20 bytes)

You will have a hard-time matching those device indices with the 
dev_num, which depends on the enumeration order and the bus allocation.

The only stable board-specific value is to use a combination of link_id 
and unique_id (possibly controller id as well).


> + *	CRC (4 bytes)
> + */

> +static int tasdevice_comp_probe(struct snd_soc_component *comp)
> +{
> +	struct tasdevice_priv *tas_dev = snd_soc_component_get_drvdata(comp);
> +	acpi_handle handle = ACPI_HANDLE(tas_dev->dev);
> +	const struct firmware *fw_entry = NULL;
> +	const char *sub = NULL;
> +	int ret, value_sdw;
> +
> +	if (handle) {
> +		sub = acpi_get_subsystem_id(handle);
> +		if (IS_ERR(sub))
> +			sub = NULL;
> +	}
> +
> +	tas_dev->component = comp;
> +
> +	/*
> +	 * Each tas2783 in the system has its own dspfw.
> +	 */
> +	if (comp->name_prefix) {
> +		/*
> +		 * name_prefix.bin stores the dsp firmware including speaker
> +		 * protection algorithm, audio acoustic algorithm, speaker
> +		 * characters and algorithm params, it must be copied into
> +		 * firmware folder.
> +		 */
> +		scnprintf(tas_dev->dspfw_binaryname,
> +			TAS2783_DSPFW_FILENAME_LEN, "%s-tas2783.bin",
> +			comp->name_prefix);
> +	} else {
> +		/* Compatible with the previous naming rule */
> +		if (sub) {
> +		/*
> +		 * subsystem_id-link_id[0,1,...,N]-dev_num[1,...,4].bin stores
> +		 * the dsp firmware including speaker protection algorithm,
> +		 * audio acoustic algorithm, speaker characters and algorithm
> +		 * params, it must be copied into firmware folder.

no the dev_num cannot be used. It's only used for host-device 
communication and cannot be used to identify a device position.

The link_id+unique_unique is the only way to go.

But in addition you want want to consider a platform-specific prefix 
which contains the OEM name or device SKU.

> +		 */
> +			scnprintf(tas_dev->dspfw_binaryname,
> +				TAS2783_DSPFW_FILENAME_LEN,
> +				"%s-%d-%d.bin", sub,
> +				tas_dev->sdw_peripheral->bus->link_id,
> +				tas_dev->sdw_peripheral->dev_num);
> +		} else {
> +		/*
> +		 * tas2783-link_id[0,1,...,N]-dev_num[1,...,4].bin stores
> +		 * the dsp firmware including speaker protection algorithm,
> +		 * audio acoustic algorithm, speaker characters and algorithm
> +		 * params, it must be copied into firmware folder.
> +		 */
> +			scnprintf(tas_dev->dspfw_binaryname,
> +				TAS2783_DSPFW_FILENAME_LEN,
> +				"tas2783-%d-%d.bin",
> +				tas_dev->sdw_peripheral->bus->link_id,
> +				tas_dev->sdw_peripheral->dev_num);
> +		}
> +	}
> +
> +	ret = request_firmware(&fw_entry, tas_dev->dspfw_binaryname,
> +		tas_dev->dev);
> +	if (ret) {
> +		dev_err(tas_dev->dev,
> +			"%s: request_firmware %x open status: %d.\n", __func__,
> +			tas_dev->sdw_peripheral->id.unique_id, ret);
> +		goto out;
> +	}
> +
> +	tasdevice_dspfw_ready(fw_entry, tas_dev);
> +
> +	/* Select left/right channel based on device number. */
> +	value_sdw = 0x1a;
> +	value_sdw |= (tas_dev->sdw_peripheral->dev_num & BIT(0)) << 4;
> +	dev_dbg(tas_dev->dev, "%s: dev_num = %u", __func__,
> +		tas_dev->sdw_peripheral->dev_num);
> +	regmap_write(tas_dev->regmap, TAS2783_REG_TDM_RX_CFG, value_sdw);
> +	if (ret != 0)
> +		dev_warn(tas_dev->dev, "%s: L/R setting failed: %d.\n",
> +			__func__, ret);
> +
> +out:
> +	if (fw_entry)
> +		release_firmware(fw_entry);
> +	return 0;
> +}

> +static int tasdevice_io_init(struct device *dev,
> +	struct sdw_slave *slave)
> +{
> +	struct tasdevice_priv *tas_priv = dev_get_drvdata(dev);
> +	int ret;
> +
> +	regcache_cache_only(tas_priv->regmap, false);
> +
> +	if (tas_priv->first_hw_init) {
> +		regcache_cache_bypass(tas_priv->regmap, true);
> +	} else {
> +	/*
> +	 * PM runtime is only enabled when a Slave reports as Attached
> +	 * Update count of parent 'active' children
> +	 */

weird indentation for comments in multiple places.

> +		pm_runtime_set_active(&slave->dev);
> +	}
> +
> +	/* sw reset */
> +	ret = regmap_write(tas_priv->regmap, TAS2873_REG_SWRESET,
> +		TAS2873_REG_SWRESET_RESET);
> +	if (ret) {
> +		dev_err(tas_priv->dev, "Reset failed.\n");
> +		goto out;
> +	}
> +
> +	if (tas_priv->first_hw_init) {
> +		regcache_cache_bypass(tas_priv->regmap, false);
> +		regcache_mark_dirty(tas_priv->regmap);
> +	}
> +
> +	tas_priv->first_hw_init = true;
> +	tas_priv->hw_init = true;
> +
> +out:
> +	return ret;
> +}