static int mcp4725_probe()

in dac/mcp4725.c [371:486]

• 97 lines of code
• 25 McCabe index (conditional complexity)

static int mcp4725_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct mcp4725_data *data;
	struct iio_dev *indio_dev;
	struct mcp4725_platform_data *pdata, pdata_dt;
	u8 inbuf[4];
	u8 pd;
	u8 ref;
	int err;

	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
	if (indio_dev == NULL)
		return -ENOMEM;
	data = iio_priv(indio_dev);
	i2c_set_clientdata(client, indio_dev);
	data->client = client;
	if (dev_fwnode(&client->dev))
		data->id = (uintptr_t)device_get_match_data(&client->dev);
	else
		data->id = id->driver_data;
	pdata = dev_get_platdata(&client->dev);

	if (!pdata) {
		err = mcp4725_probe_dt(&client->dev, &pdata_dt);
		if (err) {
			dev_err(&client->dev,
				"invalid platform or devicetree data");
			return err;
		}
		pdata = &pdata_dt;
	}

	if (data->id == MCP4725 && pdata->use_vref) {
		dev_err(&client->dev,
			"external reference is unavailable on MCP4725");
		return -EINVAL;
	}

	if (!pdata->use_vref && pdata->vref_buffered) {
		dev_err(&client->dev,
			"buffering is unavailable on the internal reference");
		return -EINVAL;
	}

	if (!pdata->use_vref)
		data->ref_mode = MCP472X_REF_VDD;
	else
		data->ref_mode = pdata->vref_buffered ?
			MCP472X_REF_VREF_BUFFERED :
			MCP472X_REF_VREF_UNBUFFERED;

	data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
	if (IS_ERR(data->vdd_reg))
		return PTR_ERR(data->vdd_reg);

	err = regulator_enable(data->vdd_reg);
	if (err)
		return err;

	if (pdata->use_vref) {
		data->vref_reg = devm_regulator_get(&client->dev, "vref");
		if (IS_ERR(data->vref_reg)) {
			err = PTR_ERR(data->vref_reg);
			goto err_disable_vdd_reg;
		}

		err = regulator_enable(data->vref_reg);
		if (err)
			goto err_disable_vdd_reg;
	}

	indio_dev->name = id->name;
	indio_dev->info = &mcp4725_info;
	indio_dev->channels = &mcp472x_channel[id->driver_data];
	indio_dev->num_channels = 1;
	indio_dev->modes = INDIO_DIRECT_MODE;

	/* read current DAC value and settings */
	err = i2c_master_recv(client, inbuf, data->id == MCP4725 ? 3 : 4);

	if (err < 0) {
		dev_err(&client->dev, "failed to read DAC value");
		goto err_disable_vref_reg;
	}
	pd = (inbuf[0] >> 1) & 0x3;
	data->powerdown = pd > 0;
	data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */
	data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
	if (data->id == MCP4726)
		ref = (inbuf[3] >> 3) & 0x3;

	if (data->id == MCP4726 && ref != data->ref_mode) {
		dev_info(&client->dev,
			"voltage reference mode differs (conf: %u, eeprom: %u), setting %u",
			data->ref_mode, ref, data->ref_mode);
		err = mcp4726_set_cfg(indio_dev);
		if (err < 0)
			goto err_disable_vref_reg;
	}
 
	err = iio_device_register(indio_dev);
	if (err)
		goto err_disable_vref_reg;

	return 0;

err_disable_vref_reg:
	if (data->vref_reg)
		regulator_disable(data->vref_reg);

err_disable_vdd_reg:
	regulator_disable(data->vdd_reg);

	return err;
}