Re: [PATCH v3 6/8] iio: adc: add ti-ads112c14 driver

[Andy Shevchenko]

On Fri, Jul 10, 2026 at 05:50:39PM -0500, David Lechner (TI) wrote:
> Add a new driver for the TI ADS112C14/ADS122C14 ADC chips.
> 
> This first step is adding a very basic driver that only supports power
> on/reset and reading the system monitor channels.
> 
> ADS112C14_SYS_MON_CHANNEL_SHORT is the last channel rather than being in
> logical order by address to keep the voltage channels together and in
> case we find we need to add variants of this channel with different
> voltage reference later.

...

> +static int ads112c14_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	const struct ads112c14_chip_info *info;
> +	struct iio_dev *indio_dev;
> +	struct ads112c14_data *data;
> +	u32 reg_val;
> +	int ret;
> +
> +	info = i2c_get_match_data(client);
> +	if (!info)
> +		return dev_err_probe(dev, -EINVAL, "missing match data\n");

I think -ENODEV suits better here.

> +	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	data = iio_priv(indio_dev);
> +	data->chip_info = info;
> +
> +	ret = devm_regulator_get_enable(dev, "dvdd");
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to get dvdd regulator\n");
> +
> +	ret = devm_regulator_get_enable(dev, "avdd");
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to get avdd regulator\n");
> +
> +	data->regmap = devm_regmap_init_i2c(client, &ads112c14_regmap_config);
> +	if (IS_ERR(data->regmap))
> +		return dev_err_probe(dev, PTR_ERR(data->regmap),
> +				     "failed to init regmap\n");

Do we have a guarantee that device is powered on here?

> +	/* Write magic reset value (0x16) to ensure known state. */
> +	ret = regmap_write(data->regmap, ADS112C14_REG_CONVERSION_CTRL,
> +			   FIELD_PREP(ADS112C14_CONVERSION_CTRL_RESET, 0x16));
> +	/*
> +	 * The reset may cause an -EREMOTEIO error because of failing to get the
> +	 * I2C ACK at the end of the message. The device still gets reset so it
> +	 * is safe to ignore this error.
> +	 */
> +	if (ret == -EREMOTEIO)
> +		ret = 0;
> +	if (ret)
> +		return ret;
> +
> +	fsleep(ADS112C14_DELAY_RESET_US);
> +
> +	ret = regmap_read(data->regmap, ADS112C14_REG_STATUS_MSB, &reg_val);
> +	if (ret)
> +		return ret;
> +
> +	if (FIELD_GET(ADS112C14_STATUS_MSB_RESETN, reg_val))
> +		return dev_err_probe(dev, -EIO, "reset failed\n");
> +
> +	/*
> +	 * Clear reset bit to prepare for next probe. And clear AVDD fault since
> +	 * that happens on every reset.
> +	 */
> +	ret = regmap_write(data->regmap, ADS112C14_REG_STATUS_MSB,
> +			   ADS112C14_STATUS_MSB_RESETN |
> +			   ADS112C14_STATUS_MSB_AVDD_UVN);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_read(data->regmap, ADS112C14_REG_DEVICE_ID, &reg_val);
> +	if (ret)
> +		return ret;
> +
> +	if (FIELD_GET(ADS112C14_DEVICE_ID_BITS, reg_val) != info->device_id)
> +		dev_info(dev, "device ID mismatch, expected 0xX%X, got 0x%lX\n",
> +			 info->device_id,
> +			 FIELD_GET(ADS112C14_DEVICE_ID_BITS, reg_val));
> +
> +	/* Place in single-shot conversion mode to make ready for raw read. */
> +	ret = regmap_set_bits(data->regmap, ADS112C14_REG_DEVICE_CFG,
> +			      ADS112C14_DEVICE_CFG_CONV_MODE);
> +	if (ret)
> +		return ret;
> +
> +	indio_dev->name = info->name;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->channels = ads112c14_sys_mon_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(ads112c14_sys_mon_channels);
> +	indio_dev->info = &ads112c14_info;
> +
> +	return devm_iio_device_register(dev, indio_dev);
> +}

-- 
With Best Regards,
Andy Shevchenko