Re: [PATCH v7 2/2] iio: adc: ti-ads112c04: Add support for TI ADS112C04

[Andy Shevchenko]

On Mon, Aug 24, 2026 at 04:49:39PM +0800, Kyle Hsieh wrote:
> Add IIO driver support for the Texas Instruments ADS112C04 (16-bit)
> delta-sigma ADCs.
> 
> The driver implements:
> - Single-shot conversions using the IIO raw read interface.
> - Dynamic parsing of single-ended and differential channels from
>   device tree child nodes.
> - Hardware interrupt support via the DRDY pin, falling back to
>   software polling if no IRQ is provided.
> - Per-channel reference source selection (internal 2.048V, external
>   REFP/REFN, or AVDD) via the reference-sources device tree property.
>   refn-supply is not yet supported.
> - Hardware reset via the reset controller framework, falling back to
>   the RESET command when no reset controller is present.

FWIW,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>

...

> +static int ads112c04_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct iio_dev *indio_dev;
> +	struct ads112c04_state *st;
> +	struct reset_control *reset;
> +	bool need_avdd_ref = false, need_ext_ref = false;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	st = iio_priv(indio_dev);
> +	st->client = client;
> +
> +	ret = devm_mutex_init(dev, &st->lock);
> +	if (ret)
> +		return ret;
> +
> +	init_completion(&st->completion);
> +
> +	indio_dev->name = "ads112c04";
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->info = &ads112c04_info;
> +
> +	/* Forward compatibility checks for unimplemented DT properties */
> +	if (device_property_present(dev, "refn-supply") ||
> +	    device_property_present(dev, "ti,refp-refn-resistor-ohms"))
> +		return dev_err_probe(dev, -EOPNOTSUPP,
> +				     "refn-supply and external resistors are not supported yet\n");
> +
> +	ret = ads112c04_parse_channels(indio_dev, &need_avdd_ref, &need_ext_ref);
> +	if (ret)
> +		return ret;
> +
> +	if (need_avdd_ref) {
> +		ret = devm_regulator_get_enable_read_voltage(dev, "avdd");
> +		if (ret < 0)
> +			return dev_err_probe(dev, ret, "failed to get avdd voltage\n");
> +
> +		st->avdd_mV = ret / (MICRO / MILLI);
> +	} else {
> +		ret = devm_regulator_get_enable(dev, "avdd");
> +		if (ret)
> +			return dev_err_probe(dev, ret, "failed to get avdd regulator\n");
> +	}
> +
> +	ret = devm_regulator_get_enable(dev, "dvdd");
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to get dvdd regulator\n");
> +
> +	if (device_property_present(dev, "refp-supply")) {
> +		ret = devm_regulator_get_enable_read_voltage(dev, "refp");
> +		if (ret < 0)
> +			return dev_err_probe(dev, ret, "failed to get refp voltage\n");
> +
> +		st->ext_ref_mV = ret / (MICRO / MILLI);
> +	}
> +
> +	if (need_ext_ref && !st->ext_ref_mV)
> +		return dev_err_probe(dev, -EINVAL,
> +				     "external reference measurements require refp-supply\n");
> +
> +	/* Datasheet: POR releases ~500us after supplies are stable */
> +	fsleep(500);
> +
> +	reset = devm_reset_control_get_optional_exclusive(dev, NULL);
> +	if (IS_ERR(reset))
> +		return dev_err_probe(dev, PTR_ERR(reset), "failed to get reset\n");
> +
> +	if (reset) {
> +		/* Datasheet: tw(RSL), the RESET low pulse, is 250ns minimum */
> +		fsleep(1);
> +
> +		ret = reset_control_deassert(reset);
> +		if (ret)
> +			return dev_err_probe(dev, ret, "failed to deassert reset\n");
> +	} else {
> +		ret = ads112c04_write_cmd(client, ADS112C04_CMD_RESET);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	/* Datasheet: td(RSSTA) is 100ns minimum after the RESET rising edge */
> +	fsleep(1);

Perhaps simply ndelay(100) ?

> +	/*
> +	 * Initialize CONFIG0 with all fields explicit: gain of 1 with the PGA
> +	 * bypassed, which allows full-scale single-ended measurements. The MUX
> +	 * field is updated per channel before each conversion.
> +	 */
> +	st->config0 = FIELD_PREP(ADS112C04_CONF0_MUX,
> +				 ADS112C04_CONF0_MUX_AIN0_AIN1) |
> +		      FIELD_PREP(ADS112C04_CONF0_GAIN,
> +				 ADS112C04_CONF0_GAIN_X1) |
> +		      ADS112C04_CONF0_PGA_BYPASS;
> +
> +	ret = ads112c04_write_reg(client, ADS112C04_REG_CONFIG0, st->config0);
> +	if (ret)
> +		return ret;
> +
> +	st->config1 = FIELD_PREP(ADS112C04_CONF1_DR,
> +				 ADS112C04_CONF1_DR_20SPS) |
> +		      FIELD_PREP(ADS112C04_CONF1_MODE,
> +				 ADS112C04_CONF1_MODE_NORMAL) |
> +		      FIELD_PREP(ADS112C04_CONF1_CM,
> +				 ADS112C04_CONF1_CM_SINGLE_SHOT) |
> +		      FIELD_PREP(ADS112C04_CONF1_VREF,
> +				 ADS112C04_CONF1_VREF_INTERNAL) |
> +		      FIELD_PREP(ADS112C04_CONF1_TS,
> +				 ADS112C04_CONF1_TS_DISABLED);
> +
> +	ret = ads112c04_write_reg(client, ADS112C04_REG_CONFIG1, st->config1);
> +	if (ret)
> +		return ret;
> +
> +	if (client->irq > 0) {
> +		ret = devm_request_irq(dev, client->irq, ads112c04_irq_handler, 0,
> +				       indio_dev->name, indio_dev);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return devm_iio_device_register(dev, indio_dev);
> +}

-- 
With Best Regards,
Andy Shevchenko