Re: [PATCH v6 05/17] iio: adc: Add AD7768 and AD7768-4 core support

[Jonathan Cameron]

> Add core support for the AD7768 and AD7768-4 simultaneous sampling ADCs.
> Configure supplies, clock and reset, use a custom regmap bus for the SPI
> protocol, and parse the enabled channels and input buffer settings from
> devicetree.
> 
> Connect the converter to an IIO backend for buffered capture with CRC,
> provide a fixed safe wideband sampling configuration and add runtime
> power management.
> 
> Signed-off-by: Janani Sunil <janani.sunil@xxxxxxxxxx>

Just a few minor things I spotted on a fresh look at this.



> diff --git a/drivers/iio/adc/ad7768.c b/drivers/iio/adc/ad7768.c
> new file mode 100644
> index 000000000000..c80056a9edd8
> --- /dev/null
> +++ b/drivers/iio/adc/ad7768.c

> +
> +static int ad7768_regmap_write(void *context, const void *data, size_t count)
> +{
> +	struct spi_device *spi = context;

I'm not seeing huge value in teh local variable. I'd rename context
to spi and just pass it directly to spi_write()

Not important if you strongly prefer this way though.
> +
> +	return spi_write(spi, data, count);
> +}
> +

...

> +
> +static int ad7768_get_enable_vref(struct device *dev, unsigned int index)
> +{
> +	const char * const *supply = ad7768_vref_supply_names[index];
> +	int refp_uV;
> +	int refn_uV;
> +
> +	refp_uV = devm_regulator_get_enable_read_voltage(dev, supply[0]);
> +	if (refp_uV < 0)
> +		return dev_err_probe(dev, refp_uV,
> +				     "Failed to get %s supply voltage\n", supply[0]);
> +
> +	refn_uV = devm_regulator_get_enable_read_voltage(dev, supply[1]);
> +	if (refn_uV == -ENODEV)
> +		refn_uV = 0;
> +	else if (refn_uV < 0)
> +		return dev_err_probe(dev, refn_uV,
> +				     "Failed to get %s supply voltage\n", supply[1]);
> +
> +	if (refp_uV <= refn_uV)
> +		return dev_err_probe(dev, -EINVAL,
> +				     "Invalid reference %u voltage\n", index + 1);
> +
> +	return refp_uV - refn_uV;

Do we never care about the offset inherent in where the negative sits?

-- 
Jonathan Cameron <jonathan.cameron@xxxxxxxxxxxxxxxx>