Re: [PATCH v4 04/10] iio: adc: ti-ads1262: support per-channel sampling frequency

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 28 Aug 2026 01:38:19 -0500
Kurt Borja <kuurtb@gmail.com> wrote:

> Add per-channel sampling frequency support. The "available" attribute is
> assigned per-channel too, in order to eventually support per-filter
> availability.
> 
> Signed-off-by: Kurt Borja <kuurtb@gmail.com>
A build issue below.

>  };
>  
> +static const struct ads1262_channel ads1262_default_channel = {
> +	.data_rate = ADS1262_DR_20_SPS,
> +	.filter = ADS1262_FILTER_FIR,
> +};

See below - this probably wants to be a slightly more complex define.



> @@ -763,8 +970,15 @@ static int ads1262_parse_channels(struct iio_dev *indio_dev)
>  	if (!chan_specs)
>  		return -ENOMEM;
>  
> +	st->num_channels = num_fw_channels + ADS1262_MON_CHANNEL_COUNT;
> +	st->channels = devm_kcalloc(dev, st->num_channels, sizeof(*st->channels),
> +				    GFP_KERNEL);
> +	if (!st->channels)
> +		return -ENOMEM;
> +
>  	device_for_each_named_child_node_scoped(dev, node, "channel") {
>  		struct iio_chan_spec *spec = &chan_specs[i];
> +		struct ads1262_channel *chan = &st->channels[i];
>  
>  		ret = fwnode_property_read_u32(node, "reg", &reg);
>  		if (ret)
> @@ -772,6 +986,8 @@ static int ads1262_parse_channels(struct iio_dev *indio_dev)
>  		if (reg >= ADS1262_MONITOR_ADDR_OFFSET)
>  			return dev_err_probe(dev, -EINVAL, "%pfwP: reg out of range\n", node);
>  
> +		*chan = (struct ads1262_channel)ads1262_default_channel;

This is giving me a build warning:

drivers/iio/adc/ti-ads1262.c:1913:26: warning: cast to non-scalar
drivers/iio/adc/ti-ads1262.c:1913:26: warning: cast from non-scalar

So we can't do this... Hmm. It's pretty simply. Use a define for
the default channel with the (struct adds1262_channel)
and that should work for us.

> +
>  		ret = ads1262_parse_channel_node(st, spec, node);
>  		if (ret)
>  			return ret;
> @@ -786,7 +1002,9 @@ static int ads1262_parse_channels(struct iio_dev *indio_dev)
>  			.storagebits = 32,
>  			.endianness = IIO_BE,
>  		};
> -		spec->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
> +		spec->info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +					   BIT(IIO_CHAN_INFO_SAMP_FREQ);
> +		spec->info_mask_separate_available = BIT(IIO_CHAN_INFO_SAMP_FREQ);
>  
>  		i++;
>  	}
> @@ -795,6 +1013,7 @@ static int ads1262_parse_channels(struct iio_dev *indio_dev)
>  	       sizeof(ads1262_monitor_chan_specs));
>  
>  	for (unsigned int mon = 0; mon < ADS1262_MON_CHANNEL_COUNT; mon++) {
> +		st->channels[i] = (struct ads1262_channel)ads1262_default_channel;
Same here - a define would allow this to work rather than giving build
problems as it currently does.

>  		chan_specs[i].scan_index = i;
>  		i++;
>  	}
> @@ -890,6 +1109,10 @@ static int ads1262_spi_probe(struct spi_device *spi)
>  
>  	indio_dev->name = ads1262_device_id_to_name[st->dev_id];
>  
> +	ret = ads1262_populate_tables(indio_dev);
> +	if (ret)
> +		return ret;
> +
>  	/*
>  	 * REVISIT: This chip has software polling capabilities, which could be
>  	 * used to stop depending on the DRDY signal.
>