iio: adc: nau7802: Expose possible gains in sysfs (44072b2c) · Commits · 戴 / test

The Nuvoton NAU7802 ADC is able to adjust its gain but prior knowledge of its possible values was required to adjust it. Users had to guess the possible gain values based on the ADC datasheet or on this driver's code. This exposes the possible values in the in_voltage_scale_available file of each nau7802 ADC device. The gain is set for the whole ADC and is therefore not configurable by channel. Thus, there exists only one in_voltage_scale_available file for each nau7802 ADC device even if it has two separate channels. Signed-off-by:

Quentin Schulz <quentin.schulz@free-electrons.com> Acked-by:

Alexandre Belloni <alexandre.belloni@free-electrons.com> Signed-off-by:

Jonathan Cameron <jic23@kernel.org>

drivers/iio/adc/nau7802.c

+19 −0

Original line number	Diff line number	Diff line
		@@ -79,10 +79,29 @@ static const struct iio_chan_spec nau7802_chan_array[] = {
		static const u16 nau7802_sample_freq_avail[] = {10, 20, 40, 80,
		10, 10, 10, 320};

		static ssize_t nau7802_show_scales(struct device *dev,
		struct device_attribute attr, char buf)
		{
		struct nau7802_state *st = iio_priv(dev_to_iio_dev(dev));
		int i, len = 0;

		for (i = 0; i < ARRAY_SIZE(st->scale_avail); i++)
		len += scnprintf(buf + len, PAGE_SIZE - len, "0.%09d ",
		st->scale_avail[i]);

		buf[len-1] = '\n';

		return len;
		}

		static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("10 40 80 320");

		static IIO_DEVICE_ATTR(in_voltage_scale_available, S_IRUGO, nau7802_show_scales,
		NULL, 0);

		static struct attribute *nau7802_attributes[] = {
		&iio_const_attr_sampling_frequency_available.dev_attr.attr,
		&iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
		NULL
		};

Admin message