From 44072b2c8da876e19c862ef609c14c8c4aecb48f Mon Sep 17 00:00:00 2001 From: Quentin Schulz Date: Wed, 18 May 2016 17:16:18 +0200 Subject: [PATCH] iio: adc: nau7802: Expose possible gains in sysfs 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 Acked-by: Alexandre Belloni Signed-off-by: Jonathan Cameron --- drivers/iio/adc/nau7802.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/drivers/iio/adc/nau7802.c b/drivers/iio/adc/nau7802.c index e525aa6475c4..57365c504093 100644 --- a/drivers/iio/adc/nau7802.c +++ b/drivers/iio/adc/nau7802.c @@ -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 }; -- 2.20.1