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authorQuentin Schulz <quentin.schulz@free-electrons.com>2016-05-18 17:16:18 +0200
committerJonathan Cameron <jic23@kernel.org>2016-05-21 20:15:04 +0100
commit44072b2c8da876e19c862ef609c14c8c4aecb48f (patch)
treeafeb4ba4b951bc0e2af03da5512728677d0d1a5f
parent9a47894fbeda2ab92c6ec57ee359adeaf283b962 (diff)
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 <quentin.schulz@free-electrons.com> Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
-rw-r--r--drivers/iio/adc/nau7802.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/drivers/iio/adc/nau7802.c b/drivers/iio/adc/nau7802.c
index e525aa6..57365c5 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
};