[PATCH v2 1/6] iio: accel: adxl372: Add support for FIFO peak mode

Alexandru Tachici
2020-02-25T12:09:34Z

From: Stefan Popa <stefan.popa@analog.com>

By default, if all three channels (x, y, z) are enabled, sample sets of
concurrent 3-axis data is stored in the FIFO. This patch adds the option
to configure the FIFO to store peak acceleration (x, y and z) of every
over-threshold event. Since we cannot store 1 or 2 axis peak acceleration
data in the FIFO, then all three axis need to be enabled in order for this
mode to work.

Signed-off-by: Stefan Popa <stefan.popa@analog.com>
---
drivers/iio/accel/adxl372.c | 46 +++++++++++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)

diff --git a/drivers/iio/accel/adxl372.c b/drivers/iio/accel/adxl372.c
index 67b8817995c0..ed93534f8dba 100644
--- a/drivers/iio/accel/adxl372.c
+++ b/drivers/iio/accel/adxl372.c
@@ -264,6 +264,7 @@ struct adxl372_state {
u8 int2_bitmask;
u16 watermark;
__be16 fifo_buf[ADXL372_FIFO_SIZE];
+ bool peak_fifo_mode_en;
};

static const unsigned long adxl372_channel_masks[] = {
@@ -722,6 +723,40 @@ static int adxl372_write_raw(struct iio_dev *indio_dev,
}
}

+static ssize_t adxl372_peak_fifo_en_get(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct adxl372_state *st = iio_priv(dev_to_iio_dev(dev));
+
+ return sprintf(buf, "%d\n", st->peak_fifo_mode_en);
+}
+
+static ssize_t adxl372_peak_fifo_en_set(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct adxl372_state *st = iio_priv(indio_dev);
+ bool val;
+ int ret;
+
+ if (iio_buffer_enabled(indio_dev))
+ return -EBUSY;
+
+ ret = kstrtobool(buf, &val);
+ if (ret)
+ return ret;
+
+ st->peak_fifo_mode_en = val;
+
+ return len;
+}
+
+static IIO_DEVICE_ATTR(buffer_peak_mode_enable, 0644,
+ adxl372_peak_fifo_en_get,
+ adxl372_peak_fifo_en_set, 0);
+
static ssize_t adxl372_show_filter_freq_avail(struct device *dev,
struct device_attribute *attr,
char *buf)
@@ -817,11 +852,21 @@ static int adxl372_buffer_postenable(struct iio_dev *indio_dev)
st->fifo_format = adxl372_axis_lookup_table[i].fifo_format;
st->fifo_set_size = bitmap_weight(indio_dev->active_scan_mask,
indio_dev->masklength);
+
+ /* Configure the FIFO to store sets of impact event peak. */
+ if (st->peak_fifo_mode_en) {
+ st->fifo_format = ADXL372_XYZ_PEAK_FIFO;
+ if (st->fifo_set_size != 3)
+ dev_warn(&indio_dev->dev,
+ "All axis must be enabled in peak mode.");
+ }
+
/*
* The 512 FIFO samples can be allotted in several ways, such as:
* 170 sample sets of concurrent 3-axis data
* 256 sample sets of concurrent 2-axis data (user selectable)
* 512 sample sets of single-axis data
+ * 170 sets of impact event peak (x, y, z)
*/
if ((st->watermark * st->fifo_set_size) > ADXL372_FIFO_SIZE)
st->watermark = (ADXL372_FIFO_SIZE / st->fifo_set_size);
@@ -894,6 +939,7 @@ static IIO_DEVICE_ATTR(in_accel_filter_low_pass_3db_frequency_available,
static struct attribute *adxl372_attributes[] = {
&iio_const_attr_sampling_frequency_available.dev_attr.attr,
&iio_dev_attr_in_accel_filter_low_pass_3db_frequency_available.dev_attr.attr,
+ &iio_dev_attr_buffer_peak_mode_enable.dev_attr.attr,
NULL,
};

--
2.20.1