Allow the cutoff frequency of the high pass filter to be configured.
Signed-off-by: Martin Fuzzey <mfuzzey@xxxxxxxxxxx>
---
drivers/iio/accel/mma8452.c | 65 ++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 63 insertions(+), 2 deletions(-)
diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
index 7e0c29c..66933b2 100644
--- a/drivers/iio/accel/mma8452.c
+++ b/drivers/iio/accel/mma8452.c
@@ -29,6 +29,8 @@
#define MMA8452_INT_SRC 0x0c
#define MMA8452_WHO_AM_I 0x0d
#define MMA8452_DATA_CFG 0x0e
+#define MMA8452_HP_FILTER_CUTOFF 0x0f
+#define MMA8452_HP_FILTER_CUTOFF_SEL_MASK (BIT(0) | BIT(1))
#define MMA8452_TRANSIENT_CFG 0x1d
#define MMA8452_TRANSIENT_CFG_ELE BIT(4)
#define MMA8452_TRANSIENT_CFG_CHAN_MASK(chan) (BIT(1) << chan)
@@ -162,6 +164,18 @@ static const int mma8452_transient_time_step_us[8] = {
20000
};
+/* Datasheet table 18 (normal mode) */
+static const int mma8452_hp_filter_cutoff[8][4][2] = {
+ { {16, 0}, {8, 0}, {4, 0}, {2, 0} }, /* 800 Hz sample */
+ { {16, 0}, {8, 0}, {4, 0}, {2, 0} }, /* 400 Hz sample */
+ { {8, 0}, {4, 0}, {2, 0}, {1, 0} }, /* 200 Hz sample */
+ { {4, 0}, {2, 0}, {1, 0}, {0, 500000} }, /* 100 Hz sample */
+ { {2, 0}, {1, 0}, {0, 500000}, {0, 250000} }, /* 50 Hz sample */
+ { {2, 0}, {1, 0}, {0, 500000}, {0, 250000} }, /* 12.5 Hz sample */
+ { {2, 0}, {1, 0}, {0, 500000}, {0, 250000} }, /* 6.25 Hz sample */
+ { {2, 0}, {1, 0}, {0, 500000}, {0, 250000} } /* 1.56 Hz sample */
+};
+
static ssize_t mma8452_show_samp_freq_avail(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -176,9 +190,22 @@ static ssize_t mma8452_show_scale_avail(struct device *dev,
ARRAY_SIZE(mma8452_scales));
}
+static ssize_t mma8452_show_hp_cutoff_avail(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct mma8452_data *data = iio_priv(indio_dev);
+ int i = mma8452_get_odr_index(data);
+
+ return mma8452_show_int_plus_micros(buf, mma8452_hp_filter_cutoff[i],
+ ARRAY_SIZE(mma8452_hp_filter_cutoff[0]));
+}
+
static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mma8452_show_samp_freq_avail);
static IIO_DEVICE_ATTR(in_accel_scale_available, S_IRUGO,
mma8452_show_scale_avail, NULL, 0);
+static IIO_DEVICE_ATTR(in_accel_filter_high_pass_3db_frequency_available,
+ S_IRUGO, mma8452_show_hp_cutoff_avail, NULL, 0);
static int mma8452_get_samp_freq_index(struct mma8452_data *data,
int val, int val2)
@@ -194,6 +221,15 @@ static int mma8452_get_scale_index(struct mma8452_data *data,
ARRAY_SIZE(mma8452_scales), val, val2);
}
+static int mma8452_get_hp_filter_index(struct mma8452_data *data,
+ int val, int val2)
+{
+ int i = mma8452_get_odr_index(data);
+
+ return mma8452_get_int_plus_micros_index(mma8452_hp_filter_cutoff[i],
+ ARRAY_SIZE(mma8452_scales[0]), val, val2);
+}
+
static int mma8452_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
@@ -232,6 +268,16 @@ static int mma8452_read_raw(struct iio_dev *indio_dev,
return ret;
*val = sign_extend32(ret, 7);
return IIO_VAL_INT;
+ case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
+ ret = i2c_smbus_read_byte_data(data->client,
+ MMA8452_HP_FILTER_CUTOFF);
+ if (ret < 0)
+ return ret;
+ i = mma8452_get_odr_index(data);
+ ret &= MMA8452_HP_FILTER_CUTOFF_SEL_MASK;
+ *val = mma8452_hp_filter_cutoff[i][ret][0];
+ *val2 = mma8452_hp_filter_cutoff[i][ret][1];
+ return IIO_VAL_INT_PLUS_MICRO;
}
return -EINVAL;
}
@@ -278,7 +324,7 @@ static int mma8452_write_raw(struct iio_dev *indio_dev,
int val, int val2, long mask)
{
struct mma8452_data *data = iio_priv(indio_dev);
- int i;
+ int i, reg;
if (iio_buffer_enabled(indio_dev))
return -EBUSY;
@@ -306,6 +352,19 @@ static int mma8452_write_raw(struct iio_dev *indio_dev,
return -EINVAL;
return mma8452_change_config(data, MMA8452_OFF_X +
chan->scan_index, val);
+ case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
+ i = mma8452_get_hp_filter_index(data, val, val2);
+ if (i < 0)
+ return -EINVAL;
+
+ reg = i2c_smbus_read_byte_data(data->client,
+ MMA8452_HP_FILTER_CUTOFF);
+ if (reg < 0)
+ return reg;
+ reg &= ~MMA8452_HP_FILTER_CUTOFF_SEL_MASK;
+ reg |= i;
+ return mma8452_change_config(data,
+ MMA8452_HP_FILTER_CUTOFF, reg);
default:
return -EINVAL;
}
@@ -552,7 +611,8 @@ static struct attribute_group mma8452_event_attribute_group = {
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
BIT(IIO_CHAN_INFO_CALIBBIAS), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
- BIT(IIO_CHAN_INFO_SCALE), \
+ BIT(IIO_CHAN_INFO_SCALE) | \
+ BIT(IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY), \
.scan_index = idx, \
.scan_type = { \
.sign = 's', \
@@ -575,6 +635,7 @@ static const struct iio_chan_spec mma8452_channels[] = {
static struct attribute *mma8452_attributes[] = {
&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
&iio_dev_attr_in_accel_scale_available.dev_attr.attr,
+ &iio_dev_attr_in_accel_filter_high_pass_3db_frequency_available.dev_attr.attr,
NULL
};
--
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