The hardware contains a single configurable highpass filter which
is normally used for transient detection (event).
However it is also possible to enable this filter for normal channel
reading. Add a new attribute in_accel_high_pass_filter_en to do this.
Signed-off-by: Martin Fuzzey <mfuzzey@xxxxxxxxxxx>
---
drivers/iio/accel/mma8452.c | 115 +++++++++++++++++++++++++++++--------------
1 file changed, 78 insertions(+), 37 deletions(-)
diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
index eb68f9a..62589f9 100644
--- a/drivers/iio/accel/mma8452.c
+++ b/drivers/iio/accel/mma8452.c
@@ -62,6 +62,7 @@
#define MMA8452_DATA_CFG_FS_2G 0
#define MMA8452_DATA_CFG_FS_4G 1
#define MMA8452_DATA_CFG_FS_8G 2
+#define MMA8452_DATA_CFG_HPF_MASK BIT(4)
#define MMA8452_INT_DRDY BIT(0)
#define MMA8452_INT_FF_MT BIT(2)
@@ -106,6 +107,43 @@ static int mma8452_read(struct mma8452_data *data, __be16 buf[3])
MMA8452_OUT_X, 3 * sizeof(__be16), (u8 *) buf);
}
+static int mma8452_standby(struct mma8452_data *data)
+{
+ return i2c_smbus_write_byte_data(data->client, MMA8452_CTRL_REG1,
+ data->ctrl_reg1 & ~MMA8452_CTRL_ACTIVE);
+}
+
+static int mma8452_active(struct mma8452_data *data)
+{
+ return i2c_smbus_write_byte_data(data->client, MMA8452_CTRL_REG1,
+ data->ctrl_reg1);
+}
+
+static int mma8452_change_config(struct mma8452_data *data, u8 reg, u8 val)
+{
+ int ret;
+
+ mutex_lock(&data->lock);
+
+ /* config can only be changed when in standby */
+ ret = mma8452_standby(data);
+ if (ret < 0)
+ goto fail;
+
+ ret = i2c_smbus_write_byte_data(data->client, reg, val);
+ if (ret < 0)
+ goto fail;
+
+ ret = mma8452_active(data);
+ if (ret < 0)
+ goto fail;
+
+ ret = 0;
+fail:
+ mutex_unlock(&data->lock);
+ return ret;
+}
+
static ssize_t mma8452_show_int_plus_micros(char *buf,
const int (*vals)[2], int n)
{
@@ -201,11 +239,50 @@ static ssize_t mma8452_show_hp_cutoff_avail(struct device *dev,
ARRAY_SIZE(mma8452_hp_filter_cutoff[0]));
}
+static ssize_t mma8452_show_hp_cutoff_en(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);
+
+ return sprintf(buf, "%d\n",
+ data->data_cfg & MMA8452_DATA_CFG_HPF_MASK ? 1 : 0);
+}
+
+static ssize_t mma8452_store_hp_cutoff_en(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct mma8452_data *data = iio_priv(indio_dev);
+ bool state;
+ int ret;
+
+ ret = strtobool(buf, &state);
+ if (ret < 0)
+ return ret;
+
+ if (state)
+ data->data_cfg |= MMA8452_DATA_CFG_HPF_MASK;
+ else
+ data->data_cfg &= ~MMA8452_DATA_CFG_HPF_MASK;
+
+ ret = mma8452_change_config(data, MMA8452_DATA_CFG, data->data_cfg);
+ if (ret)
+ return ret;
+
+ return len;
+}
+
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 IIO_DEVICE_ATTR(in_accel_filter_high_pass_en,
+ S_IRUGO | S_IWUSR,
+ mma8452_show_hp_cutoff_en,
+ mma8452_store_hp_cutoff_en, 0);
static int mma8452_get_samp_freq_index(struct mma8452_data *data,
int val, int val2)
@@ -282,43 +359,6 @@ static int mma8452_read_raw(struct iio_dev *indio_dev,
return -EINVAL;
}
-static int mma8452_standby(struct mma8452_data *data)
-{
- return i2c_smbus_write_byte_data(data->client, MMA8452_CTRL_REG1,
- data->ctrl_reg1 & ~MMA8452_CTRL_ACTIVE);
-}
-
-static int mma8452_active(struct mma8452_data *data)
-{
- return i2c_smbus_write_byte_data(data->client, MMA8452_CTRL_REG1,
- data->ctrl_reg1);
-}
-
-static int mma8452_change_config(struct mma8452_data *data, u8 reg, u8 val)
-{
- int ret;
-
- mutex_lock(&data->lock);
-
- /* config can only be changed when in standby */
- ret = mma8452_standby(data);
- if (ret < 0)
- goto fail;
-
- ret = i2c_smbus_write_byte_data(data->client, reg, val);
- if (ret < 0)
- goto fail;
-
- ret = mma8452_active(data);
- if (ret < 0)
- goto fail;
-
- ret = 0;
-fail:
- mutex_unlock(&data->lock);
- return ret;
-}
-
static int mma8452_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
@@ -636,6 +676,7 @@ 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,
+ &iio_dev_attr_in_accel_filter_high_pass_en.dev_attr.attr,
NULL
};
--
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