iio: mma8452: Add highpass filter configuration.

Allow the cutoff frequency of the high pass filter to be configured.

Signed-off-by: Martin Fuzzey <mfuzzey@parkeon.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
index 7429df3a191eb21da0705f2e0f47fb12f39ac431..51ae751e64a723c8f6a4a37429d8c5549368145a 100644 (file)
--- a/drivers/iio/accel/mma8452.c
+++ b/drivers/iio/accel/mma8452.c
@@ -29,9 +29,12 @@
 #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(chan)       BIT(chan + 1)
+#define MMA8452_TRANSIENT_CFG_HPF_BYP          BIT(0)
 #define MMA8452_TRANSIENT_SRC 0x1e
 #define MMA8452_TRANSIENT_SRC_XTRANSE          BIT(1)
 #define MMA8452_TRANSIENT_SRC_YTRANSE          BIT(3)
@@ -61,6 +64,7 @@
 #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_TRANS      BIT(5)
 
@@ -158,6 +162,18 @@ 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)
 {
@@ -172,9 +188,23 @@ 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)
@@ -190,6 +220,31 @@ 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_hp_filter(struct mma8452_data *data, int *hz, int *uHz)
+{
+       int i, ret;
+
+       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;
+       *hz = mma8452_hp_filter_cutoff[i][ret][0];
+       *uHz = mma8452_hp_filter_cutoff[i][ret][1];
+
+       return 0;
+}
+
 static int mma8452_read_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan,
                            int *val, int *val2, long mask)
@@ -228,6 +283,16 @@ 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:
+               if (data->data_cfg & MMA8452_DATA_CFG_HPF_MASK) {
+                       ret = mma8452_read_hp_filter(data, val, val2);
+                       if (ret < 0)
+                               return ret;
+               } else {
+                       *val = 0;
+                       *val2 = 0;
+               }
+               return IIO_VAL_INT_PLUS_MICRO;
        }
        return -EINVAL;
 }
@@ -269,12 +334,31 @@ fail:
        return ret;
 }
 
+static int mma8452_set_hp_filter_frequency(struct mma8452_data *data,
+                                          int val, int val2)
+{
+       int i, reg;
+
+       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);
+}
+
 static int mma8452_write_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan,
                             int val, int val2, long mask)
 {
        struct mma8452_data *data = iio_priv(indio_dev);
-       int i;
+       int i, ret;
 
        if (iio_buffer_enabled(indio_dev))
                return -EBUSY;
@@ -302,6 +386,19 @@ 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:
+               if (val == 0 && val2 == 0) {
+                       data->data_cfg &= ~MMA8452_DATA_CFG_HPF_MASK;
+               } else {
+                       data->data_cfg |= MMA8452_DATA_CFG_HPF_MASK;
+                       ret = mma8452_set_hp_filter_frequency(data, val, val2);
+                       if (ret < 0)
+                               return ret;
+               }
+               return mma8452_change_config(data, MMA8452_DATA_CFG,
+                                               data->data_cfg);
+
        default:
                return -EINVAL;
        }
@@ -339,6 +436,22 @@ static int mma8452_read_thresh(struct iio_dev *indio_dev,
                *val2 = us % USEC_PER_SEC;
                return IIO_VAL_INT_PLUS_MICRO;
 
+       case IIO_EV_INFO_HIGH_PASS_FILTER_3DB:
+               ret = i2c_smbus_read_byte_data(data->client,
+                                              MMA8452_TRANSIENT_CFG);
+               if (ret < 0)
+                       return ret;
+
+               if (ret & MMA8452_TRANSIENT_CFG_HPF_BYP) {
+                       *val = 0;
+                       *val2 = 0;
+               } else {
+                       ret = mma8452_read_hp_filter(data, val, val2);
+                       if (ret < 0)
+                               return ret;
+               }
+               return IIO_VAL_INT_PLUS_MICRO;
+
        default:
                return -EINVAL;
        }
@@ -352,7 +465,7 @@ static int mma8452_write_thresh(struct iio_dev *indio_dev,
                                int val, int val2)
 {
        struct mma8452_data *data = iio_priv(indio_dev);
-       int steps;
+       int ret, reg, steps;
 
        switch (info) {
        case IIO_EV_INFO_VALUE:
@@ -369,6 +482,22 @@ static int mma8452_write_thresh(struct iio_dev *indio_dev,
 
                return mma8452_change_config(data, MMA8452_TRANSIENT_COUNT,
                                             steps);
+       case IIO_EV_INFO_HIGH_PASS_FILTER_3DB:
+               reg = i2c_smbus_read_byte_data(data->client,
+                                              MMA8452_TRANSIENT_CFG);
+               if (reg < 0)
+                       return reg;
+
+               if (val == 0 && val2 == 0) {
+                       reg |= MMA8452_TRANSIENT_CFG_HPF_BYP;
+               } else {
+                       reg &= ~MMA8452_TRANSIENT_CFG_HPF_BYP;
+                       ret = mma8452_set_hp_filter_frequency(data, val, val2);
+                       if (ret < 0)
+                               return ret;
+               }
+               return mma8452_change_config(data, MMA8452_TRANSIENT_CFG, reg);
+
        default:
                return -EINVAL;
        }
@@ -510,7 +639,8 @@ static const struct iio_event_spec mma8452_transient_event[] = {
                .dir = IIO_EV_DIR_RISING,
                .mask_separate = BIT(IIO_EV_INFO_ENABLE),
                .mask_shared_by_type = BIT(IIO_EV_INFO_VALUE) |
-                                       BIT(IIO_EV_INFO_PERIOD)
+                                       BIT(IIO_EV_INFO_PERIOD) |
+                                       BIT(IIO_EV_INFO_HIGH_PASS_FILTER_3DB)
        },
 };
 
@@ -537,7 +667,8 @@ 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', \
@@ -560,6 +691,7 @@ 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
 };