From 1e79841a00e46506da887c718dd36a86b24b63e5 Mon Sep 17 00:00:00 2001 From: Martin Fuzzey Date: Mon, 1 Jun 2015 15:39:56 +0200 Subject: [PATCH] iio: mma8452: Add highpass filter configuration. Allow the cutoff frequency of the high pass filter to be configured. Signed-off-by: Martin Fuzzey Signed-off-by: Jonathan Cameron --- drivers/iio/accel/mma8452.c | 140 ++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 136 insertions(+), 4 deletions(-) diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c index 7429df3..51ae751 100644 --- 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 }; -- 2.7.4