| Message ID | 20200122085414.16950-1-alexandru.tachici@analog.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | iio: adc: ad7124: add 3db filter | expand |
On Wed, 22 Jan 2020 10:54:14 +0200 Alexandru Tachici <alexandru.tachici@analog.com> wrote: > This patch adds the LOW_PASS_FILTER_3DB_FREQUENCY attribute > in iio_chan_spec for each channel. The used filters are sinc3 > or sinc4. The filter type with the highest output data rate > is used when setting a low pass frequency in the channel's sysfs. > > Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com> Applied to the togreg branch of iio.git and pushed out as testing for the autobuilders to play with it. thanks, Jonathan > --- > drivers/iio/adc/ad7124.c | 69 +++++++++++++++++++++++++++++++++++++++- > 1 file changed, 68 insertions(+), 1 deletion(-) > > diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c > index 52f45b13da4a..8f48c0581f02 100644 > --- a/drivers/iio/adc/ad7124.c > +++ b/drivers/iio/adc/ad7124.c > @@ -70,6 +70,11 @@ > /* AD7124_FILTER_X */ > #define AD7124_FILTER_FS_MSK GENMASK(10, 0) > #define AD7124_FILTER_FS(x) FIELD_PREP(AD7124_FILTER_FS_MSK, x) > +#define AD7124_FILTER_TYPE_MSK GENMASK(23, 21) > +#define AD7124_FILTER_TYPE_SEL(x) FIELD_PREP(AD7124_FILTER_TYPE_MSK, x) > + > +#define AD7124_SINC3_FILTER 2 > +#define AD7124_SINC4_FILTER 0 > > enum ad7124_ids { > ID_AD7124_4, > @@ -119,6 +124,7 @@ struct ad7124_channel_config { > unsigned int vref_mv; > unsigned int pga_bits; > unsigned int odr; > + unsigned int filter_type; > }; > > struct ad7124_state { > @@ -138,7 +144,8 @@ static const struct iio_chan_spec ad7124_channel_template = { > .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | > BIT(IIO_CHAN_INFO_SCALE) | > BIT(IIO_CHAN_INFO_OFFSET) | > - BIT(IIO_CHAN_INFO_SAMP_FREQ), > + BIT(IIO_CHAN_INFO_SAMP_FREQ) | > + BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY), > .scan_type = { > .sign = 'u', > .realbits = 24, > @@ -281,6 +288,58 @@ static int ad7124_set_channel_gain(struct ad7124_state *st, > return 0; > } > > +static int ad7124_get_3db_filter_freq(struct ad7124_state *st, > + unsigned int channel) > +{ > + unsigned int fadc; > + > + fadc = st->channel_config[channel].odr; > + > + switch (st->channel_config[channel].filter_type) { > + case AD7124_SINC3_FILTER: > + return DIV_ROUND_CLOSEST(fadc * 230, 1000); > + case AD7124_SINC4_FILTER: > + return DIV_ROUND_CLOSEST(fadc * 262, 1000); > + default: > + return -EINVAL; > + } > +} > + > +static int ad7124_set_3db_filter_freq(struct ad7124_state *st, > + unsigned int channel, > + unsigned int freq) > +{ > + unsigned int sinc4_3db_odr; > + unsigned int sinc3_3db_odr; > + unsigned int new_filter; > + unsigned int new_odr; > + > + sinc4_3db_odr = DIV_ROUND_CLOSEST(freq * 1000, 230); > + sinc3_3db_odr = DIV_ROUND_CLOSEST(freq * 1000, 262); > + > + if (sinc4_3db_odr > sinc3_3db_odr) { > + new_filter = AD7124_SINC3_FILTER; > + new_odr = sinc4_3db_odr; > + } else { > + new_filter = AD7124_SINC4_FILTER; > + new_odr = sinc3_3db_odr; > + } > + > + if (st->channel_config[channel].filter_type != new_filter) { > + int ret; > + > + st->channel_config[channel].filter_type = new_filter; > + ret = ad7124_spi_write_mask(st, AD7124_FILTER(channel), > + AD7124_FILTER_TYPE_MSK, > + AD7124_FILTER_TYPE_SEL(new_filter), > + 3); > + if (ret < 0) > + return ret; > + } > + > + return ad7124_set_channel_odr(st, channel, new_odr); > +} > + > static int ad7124_read_raw(struct iio_dev *indio_dev, > struct iio_chan_spec const *chan, > int *val, int *val2, long info) > @@ -322,6 +381,9 @@ static int ad7124_read_raw(struct iio_dev *indio_dev, > case IIO_CHAN_INFO_SAMP_FREQ: > *val = st->channel_config[chan->address].odr; > > + return IIO_VAL_INT; > + case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY: > + *val = ad7124_get_3db_filter_freq(st, chan->scan_index); > return IIO_VAL_INT; > default: > return -EINVAL; > @@ -355,6 +417,11 @@ static int ad7124_write_raw(struct iio_dev *indio_dev, > gain = DIV_ROUND_CLOSEST(res, val2); > > return ad7124_set_channel_gain(st, chan->address, gain); > + case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY: > + if (val2 != 0) > + return -EINVAL; > + > + return ad7124_set_3db_filter_freq(st, chan->address, val); > default: > return -EINVAL; > }
diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c index 52f45b13da4a..8f48c0581f02 100644 --- a/drivers/iio/adc/ad7124.c +++ b/drivers/iio/adc/ad7124.c @@ -70,6 +70,11 @@ /* AD7124_FILTER_X */ #define AD7124_FILTER_FS_MSK GENMASK(10, 0) #define AD7124_FILTER_FS(x) FIELD_PREP(AD7124_FILTER_FS_MSK, x) +#define AD7124_FILTER_TYPE_MSK GENMASK(23, 21) +#define AD7124_FILTER_TYPE_SEL(x) FIELD_PREP(AD7124_FILTER_TYPE_MSK, x) + +#define AD7124_SINC3_FILTER 2 +#define AD7124_SINC4_FILTER 0 enum ad7124_ids { ID_AD7124_4, @@ -119,6 +124,7 @@ struct ad7124_channel_config { unsigned int vref_mv; unsigned int pga_bits; unsigned int odr; + unsigned int filter_type; }; struct ad7124_state { @@ -138,7 +144,8 @@ static const struct iio_chan_spec ad7124_channel_template = { .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET) | - BIT(IIO_CHAN_INFO_SAMP_FREQ), + BIT(IIO_CHAN_INFO_SAMP_FREQ) | + BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY), .scan_type = { .sign = 'u', .realbits = 24, @@ -281,6 +288,58 @@ static int ad7124_set_channel_gain(struct ad7124_state *st, return 0; } +static int ad7124_get_3db_filter_freq(struct ad7124_state *st, + unsigned int channel) +{ + unsigned int fadc; + + fadc = st->channel_config[channel].odr; + + switch (st->channel_config[channel].filter_type) { + case AD7124_SINC3_FILTER: + return DIV_ROUND_CLOSEST(fadc * 230, 1000); + case AD7124_SINC4_FILTER: + return DIV_ROUND_CLOSEST(fadc * 262, 1000); + default: + return -EINVAL; + } +} + +static int ad7124_set_3db_filter_freq(struct ad7124_state *st, + unsigned int channel, + unsigned int freq) +{ + unsigned int sinc4_3db_odr; + unsigned int sinc3_3db_odr; + unsigned int new_filter; + unsigned int new_odr; + + sinc4_3db_odr = DIV_ROUND_CLOSEST(freq * 1000, 230); + sinc3_3db_odr = DIV_ROUND_CLOSEST(freq * 1000, 262); + + if (sinc4_3db_odr > sinc3_3db_odr) { + new_filter = AD7124_SINC3_FILTER; + new_odr = sinc4_3db_odr; + } else { + new_filter = AD7124_SINC4_FILTER; + new_odr = sinc3_3db_odr; + } + + if (st->channel_config[channel].filter_type != new_filter) { + int ret; + + st->channel_config[channel].filter_type = new_filter; + ret = ad7124_spi_write_mask(st, AD7124_FILTER(channel), + AD7124_FILTER_TYPE_MSK, + AD7124_FILTER_TYPE_SEL(new_filter), + 3); + if (ret < 0) + return ret; + } + + return ad7124_set_channel_odr(st, channel, new_odr); +} + static int ad7124_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long info) @@ -322,6 +381,9 @@ static int ad7124_read_raw(struct iio_dev *indio_dev, case IIO_CHAN_INFO_SAMP_FREQ: *val = st->channel_config[chan->address].odr; + return IIO_VAL_INT; + case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY: + *val = ad7124_get_3db_filter_freq(st, chan->scan_index); return IIO_VAL_INT; default: return -EINVAL; @@ -355,6 +417,11 @@ static int ad7124_write_raw(struct iio_dev *indio_dev, gain = DIV_ROUND_CLOSEST(res, val2); return ad7124_set_channel_gain(st, chan->address, gain); + case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY: + if (val2 != 0) + return -EINVAL; + + return ad7124_set_3db_filter_freq(st, chan->address, val); default: return -EINVAL; }
This patch adds the LOW_PASS_FILTER_3DB_FREQUENCY attribute in iio_chan_spec for each channel. The used filters are sinc3 or sinc4. The filter type with the highest output data rate is used when setting a low pass frequency in the channel's sysfs. Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com> --- drivers/iio/adc/ad7124.c | 69 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 68 insertions(+), 1 deletion(-)