[PATCH v5 11/20] iio: adc: ad7768: Add per-channel filter controls

[Janani Sunil]

Expose wideband and sinc5 filter selection for each channel. Group
enabled channels by their requested sampling frequency and filter pairs
and program each pair into one of the two hardware mode profiles.

Signed-off-by: Janani Sunil <janani.sunil@xxxxxxxxxx>
---
 drivers/iio/adc/ad7768.c | 72 ++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 66 insertions(+), 6 deletions(-)

diff --git a/drivers/iio/adc/ad7768.c b/drivers/iio/adc/ad7768.c
index 1245ec94b637..4c67f692861e 100644
--- a/drivers/iio/adc/ad7768.c
+++ b/drivers/iio/adc/ad7768.c
@@ -113,6 +113,11 @@
 #define AD7768_MAX_CHANNEL				8
 #define AD7768_NUM_CHANNEL_MODES			2
 
+enum ad7768_filter_type {
+	AD7768_FILTER_TYPE_WIDEBAND,
+	AD7768_FILTER_TYPE_SINC5,
+};
+
 enum ad7768_clock_source {
 	AD7768_CLOCK_SOURCE_MCLK,
 	AD7768_CLOCK_SOURCE_XTAL,
@@ -173,6 +178,7 @@ struct ad7768_state {
 	unsigned int n_freqs;
 	int freqs[AD7768_MAX_FREQS];
 	unsigned int ch_freq[AD7768_MAX_CHANNEL];
+	enum ad7768_filter_type ch_filter[AD7768_MAX_CHANNEL];
 	struct iio_backend *back;
 	unsigned int vref_uV[2];
 
@@ -527,12 +533,59 @@ static int ad7768_set_sampling_freq(struct iio_dev *indio_dev,
 	return 0;
 }
 
+static int ad7768_set_filter_mode(struct iio_dev *indio_dev,
+				  const struct iio_chan_spec *chan,
+				  unsigned int mode)
+{
+	struct ad7768_state *st = iio_priv(indio_dev);
+
+	IIO_DEV_ACQUIRE_DIRECT_MODE(indio_dev, claim);
+	if (IIO_DEV_ACQUIRE_FAILED(claim))
+		return -EBUSY;
+
+	guard(mutex)(&st->lock);
+	st->ch_filter[chan->channel] = mode;
+
+	return 0;
+}
+
+static int ad7768_get_filter_mode(struct iio_dev *indio_dev,
+				  const struct iio_chan_spec *chan)
+{
+	struct ad7768_state *st = iio_priv(indio_dev);
+
+	guard(mutex)(&st->lock);
+
+	return st->ch_filter[chan->channel];
+}
+
+static const char *const ad7768_filter_types[] = {
+	[AD7768_FILTER_TYPE_WIDEBAND] = "wideband",
+	[AD7768_FILTER_TYPE_SINC5] = "sinc5",
+};
+
+static const struct iio_enum ad7768_filter_types_enum = {
+	.items = ad7768_filter_types,
+	.num_items = ARRAY_SIZE(ad7768_filter_types),
+	.set = ad7768_set_filter_mode,
+	.get = ad7768_get_filter_mode,
+};
+
+static struct iio_chan_spec_ext_info ad7768_ext_info[] = {
+	IIO_ENUM("filter_type", IIO_SEPARATE, &ad7768_filter_types_enum),
+	IIO_ENUM_AVAILABLE("filter_type", IIO_SEPARATE, &ad7768_filter_types_enum),
+	{ }
+};
+
 static int ad7768_find_matching_mode(const bool *mode_used,
 				     const unsigned int *mode_freq,
-				     unsigned int freq)
+				     const enum ad7768_filter_type *mode_filter,
+				     unsigned int freq,
+				     enum ad7768_filter_type filter)
 {
 	for (unsigned int mode = 0; mode < AD7768_NUM_CHANNEL_MODES; mode++) {
-		if (!mode_used[mode] || mode_freq[mode] == freq)
+		if (!mode_used[mode] ||
+		    (mode_freq[mode] == freq && mode_filter[mode] == filter))
 			return mode;
 	}
 
@@ -542,6 +595,7 @@ static int ad7768_find_matching_mode(const bool *mode_used,
 static int ad7768_apply_channel_modes(struct iio_dev *indio_dev,
 				      const unsigned long *scan_mask)
 {
+	enum ad7768_filter_type mode_filter[AD7768_NUM_CHANNEL_MODES] = { };
 	unsigned int mode_freq[AD7768_NUM_CHANNEL_MODES] = { };
 	bool mode_used[AD7768_NUM_CHANNEL_MODES] = { };
 	struct ad7768_state *st = iio_priv(indio_dev);
@@ -576,13 +630,15 @@ static int ad7768_apply_channel_modes(struct iio_dev *indio_dev,
 		int mode;
 
 		mode = ad7768_find_matching_mode(mode_used, mode_freq,
-						 st->ch_freq[c]);
+						 mode_filter, st->ch_freq[c],
+						 st->ch_filter[c]);
 		if (mode < 0)
 			return dev_err_probe(dev, -EINVAL,
 					     "Over %d channel modes required\n",
 					     AD7768_NUM_CHANNEL_MODES);
 
 		mode_freq[mode] = st->ch_freq[c];
+		mode_filter[mode] = st->ch_filter[c];
 		mode_used[mode] = true;
 
 		mask = ad7768_channel_mode_mask(st, c);
@@ -605,8 +661,9 @@ static int ad7768_apply_channel_modes(struct iio_dev *indio_dev,
 		if (ret)
 			return ret;
 
-		ret = regmap_clear_bits(st->regmap, AD7768_REG_CH_MODE(mode),
-					AD7768_CH_MODE_FILTER_TYPE_MSK);
+		ret = regmap_assign_bits(st->regmap, AD7768_REG_CH_MODE(mode),
+					 AD7768_CH_MODE_FILTER_TYPE_MSK,
+					 mode_filter[mode]);
 		if (ret)
 			return ret;
 
@@ -857,8 +914,10 @@ static int ad7768_init_sampling_freqs(struct ad7768_state *st)
 	avail_freq = &st->avail_freq[st->power_mode_idx];
 	default_freq = avail_freq->freq_cfg[avail_freq->n_freqs - 1].freq_hz;
 	for (unsigned int channel = 0;
-	     channel < st->chip_info->num_channels; channel++)
+	     channel < st->chip_info->num_channels; channel++) {
 		st->ch_freq[channel] = default_freq;
+		st->ch_filter[channel] = AD7768_FILTER_TYPE_WIDEBAND;
+	}
 
 	return 0;
 }
@@ -952,6 +1011,7 @@ static int ad7768_parse_config(struct iio_dev *indio_dev,
 				.realbits = 24,
 				.storagebits = 32,
 			},
+			.ext_info = ad7768_ext_info,
 		};
 		chan_idx++;
 	}

-- 
2.43.0