[PATCH v6 10/17] iio: adc: ad7768: Add sampling frequency controls

[Janani Sunil]

Expose the requested sampling frequency and available rates for each
channel. Validate requests against the rates supported by the power mode
tables and apply them when buffered capture starts.

Signed-off-by: Janani Sunil <janani.sunil@xxxxxxxxxx>
---
 drivers/iio/adc/ad7768.c | 101 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 99 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/ad7768.c b/drivers/iio/adc/ad7768.c
index 868130ebcc8f..d5eaef92cbf2 100644
--- a/drivers/iio/adc/ad7768.c
+++ b/drivers/iio/adc/ad7768.c
@@ -125,6 +125,9 @@ static const struct ad7768_power_mode_info ad7768_power_modes[] = {
 	{ .mode = AD7768_POWER_MODE_POWER_MODE_FAST, .mclk_div = 4 },
 };
 
+#define AD7768_MAX_FREQS \
+	(AD7768_MAX_FREQ_PER_MODE + ARRAY_SIZE(ad7768_power_modes))
+
 struct ad7768_precharge_config {
 	bool prebufp_en;
 	bool prebufn_en;
@@ -161,10 +164,12 @@ struct ad7768_state {
 	enum ad7768_clock_source clock_source;
 	const struct ad7768_chip_info *chip_info;
 	struct ad7768_avail_freq avail_freq[ARRAY_SIZE(ad7768_power_modes)];
+	unsigned int n_freqs;
+	int freqs[AD7768_MAX_FREQS];
 	unsigned int ch_freq[AD7768_MAX_CHANNEL];
+	unsigned int power_mode_idx;
 	struct iio_backend *back;
 	unsigned int vref_uV[2];
-	unsigned int power_mode_idx;
 
 	__be16 d16 __aligned(IIO_DMA_MINALIGN);
 };
@@ -500,6 +505,32 @@ static int ad7768_set_lowest_noise_mode(struct ad7768_state *st,
 	return -EINVAL;
 }
 
+static bool ad7768_freq_supported_in_any_mode(const struct ad7768_state *st,
+					      unsigned int freq)
+{
+	for (unsigned int mode_idx = 0;
+	     mode_idx < ARRAY_SIZE(ad7768_power_modes); mode_idx++) {
+		if (ad7768_find_freq_config(st, mode_idx, freq))
+			return true;
+	}
+
+	return false;
+}
+
+static int ad7768_set_sampling_freq(struct iio_dev *indio_dev,
+				    unsigned int freq, unsigned int channel)
+{
+	struct ad7768_state *st = iio_priv(indio_dev);
+
+	if (!freq || !ad7768_freq_supported_in_any_mode(st, freq))
+		return -EINVAL;
+
+	guard(mutex)(&st->lock);
+	st->ch_freq[channel] = freq;
+
+	return 0;
+}
+
 static int ad7768_find_matching_mode(const bool *mode_used,
 				     const unsigned int *mode_freq,
 				     unsigned int freq)
@@ -678,14 +709,63 @@ static int ad7768_read_raw(struct iio_dev *indio_dev,
 	switch (info) {
 	case IIO_CHAN_INFO_SCALE:
 		return ad7768_read_scale(st, chan, val, val2);
+	case IIO_CHAN_INFO_SAMP_FREQ: {
+		guard(mutex)(&st->lock);
+		*val = st->ch_freq[chan->channel];
+
+		return IIO_VAL_INT;
+	}
 	default:
 		return -EINVAL;
 	}
 }
 
+static int ad7768_write_raw_get_fmt(struct iio_dev *indio_dev,
+				    struct iio_chan_spec const *chan, long info)
+{
+	if (info == IIO_CHAN_INFO_SAMP_FREQ)
+		return IIO_VAL_INT;
+
+	return -EINVAL;
+}
+
+static int ad7768_write_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int val, int val2, long info)
+{
+	IIO_DEV_ACQUIRE_DIRECT_MODE(indio_dev, claim);
+	if (IIO_DEV_ACQUIRE_FAILED(claim))
+		return -EBUSY;
+
+	if (info == IIO_CHAN_INFO_SAMP_FREQ)
+		return ad7768_set_sampling_freq(indio_dev, val, chan->channel);
+
+	return -EINVAL;
+}
+
+static int ad7768_read_avail(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     const int **vals, int *type, int *length,
+			     long info)
+{
+	struct ad7768_state *st = iio_priv(indio_dev);
+
+	if (info != IIO_CHAN_INFO_SAMP_FREQ)
+		return -EINVAL;
+
+	*vals = st->freqs;
+	*type = IIO_VAL_INT;
+	*length = st->n_freqs;
+
+	return IIO_AVAIL_LIST;
+}
+
 static const struct iio_info ad7768_info = {
 	.debugfs_reg_access = ad7768_reg_access,
 	.read_raw = ad7768_read_raw,
+	.write_raw_get_fmt = ad7768_write_raw_get_fmt,
+	.write_raw = ad7768_write_raw,
+	.read_avail = ad7768_read_avail,
 	.update_scan_mode = ad7768_update_scan_mode,
 };
 
@@ -758,6 +838,20 @@ static void ad7768_set_available_sampling_freqs(struct ad7768_state *st)
 	if (st->datalines == 1 &&
 	    st->chip_info->num_channels == AD7768_MAX_CHANNEL)
 		st->avail_freq[n_power_modes - 1].n_freqs--;
+
+	for (unsigned int mode_idx = 0; mode_idx < n_power_modes; mode_idx++) {
+		const struct ad7768_avail_freq *avail_freq;
+
+		avail_freq = &st->avail_freq[mode_idx];
+		for (unsigned int i = 0; i < avail_freq->n_freqs; i++) {
+			unsigned int freq = avail_freq->freq_cfg[i].freq_hz;
+
+			if (st->n_freqs && st->freqs[st->n_freqs - 1] >= freq)
+				continue;
+
+			st->freqs[st->n_freqs++] = freq;
+		}
+	}
 }
 
 static int ad7768_init_sampling_freqs(struct ad7768_state *st)
@@ -855,7 +949,10 @@ static int ad7768_parse_config(struct iio_dev *indio_dev,
 
 		chan[chan_idx] = (struct iio_chan_spec) {
 			.type = IIO_VOLTAGE,
-			.info_mask_separate = BIT(IIO_CHAN_INFO_SCALE),
+			.info_mask_separate = BIT(IIO_CHAN_INFO_SCALE) |
+					      BIT(IIO_CHAN_INFO_SAMP_FREQ),
+			.info_mask_separate_available =
+				BIT(IIO_CHAN_INFO_SAMP_FREQ),
 			.indexed = 1,
 			.channel = channel,
 			.scan_index = channel,

-- 
2.43.0