iio: adc: ad7192: Use standard attribute

Replace custom attribute filter_low_pass_3db_frequency_available with
standard attribute.

Store the available values in ad7192_state struct.

The function that used to compute those values replaced by
ad7192_update_filter_freq_avail().

Function ad7192_show_filter_avail() is no longer needed.

Note that the initial available values are hardcoded.

Also moved the mutex lock and unlock in order to protect the whole
switch statement since each branch modifies the state of the device.
Reviewed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Alisa-Dariana Roman <alisa.roman@analog.com>
Link: https://lore.kernel.org/r/20240514120222.56488-2-alisa.roman@analog.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/ad7192.c

@@ -190,6 +190,7 @@ struct ad7192_state {
 	u32				mode;
 	u32				conf;
 	u32				scale_avail[8][2];
+	u32				filter_freq_avail[4][2];
 	u32				oversampling_ratio_avail[4];
 	u8				gpocon;
 	u8				clock_sel;
@@ -473,6 +474,16 @@ static int ad7192_setup(struct iio_dev *indio_dev, struct device *dev)
 	st->oversampling_ratio_avail[2] = 8;
 	st->oversampling_ratio_avail[3] = 16;
 
+	st->filter_freq_avail[0][0] = 600;
+	st->filter_freq_avail[1][0] = 800;
+	st->filter_freq_avail[2][0] = 2300;
+	st->filter_freq_avail[3][0] = 2720;
+
+	st->filter_freq_avail[0][1] = 1000;
+	st->filter_freq_avail[1][1] = 1000;
+	st->filter_freq_avail[2][1] = 1000;
+	st->filter_freq_avail[3][1] = 1000;
+
 	return 0;
 }
 
@@ -586,48 +597,24 @@ static int ad7192_get_f_adc(struct ad7192_state *st)
 				 f_order * FIELD_GET(AD7192_MODE_RATE_MASK, st->mode));
 }
 
-static void ad7192_get_available_filter_freq(struct ad7192_state *st,
-						    int *freq)
+static void ad7192_update_filter_freq_avail(struct ad7192_state *st)
 {
 	unsigned int fadc;
 
 	/* Formulas for filter at page 25 of the datasheet */
 	fadc = ad7192_compute_f_adc(st, false, true);
-	freq[0] = DIV_ROUND_CLOSEST(fadc * 240, 1024);
+	st->filter_freq_avail[0][0] = DIV_ROUND_CLOSEST(fadc * 240, 1024);
 
 	fadc = ad7192_compute_f_adc(st, true, true);
-	freq[1] = DIV_ROUND_CLOSEST(fadc * 240, 1024);
+	st->filter_freq_avail[1][0] = DIV_ROUND_CLOSEST(fadc * 240, 1024);
 
 	fadc = ad7192_compute_f_adc(st, false, false);
-	freq[2] = DIV_ROUND_CLOSEST(fadc * 230, 1024);
+	st->filter_freq_avail[2][0] = DIV_ROUND_CLOSEST(fadc * 230, 1024);
 
 	fadc = ad7192_compute_f_adc(st, true, false);
-	freq[3] = DIV_ROUND_CLOSEST(fadc * 272, 1024);
+	st->filter_freq_avail[3][0] = DIV_ROUND_CLOSEST(fadc * 272, 1024);
 }
 
-static ssize_t ad7192_show_filter_avail(struct device *dev,
-					struct device_attribute *attr,
-					char *buf)
-{
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct ad7192_state *st = iio_priv(indio_dev);
-	unsigned int freq_avail[4], i;
-	size_t len = 0;
-
-	ad7192_get_available_filter_freq(st, freq_avail);
-
-	for (i = 0; i < ARRAY_SIZE(freq_avail); i++)
-		len += sysfs_emit_at(buf, len, "%d.%03d ", freq_avail[i] / 1000,
-				     freq_avail[i] % 1000);
-
-	buf[len - 1] = '\n';
-
-	return len;
-}
-
-static IIO_DEVICE_ATTR(filter_low_pass_3db_frequency_available,
-		       0444, ad7192_show_filter_avail, NULL, 0);
-
 static IIO_DEVICE_ATTR(bridge_switch_en, 0644,
 		       ad7192_show_bridge_switch, ad7192_set,
 		       AD7192_REG_GPOCON);
@@ -637,7 +624,6 @@ static IIO_DEVICE_ATTR(ac_excitation_en, 0644,
 		       AD7192_REG_CONF);
 
 static struct attribute *ad7192_attributes[] = {
-	&iio_dev_attr_filter_low_pass_3db_frequency_available.dev_attr.attr,
 	&iio_dev_attr_bridge_switch_en.dev_attr.attr,
 	NULL
 };
@@ -647,7 +633,6 @@ static const struct attribute_group ad7192_attribute_group = {
 };
 
 static struct attribute *ad7195_attributes[] = {
-	&iio_dev_attr_filter_low_pass_3db_frequency_available.dev_attr.attr,
 	&iio_dev_attr_bridge_switch_en.dev_attr.attr,
 	&iio_dev_attr_ac_excitation_en.dev_attr.attr,
 	NULL
@@ -665,17 +650,15 @@ static unsigned int ad7192_get_temp_scale(bool unipolar)
 static int ad7192_set_3db_filter_freq(struct ad7192_state *st,
 				      int val, int val2)
 {
-	int freq_avail[4], i, ret, freq;
+	int i, ret, freq;
 	unsigned int diff_new, diff_old;
 	int idx = 0;
 
 	diff_old = U32_MAX;
 	freq = val * 1000 + val2;
 
-	ad7192_get_available_filter_freq(st, freq_avail);
-
-	for (i = 0; i < ARRAY_SIZE(freq_avail); i++) {
-		diff_new = abs(freq - freq_avail[i]);
+	for (i = 0; i < ARRAY_SIZE(st->filter_freq_avail); i++) {
+		diff_new = abs(freq - st->filter_freq_avail[i][0]);
 		if (diff_new < diff_old) {
 			diff_old = diff_new;
 			idx = i;
@@ -792,10 +775,11 @@ static int ad7192_write_raw(struct iio_dev *indio_dev,
 	if (ret)
 		return ret;
 
+	mutex_lock(&st->lock);
+
 	switch (mask) {
 	case IIO_CHAN_INFO_SCALE:
 		ret = -EINVAL;
-		mutex_lock(&st->lock);
 		for (i = 0; i < ARRAY_SIZE(st->scale_avail); i++)
 			if (val2 == st->scale_avail[i][1]) {
 				ret = 0;
@@ -809,7 +793,6 @@ static int ad7192_write_raw(struct iio_dev *indio_dev,
 				ad7192_calibrate_all(st);
 				break;
 			}
-		mutex_unlock(&st->lock);
 		break;
 	case IIO_CHAN_INFO_SAMP_FREQ:
 		if (!val) {
@@ -826,13 +809,13 @@ static int ad7192_write_raw(struct iio_dev *indio_dev,
 		st->mode &= ~AD7192_MODE_RATE_MASK;
 		st->mode |= FIELD_PREP(AD7192_MODE_RATE_MASK, div);
 		ad_sd_write_reg(&st->sd, AD7192_REG_MODE, 3, st->mode);
+		ad7192_update_filter_freq_avail(st);
 		break;
 	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
 		ret = ad7192_set_3db_filter_freq(st, val, val2 / 1000);
 		break;
 	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
 		ret = -EINVAL;
-		mutex_lock(&st->lock);
 		for (i = 0; i < ARRAY_SIZE(st->oversampling_ratio_avail); i++)
 			if (val == st->oversampling_ratio_avail[i]) {
 				ret = 0;
@@ -845,12 +828,14 @@ static int ad7192_write_raw(struct iio_dev *indio_dev,
 						3, st->mode);
 				break;
 			}
-		mutex_unlock(&st->lock);
+		ad7192_update_filter_freq_avail(st);
 		break;
 	default:
 		ret = -EINVAL;
 	}
 
+	mutex_unlock(&st->lock);
+
 	iio_device_release_direct_mode(indio_dev);
 
 	return ret;
@@ -888,6 +873,12 @@ static int ad7192_read_avail(struct iio_dev *indio_dev,
 		/* Values are stored in a 2D matrix  */
 		*length = ARRAY_SIZE(st->scale_avail) * 2;
 
+		return IIO_AVAIL_LIST;
+	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
+		*vals = (int *)st->filter_freq_avail;
+		*type = IIO_VAL_FRACTIONAL;
+		*length = ARRAY_SIZE(st->filter_freq_avail) * 2;
+
 		return IIO_AVAIL_LIST;
 	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
 		*vals = (int *)st->oversampling_ratio_avail;
@@ -956,7 +947,9 @@ static const struct iio_info ad7195_info = {
 			BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY) | \
 			(_mask_all), \
 		.info_mask_shared_by_type_available = (_mask_type_av), \
-		.info_mask_shared_by_all_available = (_mask_all_av), \
+		.info_mask_shared_by_all_available = \
+			BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY) | \
+			(_mask_all_av), \
 		.ext_info = (_ext_info), \
 		.scan_index = (_si), \
 		.scan_type = { \