staging: iio: ad7192: implement IIO_CHAN_INFO_SAMP_FREQ

This driver predates the availability of IIO_CHAN_INFO_SAMP_FREQ
attribute wherein usage has some advantages like it can be accessed by
in-kernel consumers as well as reduces the code size.

Therefore, use IIO_CHAN_INFO_SAMP_FREQ to implement the
sampling_frequency attribute instead of using IIO_DEV_ATTR_SAMP_FREQ()
macro.

Move code from the functions associated with IIO_DEV_ATTR_SAMP_FREQ()
into respective read and write hooks with the mask set to
IIO_CHAN_INFO_SAMP_FREQ.

Signed-off-by: Eva Rachel Retuya <eraretuya@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/staging/iio/adc/ad7192.c

@@ -322,57 +322,6 @@ out:
 	return ret;
 }
 
-static ssize_t ad7192_read_frequency(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);
-
-	return sprintf(buf, "%d\n", st->mclk /
-			(st->f_order * 1024 * AD7192_MODE_RATE(st->mode)));
-}
-
-static ssize_t ad7192_write_frequency(struct device *dev,
-				      struct device_attribute *attr,
-				      const char *buf,
-				      size_t len)
-{
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct ad7192_state *st = iio_priv(indio_dev);
-	unsigned long lval;
-	int div, ret;
-
-	ret = kstrtoul(buf, 10, &lval);
-	if (ret)
-		return ret;
-	if (lval == 0)
-		return -EINVAL;
-
-	ret = iio_device_claim_direct_mode(indio_dev);
-	if (ret)
-		return ret;
-
-	div = st->mclk / (lval * st->f_order * 1024);
-	if (div < 1 || div > 1023) {
-		ret = -EINVAL;
-		goto out;
-	}
-
-	st->mode &= ~AD7192_MODE_RATE(-1);
-	st->mode |= AD7192_MODE_RATE(div);
-	ad_sd_write_reg(&st->sd, AD7192_REG_MODE, 3, st->mode);
-
-out:
-	iio_device_release_direct_mode(indio_dev);
-
-	return ret ? ret : len;
-}
-
-static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
-		ad7192_read_frequency,
-		ad7192_write_frequency);
-
 static ssize_t
 ad7192_show_scale_available(struct device *dev,
 			    struct device_attribute *attr, char *buf)
@@ -471,7 +420,6 @@ static IIO_DEVICE_ATTR(ac_excitation_en, S_IRUGO | S_IWUSR,
 		       AD7192_REG_MODE);
 
 static struct attribute *ad7192_attributes[] = {
-	&iio_dev_attr_sampling_frequency.dev_attr.attr,
 	&iio_dev_attr_in_v_m_v_scale_available.dev_attr.attr,
 	&iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
 	&iio_dev_attr_bridge_switch_en.dev_attr.attr,
@@ -484,7 +432,6 @@ static const struct attribute_group ad7192_attribute_group = {
 };
 
 static struct attribute *ad7195_attributes[] = {
-	&iio_dev_attr_sampling_frequency.dev_attr.attr,
 	&iio_dev_attr_in_v_m_v_scale_available.dev_attr.attr,
 	&iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
 	&iio_dev_attr_bridge_switch_en.dev_attr.attr,
@@ -536,6 +483,10 @@ static int ad7192_read_raw(struct iio_dev *indio_dev,
 		if (chan->type == IIO_TEMP)
 			*val -= 273 * ad7192_get_temp_scale(unipolar);
 		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		*val = st->mclk /
+			(st->f_order * 1024 * AD7192_MODE_RATE(st->mode));
+		return IIO_VAL_INT;
 	}
 
 	return -EINVAL;
@@ -548,7 +499,7 @@ static int ad7192_write_raw(struct iio_dev *indio_dev,
 			    long mask)
 {
 	struct ad7192_state *st = iio_priv(indio_dev);
-	int ret, i;
+	int ret, i, div;
 	unsigned int tmp;
 
 	ret = iio_device_claim_direct_mode(indio_dev);
@@ -572,6 +523,22 @@ static int ad7192_write_raw(struct iio_dev *indio_dev,
 				break;
 			}
 		break;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		if (!val) {
+			ret = -EINVAL;
+			break;
+		}
+
+		div = st->mclk / (val * st->f_order * 1024);
+		if (div < 1 || div > 1023) {
+			ret = -EINVAL;
+			break;
+		}
+
+		st->mode &= ~AD7192_MODE_RATE(-1);
+		st->mode |= AD7192_MODE_RATE(div);
+		ad_sd_write_reg(&st->sd, AD7192_REG_MODE, 3, st->mode);
+		break;
 	default:
 		ret = -EINVAL;
 	}
@@ -585,7 +552,14 @@ static int ad7192_write_raw_get_fmt(struct iio_dev *indio_dev,
 				    struct iio_chan_spec const *chan,
 				    long mask)
 {
-	return IIO_VAL_INT_PLUS_NANO;
+	switch (mask) {
+	case IIO_CHAN_INFO_SCALE:
+		return IIO_VAL_INT_PLUS_NANO;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		return IIO_VAL_INT;
+	default:
+		return -EINVAL;
+	}
 }
 
 static const struct iio_info ad7192_info = {

include/linux/iio/adc/ad_sigma_delta.h

@@ -136,6 +136,7 @@ int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig);
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
 			BIT(IIO_CHAN_INFO_OFFSET), \
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
 		.scan_index = (_si), \
 		.scan_type = { \
 			.sign = 'u', \