Staging: iio: meter: ade7758_core: 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.

Hence moving functionality from IIO_DEV_ATTR_SAMP_FREQ attribute into
IIO_CHAN_INFO_SAMP_FREQ handlers. Also Adding ade7758_read_raw() and
ade7758_write_raw() to allow reading/writing the element as well.

Signed-off-by: Sandhya Bankar <bankarsandhya512@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/staging/iio/meter/ade7758_core.c

@@ -465,38 +465,26 @@ err_ret:
 	return ret;
 }
 
-static ssize_t ade7758_read_frequency(struct device *dev,
-				      struct device_attribute *attr, char *buf)
+static int ade7758_read_samp_freq(struct device *dev, int *val)
 {
 	int ret;
 	u8 t;
-	int sps;
 
 	ret = ade7758_spi_read_reg_8(dev, ADE7758_WAVMODE, &t);
 	if (ret)
 		return ret;
 
 	t = (t >> 5) & 0x3;
-	sps = 26040 / (1 << t);
+	*val = 26040 / (1 << t);
 
-	return sprintf(buf, "%d SPS\n", sps);
+	return 0;
 }
 
-static ssize_t ade7758_write_frequency(struct device *dev,
-				       struct device_attribute *attr,
-				       const char *buf, size_t len)
+static int ade7758_write_samp_freq(struct device *dev, int val)
 {
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	u16 val;
 	int ret;
 	u8 reg, t;
 
-	ret = kstrtou16(buf, 10, &val);
-	if (ret)
-		return ret;
-
-	mutex_lock(&indio_dev->mlock);
-
 	switch (val) {
 	case 26040:
 		t = 0;
@@ -525,9 +513,49 @@ static ssize_t ade7758_write_frequency(struct device *dev,
 	ret = ade7758_spi_write_reg_8(dev, ADE7758_WAVMODE, reg);
 
 out:
-	mutex_unlock(&indio_dev->mlock);
+	return ret;
+}
 
-	return ret ? ret : len;
+static int ade7758_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int *val,
+			    int *val2,
+			    long mask)
+{
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		mutex_lock(&indio_dev->mlock);
+		ret = ade7758_read_samp_freq(&indio_dev->dev, val);
+		mutex_unlock(&indio_dev->mlock);
+		return ret;
+	default:
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static int ade7758_write_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int val, int val2, long mask)
+{
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		if (val2)
+			return -EINVAL;
+		mutex_lock(&indio_dev->mlock);
+		ret = ade7758_write_samp_freq(&indio_dev->dev, val);
+		mutex_unlock(&indio_dev->mlock);
+		return ret;
+	default:
+		return -EINVAL;
+	}
+
+	return ret;
 }
 
 static IIO_DEV_ATTR_TEMP_RAW(ade7758_read_8bit);
@@ -553,17 +581,12 @@ static IIO_DEV_ATTR_BVAHR(ade7758_read_16bit,
 static IIO_DEV_ATTR_CVAHR(ade7758_read_16bit,
 		ADE7758_CVAHR);
 
-static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
-		ade7758_read_frequency,
-		ade7758_write_frequency);
-
 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("26040 13020 6510 3255");
 
 static struct attribute *ade7758_attributes[] = {
 	&iio_dev_attr_in_temp_raw.dev_attr.attr,
 	&iio_const_attr_in_temp_offset.dev_attr.attr,
 	&iio_const_attr_in_temp_scale.dev_attr.attr,
-	&iio_dev_attr_sampling_frequency.dev_attr.attr,
 	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
 	&iio_dev_attr_awatthr.dev_attr.attr,
 	&iio_dev_attr_bwatthr.dev_attr.attr,
@@ -611,6 +634,7 @@ static const struct iio_chan_spec ade7758_channels[] = {
 		.type = IIO_VOLTAGE,
 		.indexed = 1,
 		.channel = 0,
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 		.address = AD7758_WT(AD7758_PHASE_A, AD7758_VOLTAGE),
 		.scan_index = 0,
 		.scan_type = {
@@ -622,6 +646,7 @@ static const struct iio_chan_spec ade7758_channels[] = {
 		.type = IIO_CURRENT,
 		.indexed = 1,
 		.channel = 0,
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 		.address = AD7758_WT(AD7758_PHASE_A, AD7758_CURRENT),
 		.scan_index = 1,
 		.scan_type = {
@@ -634,6 +659,7 @@ static const struct iio_chan_spec ade7758_channels[] = {
 		.indexed = 1,
 		.channel = 0,
 		.extend_name = "apparent",
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 		.address = AD7758_WT(AD7758_PHASE_A, AD7758_APP_PWR),
 		.scan_index = 2,
 		.scan_type = {
@@ -646,6 +672,7 @@ static const struct iio_chan_spec ade7758_channels[] = {
 		.indexed = 1,
 		.channel = 0,
 		.extend_name = "active",
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 		.address = AD7758_WT(AD7758_PHASE_A, AD7758_ACT_PWR),
 		.scan_index = 3,
 		.scan_type = {
@@ -658,6 +685,7 @@ static const struct iio_chan_spec ade7758_channels[] = {
 		.indexed = 1,
 		.channel = 0,
 		.extend_name = "reactive",
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 		.address = AD7758_WT(AD7758_PHASE_A, AD7758_REACT_PWR),
 		.scan_index = 4,
 		.scan_type = {
@@ -669,6 +697,7 @@ static const struct iio_chan_spec ade7758_channels[] = {
 		.type = IIO_VOLTAGE,
 		.indexed = 1,
 		.channel = 1,
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 		.address = AD7758_WT(AD7758_PHASE_B, AD7758_VOLTAGE),
 		.scan_index = 5,
 		.scan_type = {
@@ -680,6 +709,7 @@ static const struct iio_chan_spec ade7758_channels[] = {
 		.type = IIO_CURRENT,
 		.indexed = 1,
 		.channel = 1,
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 		.address = AD7758_WT(AD7758_PHASE_B, AD7758_CURRENT),
 		.scan_index = 6,
 		.scan_type = {
@@ -692,6 +722,7 @@ static const struct iio_chan_spec ade7758_channels[] = {
 		.indexed = 1,
 		.channel = 1,
 		.extend_name = "apparent",
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 		.address = AD7758_WT(AD7758_PHASE_B, AD7758_APP_PWR),
 		.scan_index = 7,
 		.scan_type = {
@@ -704,6 +735,7 @@ static const struct iio_chan_spec ade7758_channels[] = {
 		.indexed = 1,
 		.channel = 1,
 		.extend_name = "active",
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 		.address = AD7758_WT(AD7758_PHASE_B, AD7758_ACT_PWR),
 		.scan_index = 8,
 		.scan_type = {
@@ -716,6 +748,7 @@ static const struct iio_chan_spec ade7758_channels[] = {
 		.indexed = 1,
 		.channel = 1,
 		.extend_name = "reactive",
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 		.address = AD7758_WT(AD7758_PHASE_B, AD7758_REACT_PWR),
 		.scan_index = 9,
 		.scan_type = {
@@ -727,6 +760,7 @@ static const struct iio_chan_spec ade7758_channels[] = {
 		.type = IIO_VOLTAGE,
 		.indexed = 1,
 		.channel = 2,
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 		.address = AD7758_WT(AD7758_PHASE_C, AD7758_VOLTAGE),
 		.scan_index = 10,
 		.scan_type = {
@@ -738,6 +772,7 @@ static const struct iio_chan_spec ade7758_channels[] = {
 		.type = IIO_CURRENT,
 		.indexed = 1,
 		.channel = 2,
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 		.address = AD7758_WT(AD7758_PHASE_C, AD7758_CURRENT),
 		.scan_index = 11,
 		.scan_type = {
@@ -750,6 +785,7 @@ static const struct iio_chan_spec ade7758_channels[] = {
 		.indexed = 1,
 		.channel = 2,
 		.extend_name = "apparent",
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 		.address = AD7758_WT(AD7758_PHASE_C, AD7758_APP_PWR),
 		.scan_index = 12,
 		.scan_type = {
@@ -762,6 +798,7 @@ static const struct iio_chan_spec ade7758_channels[] = {
 		.indexed = 1,
 		.channel = 2,
 		.extend_name = "active",
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 		.address = AD7758_WT(AD7758_PHASE_C, AD7758_ACT_PWR),
 		.scan_index = 13,
 		.scan_type = {
@@ -774,6 +811,7 @@ static const struct iio_chan_spec ade7758_channels[] = {
 		.indexed = 1,
 		.channel = 2,
 		.extend_name = "reactive",
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 		.address = AD7758_WT(AD7758_PHASE_C, AD7758_REACT_PWR),
 		.scan_index = 14,
 		.scan_type = {
@@ -787,6 +825,8 @@ static const struct iio_chan_spec ade7758_channels[] = {
 
 static const struct iio_info ade7758_info = {
 	.attrs = &ade7758_attribute_group,
+	.read_raw = &ade7758_read_raw,
+	.write_raw = &ade7758_write_raw,
 	.driver_module = THIS_MODULE,
 };