staging: iio: cdc: ad7152: Implement IIO_CHAN_INFO_SAMP_FREQ attribute

Attributes that were once privately defined become standard with time
and hence a special global define is used. Hence update driver ad7152 to use
IIO_CHAN_INFO_SAMP_FREQ which is a global define instead of
IIO_DEV_ATTR_SAMP_FREQ.
Move functionality from IIO_DEV_ATTR_SAMP_FREQ attribute into
IIO_CHAN_INFO_SAMP_FREQ to implement the sampling_frequency attribute.
Modify ad7152_read_raw() and ad7152_write_raw() to allow reading and
writing the element as well. Also add a lock in the driver's private
data.
Signed-off-by: sayli karnik <karniksayli1995@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/staging/iio/cdc/ad7152.c

@@ -167,63 +167,12 @@ static const unsigned char ad7152_filter_rate_table[][2] = {
 	{200, 5 + 1}, {50, 20 + 1}, {20, 50 + 1}, {17, 60 + 1},
 };
 
-static ssize_t ad7152_show_filter_rate_setup(struct device *dev,
-		struct device_attribute *attr,
-		char *buf)
-{
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct ad7152_chip_info *chip = iio_priv(indio_dev);
-
-	return sprintf(buf, "%d\n",
-		       ad7152_filter_rate_table[chip->filter_rate_setup][0]);
-}
-
-static ssize_t ad7152_store_filter_rate_setup(struct device *dev,
-		struct device_attribute *attr,
-		const char *buf,
-		size_t len)
-{
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct ad7152_chip_info *chip = iio_priv(indio_dev);
-	u8 data;
-	int ret, i;
-
-	ret = kstrtou8(buf, 10, &data);
-	if (ret < 0)
-		return ret;
-
-	for (i = 0; i < ARRAY_SIZE(ad7152_filter_rate_table); i++)
-		if (data >= ad7152_filter_rate_table[i][0])
-			break;
-
-	if (i >= ARRAY_SIZE(ad7152_filter_rate_table))
-		i = ARRAY_SIZE(ad7152_filter_rate_table) - 1;
-
-	mutex_lock(&indio_dev->mlock);
-	ret = i2c_smbus_write_byte_data(chip->client,
-			AD7152_REG_CFG2, AD7152_CFG2_OSR(i));
-	if (ret < 0) {
-		mutex_unlock(&indio_dev->mlock);
-		return ret;
-	}
-
-	chip->filter_rate_setup = i;
-	mutex_unlock(&indio_dev->mlock);
-
-	return len;
-}
-
-static IIO_DEV_ATTR_SAMP_FREQ(S_IRUGO | S_IWUSR,
-		ad7152_show_filter_rate_setup,
-		ad7152_store_filter_rate_setup);
-
 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("200 50 20 17");
 
 static IIO_CONST_ATTR(in_capacitance_scale_available,
 		      "0.000061050 0.000030525 0.000015263 0.000007631");
 
 static struct attribute *ad7152_attributes[] = {
-	&iio_dev_attr_sampling_frequency.dev_attr.attr,
 	&iio_dev_attr_in_capacitance0_calibbias_calibration.dev_attr.attr,
 	&iio_dev_attr_in_capacitance1_calibbias_calibration.dev_attr.attr,
 	&iio_dev_attr_in_capacitance0_calibscale_calibration.dev_attr.attr,
@@ -249,6 +198,51 @@ static const int ad7152_scale_table[] = {
 	30525, 7631, 15263, 61050
 };
 
+/**
+ * read_raw handler for IIO_CHAN_INFO_SAMP_FREQ
+ *
+ * lock must be held
+ **/
+static int ad7152_read_raw_samp_freq(struct device *dev, int *val)
+{
+	struct ad7152_chip_info *chip = iio_priv(dev_to_iio_dev(dev));
+
+	*val = ad7152_filter_rate_table[chip->filter_rate_setup][0];
+
+	return 0;
+}
+
+/**
+ * write_raw handler for IIO_CHAN_INFO_SAMP_FREQ
+ *
+ * lock must be held
+ **/
+static int ad7152_write_raw_samp_freq(struct device *dev, int val)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct ad7152_chip_info *chip = iio_priv(indio_dev);
+	int ret, i;
+
+	for (i = 0; i < ARRAY_SIZE(ad7152_filter_rate_table); i++)
+		if (val >= ad7152_filter_rate_table[i][0])
+			break;
+
+	if (i >= ARRAY_SIZE(ad7152_filter_rate_table))
+		i = ARRAY_SIZE(ad7152_filter_rate_table) - 1;
+
+	mutex_lock(&indio_dev->mlock);
+	ret = i2c_smbus_write_byte_data(chip->client,
+					AD7152_REG_CFG2, AD7152_CFG2_OSR(i));
+	if (ret < 0) {
+		mutex_unlock(&indio_dev->mlock);
+		return ret;
+	}
+
+	chip->filter_rate_setup = i;
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret;
+}
 static int ad7152_write_raw(struct iio_dev *indio_dev,
 			    struct iio_chan_spec const *chan,
 			    int val,
@@ -309,6 +303,17 @@ static int ad7152_write_raw(struct iio_dev *indio_dev,
 		if (ret < 0)
 			goto out;
 
+		ret = 0;
+		break;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		if (val2) {
+			ret = -EINVAL;
+			goto out;
+		}
+		ret = ad7152_write_raw_samp_freq(&indio_dev->dev, val);
+		if (ret < 0)
+			goto out;
+
 		ret = 0;
 		break;
 	default:
@@ -406,6 +411,13 @@ static int ad7152_read_raw(struct iio_dev *indio_dev,
 
 		ret = IIO_VAL_INT_PLUS_NANO;
 		break;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		ret = ad7152_read_raw_samp_freq(&indio_dev->dev, val);
+		if (ret < 0)
+			goto out;
+
+		ret = IIO_VAL_INT;
+		break;
 	default:
 		ret = -EINVAL;
 	}
@@ -443,6 +455,7 @@ static const struct iio_chan_spec ad7152_channels[] = {
 		BIT(IIO_CHAN_INFO_CALIBSCALE) |
 		BIT(IIO_CHAN_INFO_CALIBBIAS) |
 		BIT(IIO_CHAN_INFO_SCALE),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 	}, {
 		.type = IIO_CAPACITANCE,
 		.differential = 1,
@@ -453,6 +466,7 @@ static const struct iio_chan_spec ad7152_channels[] = {
 		BIT(IIO_CHAN_INFO_CALIBSCALE) |
 		BIT(IIO_CHAN_INFO_CALIBBIAS) |
 		BIT(IIO_CHAN_INFO_SCALE),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 	}, {
 		.type = IIO_CAPACITANCE,
 		.indexed = 1,
@@ -461,6 +475,7 @@ static const struct iio_chan_spec ad7152_channels[] = {
 		BIT(IIO_CHAN_INFO_CALIBSCALE) |
 		BIT(IIO_CHAN_INFO_CALIBBIAS) |
 		BIT(IIO_CHAN_INFO_SCALE),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 	}, {
 		.type = IIO_CAPACITANCE,
 		.differential = 1,
@@ -471,6 +486,7 @@ static const struct iio_chan_spec ad7152_channels[] = {
 		BIT(IIO_CHAN_INFO_CALIBSCALE) |
 		BIT(IIO_CHAN_INFO_CALIBBIAS) |
 		BIT(IIO_CHAN_INFO_SCALE),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 	}
 };