staging:iio:ad799x: Use event spec for threshold hysteresis

Register the event threshold hysteresis attributes by using the new
IIO_EV_INFO_HYSTERESIS event spec type. This allows us to throw away a good
portion of boiler-plate code.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/staging/iio/adc/ad799x_core.c

@@ -259,13 +259,23 @@ static int ad799x_read_event_config(struct iio_dev *indio_dev,
 	return 1;
 }
 
-static int ad799x_threshold_reg(const struct iio_chan_spec *chan,
-					enum iio_event_direction dir)
+static unsigned int ad799x_threshold_reg(const struct iio_chan_spec *chan,
+					 enum iio_event_direction dir,
+					 enum iio_event_info info)
 {
-	if (dir == IIO_EV_DIR_FALLING)
-		return AD7998_DATALOW_REG(chan->channel);
-	else
-		return AD7998_DATAHIGH_REG(chan->channel);
+	switch (info) {
+	case IIO_EV_INFO_VALUE:
+		if (dir == IIO_EV_DIR_FALLING)
+			return AD7998_DATALOW_REG(chan->channel);
+		else
+			return AD7998_DATAHIGH_REG(chan->channel);
+	case IIO_EV_INFO_HYSTERESIS:
+		return AD7998_HYST_REG(chan->channel);
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
 }
 
 static int ad799x_write_event_value(struct iio_dev *indio_dev,
@@ -279,7 +289,8 @@ static int ad799x_write_event_value(struct iio_dev *indio_dev,
 	struct ad799x_state *st = iio_priv(indio_dev);
 
 	mutex_lock(&indio_dev->mlock);
-	ret = ad799x_i2c_write16(st, ad799x_threshold_reg(chan, dir), val);
+	ret = ad799x_i2c_write16(st, ad799x_threshold_reg(chan, dir, info),
+		val);
 	mutex_unlock(&indio_dev->mlock);
 
 	return ret;
@@ -297,7 +308,8 @@ static int ad799x_read_event_value(struct iio_dev *indio_dev,
 	u16 valin;
 
 	mutex_lock(&indio_dev->mlock);
-	ret = ad799x_i2c_read16(st, ad799x_threshold_reg(chan, dir), &valin);
+	ret = ad799x_i2c_read16(st, ad799x_threshold_reg(chan, dir, info),
+		&valin);
 	mutex_unlock(&indio_dev->mlock);
 	if (ret < 0)
 		return ret;
@@ -306,46 +318,6 @@ static int ad799x_read_event_value(struct iio_dev *indio_dev,
 	return IIO_VAL_INT;
 }
 
-static ssize_t ad799x_read_channel_config(struct device *dev,
-					struct device_attribute *attr,
-					char *buf)
-{
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct ad799x_state *st = iio_priv(indio_dev);
-	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
-
-	int ret;
-	u16 val;
-	ret = ad799x_i2c_read16(st, this_attr->address, &val);
-	if (ret)
-		return ret;
-
-	return sprintf(buf, "%d\n", val);
-}
-
-static ssize_t ad799x_write_channel_config(struct device *dev,
-					 struct device_attribute *attr,
-					 const char *buf,
-					 size_t len)
-{
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct ad799x_state *st = iio_priv(indio_dev);
-	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
-
-	long val;
-	int ret;
-
-	ret = kstrtol(buf, 10, &val);
-	if (ret)
-		return ret;
-
-	mutex_lock(&indio_dev->mlock);
-	ret = ad799x_i2c_write16(st, this_attr->address, val);
-	mutex_unlock(&indio_dev->mlock);
-
-	return ret ? ret : len;
-}
-
 static irqreturn_t ad799x_event_handler(int irq, void *private)
 {
 	struct iio_dev *indio_dev = private;
@@ -381,60 +353,19 @@ static irqreturn_t ad799x_event_handler(int irq, void *private)
 	return IRQ_HANDLED;
 }
 
-static IIO_DEVICE_ATTR(in_voltage0_thresh_both_hyst_raw,
-		       S_IRUGO | S_IWUSR,
-		       ad799x_read_channel_config,
-		       ad799x_write_channel_config,
-		       AD7998_HYST_REG(0));
-
-static IIO_DEVICE_ATTR(in_voltage1_thresh_both_hyst_raw,
-		       S_IRUGO | S_IWUSR,
-		       ad799x_read_channel_config,
-		       ad799x_write_channel_config,
-		       AD7998_HYST_REG(1));
-
-static IIO_DEVICE_ATTR(in_voltage2_thresh_both_hyst_raw,
-		       S_IRUGO | S_IWUSR,
-		       ad799x_read_channel_config,
-		       ad799x_write_channel_config,
-		       AD7998_HYST_REG(2));
-
-static IIO_DEVICE_ATTR(in_voltage3_thresh_both_hyst_raw,
-		       S_IRUGO | S_IWUSR,
-		       ad799x_read_channel_config,
-		       ad799x_write_channel_config,
-		       AD7998_HYST_REG(3));
-
 static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
 			      ad799x_read_frequency,
 			      ad799x_write_frequency);
 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("15625 7812 3906 1953 976 488 244 0");
 
-static struct attribute *ad7993_4_7_8_event_attributes[] = {
-	&iio_dev_attr_in_voltage0_thresh_both_hyst_raw.dev_attr.attr,
-	&iio_dev_attr_in_voltage1_thresh_both_hyst_raw.dev_attr.attr,
-	&iio_dev_attr_in_voltage2_thresh_both_hyst_raw.dev_attr.attr,
-	&iio_dev_attr_in_voltage3_thresh_both_hyst_raw.dev_attr.attr,
-	&iio_dev_attr_sampling_frequency.dev_attr.attr,
-	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
-	NULL,
-};
-
-static struct attribute_group ad7993_4_7_8_event_attrs_group = {
-	.attrs = ad7993_4_7_8_event_attributes,
-	.name = "events",
-};
-
-static struct attribute *ad7992_event_attributes[] = {
-	&iio_dev_attr_in_voltage0_thresh_both_hyst_raw.dev_attr.attr,
-	&iio_dev_attr_in_voltage1_thresh_both_hyst_raw.dev_attr.attr,
+static struct attribute *ad799x_event_attributes[] = {
 	&iio_dev_attr_sampling_frequency.dev_attr.attr,
 	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
 	NULL,
 };
 
-static struct attribute_group ad7992_event_attrs_group = {
-	.attrs = ad7992_event_attributes,
+static struct attribute_group ad799x_event_attrs_group = {
+	.attrs = ad799x_event_attributes,
 	.name = "events",
 };
 
@@ -443,18 +374,9 @@ static const struct iio_info ad7991_info = {
 	.driver_module = THIS_MODULE,
 };
 
-static const struct iio_info ad7992_info = {
-	.read_raw = &ad799x_read_raw,
-	.event_attrs = &ad7992_event_attrs_group,
-	.read_event_config_new = &ad799x_read_event_config,
-	.read_event_value_new = &ad799x_read_event_value,
-	.write_event_value_new = &ad799x_write_event_value,
-	.driver_module = THIS_MODULE,
-};
-
 static const struct iio_info ad7993_4_7_8_info = {
 	.read_raw = &ad799x_read_raw,
-	.event_attrs = &ad7993_4_7_8_event_attrs_group,
+	.event_attrs = &ad799x_event_attrs_group,
 	.read_event_config_new = &ad799x_read_event_config,
 	.read_event_value_new = &ad799x_read_event_value,
 	.write_event_value_new = &ad799x_write_event_value,
@@ -473,6 +395,10 @@ static const struct iio_event_spec ad799x_events[] = {
 		.dir = IIO_EV_DIR_FALLING,
 		.mask_separate = BIT(IIO_EV_INFO_VALUE),
 			BIT(IIO_EV_INFO_ENABLE),
+	}, {
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_EITHER,
+		.mask_separate = BIT(IIO_EV_INFO_HYSTERESIS),
 	},
 };
 
@@ -537,7 +463,7 @@ static const struct ad799x_chip_info ad799x_chip_info_tbl[] = {
 		},
 		.num_channels = 3,
 		.default_config = AD7998_ALERT_EN,
-		.info = &ad7992_info,
+		.info = &ad7993_4_7_8_info,
 	},
 	[ad7993] = {
 		.channel = {