staging: iio: tsl2x7x: use IIO_CONST_ATTR for calibscale_available

The in_intensity0_calibscale_available sysfs attribute has code that
checks the device type to determine which calibration scales are
available. This check is not necessary since all of the supported
ALS device types use the scales 1 8 16 120. This patch converts the
sysfs attribute to use IIO_CONST_ATTR. The following device datasheets
were checked: tsl2571, tsl2771, tmd2771, tsl2572, tsl2772, tmd2772.

Signed-off-by: Brian Masney <masneyb@onstation.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/staging/iio/light/tsl2x7x.c

@@ -776,24 +776,7 @@ static int tsl2x7x_prox_cal(struct iio_dev *indio_dev)
 	return tsl2x7x_invoke_change(indio_dev);
 }
 
-static ssize_t
-in_intensity0_calibscale_available_show(struct device *dev,
-					struct device_attribute *attr,
-					char *buf)
-{
-	struct tsl2X7X_chip *chip = iio_priv(dev_to_iio_dev(dev));
-
-	switch (chip->id) {
-	case tsl2571:
-	case tsl2671:
-	case tmd2671:
-	case tsl2771:
-	case tmd2771:
-		return snprintf(buf, PAGE_SIZE, "%s\n", "1 8 16 128");
-	}
-
-	return snprintf(buf, PAGE_SIZE, "%s\n", "1 8 16 120");
-}
+static IIO_CONST_ATTR(in_intensity0_calibscale_available, "1 8 16 120");
 
 static IIO_CONST_ATTR(in_proximity0_calibscale_available, "1 2 4 8");
 
@@ -1190,25 +1173,6 @@ static int tsl2x7x_write_raw(struct iio_dev *indio_dev,
 				chip->settings.als_gain = 2;
 				break;
 			case 120:
-				switch (chip->id) {
-				case tsl2572:
-				case tsl2672:
-				case tmd2672:
-				case tsl2772:
-				case tmd2772:
-					return -EINVAL;
-				}
-				chip->settings.als_gain = 3;
-				break;
-			case 128:
-				switch (chip->id) {
-				case tsl2571:
-				case tsl2671:
-				case tmd2671:
-				case tsl2771:
-				case tmd2771:
-					return -EINVAL;
-				}
 				chip->settings.als_gain = 3;
 				break;
 			default:
@@ -1247,8 +1211,6 @@ static int tsl2x7x_write_raw(struct iio_dev *indio_dev,
 	return tsl2x7x_invoke_change(indio_dev);
 }
 
-static DEVICE_ATTR_RO(in_intensity0_calibscale_available);
-
 static DEVICE_ATTR_RW(in_illuminance0_target_input);
 
 static DEVICE_ATTR_WO(in_illuminance0_calibrate);
@@ -1321,7 +1283,7 @@ static irqreturn_t tsl2x7x_event_handler(int irq, void *private)
 }
 
 static struct attribute *tsl2x7x_ALS_device_attrs[] = {
-	&dev_attr_in_intensity0_calibscale_available.attr,
+	&iio_const_attr_in_intensity0_calibscale_available.dev_attr.attr,
 	&iio_const_attr_in_intensity0_integration_time_available.dev_attr.attr,
 	&dev_attr_in_illuminance0_target_input.attr,
 	&dev_attr_in_illuminance0_calibrate.attr,
@@ -1335,7 +1297,7 @@ static struct attribute *tsl2x7x_PRX_device_attrs[] = {
 };
 
 static struct attribute *tsl2x7x_ALSPRX_device_attrs[] = {
-	&dev_attr_in_intensity0_calibscale_available.attr,
+	&iio_const_attr_in_intensity0_calibscale_available.dev_attr.attr,
 	&iio_const_attr_in_intensity0_integration_time_available.dev_attr.attr,
 	&dev_attr_in_illuminance0_target_input.attr,
 	&dev_attr_in_illuminance0_calibrate.attr,
@@ -1350,7 +1312,7 @@ static struct attribute *tsl2x7x_PRX2_device_attrs[] = {
 };
 
 static struct attribute *tsl2x7x_ALSPRX2_device_attrs[] = {
-	&dev_attr_in_intensity0_calibscale_available.attr,
+	&iio_const_attr_in_intensity0_calibscale_available.dev_attr.attr,
 	&iio_const_attr_in_intensity0_integration_time_available.dev_attr.attr,
 	&dev_attr_in_illuminance0_target_input.attr,
 	&dev_attr_in_illuminance0_calibrate.attr,