staging: iio: tsl2583: convert illuminance0_calibscale sysfs attr to use iio_chan_spec

The illuminance0_calibscale sysfs attribute is not currently created by
the IIO core. This patch adds the appropriate mask to iio_chan_spec,
along with the appropriate data handling in the read_raw() and
write_raw() functions, so that the sysfs attribute is created by the IIO
core. With this change, this sysfs entry will have its prefix changed
from illuminance0_ to in_illuminance_.
Signed-off-by: Brian Masney <masneyb@onstation.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/staging/iio/light/tsl2583.c

@@ -124,14 +124,15 @@ static struct taos_lux taos_device_lux[11] = {
 struct gainadj {
 	s16 ch0;
 	s16 ch1;
+	s16 mean;
 };
 
 /* Index = (0 - 3) Used to validate the gain selection index */
 static const struct gainadj gainadj[] = {
-	{ 1, 1 },
-	{ 8, 8 },
-	{ 16, 16 },
-	{ 107, 115 }
+	{ 1, 1, 1 },
+	{ 8, 8, 8 },
+	{ 16, 16, 16 },
+	{ 107, 115, 111 }
 };
 
 /*
@@ -505,63 +506,6 @@ static int taos_chip_off(struct iio_dev *indio_dev)
 
 /* Sysfs Interface Functions */
 
-static ssize_t taos_gain_show(struct device *dev,
-			      struct device_attribute *attr, char *buf)
-{
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct tsl2583_chip *chip = iio_priv(indio_dev);
-	char gain[4] = {0};
-
-	switch (chip->taos_settings.als_gain) {
-	case 0:
-		strcpy(gain, "001");
-		break;
-	case 1:
-		strcpy(gain, "008");
-		break;
-	case 2:
-		strcpy(gain, "016");
-		break;
-	case 3:
-		strcpy(gain, "111");
-		break;
-	}
-
-	return sprintf(buf, "%s\n", gain);
-}
-
-static ssize_t taos_gain_store(struct device *dev,
-			       struct device_attribute *attr,
-			       const char *buf, size_t len)
-{
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct tsl2583_chip *chip = iio_priv(indio_dev);
-	int value;
-
-	if (kstrtoint(buf, 0, &value))
-		return -EINVAL;
-
-	switch (value) {
-	case 1:
-		chip->taos_settings.als_gain = 0;
-		break;
-	case 8:
-		chip->taos_settings.als_gain = 1;
-		break;
-	case 16:
-		chip->taos_settings.als_gain = 2;
-		break;
-	case 111:
-		chip->taos_settings.als_gain = 3;
-		break;
-	default:
-		dev_err(dev, "Invalid Gain Index (must be 1,8,16,111)\n");
-		return -1;
-	}
-
-	return len;
-}
-
 static ssize_t taos_gain_available_show(struct device *dev,
 					struct device_attribute *attr,
 					char *buf)
@@ -691,8 +635,6 @@ static ssize_t taos_luxtable_store(struct device *dev,
 	return ret;
 }
 
-static DEVICE_ATTR(illuminance0_calibscale, S_IRUGO | S_IWUSR,
-		taos_gain_show, taos_gain_store);
 static DEVICE_ATTR(illuminance0_calibscale_available, S_IRUGO,
 		taos_gain_available_show, NULL);
 
@@ -707,7 +649,6 @@ static DEVICE_ATTR(illuminance0_lux_table, S_IRUGO | S_IWUSR,
 		taos_luxtable_show, taos_luxtable_store);
 
 static struct attribute *sysfs_attrs_ctrl[] = {
-	&dev_attr_illuminance0_calibscale.attr,			/* Gain  */
 	&dev_attr_illuminance0_calibscale_available.attr,
 	&dev_attr_illuminance0_integration_time_available.attr,
 	&dev_attr_illuminance0_input_target.attr,
@@ -743,6 +684,7 @@ static const struct iio_chan_spec tsl2583_channels[] = {
 		.type = IIO_LIGHT,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
 				      BIT(IIO_CHAN_INFO_CALIBBIAS) |
+				      BIT(IIO_CHAN_INFO_CALIBSCALE) |
 				      BIT(IIO_CHAN_INFO_INT_TIME),
 	},
 };
@@ -801,6 +743,12 @@ static int tsl2583_read_raw(struct iio_dev *indio_dev,
 			ret = IIO_VAL_INT;
 		}
 		break;
+	case IIO_CHAN_INFO_CALIBSCALE:
+		if (chan->type == IIO_LIGHT) {
+			*val = gainadj[chip->taos_settings.als_gain].mean;
+			ret = IIO_VAL_INT;
+		}
+		break;
 	case IIO_CHAN_INFO_INT_TIME:
 		if (chan->type == IIO_LIGHT) {
 			*val = 0;
@@ -839,6 +787,19 @@ static int tsl2583_write_raw(struct iio_dev *indio_dev,
 			ret = 0;
 		}
 		break;
+	case IIO_CHAN_INFO_CALIBSCALE:
+		if (chan->type == IIO_LIGHT) {
+			int i;
+
+			for (i = 0; i < ARRAY_SIZE(gainadj); i++) {
+				if (gainadj[i].mean == val) {
+					chip->taos_settings.als_gain = i;
+					ret = 0;
+					break;
+				}
+			}
+		}
+		break;
 	case IIO_CHAN_INFO_INT_TIME:
 		if (chan->type == IIO_LIGHT && !val && val2 >= 50 &&
 		    val2 <= 650 && !(val2 % 50)) {