[PATCH v2] iio: core: split __iio_device_attr_init() to init only the attr object

[Alexandru Ardelean <alexandru.ardelean@analog.com>]

The __iio_device_attr_init() function initializes a device_attribute
object, but mostly it just does a lot of name creation logic.

We will want to re-use this logic for name-creation, so this change
re-purposes the __iio_device_attr_init() to be a __iio_attr_init() function
which just handles the creation of the attribute name.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---

Changelog v1 -> v2:
* https://lore.kernel.org/linux-iio/20201117162340.43924-6-alexandru.ardelean@analog.com/
* split away from series; I don't know when I will have time to re-visit
  the entire original series, so might as well move forward a few patches

 drivers/iio/industrialio-core.c | 43 +++++++++++++--------------------
 1 file changed, 17 insertions(+), 26 deletions(-)

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 1da7e518435a..5bfcee277879 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -935,22 +935,15 @@ static ssize_t iio_write_channel_info(struct device *dev,
 }
 
 static
-int __iio_device_attr_init(struct device_attribute *dev_attr,
-			   const char *postfix,
-			   struct iio_chan_spec const *chan,
-			   ssize_t (*readfunc)(struct device *dev,
-					       struct device_attribute *attr,
-					       char *buf),
-			   ssize_t (*writefunc)(struct device *dev,
-						struct device_attribute *attr,
-						const char *buf,
-						size_t len),
-			   enum iio_shared_by shared_by)
+int iio_attr_init(struct attribute *attr,
+		  const char *postfix,
+		  struct iio_chan_spec const *chan,
+		  enum iio_shared_by shared_by)
 {
 	int ret = 0;
 	char *name = NULL;
 	char *full_postfix;
-	sysfs_attr_init(&dev_attr->attr);
+	sysfs_attr_init(attr);
 
 	/* Build up postfix of <extend_name>_<modifier>_postfix */
 	if (chan->modified && (shared_by == IIO_SEPARATE)) {
@@ -1046,17 +1039,7 @@ int __iio_device_attr_init(struct device_attribute *dev_attr,
 		ret = -ENOMEM;
 		goto error_free_full_postfix;
 	}
-	dev_attr->attr.name = name;
-
-	if (readfunc) {
-		dev_attr->attr.mode |= S_IRUGO;
-		dev_attr->show = readfunc;
-	}
-
-	if (writefunc) {
-		dev_attr->attr.mode |= S_IWUSR;
-		dev_attr->store = writefunc;
-	}
+	attr->name = name;
 
 error_free_full_postfix:
 	kfree(full_postfix);
@@ -1089,9 +1072,7 @@ int __iio_add_chan_devattr(const char *postfix,
 	iio_attr = kzalloc(sizeof(*iio_attr), GFP_KERNEL);
 	if (iio_attr == NULL)
 		return -ENOMEM;
-	ret = __iio_device_attr_init(&iio_attr->dev_attr,
-				     postfix, chan,
-				     readfunc, writefunc, shared_by);
+	ret = iio_attr_init(&iio_attr->dev_attr.attr, postfix, chan, shared_by);
 	if (ret)
 		goto error_iio_dev_attr_free;
 	iio_attr->c = chan;
@@ -1107,6 +1088,16 @@ int __iio_add_chan_devattr(const char *postfix,
 		}
 	list_add(&iio_attr->l, attr_list);
 
+	if (readfunc) {
+		iio_attr->dev_attr.attr.mode |= S_IRUGO;
+		iio_attr->dev_attr.show = readfunc;
+	}
+
+	if (writefunc) {
+		iio_attr->dev_attr.attr.mode |= S_IWUSR;
+		iio_attr->dev_attr.store = writefunc;
+	}
+
 	return 0;
 
 error_device_attr_deinit:
-- 
2.27.0