[PATCH v2 3/3] staging: iio: ad9834: use sysfs_emit() and simplify show functions

[Gabriel Rondon <grondon@gmail.com>]

Replace sprintf() with sysfs_emit() in sysfs attribute show functions.
sysfs_emit() is the preferred API for sysfs callbacks as it is aware
of the PAGE_SIZE buffer limit.

Also simplify the wavetype_available show functions by removing
the intermediate string variable and returning directly from each
branch.

Signed-off-by: Gabriel Rondon <grondon@gmail.com>
---
 drivers/staging/iio/frequency/ad9834.c | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/drivers/staging/iio/frequency/ad9834.c b/drivers/staging/iio/frequency/ad9834.c
index d339d5e8e..bdb2580e2 100644
--- a/drivers/staging/iio/frequency/ad9834.c
+++ b/drivers/staging/iio/frequency/ad9834.c
@@ -281,16 +281,12 @@ ssize_t ad9834_show_out0_wavetype_available(struct device *dev,
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	struct ad9834_state *st = iio_priv(indio_dev);
-	char *str;
 
 	if (st->devid == ID_AD9833 || st->devid == ID_AD9837)
-		str = "sine triangle square";
-	else if (st->control & AD9834_OPBITEN)
-		str = "sine";
-	else
-		str = "sine triangle";
-
-	return sprintf(buf, "%s\n", str);
+		return sysfs_emit(buf, "sine triangle square\n");
+	if (st->control & AD9834_OPBITEN)
+		return sysfs_emit(buf, "sine\n");
+	return sysfs_emit(buf, "sine triangle\n");
 }
 
 static IIO_DEVICE_ATTR(out_altvoltage0_out0_wavetype_available, 0444,
@@ -303,14 +299,10 @@ ssize_t ad9834_show_out1_wavetype_available(struct device *dev,
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	struct ad9834_state *st = iio_priv(indio_dev);
-	char *str;
 
 	if (st->control & AD9834_MODE)
-		str = "";
-	else
-		str = "square";
-
-	return sprintf(buf, "%s\n", str);
+		return sysfs_emit(buf, "\n");
+	return sysfs_emit(buf, "square\n");
 }
 
 static IIO_DEVICE_ATTR(out_altvoltage0_out1_wavetype_available, 0444,
-- 
2.33.0