[PATCH v2 1/2] hwmon: (pmbus/isl68137) Fix unchecked return value and use sysfs_emit()

[Pradhan, Sanman]

From: Sanman Pradhan <psanman@xxxxxxxxxxx>

isl68137_avs_enable_show_page() uses the return value of
pmbus_read_byte_data() without checking for errors. If the I2C transaction
fails, a negative error code is passed through bitwise operations,
producing incorrect output.

Add an error check to propagate the return value if it is negative.
Additionally, modernize the callback by replacing sprintf()
with sysfs_emit().

Fixes: 038a9c3d1e424 ("hwmon: (pmbus/isl68137) Add driver for Intersil ISL68137 PWM Controller")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Sanman Pradhan <psanman@xxxxxxxxxxx>
---
v2:
  - Kept explicit bitmask comparison instead of using !! operator
---
 drivers/hwmon/pmbus/isl68137.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/pmbus/isl68137.c b/drivers/hwmon/pmbus/isl68137.c
index 97b61836f53a4..e7dac26b5be61 100644
--- a/drivers/hwmon/pmbus/isl68137.c
+++ b/drivers/hwmon/pmbus/isl68137.c
@@ -98,8 +98,11 @@ static ssize_t isl68137_avs_enable_show_page(struct i2c_client *client,
 {
 	int val = pmbus_read_byte_data(client, page, PMBUS_OPERATION);
 
-	return sprintf(buf, "%d\n",
-		       (val & ISL68137_VOUT_AVS) == ISL68137_VOUT_AVS ? 1 : 0);
+	if (val < 0)
+		return val;
+
+	return sysfs_emit(buf, "%d\n",
+			   (val & ISL68137_VOUT_AVS) == ISL68137_VOUT_AVS);
 }
 
 static ssize_t isl68137_avs_enable_store_page(struct i2c_client *client,
-- 
2.34.1