linux-kernel - [PATCH v2 3/3] HID: cp2112: fix broken gpio_direction

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Date:   Fri, 10 Nov 2017 10:01:43 +0100
From:   Sébastien Szymanski 
        <sebastien.szymanski@...adeus.com>
To:     linux-input@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Benjamin Tissoires <benjamin.tissoires@...hat.com>,
        Jiri Kosina <jikos@...nel.org>,
        Julien Boibessot <julien.boibessot@...adeus.com>,
        Sébastien Szymanski 
        <sebastien.szymanski@...adeus.com>
Subject: [PATCH v2 3/3] HID: cp2112: fix broken gpio_direction_input callback

When everything goes smoothly, ret is set to 0 which makes the function
to return EIO error.

Fixes: 8e9faa15469e ("HID: cp2112: fix gpio-callback error handling")
Signed-off-by: Sébastien Szymanski <sebastien.szymanski@...adeus.com>
---
Changes in v2:
 - rework error handling to have only one exit path as suggested by
   Benjamin Tissoires <benjamin.tissoires@...hat.com>

 drivers/hid/hid-cp2112.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c
index 28e3c18..68cdc96 100644
--- a/drivers/hid/hid-cp2112.c
+++ b/drivers/hid/hid-cp2112.c
@@ -196,6 +196,8 @@ static int cp2112_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 				 HID_REQ_GET_REPORT);
 	if (ret != CP2112_GPIO_CONFIG_LENGTH) {
 		hid_err(hdev, "error requesting GPIO config: %d\n", ret);
+		if (ret >= 0)
+			ret = -EIO;
 		goto exit;
 	}
 
@@ -205,8 +207,10 @@ static int cp2112_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 	ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
 				 CP2112_GPIO_CONFIG_LENGTH, HID_FEATURE_REPORT,
 				 HID_REQ_SET_REPORT);
-	if (ret < 0) {
+	if (ret != CP2112_GPIO_CONFIG_LENGTH) {
 		hid_err(hdev, "error setting GPIO config: %d\n", ret);
+		if (ret >= 0)
+			ret = -EIO;
 		goto exit;
 	}
 
@@ -214,7 +218,7 @@ static int cp2112_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 
 exit:
 	mutex_unlock(&dev->lock);
-	return ret < 0 ? ret : -EIO;
+	return ret;
 }
 
 static void cp2112_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
-- 
2.7.3