From:   Xin Ji <xji@analogixsemi.com>
To:     narmstrong@baylibre.com, dan.carpenter@oracle.com,
        robert.foss@linaro.org, Laurent.pinchart@ideasonboard.com,
        jonas@kwiboo.se, jernej.skrabec@gmail.com, airlied@linux.ie,
        daniel@ffwll.ch, sam@ravnborg.org, pihsun@chromium.org,
        tzungbi@google.com, maxime@cerno.tech, drinkcat@google.com,
        hsinyi@chromium.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, bliang@analogixsemi.com,
        qwen@analogixsemi.com
Cc:     Xin Ji <xji@analogixsemi.com>
Subject: [PATCH v2] drm/bridge: anx7625: Check GPIO description to avoid crash
Date:   Thu, 18 Nov 2021 13:45:02 +0800
Message-Id: <20211118054502.3796946-1-xji@analogixsemi.com>
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?Py2KM3t2/HSrYSMtLI/V9Hjltukji4sqUSrv5fgtIWeNzxtNXkHG/5N4jFve?=
 =?us-ascii?Q?kMYVRRlsC1QPy225npefndXOVSCxFA92auJ/eAZ8M1/6CB12GFsznbC0owMT?=
 =?us-ascii?Q?QoR9zIDHUBKUl3BMz/Mz1zLVzQkC21cDidpo4qhLM5xLNq3+xz/qEqQkhV/J?=
 =?us-ascii?Q?BiSg6Nn5ZBSyWFhc3c4nPZy7XF3Hmt7KC2dGl4xBMbnLm9twP+6+dlY1FFos?=
 =?us-ascii?Q?exizyPLaIxb0xJC58ROqdCeXdxIAY4RZGoD8KaQUUJjwyYx5YYxJMjkb5GyS?=
 =?us-ascii?Q?OTwvPnBSjZad4P/k7oBjnCNqKSX4VAW+QOla4+b/mx3NinCsvAg01cbhSqev?=
 =?us-ascii?Q?e5h+tS11ouOEOD49hF/JnBwAKkExTzy813RgGgcmFEpP8jf1uW+I+dVsgj9K?=
 =?us-ascii?Q?yCxhNEbMslQPDLL82DcveeCiRzD4TkJ1sI2rVR72k3V5t5WfAIqSrtxSMFoc?=
 =?us-ascii?Q?2aYGtXjx5HNI76XQEVthPYVi5KfVNE6agl1zSqEfg/coulnAe00PO/UqSu2y?=
 =?us-ascii?Q?SwavJn9be9+zE+VMevp4L4BnTC9fsBsckWIK3tkMMVfYOpvGzujbgN5LzuwG?=
 =?us-ascii?Q?qnBtqtKsMlk/LhCIOMm8lKE7vKHsVefXicxKOVDkTJN3v6/sI8QKmuVRrHVk?=
 =?us-ascii?Q?j4z7u8sHh+uTbrTN2sFS9H/ItMfAC1WHbcrqRR+HtNR0n+myp/mmGUqycA22?=
 =?us-ascii?Q?1EOmogg6i7gQjIksoGoFP9JzZawbKSstbGkYGknxisOrcnu3CXCNvFoVYLa3?=
 =?us-ascii?Q?1pqiafex6a+YMqcSVlUwI42mSzQaykAd9waRp9YjkVnrR0doJdB79lY26yBe?=
 =?us-ascii?Q?Kuv6KaJpQ0Iw5zTqExv1i3fD6vzUWVzwq143VShaQeBNycOB37c4IEuOJ5NO?=
 =?us-ascii?Q?/58XrFvEvJUkW3zk+pxpicPw0wdXg5Xcv5m6+9tCch+H6gGSknvusR2O4I/2?=
 =?us-ascii?Q?zkoCFJxykXPD+kzOHw7c63Fh9o+mfjLkHyMVS/hW1snLxmkbAtA81k7vqLXY?=
 =?us-ascii?Q?phYMp7luStQubiPzF8o5GRUKvYFN0RJ/02wsXun5UYyUkojhlYumsgYkUstd?=
 =?us-ascii?Q?E2wka8mAjFPQDD/xaM2G2SN50gUWoYa+tXSeTNPyA11T+jFv940aUGIaVwaw?=
 =?us-ascii?Q?eqlYiOHTsLA20xd7XsKekiBT0m0qwRxHTzojG188LZAmuaVblRzxI1zBbq/R?=
 =?us-ascii?Q?pWeYC2IDzrhjP2txv7vBR7fHelg3NeJGGXR/YRYgTnh7xw7ibag0SdpASSwC?=
 =?us-ascii?Q?P7xvJtSSstGvepBVzoMSYiQf43I1NdulrZ4in4KBZF9NN72/1eo2P1WKoJr4?=
 =?us-ascii?Q?hi6eGEnyE1OIglDBFaUD1K24yYL+mCglhxeXRPO4mNDmrG0qA0wD2JOr34eV?=
 =?us-ascii?Q?4DBAf5proB/smyXBvmJVff0AQkFnMzapTE89hRqXN44kCKSBAhIykDYbjzHX?=
 =?us-ascii?Q?JerxeBh9TJJhZR/A+6TpRTV6i8e3G/HQh0I4il7uKAK7uD5OiwMbc5uKzaBu?=
 =?us-ascii?Q?Zb8cPOKMpMTffmtONKqR8dcBShdrTwyeuXahuei6HUMTS7jAD+uuiAarcGZq?=
 =?us-ascii?Q?+zE+NNssrXiQimRQeWkV5JG+2Gu79UiGY3F74H6mtn+4eQuhnbtZvVyauJbG?=
 =?us-ascii?Q?PSx+Lb9Qn3JXIE4hTSEhVmk=3D?=
X-OriginatorOrg: analogixsemi.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 03848f13-8a69-497d-b3a8-08d9aa569797
X-MS-Exchange-CrossTenant-AuthSource: CH2PR04MB6741.namprd04.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Nov 2021 05:45:13.9783
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: b099b0b4-f26c-4cf5-9a0f-d5be9acab205
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: 5bWDKGm98FemNi91rtXW85Ya/8ntWfOewpFCiVf8E/2owqLZAEAzGPek7NpJ2t4eptjzf+hvgotZVxb6vQDQXA==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH2PR04MB6710
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

As GPIO probe function "devm_gpiod_get_optional()" may return error
code, driver should identify GPIO desc as NULL to avoid crash.

Acked-by: Tzung-Bi Shih <tzungbi@google.com>
Signed-off-by: Xin Ji <xji@analogixsemi.com>
---
 drivers/gpu/drm/bridge/analogix/anx7625.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
index 001fb39d9919..a872cfaf6257 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.c
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
@@ -1098,9 +1098,18 @@ static void anx7625_init_gpio(struct anx7625_data *platform)
 	/* Gpio for chip power enable */
 	platform->pdata.gpio_p_on =
 		devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_LOW);
+	if (IS_ERR_OR_NULL(platform->pdata.gpio_p_on)) {
+		DRM_DEV_DEBUG_DRIVER(dev, "no enable gpio found\n");
+		platform->pdata.gpio_p_on = NULL;
+	}
+
 	/* Gpio for chip reset */
 	platform->pdata.gpio_reset =
 		devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR_OR_NULL(platform->pdata.gpio_reset)) {
+		DRM_DEV_DEBUG_DRIVER(dev, "no reset gpio found\n");
+		platform->pdata.gpio_p_on = NULL;
+	}
 
 	if (platform->pdata.gpio_p_on && platform->pdata.gpio_reset) {
 		platform->pdata.low_power_mode = 1;
-- 
2.25.1