From:   Xin Ji <xji@analogixsemi.com>
To:     a.hajda@samsung.com, 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] drm/bridge: anx7625: Check GPIO description to avoid crash
Date:   Thu, 18 Nov 2021 11:11:25 +0800
Message-Id: <20211118031125.3778969-1-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?gRRzy0Nb1m2z1pun1824szfRS1/aTS55hqBG/CINDFIFEMUtVEvzImqXDIoc?=
 =?us-ascii?Q?JCuxt9oO74fDv3DjrbHmL/VqL1C70PGTCvQBxux9T5WJe8ES30pFms3QCBz8?=
 =?us-ascii?Q?4gDegxlbYLuE+VbsQp3gGJuLaAcL0e5VDJwmB3rHPaeHzotRVdD31agfTrrh?=
 =?us-ascii?Q?jxru8jtMa1y1V+neLNadOlwM5VSQRVOcd+lQ3QVbr+hpohn1XQBL4GKY85Kq?=
 =?us-ascii?Q?KOfyvs1lsy39A7RrYtzUfzhY5PEmESrehgRUGAtpS63BxOds/DJoVIQR8slj?=
 =?us-ascii?Q?aNbEYUgIOXxbRjmZLWWc2WVlpP9dQlCr8o0pSydWJn2Y0VfNNpc4cSUpnq4c?=
 =?us-ascii?Q?FxG4ZPzarwoU96iaIDhNljZ3+ccU3zYxFfSSx35FU8HF2i1LZ+B9KAPjEJth?=
 =?us-ascii?Q?pJglYG6abnvE4vW+88XxOKDkRA7N6IPS6QxlEYfO+73wQ/aMGDGjOPUbeizg?=
 =?us-ascii?Q?hpneiA6wHwXVrY3zT1ULyTiZi1O5ZuSIIvy0EuimKGd1vwS8zI3SUF0Njyd9?=
 =?us-ascii?Q?4u1mlk4O6rlZhL1HXCCW+ayKsXiSfdQCFOb4jwGN+M9hTuZaz1665hRFz6uI?=
 =?us-ascii?Q?LNdiHFgi8bbeJgalKqn7bdrU0uRwORasAx6Z9jlFQ3BgE1TfL5TQ7OgRgC7O?=
 =?us-ascii?Q?4pPo3/H0nfq+qiqnz8hip/LvLQYO9NyPs1w/d23manWUQJueSdbCkZ54JW74?=
 =?us-ascii?Q?lNmLVDuybIY6aPHOwOOGfLyNUy8W0ZdHu3Fo+mORUmCsfe9S5ndqAFBiy0S1?=
 =?us-ascii?Q?PjTINEnyC5oQK09FxokdTE558J4oObYtEZngz89lNUOJ0zBjddNsA9fxeuH4?=
 =?us-ascii?Q?h2iXlwEQb+zi4VvZXf+FHaolty157drsuWpeLqCT1tNYpyAna77b35QPiUD/?=
 =?us-ascii?Q?jjuVf63IdwIO3APeRoLw2RgddNMZvD15bQMM0Egus1ORGAywcbEKXh7Blh7V?=
 =?us-ascii?Q?bDQQjAVZjtM4LC7uYs7tplfj3aL6uZfwmQqNf6IXlIAdzyhTvQJj1ZfAPnzD?=
 =?us-ascii?Q?0wrEEYCZq65gGZFNMN/7CjzgVhgE1TQY2n1I3jtZDqj/E1rLEw/B6NKJqa2G?=
 =?us-ascii?Q?BMjTtG4ni1VIPAp4d2pk9LhqruBgwPPJ758k7J8wNh4qeyrxMw7CdYWq1I0R?=
 =?us-ascii?Q?GBuVJY03AfJKMR104RwgY3fknXN8IvN29iTNJ0+eD1F3NxAno9yQcIJTQkeS?=
 =?us-ascii?Q?yoId2vRH+XNsm/w2C6bmYKVJx/YV0Z9wwoP0jVcUnv4ykzZXw7/tzjXNvEcQ?=
 =?us-ascii?Q?6aWPiQIFnRayq0RvOZ7zvCVkS1ufJXeo38+o6q/i8yvqt6ESM16esRQcrS6V?=
 =?us-ascii?Q?e6TOj8E3eVqianbp1H1P4l3mK5WsDkXyhVrO34lwWqdN9aC2/uW40neZjgH3?=
 =?us-ascii?Q?coIstQrxElTGMz0TvtFylv9PbSW9KLyqOFJOTYyUtco5dmViZfxJbF0cvfl4?=
 =?us-ascii?Q?0rqihHvrUToiOC1Up+l+zUBlDCCmovSJ/na9x+Py1sowbATi78c5XS+Fk4NQ?=
 =?us-ascii?Q?PvmU/bUIHPb/gvw1+uM579SAQPIzF2ulTKXLSTJzjFbZnhHlLKSdTtpnJzmE?=
 =?us-ascii?Q?dlqq2jusVQdKg/KieuiROnIExYnlXkArTzAYyuNPTFVFHPddy8k0SDiEv3IQ?=
 =?us-ascii?Q?833vo8V8VAI0Gnts+fOk8TE=3D?=
X-OriginatorOrg: analogixsemi.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 91070a6a-8400-4b24-40b1-08d9aa41244e
X-MS-Exchange-CrossTenant-AuthSource: BY5PR04MB6739.namprd04.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Nov 2021 03:11:41.1297
 (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: HYCHWFCW7guMtAo7G6ol2fQ8taL5PE99mkOifBuaSsDjvei79Z4be8BWM+cnmojvvhz2dGV8MrmxIM6ghUWYKQ==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BY5PR04MB6788
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.

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..36e0ae5a1c7b 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(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(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