Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Ying Liu <victor.liu@nxp.com>
To:     "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>,
        "linux-fbdev@vger.kernel.org" <linux-fbdev@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     "lee@kernel.org" <lee@kernel.org>,
        "daniel.thompson@linaro.org" <daniel.thompson@linaro.org>,
        "jingoohan1@gmail.com" <jingoohan1@gmail.com>,
        "deller@gmx.de" <deller@gmx.de>,
        "andy@kernel.org" <andy@kernel.org>,
        "linus.walleij@linaro.org" <linus.walleij@linaro.org>,
        "brgl@bgdev.pl" <brgl@bgdev.pl>
Subject: [PATCH v2] backlight: gpio_backlight: Drop output gpio direction
 check for initial power state
Thread-Topic: [PATCH v2] backlight: gpio_backlight: Drop output gpio direction
 check for initial power state
Thread-Index: Adm7pWHkE3L5gGu8m0ilbj6s2t0e8g==
Date:   Fri, 21 Jul 2023 07:31:37 +0000
Message-ID: <20230721073555.1377236-1-victor.liu@nxp.com>
Accept-Language: en-US
Content-Language: en-US
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0: =?iso-8859-1?Q?NiWZE13aWilcX0kM2AbE2ejB7ZnwfX3G5lRc3a3p+L5IIQ7ZH/IT6xdFb4?=
 =?iso-8859-1?Q?0vcyO3zVMJgMJoMKMfVgSR3EviAH877mQC7YHlDfw3c1qVtaiqoCE7eEa3?=
 =?iso-8859-1?Q?5byIsP1mGdy/9BAsCygwgfaZm6+vOHvnWNi4a7pd8JB0C7dngH8jPdyKzl?=
 =?iso-8859-1?Q?jh3PtYCy2Q342SUZzK9F63wqg0tyQ3VBJ0II9Mss2+n11vgedMHiMzB/Pe?=
 =?iso-8859-1?Q?0zdKWVeRPzzPDpF0HrhqSAlON4WPM8YdrKn/yNf+kr5CBCQCSqC6TFbt7i?=
 =?iso-8859-1?Q?rsmrFMYeC7jKs/hFDVHM4f6rpU3hM7XEE3ci7I3726kBMYehN6fhSQ+vc+?=
 =?iso-8859-1?Q?DtD5+Ok1A0rZVdKUuPtb1Ovd6VVS2NzdTDvlUtBHJX1edhgW38LwfgkjNS?=
 =?iso-8859-1?Q?DKlkHNku7CXai31xCPWf74x83JQz6RxFSetVuAoflAVZ1qh4v66fO49A9t?=
 =?iso-8859-1?Q?DUNJgcNTCQ9TyjYBz5xZWlQVUacKbKpqLqo2YX0ensxARagmly4k0FSXMY?=
 =?iso-8859-1?Q?HIqI/e1EbHFoYU9GwogIlDP2dwdYE7whsYBi9CdhsWCd9M0yTCL8Z0pNqp?=
 =?iso-8859-1?Q?pEbMp+op+cab6386MIkqCzOlnhwfCjzk04sJqXUo1jKncKk/KBnP5YnV3F?=
 =?iso-8859-1?Q?frSPtNldelSm6diag4pv93xUQhgDO/gWyNeBOqwDqbRB/lZLTbNenvqWA9?=
 =?iso-8859-1?Q?itamjbWXiyTJsuGUthsiZZ4gvxOcy6YZaKnlZCAjyTZfkOcBuweJzg0ssn?=
 =?iso-8859-1?Q?xQN69YqjlmHk7X8fCQm26WmEZEjc4T/Zpl14J1GBGw6y2xat9zhD9FWsQr?=
 =?iso-8859-1?Q?Zmn34nEBaFf6j1zuiLJPi0Lwp0WmcnpbrC9jf22D7CIW/3S0gcxvMRMP2b?=
 =?iso-8859-1?Q?qOz51yHY3L0vsN6LgJDGC1019m039OOdOESCXBL72v+atGVJA+O++tIDJh?=
 =?iso-8859-1?Q?ZXUln17aW4finlS/bfOiKC1SPAZSVCaH7jMXZY0RLPbXh0o12gyHoXS+1H?=
 =?iso-8859-1?Q?mVkSBXui6n+vsRoTbT1fjXa1Iege8u0kiqQ5r80bkx0pBLpdiUFYy+1yKN?=
 =?iso-8859-1?Q?P4GaUpNaVJzA3qogfD15E8i54nmdBs0VyjdERmFl1ZR56OvdGbHtDsIy0V?=
 =?iso-8859-1?Q?BkbNljBuQBR7vDnmFe+e5ldmgB1+B2baKC9sU5uOz3V9doW4mUPMP8c8+f?=
 =?iso-8859-1?Q?sSrNFzPQewznRPFLAXVcHXY+Eq8Rk7hWTEAsn7PCFm4qMZ8gNZ1blc5xIn?=
 =?iso-8859-1?Q?d6Bo3Frsqj48WW5EMY8I4sxgH4unVLqfrjwWexaO1H/22xyUcDEoPY1OFi?=
 =?iso-8859-1?Q?P3jgfyMkhHX6iJ2N3dh40iZkEu5izjege1aYc+tClu/PGPXw+tGPsAzWSY?=
 =?iso-8859-1?Q?kbMBbWVHv32XwFF/CRGZMBne0TtAomte+/S5mzcAw2m/zKeumnVjnC5N67?=
 =?iso-8859-1?Q?IISbR5oEDeSvnPm0OmOVWUwtepMmYQ2N0/migLZ4JOlOqXTxDeDLSKYd8A?=
 =?iso-8859-1?Q?4cBzIzOfANBiMd6CJJmdK/K0nRYc6VtsXjR3t7IP9Xzz3nnnQ/0w6eZEdU?=
 =?iso-8859-1?Q?yI7xFgpaqXS8tA4UmNZQ7enLpgv8TOFOx4k0RsXHZ559aMYx8V+OozRxgT?=
 =?iso-8859-1?Q?Sayl8AkvtD7TwVDAXDgn1RjOjigdnv8inf?=
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-OriginatorOrg: nxp.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: AM7PR04MB7046.eurprd04.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 2e085f9b-d50d-4b48-3c54-08db89bc846c
X-MS-Exchange-CrossTenant-originalarrivaltime: 21 Jul 2023 07:31:37.0813
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: LZy4KYHSMWqSHLFxcpyCzH7jAD9f68gPGQkMt9BCieqnR0+5/zo9ERsj4i5yWsnt64RyqvyktefiGtPzF5vLNg==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: DB9PR04MB8314
X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_BLOCKED,
        RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,SPF_PASS,T_SCC_BODY_TEXT_LINE,
        URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

If gpio pin is in input state but backlight is currently off due to
default pull downs, then initial power state is set to FB_BLANK_UNBLANK
in DT boot mode with phandle link and the backlight is effectively
turned on in gpio_backlight_probe(), which is undesirable according to
patch description of commit ec665b756e6f ("backlight: gpio-backlight:
Correct initial power state handling").

Quote:
---
If in DT boot we have phandle link then leave the GPIO in a state which the
bootloader left it and let the user of the backlight to configure it furthe=
r.
---

So, let's drop output gpio direction check and only check gpio value to set
the initial power state.

Signed-off-by: Liu Ying <victor.liu@nxp.com>
---
v1->v2:
* Improve patch description. (Daniel, Bartosz, Andy)

 drivers/video/backlight/gpio_backlight.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backl=
ight/gpio_backlight.c
index 6f78d928f054..38c46936fdcd 100644
--- a/drivers/video/backlight/gpio_backlight.c
+++ b/drivers/video/backlight/gpio_backlight.c
@@ -87,8 +87,7 @@ static int gpio_backlight_probe(struct platform_device *p=
dev)
 		/* Not booted with device tree or no phandle link to the node */
 		bl->props.power =3D def_value ? FB_BLANK_UNBLANK
 					    : FB_BLANK_POWERDOWN;
-	else if (gpiod_get_direction(gbl->gpiod) =3D=3D 0 &&
-		 gpiod_get_value_cansleep(gbl->gpiod) =3D=3D 0)
+	else if (gpiod_get_value_cansleep(gbl->gpiod) =3D=3D 0)
 		bl->props.power =3D FB_BLANK_POWERDOWN;
 	else
 		bl->props.power =3D FB_BLANK_UNBLANK;
--=20
2.37.1