linux-kernel - [PATCH v2 2/4] backlight: max8925

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Date:   Mon, 20 Nov 2017 11:45:45 +0100
From:   Johan Hovold <johan@...nel.org>
To:     Lee Jones <lee.jones@...aro.org>
Cc:     Daniel Thompson <daniel.thompson@...aro.org>,
        Jingoo Han <jingoohan1@...il.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        dri-devel@...ts.freedesktop.org, linux-fbdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, Johan Hovold <johan@...nel.org>,
        stable <stable@...r.kernel.org>, Qing Xu <qingx@...vell.com>,
        Haojian Zhuang <haojian.zhuang@...il.com>
Subject: [PATCH v2 2/4] backlight: max8925_bl: fix device-tree node lookup

Fix child-node lookup during probe, which ended up searching the whole
device tree depth-first starting at the parent rather than just matching
on its children.

To make things worse, the parent mfd node was also prematurely freed,
while the child backlight node was leaked.

Fixes: 47ec340cb8e2 ("mfd: max8925: Support dt for backlight")
Cc: stable <stable@...r.kernel.org>     # 3.9
Cc: Qing Xu <qingx@...vell.com>
Cc: Haojian Zhuang <haojian.zhuang@...il.com>
Signed-off-by: Johan Hovold <johan@...nel.org>
---
 drivers/video/backlight/max8925_bl.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/video/backlight/max8925_bl.c b/drivers/video/backlight/max8925_bl.c
index 7b738d60ecc2..f3aa6088f1d9 100644
--- a/drivers/video/backlight/max8925_bl.c
+++ b/drivers/video/backlight/max8925_bl.c
@@ -116,7 +116,7 @@ static void max8925_backlight_dt_init(struct platform_device *pdev)
 	if (!pdata)
 		return;
 
-	np = of_find_node_by_name(nproot, "backlight");
+	np = of_get_child_by_name(nproot, "backlight");
 	if (!np) {
 		dev_err(&pdev->dev, "failed to find backlight node\n");
 		return;
@@ -125,6 +125,8 @@ static void max8925_backlight_dt_init(struct platform_device *pdev)
 	if (!of_property_read_u32(np, "maxim,max8925-dual-string", &val))
 		pdata->dual_string = val;
 
+	of_node_put(np);
+
 	pdev->dev.platform_data = pdata;
 }
 
-- 
2.15.0