[openwrt/openwrt] pistachio: Fix Null pointer access in pwm-img.c

[LEDE Commits]

hauke pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/bdc7d9691d8d60364f40505d44346e5fa6374f66

commit bdc7d9691d8d60364f40505d44346e5fa6374f66
Author: Hauke Mehrtens <hauke at hauke-m.de>
AuthorDate: Wed Aug 12 00:52:36 2020 +0200

    pistachio: Fix Null pointer access in pwm-img.c
    
    This fixes a crash when booting the board.
    
    Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
---
 ...-pwm-img-Fix-null-pointer-access-in-probe.patch | 42 ++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/target/linux/pistachio/patches-5.4/150-pwm-img-Fix-null-pointer-access-in-probe.patch b/target/linux/pistachio/patches-5.4/150-pwm-img-Fix-null-pointer-access-in-probe.patch
new file mode 100644
index 0000000000..d5c573c75c
--- /dev/null
+++ b/target/linux/pistachio/patches-5.4/150-pwm-img-Fix-null-pointer-access-in-probe.patch
@@ -0,0 +1,42 @@
+From 502396fe598126ffd91f962d53a507aa6c7276fc Mon Sep 17 00:00:00 2001
+From: Hauke Mehrtens <hauke at hauke-m.de>
+Date: Sat, 15 Aug 2020 16:37:43 +0200
+Subject: [PATCH v2] pwm: img: Fix null pointer access in probe
+
+dev_get_drvdata() is called in img_pwm_runtime_resume() before the
+driver data is set.
+When pm_runtime_enabled() returns false in img_pwm_probe() it calls
+img_pwm_runtime_resume() which results in a null pointer access.
+
+This patch fixes the problem by setting the driver data earlier in the
+img_pwm_probe() function.
+
+This crash was seen when booting the Imagination Technologies Creator
+Ci40 (Marduk) with kernel 5.4 in OpenWrt.
+
+Fixes: e690ae526216 ("pwm: img: Add runtime PM")
+Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
+Acked-by: Lee Jones <lee.jones at linaro.org>
+---
+ drivers/pwm/pwm-img.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+--- a/drivers/pwm/pwm-img.c
++++ b/drivers/pwm/pwm-img.c
+@@ -277,6 +277,8 @@ static int img_pwm_probe(struct platform
+ 		return PTR_ERR(pwm->pwm_clk);
+ 	}
+ 
++	platform_set_drvdata(pdev, pwm);
++
+ 	pm_runtime_set_autosuspend_delay(&pdev->dev, IMG_PWM_PM_TIMEOUT);
+ 	pm_runtime_use_autosuspend(&pdev->dev);
+ 	pm_runtime_enable(&pdev->dev);
+@@ -313,7 +315,6 @@ static int img_pwm_probe(struct platform
+ 		goto err_suspend;
+ 	}
+ 
+-	platform_set_drvdata(pdev, pwm);
+ 	return 0;
+ 
+ err_suspend: