[PATCH] of: Fix uninitialized child warning in for_each_child_of_node() if !OF

[Geert Uytterhoeven <geert@linux-m68k.org>]

If CONFIG_OF=n:

drivers/i2c/i2c-mux.c: In function ‘i2c_add_mux_adapter’:
drivers/i2c/i2c-mux.c:158: warning: ‘child’ is used uninitialized in this function
drivers/leds/leds-lp55xx-common.c: In function ‘lp55xx_of_populate_pdata’:
drivers/leds/leds-lp55xx-common.c:560: warning: ‘child’ is used uninitialized in this function
drivers/leds/leds-pwm.c: In function ‘led_pwm_probe’:
drivers/leds/leds-pwm.c:89: warning: ‘child’ is used uninitialized in this function
drivers/mfd/stmpe.c: In function ‘stmpe_of_probe’:
drivers/mfd/stmpe.c:1112: warning: ‘child’ is used uninitialized in this function
drivers/mfd/tc3589x.c: In function ‘tc3589x_probe’:
drivers/mfd/tc3589x.c:324: warning: ‘child’ is used uninitialized in this function
drivers/power/charger-manager.c: In function ‘of_cm_parse_desc’:
drivers/power/charger-manager.c:1606: warning: ‘child’ is used uninitialized in this function

Introduced by commit 00b2c76a6abbe082bb5afb89ee49ec325e9cd4d2
("include/linux/of.h: make for_each_child_of_node() reference its args when
CONFIG_OF=n").

Instead of dropping the "__of_use_dn(child)" again, explicitly set child
to NULL, to protect against code using child after the loop (child == NULL
is the loop termination condition if CONFIG_OF=y).

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
 include/linux/of.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/of.h b/include/linux/of.h
index 70c64ba17fa5..0bf44f2fe092 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -383,7 +383,7 @@ static inline void __of_use_dn(const struct device_node *np)
 }
 
 #define for_each_child_of_node(parent, child) \
-	while (__of_use_dn(parent), __of_use_dn(child), 0)
+	while (__of_use_dn(parent), child = NULL, 0)
 
 #define for_each_available_child_of_node(parent, child) \
 	while (0)
-- 
1.7.9.5