Commit c1087c29 authored by H. Nikolaus Schaller's avatar H. Nikolaus Schaller Committed by Lee Jones

leds: tca6507: Fix error handling of using fwnode_property_read_string

Commit 96f52410 ("leds: tca6507: use fwnode API instead of OF")

changed to fwnode API but did not take into account that a missing property
"linux,default-trigger" now seems to return an error and as a side effect
sets value to -1. This seems to be different from of_get_property() which
always returned NULL in any case of error.

Neglecting this side-effect leads to

[   11.201965] Unable to handle kernel paging request at virtual address ffffffff when read

in the strcmp() of led_trigger_set_default() if there is no led-trigger
defined in the DTS.

I don't know if this was recently introduced somewhere in the fwnode lib
or if the effect was missed in initial testing. Anyways it seems to be a
bug to ignore the error return value of an optional value here in the
driver.

Fixes: 96f52410 ("leds: tca6507: use fwnode API instead of OF")
Signed-off-by: default avatarH. Nikolaus Schaller <hns@goldelico.com>
Acked-by: default avatarPavel Machek <pavel@ucw.cz>
Reviewed-by: default avatarMarek Behún <kabel@kernel.org>
Signed-off-by: default avatarLee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/cbae7617db83113de726fcc423a805ebaa1bfca6.1680433978.git.hns@goldelico.com
parent 22dc3789
......@@ -691,8 +691,9 @@ tca6507_led_dt_init(struct device *dev)
if (fwnode_property_read_string(child, "label", &led.name))
led.name = fwnode_get_name(child);
fwnode_property_read_string(child, "linux,default-trigger",
&led.default_trigger);
if (fwnode_property_read_string(child, "linux,default-trigger",
&led.default_trigger))
led.default_trigger = NULL;
led.flags = 0;
if (fwnode_device_is_compatible(child, "gpio"))
......
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