[PATCH V2] pinctrl: fix signed vs unsigned conditionals inside pinmux_map_to_setting

[John Crispin <blogic-p3rKhJxN3npAfugRpC6u6w@public.gmane.org>]

pinmux_map_to_setting() uses setting->data.mux.func/group to store the return
code of pinmux_func_name_to_selector/pinctrl_get_group_selector(). However,
struct pinctrl_setting_mux defines these elements as unsigned, resulting in all
error codes getting lost. The conditionals following the assignments will always
evaluate to false thus breaking the error paths.

This bug can be triggered by loading a pinmux group map from the devicetree
with an invalid function/group string.

Signed-off-by: John Crispin <blogic-p3rKhJxN3npAfugRpC6u6w@public.gmane.org>
Cc: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Cc: Dong Aisheng <dong.aisheng-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
 drivers/pinctrl/pinmux.c |   15 ++++++++-------
 1 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c
index c494c37..1056e68 100644
--- a/drivers/pinctrl/pinmux.c
+++ b/drivers/pinctrl/pinmux.c
@@ -328,10 +328,10 @@ int pinmux_map_to_setting(struct pinctrl_map const *map,
 		return -EINVAL;
 	}
 
-	setting->data.mux.func =
-		pinmux_func_name_to_selector(pctldev, map->data.mux.function);
-	if (setting->data.mux.func < 0)
-		return setting->data.mux.func;
+	ret = pinmux_func_name_to_selector(pctldev, map->data.mux.function);
+	if (ret < 0)
+		return ret;
+	setting->data.mux.func = ret;
 
 	ret = pmxops->get_function_groups(pctldev, setting->data.mux.func,
 					  &groups, &num_groups);
@@ -355,9 +355,10 @@ int pinmux_map_to_setting(struct pinctrl_map const *map,
 		group = groups[0];
 	}
 
-	setting->data.mux.group = pinctrl_get_group_selector(pctldev, group);
-	if (setting->data.mux.group < 0)
-		return setting->data.mux.group;
+	ret = pinctrl_get_group_selector(pctldev, group);
+	if (ret < 0)
+		return ret;
+	setting->data.mux.group = ret;
 
 	ret = pctlops->get_group_pins(pctldev, setting->data.mux.group, &pins,
 				      &num_pins);
-- 
1.7.9.1