From: Drew Fustini drew@beagleboard.org
[ Upstream commit f46fe79ff1b65692a65266a5bec6dbe2bf7fc70f ]
This patch causes pcs_parse_pinconf() to return -ENOTSUPP when no pinctrl_map is added. The current behavior is to return 0 when !PCS_HAS_PINCONF or !nconfs. Thus pcs_parse_one_pinctrl_entry() incorrectly assumes that a map was added and sets num_maps = 2.
Analysis: ========= The function pcs_parse_one_pinctrl_entry() calls pcs_parse_pinconf() if PCS_HAS_PINCONF is enabled. The function pcs_parse_pinconf() returns 0 to indicate there was no error and num_maps is then set to 2:
980 static int pcs_parse_one_pinctrl_entry(struct pcs_device *pcs, 981 struct device_node *np, 982 struct pinctrl_map **map, 983 unsigned *num_maps, 984 const char **pgnames) 985 { <snip> 1053 (*map)->type = PIN_MAP_TYPE_MUX_GROUP; 1054 (*map)->data.mux.group = np->name; 1055 (*map)->data.mux.function = np->name; 1056 1057 if (PCS_HAS_PINCONF && function) { 1058 res = pcs_parse_pinconf(pcs, np, function, map); 1059 if (res) 1060 goto free_pingroups; 1061 *num_maps = 2; 1062 } else { 1063 *num_maps = 1; 1064 }
However, pcs_parse_pinconf() will also return 0 if !PCS_HAS_PINCONF or !nconfs. I believe these conditions should indicate that no map was added by returning -ENOTSUPP. Otherwise pcs_parse_one_pinctrl_entry() will set num_maps = 2 even though no maps were successfully added, as it does not reach "m++" on line 940:
895 static int pcs_parse_pinconf(struct pcs_device *pcs, struct device_node *np, 896 struct pcs_function *func, 897 struct pinctrl_map **map) 898 899 { 900 struct pinctrl_map *m = *map; <snip> 917 /* If pinconf isn't supported, don't parse properties in below. */ 918 if (!PCS_HAS_PINCONF) 919 return 0; 920 921 /* cacluate how much properties are supported in current node */ 922 for (i = 0; i < ARRAY_SIZE(prop2); i++) { 923 if (of_find_property(np, prop2[i].name, NULL)) 924 nconfs++; 925 } 926 for (i = 0; i < ARRAY_SIZE(prop4); i++) { 927 if (of_find_property(np, prop4[i].name, NULL)) 928 nconfs++; 929 } 930 if (!nconfs) 919 return 0; 932 933 func->conf = devm_kcalloc(pcs->dev, 934 nconfs, sizeof(struct pcs_conf_vals), 935 GFP_KERNEL); 936 if (!func->conf) 937 return -ENOMEM; 938 func->nconfs = nconfs; 939 conf = &(func->conf[0]); 940 m++;
This situtation will cause a boot failure [0] on the BeagleBone Black (AM3358) when am33xx_pinmux node in arch/arm/boot/dts/am33xx-l4.dtsi has compatible = "pinconf-single" instead of "pinctrl-single".
The patch fixes this issue by returning -ENOSUPP when !PCS_HAS_PINCONF or !nconfs, so that pcs_parse_one_pinctrl_entry() will know that no map was added.
Logic is also added to pcs_parse_one_pinctrl_entry() to distinguish between -ENOSUPP and other errors. In the case of -ENOSUPP, num_maps is set to 1 as it is valid for pinconf to be enabled and a given pin group to not any pinconf properties.
[0] https://lore.kernel.org/linux-omap/20200529175544.GA3766151@x1/
Fixes: 9dddb4df90d1 ("pinctrl: single: support generic pinconf") Signed-off-by: Drew Fustini drew@beagleboard.org Acked-by: Tony Lindgren tony@atomide.com Link: https://lore.kernel.org/r/20200608125143.GA2789203@x1 Signed-off-by: Linus Walleij linus.walleij@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pinctrl/pinctrl-single.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
--- a/drivers/pinctrl/pinctrl-single.c +++ b/drivers/pinctrl/pinctrl-single.c @@ -1078,7 +1078,7 @@ static int pcs_parse_pinconf(struct pcs_
/* If pinconf isn't supported, don't parse properties in below. */ if (!PCS_HAS_PINCONF) - return 0; + return -ENOTSUPP;
/* cacluate how much properties are supported in current node */ for (i = 0; i < ARRAY_SIZE(prop2); i++) { @@ -1090,7 +1090,7 @@ static int pcs_parse_pinconf(struct pcs_ nconfs++; } if (!nconfs) - return 0; + return -ENOTSUPP;
func->conf = devm_kzalloc(pcs->dev, sizeof(struct pcs_conf_vals) * nconfs, @@ -1203,9 +1203,12 @@ static int pcs_parse_one_pinctrl_entry(s
if (PCS_HAS_PINCONF) { res = pcs_parse_pinconf(pcs, np, function, map); - if (res) + if (res == 0) + *num_maps = 2; + else if (res == -ENOTSUPP) + *num_maps = 1; + else goto free_pingroups; - *num_maps = 2; } else { *num_maps = 1; }