pinctrl: disable and free setting in select_state in case of error

If enabling a pin fails in pinctrl_select_state_locked(), all the
previous enabled pins have to be disabled to get back to the previous
state.

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
index 9712345..09f79f2 100644 (file)
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -930,7 +930,7 @@ static int pinctrl_select_state_locked(struct pinctrl *p,
                }
        }
 
-       p->state = state;
+       p->state = NULL;
 
        /* Apply all the settings for the new state */
        list_for_each_entry(setting, &state->settings, node) {
@@ -946,13 +946,35 @@ static int pinctrl_select_state_locked(struct pinctrl *p,
                        ret = -EINVAL;
                        break;
                }
+
                if (ret < 0) {
-                       /* FIXME: Difficult to return to prev state */
-                       return ret;
+                       goto unapply_new_state;
                }
        }
 
+       p->state = state;
+
        return 0;
+
+unapply_new_state:
+       pr_info("Error applying setting, reverse things back\n");
+
+       /*
+        * If the loop stopped on the 1st entry, nothing has been enabled,
+        * so jump directly to the 2nd phase
+        */
+       if (list_entry(&setting->node, typeof(*setting), node) ==
+           list_first_entry(&state->settings, typeof(*setting), node))
+               goto reapply_old_state;
+
+       list_for_each_entry(setting2, &state->settings, node) {
+               if (&setting2->node == &setting->node)
+                       break;
+               pinctrl_free_setting(true, setting2);
+       }
+reapply_old_state:
+       /* FIXME: re-enable old setting */
+       return ret;
 }
 
 /**