pinctrl/pinconfig: add debug interface

This update adds a debugfs interface to modify a pin configuration
for a given state in the pinctrl map. This allows to modify the
configuration for a non-active state, typically sleep state.
This configuration is not applied right away, but only when the state
will be entered.

This solution is mandated for us by HW validation: in order
to test and verify several pin configurations during sleep without
recompiling the software.

Signed-off-by: Laurent Meunier <laurent.meunier@st.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/pinctrl/core.h b/drivers/pinctrl/core.h
index fdd350d..ee72f1f 100644
--- a/drivers/pinctrl/core.h
+++ b/drivers/pinctrl/core.h
@@ -155,6 +155,18 @@
 #endif
 };
 
+/**
+ * struct pinctrl_maps - a list item containing part of the mapping table
+ * @node: mapping table list node
+ * @maps: array of mapping table entries
+ * @num_maps: the number of entries in @maps
+ */
+struct pinctrl_maps {
+	struct list_head node;
+	struct pinctrl_map const *maps;
+	unsigned num_maps;
+};
+
 struct pinctrl_dev *get_pinctrl_dev_from_devname(const char *dev_name);
 int pin_get_from_name(struct pinctrl_dev *pctldev, const char *name);
 const char *pin_get_name(struct pinctrl_dev *pctldev, const unsigned pin);
@@ -176,3 +188,10 @@
 
 extern struct mutex pinctrl_mutex;
 extern struct list_head pinctrldev_list;
+extern struct list_head pinctrl_maps;
+
+#define for_each_maps(_maps_node_, _i_, _map_) \
+	list_for_each_entry(_maps_node_, &pinctrl_maps, node) \
+		for (_i_ = 0, _map_ = &_maps_node_->maps[_i_]; \
+			_i_ < _maps_node_->num_maps; \
+			_i_++, _map_ = &_maps_node_->maps[_i_])