42fed7ba44
This mutex avoids deadlock in case of use of multiple pin controllers. Before this modification, by using a global mutex, deadlock appeared when, for example, a call to pinctrl_pins_show() locked the pinctrl_mutex, called the ops->pin_dbg_show of a particular pin controller. If this pin controller needs I2C access to retrieve configuration information and I2C driver is using pinctrl to drive its pins, a call to pinctrl_select_state() try to lock again pinctrl_mutex which leads to a deadlock. Notice that the mutex grab from the two direction functions was moved into pinctrl_gpio_direction(). For several cases, we can't replace pinctrl_mutex by pctldev->mutex, because at this stage, pctldev is not accessible : - pinctrl_get()/pinctrl_put() - pinctrl_register_maps() So add respectively pinctrl_list_mutex and pinctrl_maps_mutex in order to protect pinctrl_list and pinctrl_maps list instead. Reintroduce pinctrldev_list_mutex in find_pinctrl_by_of_node(), pinctrl_find_and_add_gpio_range() pinctrl_request_gpio(), pinctrl_free_gpio(), pinctrl_gpio_direction(), pinctrl_devices_show(), pinctrl_register() and pinctrl_unregister() to protect pinctrldev_list. Changes v2->v3: - Fix a missing EXPORT_SYMBOL_GPL() for pinctrl_select_state(). Changes v1->v2: - pinctrl_select_state_locked() is removed, all lock mechanism is located inside pinctrl_select_state(). When parsing the state->setting list, take the per-pin-controller driver lock. (Patrice). - Introduce pinctrldev_list_mutex to protect pinctrldev_list in all functions which parse or modify pictrldev_list. (Patrice). - move find_pinctrl_by_of_node() from pinctrl/devicetree.c to pinctrl/core.c in order to protect pinctrldev_list. (Patrice). - Sink mutex:es into some functions and remove some _locked variants down to where the lists are actually accessed to make things simpler. (Linus) - Drop *all* mutexes completely from pinctrl_lookup_state() and pinctrl_select_state() - no relevant mutex was taken and it was unclear what this was protecting against. (Linus) Reported by : Seraphin Bonnaffe <seraphin.bonnaffe@stericsson.com> Signed-off-by: Patrice Chotard <patrice.chotard@st.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
200 lines
6.4 KiB
C
200 lines
6.4 KiB
C
/*
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* Core private header for the pin control subsystem
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*
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* Copyright (C) 2011 ST-Ericsson SA
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* Written on behalf of Linaro for ST-Ericsson
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*
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* Author: Linus Walleij <linus.walleij@linaro.org>
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*
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* License terms: GNU General Public License (GPL) version 2
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*/
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#include <linux/kref.h>
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#include <linux/mutex.h>
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#include <linux/radix-tree.h>
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#include <linux/pinctrl/pinconf.h>
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#include <linux/pinctrl/machine.h>
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struct pinctrl_gpio_range;
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/**
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* struct pinctrl_dev - pin control class device
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* @node: node to include this pin controller in the global pin controller list
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* @desc: the pin controller descriptor supplied when initializing this pin
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* controller
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* @pin_desc_tree: each pin descriptor for this pin controller is stored in
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* this radix tree
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* @gpio_ranges: a list of GPIO ranges that is handled by this pin controller,
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* ranges are added to this list at runtime
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* @dev: the device entry for this pin controller
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* @owner: module providing the pin controller, used for refcounting
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* @driver_data: driver data for drivers registering to the pin controller
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* subsystem
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* @p: result of pinctrl_get() for this device
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* @hog_default: default state for pins hogged by this device
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* @hog_sleep: sleep state for pins hogged by this device
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* @mutex: mutex taken on each pin controller specific action
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* @device_root: debugfs root for this device
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*/
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struct pinctrl_dev {
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struct list_head node;
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struct pinctrl_desc *desc;
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struct radix_tree_root pin_desc_tree;
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struct list_head gpio_ranges;
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struct device *dev;
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struct module *owner;
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void *driver_data;
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struct pinctrl *p;
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struct pinctrl_state *hog_default;
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struct pinctrl_state *hog_sleep;
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struct mutex mutex;
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#ifdef CONFIG_DEBUG_FS
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struct dentry *device_root;
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#endif
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};
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/**
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* struct pinctrl - per-device pin control state holder
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* @node: global list node
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* @dev: the device using this pin control handle
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* @states: a list of states for this device
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* @state: the current state
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* @dt_maps: the mapping table chunks dynamically parsed from device tree for
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* this device, if any
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* @users: reference count
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*/
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struct pinctrl {
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struct list_head node;
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struct device *dev;
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struct list_head states;
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struct pinctrl_state *state;
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struct list_head dt_maps;
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struct kref users;
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};
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/**
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* struct pinctrl_state - a pinctrl state for a device
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* @node: list node for struct pinctrl's @states field
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* @name: the name of this state
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* @settings: a list of settings for this state
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*/
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struct pinctrl_state {
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struct list_head node;
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const char *name;
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struct list_head settings;
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};
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/**
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* struct pinctrl_setting_mux - setting data for MAP_TYPE_MUX_GROUP
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* @group: the group selector to program
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* @func: the function selector to program
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*/
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struct pinctrl_setting_mux {
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unsigned group;
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unsigned func;
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};
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/**
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* struct pinctrl_setting_configs - setting data for MAP_TYPE_CONFIGS_*
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* @group_or_pin: the group selector or pin ID to program
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* @configs: a pointer to an array of config parameters/values to program into
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* hardware. Each individual pin controller defines the format and meaning
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* of config parameters.
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* @num_configs: the number of entries in array @configs
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*/
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struct pinctrl_setting_configs {
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unsigned group_or_pin;
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unsigned long *configs;
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unsigned num_configs;
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};
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/**
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* struct pinctrl_setting - an individual mux or config setting
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* @node: list node for struct pinctrl_settings's @settings field
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* @type: the type of setting
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* @pctldev: pin control device handling to be programmed. Not used for
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* PIN_MAP_TYPE_DUMMY_STATE.
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* @dev_name: the name of the device using this state
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* @data: Data specific to the setting type
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*/
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struct pinctrl_setting {
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struct list_head node;
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enum pinctrl_map_type type;
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struct pinctrl_dev *pctldev;
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const char *dev_name;
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union {
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struct pinctrl_setting_mux mux;
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struct pinctrl_setting_configs configs;
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} data;
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};
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/**
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* struct pin_desc - pin descriptor for each physical pin in the arch
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* @pctldev: corresponding pin control device
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* @name: a name for the pin, e.g. the name of the pin/pad/finger on a
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* datasheet or such
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* @dynamic_name: if the name of this pin was dynamically allocated
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* @mux_usecount: If zero, the pin is not claimed, and @owner should be NULL.
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* If non-zero, this pin is claimed by @owner. This field is an integer
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* rather than a boolean, since pinctrl_get() might process multiple
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* mapping table entries that refer to, and hence claim, the same group
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* or pin, and each of these will increment the @usecount.
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* @mux_owner: The name of device that called pinctrl_get().
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* @mux_setting: The most recent selected mux setting for this pin, if any.
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* @gpio_owner: If pinctrl_request_gpio() was called for this pin, this is
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* the name of the GPIO that "owns" this pin.
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*/
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struct pin_desc {
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struct pinctrl_dev *pctldev;
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const char *name;
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bool dynamic_name;
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/* These fields only added when supporting pinmux drivers */
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#ifdef CONFIG_PINMUX
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unsigned mux_usecount;
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const char *mux_owner;
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const struct pinctrl_setting_mux *mux_setting;
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const char *gpio_owner;
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#endif
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};
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/**
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* struct pinctrl_maps - a list item containing part of the mapping table
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* @node: mapping table list node
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* @maps: array of mapping table entries
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* @num_maps: the number of entries in @maps
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*/
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struct pinctrl_maps {
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struct list_head node;
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struct pinctrl_map const *maps;
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unsigned num_maps;
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};
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struct pinctrl_dev *get_pinctrl_dev_from_devname(const char *dev_name);
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struct pinctrl_dev *get_pinctrl_dev_from_of_node(struct device_node *np);
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int pin_get_from_name(struct pinctrl_dev *pctldev, const char *name);
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const char *pin_get_name(struct pinctrl_dev *pctldev, const unsigned pin);
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int pinctrl_get_group_selector(struct pinctrl_dev *pctldev,
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const char *pin_group);
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static inline struct pin_desc *pin_desc_get(struct pinctrl_dev *pctldev,
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unsigned int pin)
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{
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return radix_tree_lookup(&pctldev->pin_desc_tree, pin);
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}
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int pinctrl_register_map(struct pinctrl_map const *maps, unsigned num_maps,
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bool dup, bool locked);
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void pinctrl_unregister_map(struct pinctrl_map const *map);
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extern int pinctrl_force_sleep(struct pinctrl_dev *pctldev);
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extern int pinctrl_force_default(struct pinctrl_dev *pctldev);
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extern struct mutex pinctrl_maps_mutex;
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extern struct list_head pinctrl_maps;
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#define for_each_maps(_maps_node_, _i_, _map_) \
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list_for_each_entry(_maps_node_, &pinctrl_maps, node) \
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for (_i_ = 0, _map_ = &_maps_node_->maps[_i_]; \
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_i_ < _maps_node_->num_maps; \
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_i_++, _map_ = &_maps_node_->maps[_i_])
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