3712a3c488
Some pinctrl drivers (Tegra at least) program a pin to be a GPIO in a
completely different manner than they select which function to mux out of
that pin. In order to support a single "free" pinmux_op, the driver would
need to maintain a per-pin state of requested-for-gpio vs. requested-for-
function. However, that's a lot of work when the core already has explicit
separate paths for gpio request/free and function request/free.
So, add a gpio_disable_free op to struct pinmux_ops, and make pin_free()
call it when appropriate.
When doing this, I noticed that when calling pin_request():
!!gpio == (gpio_range != NULL)
... and so I collapsed those two parameters in both pin_request(), and
when adding writing the new code in pin_free().
Also, for pin_free():
!!free_func == (gpio_range != NULL)
However, I didn't want pin_free() to know about the GPIO function naming
special case, so instead, I reworked pin_free() to always return the pin's
previously requested function, and now pinmux_free_gpio() calls
kfree(function). This is much more balanced with the allocation having
been performed in pinmux_request_gpio().
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
121 lines
4.3 KiB
C
121 lines
4.3 KiB
C
/*
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* Interface the pinmux 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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* Based on bits of regulator core, gpio core and clk core
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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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#ifndef __LINUX_PINCTRL_PINMUX_H
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#define __LINUX_PINCTRL_PINMUX_H
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#include <linux/list.h>
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#include <linux/seq_file.h>
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#include "pinctrl.h"
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/* This struct is private to the core and should be regarded as a cookie */
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struct pinmux;
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#ifdef CONFIG_PINMUX
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struct pinctrl_dev;
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/**
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* struct pinmux_ops - pinmux operations, to be implemented by pin controller
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* drivers that support pinmuxing
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* @request: called by the core to see if a certain pin can be made available
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* available for muxing. This is called by the core to acquire the pins
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* before selecting any actual mux setting across a function. The driver
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* is allowed to answer "no" by returning a negative error code
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* @free: the reverse function of the request() callback, frees a pin after
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* being requested
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* @list_functions: list the number of selectable named functions available
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* in this pinmux driver, the core will begin on 0 and call this
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* repeatedly as long as it returns >= 0 to enumerate mux settings
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* @get_function_name: return the function name of the muxing selector,
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* called by the core to figure out which mux setting it shall map a
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* certain device to
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* @get_function_groups: return an array of groups names (in turn
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* referencing pins) connected to a certain function selector. The group
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* name can be used with the generic @pinctrl_ops to retrieve the
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* actual pins affected. The applicable groups will be returned in
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* @groups and the number of groups in @num_groups
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* @enable: enable a certain muxing function with a certain pin group. The
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* driver does not need to figure out whether enabling this function
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* conflicts some other use of the pins in that group, such collisions
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* are handled by the pinmux subsystem. The @func_selector selects a
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* certain function whereas @group_selector selects a certain set of pins
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* to be used. On simple controllers the latter argument may be ignored
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* @disable: disable a certain muxing selector with a certain pin group
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* @gpio_request_enable: requests and enables GPIO on a certain pin.
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* Implement this only if you can mux every pin individually as GPIO. The
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* affected GPIO range is passed along with an offset into that
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* specific GPIO range - function selectors and pin groups are orthogonal
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* to this, the core will however make sure the pins do not collide
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*/
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struct pinmux_ops {
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int (*request) (struct pinctrl_dev *pctldev, unsigned offset);
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int (*free) (struct pinctrl_dev *pctldev, unsigned offset);
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int (*list_functions) (struct pinctrl_dev *pctldev, unsigned selector);
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const char *(*get_function_name) (struct pinctrl_dev *pctldev,
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unsigned selector);
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int (*get_function_groups) (struct pinctrl_dev *pctldev,
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unsigned selector,
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const char * const **groups,
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unsigned * const num_groups);
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int (*enable) (struct pinctrl_dev *pctldev, unsigned func_selector,
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unsigned group_selector);
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void (*disable) (struct pinctrl_dev *pctldev, unsigned func_selector,
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unsigned group_selector);
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int (*gpio_request_enable) (struct pinctrl_dev *pctldev,
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struct pinctrl_gpio_range *range,
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unsigned offset);
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void (*gpio_disable_free) (struct pinctrl_dev *pctldev,
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struct pinctrl_gpio_range *range,
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unsigned offset);
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};
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/* External interface to pinmux */
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extern int pinmux_request_gpio(unsigned gpio);
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extern void pinmux_free_gpio(unsigned gpio);
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extern struct pinmux * __must_check pinmux_get(struct device *dev, const char *name);
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extern void pinmux_put(struct pinmux *pmx);
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extern int pinmux_enable(struct pinmux *pmx);
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extern void pinmux_disable(struct pinmux *pmx);
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#else /* !CONFIG_PINMUX */
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static inline int pinmux_request_gpio(unsigned gpio)
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{
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return 0;
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}
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static inline void pinmux_free_gpio(unsigned gpio)
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{
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}
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static inline struct pinmux * __must_check pinmux_get(struct device *dev, const char *name)
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{
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return NULL;
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}
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static inline void pinmux_put(struct pinmux *pmx)
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{
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}
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static inline int pinmux_enable(struct pinmux *pmx)
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{
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return 0;
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}
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static inline void pinmux_disable(struct pinmux *pmx)
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{
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}
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#endif /* CONFIG_PINMUX */
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#endif /* __LINUX_PINCTRL_PINMUX_H */
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