summaryrefslogtreecommitdiffstats
path: root/include/linux/gpio/driver.h
blob: 656a27efb2c8cdd755cd78e20a36e5dd028e5310 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
#ifndef __LINUX_GPIO_DRIVER_H
#define __LINUX_GPIO_DRIVER_H

#include <linux/types.h>

struct device;
struct gpio_desc;
struct seq_file;

/**
 * struct gpio_chip - abstract a GPIO controller
 * @label: for diagnostics
 * @dev: optional device providing the GPIOs
 * @owner: helps prevent removal of modules exporting active GPIOs
 * @list: links gpio_chips together for traversal
 * @request: optional hook for chip-specific activation, such as
 *	enabling module power and clock; may sleep
 * @free: optional hook for chip-specific deactivation, such as
 *	disabling module power and clock; may sleep
 * @get_direction: returns direction for signal "offset", 0=out, 1=in,
 *	(same as GPIOF_DIR_XXX), or negative error
 * @direction_input: configures signal "offset" as input, or returns error
 * @direction_output: configures signal "offset" as output, or returns error
 * @get: returns value for signal "offset"; for output signals this
 *	returns either the value actually sensed, or zero
 * @set: assigns output value for signal "offset"
 * @set_debounce: optional hook for setting debounce time for specified gpio in
 *      interrupt triggered gpio chips
 * @to_irq: optional hook supporting non-static gpio_to_irq() mappings;
 *	implementation may not sleep
 * @dbg_show: optional routine to show contents in debugfs; default code
 *	will be used when this is omitted, but custom code can show extra
 *	state (such as pullup/pulldown configuration).
 * @base: identifies the first GPIO number handled by this chip; or, if
 *	negative during registration, requests dynamic ID allocation.
 * @ngpio: the number of GPIOs handled by this controller; the last GPIO
 *	handled is (base + ngpio - 1).
 * @desc: array of ngpio descriptors. Private.
 * @can_sleep: flag must be set iff get()/set() methods sleep, as they
 *	must while accessing GPIO expander chips over I2C or SPI
 * @names: if set, must be an array of strings to use as alternative
 *      names for the GPIOs in this chip. Any entry in the array
 *      may be NULL if there is no alias for the GPIO, however the
 *      array must be @ngpio entries long.  A name can include a single printk
 *      format specifier for an unsigned int.  It is substituted by the actual
 *      number of the gpio.
 *
 * A gpio_chip can help platforms abstract various sources of GPIOs so
 * they can all be accessed through a common programing interface.
 * Example sources would be SOC controllers, FPGAs, multifunction
 * chips, dedicated GPIO expanders, and so on.
 *
 * Each chip controls a number of signals, identified in method calls
 * by "offset" values in the range 0..(@ngpio - 1).  When those signals
 * are referenced through calls like gpio_get_value(gpio), the offset
 * is calculated by subtracting @base from the gpio number.
 */
struct gpio_chip {
	const char		*label;
	struct device		*dev;
	struct module		*owner;
	struct list_head        list;

	int			(*request)(struct gpio_chip *chip,
						unsigned offset);
	void			(*free)(struct gpio_chip *chip,
						unsigned offset);
	int			(*get_direction)(struct gpio_chip *chip,
						unsigned offset);
	int			(*direction_input)(struct gpio_chip *chip,
						unsigned offset);
	int			(*direction_output)(struct gpio_chip *chip,
						unsigned offset, int value);
	int			(*get)(struct gpio_chip *chip,
						unsigned offset);
	void			(*set)(struct gpio_chip *chip,
						unsigned offset, int value);
	int			(*set_debounce)(struct gpio_chip *chip,
						unsigned offset,
						unsigned debounce);

	int			(*to_irq)(struct gpio_chip *chip,
						unsigned offset);

	void			(*dbg_show)(struct seq_file *s,
						struct gpio_chip *chip);
	int			base;
	u16			ngpio;
	struct gpio_desc	*desc;
	const char		*const *names;
	unsigned		can_sleep:1;
	unsigned		exported:1;

#if defined(CONFIG_OF_GPIO)
	/*
	 * If CONFIG_OF is enabled, then all GPIO controllers described in the
	 * device tree automatically may have an OF translation
	 */
	struct device_node *of_node;
	int of_gpio_n_cells;
	int (*of_xlate)(struct gpio_chip *gc,
			const struct of_phandle_args *gpiospec, u32 *flags);
#endif
#ifdef CONFIG_PINCTRL
	/*
	 * If CONFIG_PINCTRL is enabled, then gpio controllers can optionally
	 * describe the actual pin range which they serve in an SoC. This
	 * information would be used by pinctrl subsystem to configure
	 * corresponding pins for gpio usage.
	 */
	struct list_head pin_ranges;
#endif
};

extern const char *gpiochip_is_requested(struct gpio_chip *chip,
			unsigned offset);

/* add/remove chips */
extern int gpiochip_add(struct gpio_chip *chip);
extern int __must_check gpiochip_remove(struct gpio_chip *chip);
extern struct gpio_chip *gpiochip_find(void *data,
			      int (*match)(struct gpio_chip *chip, void *data));

/* lock/unlock as IRQ */
int gpiod_lock_as_irq(struct gpio_desc *desc);
void gpiod_unlock_as_irq(struct gpio_desc *desc);

/**
 * Lookup table for associating GPIOs to specific devices and functions using
 * platform data.
 */
struct gpiod_lookup {
	struct list_head list;
	/*
	 * name of the chip the GPIO belongs to
	 */
	const char *chip_label;
	/*
	 * hardware number (i.e. relative to the chip) of the GPIO
	 */
	u16 chip_hwnum;
	/*
	 * name of device that can claim this GPIO
	 */
	const char *dev_id;
	/*
	 * name of the GPIO from the device's point of view
	 */
	const char *con_id;
	/*
	 * index of the GPIO in case several GPIOs share the same name
	 */
	unsigned int idx;
	/*
	 * mask of GPIOF_* values
	 */
	unsigned long flags;
};

/*
 * Simple definition of a single GPIO under a con_id
 */
#define GPIO_LOOKUP(_chip_label, _chip_hwnum, _dev_id, _con_id, _flags) \
	GPIO_LOOKUP_IDX(_chip_label, _chip_hwnum, _dev_id, _con_id, 0, _flags)

/*
 * Use this macro if you need to have several GPIOs under the same con_id.
 * Each GPIO needs to use a different index and can be accessed using
 * gpiod_get_index()
 */
#define GPIO_LOOKUP_IDX(_chip_label, _chip_hwnum, _dev_id, _con_id, _idx, \
			_flags)                                           \
{                                                                         \
	.chip_label = _chip_label,                                        \
	.chip_hwnum = _chip_hwnum,                                        \
	.dev_id = _dev_id,                                                \
	.con_id = _con_id,                                                \
	.idx = _idx,                                                      \
	.flags = _flags,                                                  \
}

void gpiod_add_table(struct gpiod_lookup *table, size_t size);

#endif
OpenPOWER on IntegriCloud