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David Brownell4c203862007-02-12 00:53:11 -08001#ifndef _ASM_GENERIC_GPIO_H
2#define _ASM_GENERIC_GPIO_H
3
David Brownell6ea02052008-05-23 13:04:58 -07004#include <linux/types.h>
Atsushi Nemoto25947d52008-07-28 15:46:38 -07005#include <linux/errno.h>
David Brownell6ea02052008-05-23 13:04:58 -07006
Michael Buesch7444a722008-07-25 01:46:11 -07007#ifdef CONFIG_GPIOLIB
David Brownelld2876d02008-02-04 22:28:20 -08008
David Brownell6ea02052008-05-23 13:04:58 -07009#include <linux/compiler.h>
10
David Brownelld2876d02008-02-04 22:28:20 -080011/* Platforms may implement their GPIO interface with library code,
12 * at a small performance cost for non-inlined operations and some
13 * extra memory (for code and for per-GPIO table entries).
14 *
15 * While the GPIO programming interface defines valid GPIO numbers
16 * to be in the range 0..MAX_INT, this library restricts them to the
Michael Buesch6a9436d2008-07-26 15:22:26 -070017 * smaller range 0..ARCH_NR_GPIOS-1.
David Brownelld2876d02008-02-04 22:28:20 -080018 */
19
20#ifndef ARCH_NR_GPIOS
21#define ARCH_NR_GPIOS 256
22#endif
23
Guennadi Liakhovetskie6de1802008-04-28 02:14:46 -070024static inline int gpio_is_valid(int number)
25{
26 /* only some non-negative numbers are valid */
27 return ((unsigned)number) < ARCH_NR_GPIOS;
28}
29
David Brownelld2876d02008-02-04 22:28:20 -080030struct seq_file;
Guennadi Liakhovetski438d8902008-04-28 02:14:44 -070031struct module;
David Brownelld2876d02008-02-04 22:28:20 -080032
33/**
34 * struct gpio_chip - abstract a GPIO controller
35 * @label: for diagnostics
David Brownelld8f388d2008-07-25 01:46:07 -070036 * @dev: optional device providing the GPIOs
37 * @owner: helps prevent removal of modules exporting active GPIOs
David Brownell35e8bb52008-10-15 22:03:16 -070038 * @request: optional hook for chip-specific activation, such as
39 * enabling module power and clock; may sleep
40 * @free: optional hook for chip-specific deactivation, such as
41 * disabling module power and clock; may sleep
David Brownelld2876d02008-02-04 22:28:20 -080042 * @direction_input: configures signal "offset" as input, or returns error
43 * @get: returns value for signal "offset"; for output signals this
44 * returns either the value actually sensed, or zero
45 * @direction_output: configures signal "offset" as output, or returns error
46 * @set: assigns output value for signal "offset"
David Brownell0f6d5042008-10-15 22:03:14 -070047 * @to_irq: optional hook supporting non-static gpio_to_irq() mappings;
48 * implementation may not sleep
David Brownelld2876d02008-02-04 22:28:20 -080049 * @dbg_show: optional routine to show contents in debugfs; default code
50 * will be used when this is omitted, but custom code can show extra
51 * state (such as pullup/pulldown configuration).
52 * @base: identifies the first GPIO number handled by this chip; or, if
53 * negative during registration, requests dynamic ID allocation.
54 * @ngpio: the number of GPIOs handled by this controller; the last GPIO
55 * handled is (base + ngpio - 1).
56 * @can_sleep: flag must be set iff get()/set() methods sleep, as they
57 * must while accessing GPIO expander chips over I2C or SPI
Daniel Silverstone926b6632009-04-02 16:57:05 -070058 * @names: if set, must be an array of strings to use as alternative
59 * names for the GPIOs in this chip. Any entry in the array
60 * may be NULL if there is no alias for the GPIO, however the
61 * array must be @ngpio entries long.
David Brownelld2876d02008-02-04 22:28:20 -080062 *
63 * A gpio_chip can help platforms abstract various sources of GPIOs so
64 * they can all be accessed through a common programing interface.
65 * Example sources would be SOC controllers, FPGAs, multifunction
66 * chips, dedicated GPIO expanders, and so on.
67 *
68 * Each chip controls a number of signals, identified in method calls
69 * by "offset" values in the range 0..(@ngpio - 1). When those signals
70 * are referenced through calls like gpio_get_value(gpio), the offset
71 * is calculated by subtracting @base from the gpio number.
72 */
73struct gpio_chip {
Dmitry Baryshkov4fd54632008-10-15 22:03:10 -070074 const char *label;
David Brownelld8f388d2008-07-25 01:46:07 -070075 struct device *dev;
Guennadi Liakhovetski438d8902008-04-28 02:14:44 -070076 struct module *owner;
David Brownelld2876d02008-02-04 22:28:20 -080077
David Brownell35e8bb52008-10-15 22:03:16 -070078 int (*request)(struct gpio_chip *chip,
79 unsigned offset);
80 void (*free)(struct gpio_chip *chip,
81 unsigned offset);
82
David Brownelld2876d02008-02-04 22:28:20 -080083 int (*direction_input)(struct gpio_chip *chip,
84 unsigned offset);
85 int (*get)(struct gpio_chip *chip,
86 unsigned offset);
87 int (*direction_output)(struct gpio_chip *chip,
88 unsigned offset, int value);
89 void (*set)(struct gpio_chip *chip,
90 unsigned offset, int value);
David Brownell0f6d5042008-10-15 22:03:14 -070091
92 int (*to_irq)(struct gpio_chip *chip,
93 unsigned offset);
94
David Brownelld2876d02008-02-04 22:28:20 -080095 void (*dbg_show)(struct seq_file *s,
96 struct gpio_chip *chip);
97 int base;
98 u16 ngpio;
Daniel Silverstone926b6632009-04-02 16:57:05 -070099 char **names;
David Brownelld2876d02008-02-04 22:28:20 -0800100 unsigned can_sleep:1;
David Brownelld8f388d2008-07-25 01:46:07 -0700101 unsigned exported:1;
David Brownelld2876d02008-02-04 22:28:20 -0800102};
103
104extern const char *gpiochip_is_requested(struct gpio_chip *chip,
105 unsigned offset);
David Brownell6ea02052008-05-23 13:04:58 -0700106extern int __must_check gpiochip_reserve(int start, int ngpio);
David Brownelld2876d02008-02-04 22:28:20 -0800107
108/* add/remove chips */
109extern int gpiochip_add(struct gpio_chip *chip);
110extern int __must_check gpiochip_remove(struct gpio_chip *chip);
111
112
113/* Always use the library code for GPIO management calls,
114 * or when sleeping may be involved.
115 */
116extern int gpio_request(unsigned gpio, const char *label);
117extern void gpio_free(unsigned gpio);
118
119extern int gpio_direction_input(unsigned gpio);
120extern int gpio_direction_output(unsigned gpio, int value);
121
122extern int gpio_get_value_cansleep(unsigned gpio);
123extern void gpio_set_value_cansleep(unsigned gpio, int value);
124
125
126/* A platform's <asm/gpio.h> code may want to inline the I/O calls when
127 * the GPIO is constant and refers to some always-present controller,
128 * giving direct access to chip registers and tight bitbanging loops.
129 */
130extern int __gpio_get_value(unsigned gpio);
131extern void __gpio_set_value(unsigned gpio, int value);
132
133extern int __gpio_cansleep(unsigned gpio);
134
David Brownell0f6d5042008-10-15 22:03:14 -0700135extern int __gpio_to_irq(unsigned gpio);
David Brownelld2876d02008-02-04 22:28:20 -0800136
David Brownelld8f388d2008-07-25 01:46:07 -0700137#ifdef CONFIG_GPIO_SYSFS
138
139/*
140 * A sysfs interface can be exported by individual drivers if they want,
141 * but more typically is configured entirely from userspace.
142 */
143extern int gpio_export(unsigned gpio, bool direction_may_change);
144extern void gpio_unexport(unsigned gpio);
145
146#endif /* CONFIG_GPIO_SYSFS */
147
148#else /* !CONFIG_HAVE_GPIO_LIB */
David Brownelld2876d02008-02-04 22:28:20 -0800149
Guennadi Liakhovetskie6de1802008-04-28 02:14:46 -0700150static inline int gpio_is_valid(int number)
151{
152 /* only non-negative numbers are valid */
153 return number >= 0;
154}
155
David Brownell4c203862007-02-12 00:53:11 -0800156/* platforms that don't directly support access to GPIOs through I2C, SPI,
157 * or other blocking infrastructure can use these wrappers.
158 */
159
160static inline int gpio_cansleep(unsigned gpio)
161{
162 return 0;
163}
164
165static inline int gpio_get_value_cansleep(unsigned gpio)
166{
167 might_sleep();
168 return gpio_get_value(gpio);
169}
170
171static inline void gpio_set_value_cansleep(unsigned gpio, int value)
172{
173 might_sleep();
174 gpio_set_value(gpio, value);
175}
176
David Brownelld8f388d2008-07-25 01:46:07 -0700177#endif /* !CONFIG_HAVE_GPIO_LIB */
178
179#ifndef CONFIG_GPIO_SYSFS
180
181/* sysfs support is only available with gpiolib, where it's optional */
182
183static inline int gpio_export(unsigned gpio, bool direction_may_change)
184{
185 return -ENOSYS;
186}
187
188static inline void gpio_unexport(unsigned gpio)
189{
190}
191#endif /* CONFIG_GPIO_SYSFS */
David Brownelld2876d02008-02-04 22:28:20 -0800192
David Brownell4c203862007-02-12 00:53:11 -0800193#endif /* _ASM_GENERIC_GPIO_H */