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4c20386c DB |
1 | #ifndef _ASM_GENERIC_GPIO_H |
2 | #define _ASM_GENERIC_GPIO_H | |
3 | ||
d2876d08 DB |
4 | #ifdef CONFIG_HAVE_GPIO_LIB |
5 | ||
6 | /* Platforms may implement their GPIO interface with library code, | |
7 | * at a small performance cost for non-inlined operations and some | |
8 | * extra memory (for code and for per-GPIO table entries). | |
9 | * | |
10 | * While the GPIO programming interface defines valid GPIO numbers | |
11 | * to be in the range 0..MAX_INT, this library restricts them to the | |
12 | * smaller range 0..ARCH_NR_GPIOS. | |
13 | */ | |
14 | ||
15 | #ifndef ARCH_NR_GPIOS | |
16 | #define ARCH_NR_GPIOS 256 | |
17 | #endif | |
18 | ||
19 | struct seq_file; | |
20 | ||
21 | /** | |
22 | * struct gpio_chip - abstract a GPIO controller | |
23 | * @label: for diagnostics | |
24 | * @direction_input: configures signal "offset" as input, or returns error | |
25 | * @get: returns value for signal "offset"; for output signals this | |
26 | * returns either the value actually sensed, or zero | |
27 | * @direction_output: configures signal "offset" as output, or returns error | |
28 | * @set: assigns output value for signal "offset" | |
29 | * @dbg_show: optional routine to show contents in debugfs; default code | |
30 | * will be used when this is omitted, but custom code can show extra | |
31 | * state (such as pullup/pulldown configuration). | |
32 | * @base: identifies the first GPIO number handled by this chip; or, if | |
33 | * negative during registration, requests dynamic ID allocation. | |
34 | * @ngpio: the number of GPIOs handled by this controller; the last GPIO | |
35 | * handled is (base + ngpio - 1). | |
36 | * @can_sleep: flag must be set iff get()/set() methods sleep, as they | |
37 | * must while accessing GPIO expander chips over I2C or SPI | |
38 | * | |
39 | * A gpio_chip can help platforms abstract various sources of GPIOs so | |
40 | * they can all be accessed through a common programing interface. | |
41 | * Example sources would be SOC controllers, FPGAs, multifunction | |
42 | * chips, dedicated GPIO expanders, and so on. | |
43 | * | |
44 | * Each chip controls a number of signals, identified in method calls | |
45 | * by "offset" values in the range 0..(@ngpio - 1). When those signals | |
46 | * are referenced through calls like gpio_get_value(gpio), the offset | |
47 | * is calculated by subtracting @base from the gpio number. | |
48 | */ | |
49 | struct gpio_chip { | |
50 | char *label; | |
51 | ||
52 | int (*direction_input)(struct gpio_chip *chip, | |
53 | unsigned offset); | |
54 | int (*get)(struct gpio_chip *chip, | |
55 | unsigned offset); | |
56 | int (*direction_output)(struct gpio_chip *chip, | |
57 | unsigned offset, int value); | |
58 | void (*set)(struct gpio_chip *chip, | |
59 | unsigned offset, int value); | |
60 | void (*dbg_show)(struct seq_file *s, | |
61 | struct gpio_chip *chip); | |
62 | int base; | |
63 | u16 ngpio; | |
64 | unsigned can_sleep:1; | |
65 | }; | |
66 | ||
67 | extern const char *gpiochip_is_requested(struct gpio_chip *chip, | |
68 | unsigned offset); | |
69 | ||
70 | /* add/remove chips */ | |
71 | extern int gpiochip_add(struct gpio_chip *chip); | |
72 | extern int __must_check gpiochip_remove(struct gpio_chip *chip); | |
73 | ||
74 | ||
75 | /* Always use the library code for GPIO management calls, | |
76 | * or when sleeping may be involved. | |
77 | */ | |
78 | extern int gpio_request(unsigned gpio, const char *label); | |
79 | extern void gpio_free(unsigned gpio); | |
80 | ||
81 | extern int gpio_direction_input(unsigned gpio); | |
82 | extern int gpio_direction_output(unsigned gpio, int value); | |
83 | ||
84 | extern int gpio_get_value_cansleep(unsigned gpio); | |
85 | extern void gpio_set_value_cansleep(unsigned gpio, int value); | |
86 | ||
87 | ||
88 | /* A platform's <asm/gpio.h> code may want to inline the I/O calls when | |
89 | * the GPIO is constant and refers to some always-present controller, | |
90 | * giving direct access to chip registers and tight bitbanging loops. | |
91 | */ | |
92 | extern int __gpio_get_value(unsigned gpio); | |
93 | extern void __gpio_set_value(unsigned gpio, int value); | |
94 | ||
95 | extern int __gpio_cansleep(unsigned gpio); | |
96 | ||
97 | ||
98 | #else | |
99 | ||
4c20386c DB |
100 | /* platforms that don't directly support access to GPIOs through I2C, SPI, |
101 | * or other blocking infrastructure can use these wrappers. | |
102 | */ | |
103 | ||
104 | static inline int gpio_cansleep(unsigned gpio) | |
105 | { | |
106 | return 0; | |
107 | } | |
108 | ||
109 | static inline int gpio_get_value_cansleep(unsigned gpio) | |
110 | { | |
111 | might_sleep(); | |
112 | return gpio_get_value(gpio); | |
113 | } | |
114 | ||
115 | static inline void gpio_set_value_cansleep(unsigned gpio, int value) | |
116 | { | |
117 | might_sleep(); | |
118 | gpio_set_value(gpio, value); | |
119 | } | |
120 | ||
d2876d08 DB |
121 | #endif |
122 | ||
4c20386c | 123 | #endif /* _ASM_GENERIC_GPIO_H */ |