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1 | #ifndef _ASM_GENERIC_GPIO_H |
2 | #define _ASM_GENERIC_GPIO_H |
3 | |
4 | #include <linux/kernel.h> |
5 | #include <linux/types.h> |
6 | #include <linux/errno.h> |
7 | |
8 | #ifdef CONFIG_GPIOLIB |
9 | |
10 | #include <linux/compiler.h> |
11 | |
12 | /* Platforms may implement their GPIO interface with library code, |
13 | * at a small performance cost for non-inlined operations and some |
14 | * extra memory (for code and for per-GPIO table entries). |
15 | * |
16 | * While the GPIO programming interface defines valid GPIO numbers |
17 | * to be in the range 0..MAX_INT, this library restricts them to the |
18 | * smaller range 0..ARCH_NR_GPIOS-1. |
19 | */ |
20 | |
21 | #ifndef ARCH_NR_GPIOS |
22 | #define ARCH_NR_GPIOS 256 |
23 | #endif |
24 | |
25 | static inline int gpio_is_valid(int number) |
26 | { |
27 | /* only some non-negative numbers are valid */ |
28 | return ((unsigned)number) < ARCH_NR_GPIOS; |
29 | } |
30 | |
31 | struct device; |
32 | struct seq_file; |
33 | struct module; |
34 | |
35 | /** |
36 | * struct gpio_chip - abstract a GPIO controller |
37 | * @label: for diagnostics |
38 | * @dev: optional device providing the GPIOs |
39 | * @owner: helps prevent removal of modules exporting active GPIOs |
40 | * @request: optional hook for chip-specific activation, such as |
41 | * enabling module power and clock; may sleep |
42 | * @free: optional hook for chip-specific deactivation, such as |
43 | * disabling module power and clock; may sleep |
44 | * @direction_input: configures signal "offset" as input, or returns error |
45 | * @get: returns value for signal "offset"; for output signals this |
46 | * returns either the value actually sensed, or zero |
47 | * @direction_output: configures signal "offset" as output, or returns error |
48 | * @set: assigns output value for signal "offset" |
49 | * @to_irq: optional hook supporting non-static gpio_to_irq() mappings; |
50 | * implementation may not sleep |
51 | * @dbg_show: optional routine to show contents in debugfs; default code |
52 | * will be used when this is omitted, but custom code can show extra |
53 | * state (such as pullup/pulldown configuration). |
54 | * @base: identifies the first GPIO number handled by this chip; or, if |
55 | * negative during registration, requests dynamic ID allocation. |
56 | * @ngpio: the number of GPIOs handled by this controller; the last GPIO |
57 | * handled is (base + ngpio - 1). |
58 | * @can_sleep: flag must be set iff get()/set() methods sleep, as they |
59 | * must while accessing GPIO expander chips over I2C or SPI |
60 | * @names: if set, must be an array of strings to use as alternative |
61 | * names for the GPIOs in this chip. Any entry in the array |
62 | * may be NULL if there is no alias for the GPIO, however the |
63 | * array must be @ngpio entries long. |
64 | * |
65 | * A gpio_chip can help platforms abstract various sources of GPIOs so |
66 | * they can all be accessed through a common programing interface. |
67 | * Example sources would be SOC controllers, FPGAs, multifunction |
68 | * chips, dedicated GPIO expanders, and so on. |
69 | * |
70 | * Each chip controls a number of signals, identified in method calls |
71 | * by "offset" values in the range 0..(@ngpio - 1). When those signals |
72 | * are referenced through calls like gpio_get_value(gpio), the offset |
73 | * is calculated by subtracting @base from the gpio number. |
74 | */ |
75 | struct gpio_chip { |
76 | const char *label; |
77 | struct device *dev; |
78 | struct module *owner; |
79 | |
80 | int (*request)(struct gpio_chip *chip, |
81 | unsigned offset); |
82 | void (*free)(struct gpio_chip *chip, |
83 | unsigned offset); |
84 | |
85 | int (*direction_input)(struct gpio_chip *chip, |
86 | unsigned offset); |
87 | int (*get)(struct gpio_chip *chip, |
88 | unsigned offset); |
89 | int (*direction_output)(struct gpio_chip *chip, |
90 | unsigned offset, int value); |
91 | void (*set)(struct gpio_chip *chip, |
92 | unsigned offset, int value); |
93 | |
94 | int (*to_irq)(struct gpio_chip *chip, |
95 | unsigned offset); |
96 | |
97 | void (*dbg_show)(struct seq_file *s, |
98 | struct gpio_chip *chip); |
99 | int base; |
100 | u16 ngpio; |
101 | char **names; |
102 | unsigned can_sleep:1; |
103 | unsigned exported:1; |
104 | }; |
105 | |
106 | extern const char *gpiochip_is_requested(struct gpio_chip *chip, |
107 | unsigned offset); |
108 | extern int __must_check gpiochip_reserve(int start, int ngpio); |
109 | |
110 | /* add/remove chips */ |
111 | extern int gpiochip_add(struct gpio_chip *chip); |
112 | extern int __must_check gpiochip_remove(struct gpio_chip *chip); |
113 | |
114 | |
115 | /* Always use the library code for GPIO management calls, |
116 | * or when sleeping may be involved. |
117 | */ |
118 | extern int gpio_request(unsigned gpio, const char *label); |
119 | extern void gpio_free(unsigned gpio); |
120 | |
121 | extern int gpio_direction_input(unsigned gpio); |
122 | extern int gpio_direction_output(unsigned gpio, int value); |
123 | |
124 | extern int gpio_get_value_cansleep(unsigned gpio); |
125 | extern void gpio_set_value_cansleep(unsigned gpio, int value); |
126 | |
127 | |
128 | /* A platform's <asm/gpio.h> code may want to inline the I/O calls when |
129 | * the GPIO is constant and refers to some always-present controller, |
130 | * giving direct access to chip registers and tight bitbanging loops. |
131 | */ |
132 | extern int __gpio_get_value(unsigned gpio); |
133 | extern void __gpio_set_value(unsigned gpio, int value); |
134 | |
135 | extern int __gpio_cansleep(unsigned gpio); |
136 | |
137 | extern int __gpio_to_irq(unsigned gpio); |
138 | |
139 | #define GPIOF_DIR_OUT (0 << 0) |
140 | #define GPIOF_DIR_IN (1 << 0) |
141 | |
142 | #define GPIOF_INIT_LOW (0 << 1) |
143 | #define GPIOF_INIT_HIGH (1 << 1) |
144 | |
145 | #define GPIOF_IN (GPIOF_DIR_IN) |
146 | #define GPIOF_OUT_INIT_LOW (GPIOF_DIR_OUT | GPIOF_INIT_LOW) |
147 | #define GPIOF_OUT_INIT_HIGH (GPIOF_DIR_OUT | GPIOF_INIT_HIGH) |
148 | |
149 | /** |
150 | * struct gpio - a structure describing a GPIO with configuration |
151 | * @gpio: the GPIO number |
152 | * @flags: GPIO configuration as specified by GPIOF_* |
153 | * @label: a literal description string of this GPIO |
154 | */ |
155 | struct gpio { |
156 | unsigned gpio; |
157 | unsigned long flags; |
158 | const char *label; |
159 | }; |
160 | |
161 | extern int gpio_request_one(unsigned gpio, unsigned long flags, const char *label); |
162 | extern int gpio_request_array(struct gpio *array, size_t num); |
163 | extern void gpio_free_array(struct gpio *array, size_t num); |
164 | |
165 | #ifdef CONFIG_GPIO_SYSFS |
166 | |
167 | /* |
168 | * A sysfs interface can be exported by individual drivers if they want, |
169 | * but more typically is configured entirely from userspace. |
170 | */ |
171 | extern int gpio_export(unsigned gpio, bool direction_may_change); |
172 | extern int gpio_export_link(struct device *dev, const char *name, |
173 | unsigned gpio); |
174 | extern int gpio_sysfs_set_active_low(unsigned gpio, int value); |
175 | extern void gpio_unexport(unsigned gpio); |
176 | |
177 | #endif /* CONFIG_GPIO_SYSFS */ |
178 | |
179 | #else /* !CONFIG_HAVE_GPIO_LIB */ |
180 | |
181 | static inline int gpio_is_valid(int number) |
182 | { |
183 | /* only non-negative numbers are valid */ |
184 | return number >= 0; |
185 | } |
186 | |
187 | /* platforms that don't directly support access to GPIOs through I2C, SPI, |
188 | * or other blocking infrastructure can use these wrappers. |
189 | */ |
190 | |
191 | static inline int gpio_cansleep(unsigned gpio) |
192 | { |
193 | return 0; |
194 | } |
195 | |
196 | static inline int gpio_get_value_cansleep(unsigned gpio) |
197 | { |
198 | might_sleep(); |
199 | return gpio_get_value(gpio); |
200 | } |
201 | |
202 | static inline void gpio_set_value_cansleep(unsigned gpio, int value) |
203 | { |
204 | might_sleep(); |
205 | gpio_set_value(gpio, value); |
206 | } |
207 | |
208 | #endif /* !CONFIG_HAVE_GPIO_LIB */ |
209 | |
210 | #ifndef CONFIG_GPIO_SYSFS |
211 | |
212 | struct device; |
213 | |
214 | /* sysfs support is only available with gpiolib, where it's optional */ |
215 | |
216 | static inline int gpio_export(unsigned gpio, bool direction_may_change) |
217 | { |
218 | return -ENOSYS; |
219 | } |
220 | |
221 | static inline int gpio_export_link(struct device *dev, const char *name, |
222 | unsigned gpio) |
223 | { |
224 | return -ENOSYS; |
225 | } |
226 | |
227 | static inline int gpio_sysfs_set_active_low(unsigned gpio, int value) |
228 | { |
229 | return -ENOSYS; |
230 | } |
231 | |
232 | static inline void gpio_unexport(unsigned gpio) |
233 | { |
234 | } |
235 | #endif /* CONFIG_GPIO_SYSFS */ |
236 | |
237 | #endif /* _ASM_GENERIC_GPIO_H */ |
238 |
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