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 #include <linux/of.h>
8
9 #ifdef CONFIG_GPIOLIB
10
11 #include <linux/compiler.h>
12
13 /* Platforms may implement their GPIO interface with library code,
14 * at a small performance cost for non-inlined operations and some
15 * extra memory (for code and for per-GPIO table entries).
16 *
17 * While the GPIO programming interface defines valid GPIO numbers
18 * to be in the range 0..MAX_INT, this library restricts them to the
19 * smaller range 0..ARCH_NR_GPIOS-1.
20 *
21 * ARCH_NR_GPIOS is somewhat arbitrary; it usually reflects the sum of
22 * builtin/SoC GPIOs plus a number of GPIOs on expanders; the latter is
23 * actually an estimate of a board-specific value.
24 */
25
26 #ifndef ARCH_NR_GPIOS
27 #define ARCH_NR_GPIOS 256
28 #endif
29
30 /*
31 * "valid" GPIO numbers are nonnegative and may be passed to
32 * setup routines like gpio_request(). only some valid numbers
33 * can successfully be requested and used.
34 *
35 * Invalid GPIO numbers are useful for indicating no-such-GPIO in
36 * platform data and other tables.
37 */
38
gpio_is_valid(int number)39 static inline bool gpio_is_valid(int number)
40 {
41 return number >= 0 && number < ARCH_NR_GPIOS;
42 }
43
44 struct device;
45 struct gpio;
46 struct seq_file;
47 struct module;
48 struct device_node;
49
50 /**
51 * struct gpio_chip - abstract a GPIO controller
52 * @label: for diagnostics
53 * @dev: optional device providing the GPIOs
54 * @owner: helps prevent removal of modules exporting active GPIOs
55 * @request: optional hook for chip-specific activation, such as
56 * enabling module power and clock; may sleep
57 * @free: optional hook for chip-specific deactivation, such as
58 * disabling module power and clock; may sleep
59 * @direction_input: configures signal "offset" as input, or returns error
60 * @get: returns value for signal "offset"; for output signals this
61 * returns either the value actually sensed, or zero
62 * @direction_output: configures signal "offset" as output, or returns error
63 * @set: assigns output value for signal "offset"
64 * @to_irq: optional hook supporting non-static gpio_to_irq() mappings;
65 * implementation may not sleep
66 * @dbg_show: optional routine to show contents in debugfs; default code
67 * will be used when this is omitted, but custom code can show extra
68 * state (such as pullup/pulldown configuration).
69 * @base: identifies the first GPIO number handled by this chip; or, if
70 * negative during registration, requests dynamic ID allocation.
71 * @ngpio: the number of GPIOs handled by this controller; the last GPIO
72 * handled is (base + ngpio - 1).
73 * @can_sleep: flag must be set iff get()/set() methods sleep, as they
74 * must while accessing GPIO expander chips over I2C or SPI
75 * @names: if set, must be an array of strings to use as alternative
76 * names for the GPIOs in this chip. Any entry in the array
77 * may be NULL if there is no alias for the GPIO, however the
78 * array must be @ngpio entries long. A name can include a single printk
79 * format specifier for an unsigned int. It is substituted by the actual
80 * number of the gpio.
81 *
82 * A gpio_chip can help platforms abstract various sources of GPIOs so
83 * they can all be accessed through a common programing interface.
84 * Example sources would be SOC controllers, FPGAs, multifunction
85 * chips, dedicated GPIO expanders, and so on.
86 *
87 * Each chip controls a number of signals, identified in method calls
88 * by "offset" values in the range 0..(@ngpio - 1). When those signals
89 * are referenced through calls like gpio_get_value(gpio), the offset
90 * is calculated by subtracting @base from the gpio number.
91 */
92 struct gpio_chip {
93 const char *label;
94 struct device *dev;
95 struct module *owner;
96
97 int (*request)(struct gpio_chip *chip,
98 unsigned offset);
99 void (*free)(struct gpio_chip *chip,
100 unsigned offset);
101
102 int (*direction_input)(struct gpio_chip *chip,
103 unsigned offset);
104 int (*get)(struct gpio_chip *chip,
105 unsigned offset);
106 int (*direction_output)(struct gpio_chip *chip,
107 unsigned offset, int value);
108 int (*set_debounce)(struct gpio_chip *chip,
109 unsigned offset, unsigned debounce);
110
111 void (*set)(struct gpio_chip *chip,
112 unsigned offset, int value);
113
114 int (*to_irq)(struct gpio_chip *chip,
115 unsigned offset);
116
117 void (*dbg_show)(struct seq_file *s,
118 struct gpio_chip *chip);
119 int base;
120 u16 ngpio;
121 const char *const *names;
122 unsigned can_sleep:1;
123 unsigned exported:1;
124
125 #if defined(CONFIG_OF_GPIO)
126 /*
127 * If CONFIG_OF is enabled, then all GPIO controllers described in the
128 * device tree automatically may have an OF translation
129 */
130 struct device_node *of_node;
131 int of_gpio_n_cells;
132 int (*of_xlate)(struct gpio_chip *gc,
133 const struct of_phandle_args *gpiospec, u32 *flags);
134 #endif
135 };
136
137 extern const char *gpiochip_is_requested(struct gpio_chip *chip,
138 unsigned offset);
139 extern struct gpio_chip *gpio_to_chip(unsigned gpio);
140 extern int __must_check gpiochip_reserve(int start, int ngpio);
141
142 /* add/remove chips */
143 extern int gpiochip_add(struct gpio_chip *chip);
144 extern int __must_check gpiochip_remove(struct gpio_chip *chip);
145 extern struct gpio_chip *gpiochip_find(const void *data,
146 int (*match)(struct gpio_chip *chip,
147 const void *data));
148
149
150 /* Always use the library code for GPIO management calls,
151 * or when sleeping may be involved.
152 */
153 extern int gpio_request(unsigned gpio, const char *label);
154 extern void gpio_free(unsigned gpio);
155
156 extern int gpio_direction_input(unsigned gpio);
157 extern int gpio_direction_output(unsigned gpio, int value);
158
159 extern int gpio_set_debounce(unsigned gpio, unsigned debounce);
160
161 extern int gpio_get_value_cansleep(unsigned gpio);
162 extern void gpio_set_value_cansleep(unsigned gpio, int value);
163
164
165 /* A platform's <asm/gpio.h> code may want to inline the I/O calls when
166 * the GPIO is constant and refers to some always-present controller,
167 * giving direct access to chip registers and tight bitbanging loops.
168 */
169 extern int __gpio_get_value(unsigned gpio);
170 extern void __gpio_set_value(unsigned gpio, int value);
171
172 extern int __gpio_cansleep(unsigned gpio);
173
174 extern int __gpio_to_irq(unsigned gpio);
175
176 extern int gpio_request_one(unsigned gpio, unsigned long flags, const char *label);
177 extern int gpio_request_array(const struct gpio *array, size_t num);
178 extern void gpio_free_array(const struct gpio *array, size_t num);
179
180 /* bindings for managed devices that want to request gpios */
181 int devm_gpio_request(struct device *dev, unsigned gpio, const char *label);
182 void devm_gpio_free(struct device *dev, unsigned int gpio);
183
184 #ifdef CONFIG_GPIO_SYSFS
185
186 /*
187 * A sysfs interface can be exported by individual drivers if they want,
188 * but more typically is configured entirely from userspace.
189 */
190 extern int gpio_export(unsigned gpio, bool direction_may_change);
191 extern int gpio_export_link(struct device *dev, const char *name,
192 unsigned gpio);
193 extern int gpio_sysfs_set_active_low(unsigned gpio, int value);
194 extern void gpio_unexport(unsigned gpio);
195
196 #endif /* CONFIG_GPIO_SYSFS */
197
198 #else /* !CONFIG_GPIOLIB */
199
gpio_is_valid(int number)200 static inline bool gpio_is_valid(int number)
201 {
202 /* only non-negative numbers are valid */
203 return number >= 0;
204 }
205
206 /* platforms that don't directly support access to GPIOs through I2C, SPI,
207 * or other blocking infrastructure can use these wrappers.
208 */
209
gpio_cansleep(unsigned gpio)210 static inline int gpio_cansleep(unsigned gpio)
211 {
212 return 0;
213 }
214
gpio_get_value_cansleep(unsigned gpio)215 static inline int gpio_get_value_cansleep(unsigned gpio)
216 {
217 might_sleep();
218 return __gpio_get_value(gpio);
219 }
220
gpio_set_value_cansleep(unsigned gpio,int value)221 static inline void gpio_set_value_cansleep(unsigned gpio, int value)
222 {
223 might_sleep();
224 __gpio_set_value(gpio, value);
225 }
226
227 #endif /* !CONFIG_GPIOLIB */
228
229 #ifndef CONFIG_GPIO_SYSFS
230
231 struct device;
232
233 /* sysfs support is only available with gpiolib, where it's optional */
234
gpio_export(unsigned gpio,bool direction_may_change)235 static inline int gpio_export(unsigned gpio, bool direction_may_change)
236 {
237 return -ENOSYS;
238 }
239
gpio_export_link(struct device * dev,const char * name,unsigned gpio)240 static inline int gpio_export_link(struct device *dev, const char *name,
241 unsigned gpio)
242 {
243 return -ENOSYS;
244 }
245
gpio_sysfs_set_active_low(unsigned gpio,int value)246 static inline int gpio_sysfs_set_active_low(unsigned gpio, int value)
247 {
248 return -ENOSYS;
249 }
250
gpio_unexport(unsigned gpio)251 static inline void gpio_unexport(unsigned gpio)
252 {
253 }
254 #endif /* CONFIG_GPIO_SYSFS */
255
256 #endif /* _ASM_GENERIC_GPIO_H */
257