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 * ARCH_NR_GPIOS is somewhat arbitrary; it usually reflects the sum of
21 * builtin/SoC GPIOs plus a number of GPIOs on expanders; the latter is
22 * actually an estimate of a board-specific value.
23 */
24
25 #ifndef ARCH_NR_GPIOS
26 #define ARCH_NR_GPIOS 256
27 #endif
28
29 /*
30 * "valid" GPIO numbers are nonnegative and may be passed to
31 * setup routines like gpio_request(). only some valid numbers
32 * can successfully be requested and used.
33 *
34 * Invalid GPIO numbers are useful for indicating no-such-GPIO in
35 * platform data and other tables.
36 */
37
gpio_is_valid(int number)38 static inline int gpio_is_valid(int number)
39 {
40 return ((unsigned)number) < ARCH_NR_GPIOS;
41 }
42
43 struct device;
44 struct seq_file;
45 struct module;
46 struct device_node;
47
48 /**
49 * struct gpio_chip - abstract a GPIO controller
50 * @label: for diagnostics
51 * @dev: optional device providing the GPIOs
52 * @owner: helps prevent removal of modules exporting active GPIOs
53 * @request: optional hook for chip-specific activation, such as
54 * enabling module power and clock; may sleep
55 * @free: optional hook for chip-specific deactivation, such as
56 * disabling module power and clock; may sleep
57 * @direction_input: configures signal "offset" as input, or returns error
58 * @get: returns value for signal "offset"; for output signals this
59 * returns either the value actually sensed, or zero
60 * @direction_output: configures signal "offset" as output, or returns error
61 * @set: assigns output value for signal "offset"
62 * @to_irq: optional hook supporting non-static gpio_to_irq() mappings;
63 * implementation may not sleep
64 * @dbg_show: optional routine to show contents in debugfs; default code
65 * will be used when this is omitted, but custom code can show extra
66 * state (such as pullup/pulldown configuration).
67 * @base: identifies the first GPIO number handled by this chip; or, if
68 * negative during registration, requests dynamic ID allocation.
69 * @ngpio: the number of GPIOs handled by this controller; the last GPIO
70 * handled is (base + ngpio - 1).
71 * @can_sleep: flag must be set iff get()/set() methods sleep, as they
72 * must while accessing GPIO expander chips over I2C or SPI
73 * @names: if set, must be an array of strings to use as alternative
74 * names for the GPIOs in this chip. Any entry in the array
75 * may be NULL if there is no alias for the GPIO, however the
76 * array must be @ngpio entries long. A name can include a single printk
77 * format specifier for an unsigned int. It is substituted by the actual
78 * number of the gpio.
79 *
80 * A gpio_chip can help platforms abstract various sources of GPIOs so
81 * they can all be accessed through a common programing interface.
82 * Example sources would be SOC controllers, FPGAs, multifunction
83 * chips, dedicated GPIO expanders, and so on.
84 *
85 * Each chip controls a number of signals, identified in method calls
86 * by "offset" values in the range 0..(@ngpio - 1). When those signals
87 * are referenced through calls like gpio_get_value(gpio), the offset
88 * is calculated by subtracting @base from the gpio number.
89 */
90 struct gpio_chip {
91 const char *label;
92 struct device *dev;
93 struct module *owner;
94
95 int (*request)(struct gpio_chip *chip,
96 unsigned offset);
97 void (*free)(struct gpio_chip *chip,
98 unsigned offset);
99
100 int (*direction_input)(struct gpio_chip *chip,
101 unsigned offset);
102 int (*get)(struct gpio_chip *chip,
103 unsigned offset);
104 int (*direction_output)(struct gpio_chip *chip,
105 unsigned offset, int value);
106 int (*set_debounce)(struct gpio_chip *chip,
107 unsigned offset, unsigned debounce);
108
109 void (*set)(struct gpio_chip *chip,
110 unsigned offset, int value);
111
112 int (*to_irq)(struct gpio_chip *chip,
113 unsigned offset);
114
115 void (*dbg_show)(struct seq_file *s,
116 struct gpio_chip *chip);
117 int base;
118 u16 ngpio;
119 const char *const *names;
120 unsigned can_sleep:1;
121 unsigned exported:1;
122
123 #if defined(CONFIG_OF_GPIO)
124 /*
125 * If CONFIG_OF is enabled, then all GPIO controllers described in the
126 * device tree automatically may have an OF translation
127 */
128 struct device_node *of_node;
129 int of_gpio_n_cells;
130 int (*of_xlate)(struct gpio_chip *gc, struct device_node *np,
131 const void *gpio_spec, u32 *flags);
132 #endif
133 };
134
135 extern const char *gpiochip_is_requested(struct gpio_chip *chip,
136 unsigned offset);
137 extern int __must_check gpiochip_reserve(int start, int ngpio);
138
139 /* add/remove chips */
140 extern int gpiochip_add(struct gpio_chip *chip);
141 extern int __must_check gpiochip_remove(struct gpio_chip *chip);
142 extern struct gpio_chip *gpiochip_find(void *data,
143 int (*match)(struct gpio_chip *chip,
144 void *data));
145
146
147 /* Always use the library code for GPIO management calls,
148 * or when sleeping may be involved.
149 */
150 extern int gpio_request(unsigned gpio, const char *label);
151 extern void gpio_free(unsigned gpio);
152
153 extern int gpio_direction_input(unsigned gpio);
154 extern int gpio_direction_output(unsigned gpio, int value);
155
156 extern int gpio_set_debounce(unsigned gpio, unsigned debounce);
157
158 extern int gpio_get_value_cansleep(unsigned gpio);
159 extern void gpio_set_value_cansleep(unsigned gpio, int value);
160
161
162 /* A platform's <asm/gpio.h> code may want to inline the I/O calls when
163 * the GPIO is constant and refers to some always-present controller,
164 * giving direct access to chip registers and tight bitbanging loops.
165 */
166 extern int __gpio_get_value(unsigned gpio);
167 extern void __gpio_set_value(unsigned gpio, int value);
168
169 extern int __gpio_cansleep(unsigned gpio);
170
171 extern int __gpio_to_irq(unsigned gpio);
172
173 #define GPIOF_DIR_OUT (0 << 0)
174 #define GPIOF_DIR_IN (1 << 0)
175
176 #define GPIOF_INIT_LOW (0 << 1)
177 #define GPIOF_INIT_HIGH (1 << 1)
178
179 #define GPIOF_IN (GPIOF_DIR_IN)
180 #define GPIOF_OUT_INIT_LOW (GPIOF_DIR_OUT | GPIOF_INIT_LOW)
181 #define GPIOF_OUT_INIT_HIGH (GPIOF_DIR_OUT | GPIOF_INIT_HIGH)
182
183 /**
184 * struct gpio - a structure describing a GPIO with configuration
185 * @gpio: the GPIO number
186 * @flags: GPIO configuration as specified by GPIOF_*
187 * @label: a literal description string of this GPIO
188 */
189 struct gpio {
190 unsigned gpio;
191 unsigned long flags;
192 const char *label;
193 };
194
195 extern int gpio_request_one(unsigned gpio, unsigned long flags, const char *label);
196 extern int gpio_request_array(struct gpio *array, size_t num);
197 extern void gpio_free_array(struct gpio *array, size_t num);
198
199 #ifdef CONFIG_GPIO_SYSFS
200
201 /*
202 * A sysfs interface can be exported by individual drivers if they want,
203 * but more typically is configured entirely from userspace.
204 */
205 extern int gpio_export(unsigned gpio, bool direction_may_change);
206 extern int gpio_export_link(struct device *dev, const char *name,
207 unsigned gpio);
208 extern int gpio_sysfs_set_active_low(unsigned gpio, int value);
209 extern void gpio_unexport(unsigned gpio);
210
211 #endif /* CONFIG_GPIO_SYSFS */
212
213 #else /* !CONFIG_GPIOLIB */
214
gpio_is_valid(int number)215 static inline int gpio_is_valid(int number)
216 {
217 /* only non-negative numbers are valid */
218 return number >= 0;
219 }
220
221 /* platforms that don't directly support access to GPIOs through I2C, SPI,
222 * or other blocking infrastructure can use these wrappers.
223 */
224
gpio_cansleep(unsigned gpio)225 static inline int gpio_cansleep(unsigned gpio)
226 {
227 return 0;
228 }
229
gpio_get_value_cansleep(unsigned gpio)230 static inline int gpio_get_value_cansleep(unsigned gpio)
231 {
232 might_sleep();
233 return gpio_get_value(gpio);
234 }
235
gpio_set_value_cansleep(unsigned gpio,int value)236 static inline void gpio_set_value_cansleep(unsigned gpio, int value)
237 {
238 might_sleep();
239 gpio_set_value(gpio, value);
240 }
241
242 #endif /* !CONFIG_GPIOLIB */
243
244 #ifndef CONFIG_GPIO_SYSFS
245
246 struct device;
247
248 /* sysfs support is only available with gpiolib, where it's optional */
249
gpio_export(unsigned gpio,bool direction_may_change)250 static inline int gpio_export(unsigned gpio, bool direction_may_change)
251 {
252 return -ENOSYS;
253 }
254
gpio_export_link(struct device * dev,const char * name,unsigned gpio)255 static inline int gpio_export_link(struct device *dev, const char *name,
256 unsigned gpio)
257 {
258 return -ENOSYS;
259 }
260
gpio_sysfs_set_active_low(unsigned gpio,int value)261 static inline int gpio_sysfs_set_active_low(unsigned gpio, int value)
262 {
263 return -ENOSYS;
264 }
265
gpio_unexport(unsigned gpio)266 static inline void gpio_unexport(unsigned gpio)
267 {
268 }
269 #endif /* CONFIG_GPIO_SYSFS */
270
271 #endif /* _ASM_GENERIC_GPIO_H */
272