1 #ifndef _ASM_GENERIC_GPIO_H
2 #define _ASM_GENERIC_GPIO_H
4 #include <linux/kernel.h>
5 #include <linux/types.h>
6 #include <linux/errno.h>
8 #include <linux/pinctrl/pinctrl.h>
12 #include <linux/compiler.h>
14 /* Platforms may implement their GPIO interface with library code,
15 * at a small performance cost for non-inlined operations and some
16 * extra memory (for code and for per-GPIO table entries).
18 * While the GPIO programming interface defines valid GPIO numbers
19 * to be in the range 0..MAX_INT, this library restricts them to the
20 * smaller range 0..ARCH_NR_GPIOS-1.
22 * ARCH_NR_GPIOS is somewhat arbitrary; it usually reflects the sum of
23 * builtin/SoC GPIOs plus a number of GPIOs on expanders; the latter is
24 * actually an estimate of a board-specific value.
28 #define ARCH_NR_GPIOS 256
32 * "valid" GPIO numbers are nonnegative and may be passed to
33 * setup routines like gpio_request(). only some valid numbers
34 * can successfully be requested and used.
36 * Invalid GPIO numbers are useful for indicating no-such-GPIO in
37 * platform data and other tables.
40 static inline bool gpio_is_valid(int number)
42 return number >= 0 && number < ARCH_NR_GPIOS;
54 * struct gpio_pin_range - pin range controlled by a gpio chip
55 * @head: list for maintaining set of pin ranges, used internally
56 * @pctldev: pinctrl device which handles corresponding pins
57 * @range: actual range of pins controlled by a gpio controller
60 struct gpio_pin_range {
61 struct list_head node;
62 struct pinctrl_dev *pctldev;
63 struct pinctrl_gpio_range range;
66 int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
67 unsigned int pin_base, unsigned int npins);
68 void gpiochip_remove_pin_ranges(struct gpio_chip *chip);
73 * struct gpio_chip - abstract a GPIO controller
74 * @label: for diagnostics
75 * @dev: optional device providing the GPIOs
76 * @owner: helps prevent removal of modules exporting active GPIOs
77 * @request: optional hook for chip-specific activation, such as
78 * enabling module power and clock; may sleep
79 * @free: optional hook for chip-specific deactivation, such as
80 * disabling module power and clock; may sleep
81 * @direction_input: configures signal "offset" as input, or returns error
82 * @get: returns value for signal "offset"; for output signals this
83 * returns either the value actually sensed, or zero
84 * @direction_output: configures signal "offset" as output, or returns error
85 * @set_debounce: optional hook for setting debounce time for specified gpio in
86 * interrupt triggered gpio chips
87 * @set: assigns output value for signal "offset"
88 * @to_irq: optional hook supporting non-static gpio_to_irq() mappings;
89 * implementation may not sleep
90 * @dbg_show: optional routine to show contents in debugfs; default code
91 * will be used when this is omitted, but custom code can show extra
92 * state (such as pullup/pulldown configuration).
93 * @base: identifies the first GPIO number handled by this chip; or, if
94 * negative during registration, requests dynamic ID allocation.
95 * @ngpio: the number of GPIOs handled by this controller; the last GPIO
96 * handled is (base + ngpio - 1).
97 * @can_sleep: flag must be set iff get()/set() methods sleep, as they
98 * must while accessing GPIO expander chips over I2C or SPI
99 * @names: if set, must be an array of strings to use as alternative
100 * names for the GPIOs in this chip. Any entry in the array
101 * may be NULL if there is no alias for the GPIO, however the
102 * array must be @ngpio entries long. A name can include a single printk
103 * format specifier for an unsigned int. It is substituted by the actual
104 * number of the gpio.
106 * A gpio_chip can help platforms abstract various sources of GPIOs so
107 * they can all be accessed through a common programing interface.
108 * Example sources would be SOC controllers, FPGAs, multifunction
109 * chips, dedicated GPIO expanders, and so on.
111 * Each chip controls a number of signals, identified in method calls
112 * by "offset" values in the range 0..(@ngpio - 1). When those signals
113 * are referenced through calls like gpio_get_value(gpio), the offset
114 * is calculated by subtracting @base from the gpio number.
119 struct module *owner;
121 int (*request)(struct gpio_chip *chip,
123 void (*free)(struct gpio_chip *chip,
126 int (*direction_input)(struct gpio_chip *chip,
128 int (*get)(struct gpio_chip *chip,
130 int (*direction_output)(struct gpio_chip *chip,
131 unsigned offset, int value);
132 int (*set_debounce)(struct gpio_chip *chip,
133 unsigned offset, unsigned debounce);
135 void (*set)(struct gpio_chip *chip,
136 unsigned offset, int value);
138 int (*to_irq)(struct gpio_chip *chip,
141 void (*dbg_show)(struct seq_file *s,
142 struct gpio_chip *chip);
145 const char *const *names;
146 unsigned can_sleep:1;
149 #if defined(CONFIG_OF_GPIO)
151 * If CONFIG_OF is enabled, then all GPIO controllers described in the
152 * device tree automatically may have an OF translation
154 struct device_node *of_node;
156 int (*of_xlate)(struct gpio_chip *gc,
157 const struct of_phandle_args *gpiospec, u32 *flags);
159 #ifdef CONFIG_PINCTRL
161 * If CONFIG_PINCTRL is enabled, then gpio controllers can optionally
162 * describe the actual pin range which they serve in an SoC. This
163 * information would be used by pinctrl subsystem to configure
164 * corresponding pins for gpio usage.
166 struct list_head pin_ranges;
170 extern const char *gpiochip_is_requested(struct gpio_chip *chip,
172 extern struct gpio_chip *gpio_to_chip(unsigned gpio);
173 extern int __must_check gpiochip_reserve(int start, int ngpio);
175 /* add/remove chips */
176 extern int gpiochip_add(struct gpio_chip *chip);
177 extern int __must_check gpiochip_remove(struct gpio_chip *chip);
178 extern struct gpio_chip *gpiochip_find(void *data,
179 int (*match)(struct gpio_chip *chip,
183 /* Always use the library code for GPIO management calls,
184 * or when sleeping may be involved.
186 extern int gpio_request(unsigned gpio, const char *label);
187 extern void gpio_free(unsigned gpio);
189 extern int gpio_direction_input(unsigned gpio);
190 extern int gpio_direction_output(unsigned gpio, int value);
192 extern int gpio_set_debounce(unsigned gpio, unsigned debounce);
194 extern int gpio_get_value_cansleep(unsigned gpio);
195 extern void gpio_set_value_cansleep(unsigned gpio, int value);
198 /* A platform's <asm/gpio.h> code may want to inline the I/O calls when
199 * the GPIO is constant and refers to some always-present controller,
200 * giving direct access to chip registers and tight bitbanging loops.
202 extern int __gpio_get_value(unsigned gpio);
203 extern void __gpio_set_value(unsigned gpio, int value);
205 extern int __gpio_cansleep(unsigned gpio);
207 extern int __gpio_to_irq(unsigned gpio);
209 extern int gpio_request_one(unsigned gpio, unsigned long flags, const char *label);
210 extern int gpio_request_array(const struct gpio *array, size_t num);
211 extern void gpio_free_array(const struct gpio *array, size_t num);
213 /* bindings for managed devices that want to request gpios */
214 int devm_gpio_request(struct device *dev, unsigned gpio, const char *label);
215 int devm_gpio_request_one(struct device *dev, unsigned gpio,
216 unsigned long flags, const char *label);
217 void devm_gpio_free(struct device *dev, unsigned int gpio);
219 #ifdef CONFIG_GPIO_SYSFS
222 * A sysfs interface can be exported by individual drivers if they want,
223 * but more typically is configured entirely from userspace.
225 extern int gpio_export(unsigned gpio, bool direction_may_change);
226 extern int gpio_export_link(struct device *dev, const char *name,
228 extern int gpio_sysfs_set_active_low(unsigned gpio, int value);
229 extern void gpio_unexport(unsigned gpio);
231 #endif /* CONFIG_GPIO_SYSFS */
233 #else /* !CONFIG_GPIOLIB */
235 static inline bool gpio_is_valid(int number)
237 /* only non-negative numbers are valid */
241 /* platforms that don't directly support access to GPIOs through I2C, SPI,
242 * or other blocking infrastructure can use these wrappers.
245 static inline int gpio_cansleep(unsigned gpio)
250 static inline int gpio_get_value_cansleep(unsigned gpio)
253 return __gpio_get_value(gpio);
256 static inline void gpio_set_value_cansleep(unsigned gpio, int value)
259 __gpio_set_value(gpio, value);
262 #endif /* !CONFIG_GPIOLIB */
264 #ifndef CONFIG_GPIO_SYSFS
268 /* sysfs support is only available with gpiolib, where it's optional */
270 static inline int gpio_export(unsigned gpio, bool direction_may_change)
275 static inline int gpio_export_link(struct device *dev, const char *name,
281 static inline int gpio_sysfs_set_active_low(unsigned gpio, int value)
286 static inline void gpio_unexport(unsigned gpio)
289 #endif /* CONFIG_GPIO_SYSFS */
291 #endif /* _ASM_GENERIC_GPIO_H */