aboutsummaryrefslogtreecommitdiffstats
path: root/include/linux/gpio
diff options
context:
space:
mode:
authorAlexandre Courbot <acourbot@nvidia.com>2013-10-17 13:21:36 -0400
committerLinus Walleij <linus.walleij@linaro.org>2013-10-19 17:24:45 -0400
commit79a9becda8940deb2274b5aa4577c86d52ee7ecb (patch)
tree2e10b344abcf76446ff97855d280fe9b7fb34ef0 /include/linux/gpio
parentb41fb43911b4cb864812adec88d028cc6219f23e (diff)
gpiolib: export descriptor-based GPIO interface
This patch exports the gpiod_* family of API functions, a safer alternative to the legacy GPIO interface. Differences between the gpiod and legacy gpio APIs are: - gpio works with integers, whereas gpiod operates on opaque handlers which cannot be forged or used before proper acquisition - gpiod get/set functions are aware of the active low state of a GPIO - gpio consumers should now include <linux/gpio/consumer.h> to access the new interface, whereas chips drivers will use <linux/gpio/driver.h> The legacy gpio API is now built as inline functions on top of gpiod. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'include/linux/gpio')
-rw-r--r--include/linux/gpio/consumer.h238
-rw-r--r--include/linux/gpio/driver.h127
2 files changed, 365 insertions, 0 deletions
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
new file mode 100644
index 000000000000..2088eb50421c
--- /dev/null
+++ b/include/linux/gpio/consumer.h
@@ -0,0 +1,238 @@
1#ifndef __LINUX_GPIO_CONSUMER_H
2#define __LINUX_GPIO_CONSUMER_H
3
4#include <linux/err.h>
5#include <linux/kernel.h>
6
7#ifdef CONFIG_GPIOLIB
8
9struct device;
10struct gpio_chip;
11
12/**
13 * Opaque descriptor for a GPIO. These are obtained using gpiod_get() and are
14 * preferable to the old integer-based handles.
15 *
16 * Contrary to integers, a pointer to a gpio_desc is guaranteed to be valid
17 * until the GPIO is released.
18 */
19struct gpio_desc;
20
21int gpiod_get_direction(const struct gpio_desc *desc);
22int gpiod_direction_input(struct gpio_desc *desc);
23int gpiod_direction_output(struct gpio_desc *desc, int value);
24
25/* Value get/set from non-sleeping context */
26int gpiod_get_value(const struct gpio_desc *desc);
27void gpiod_set_value(struct gpio_desc *desc, int value);
28int gpiod_get_raw_value(const struct gpio_desc *desc);
29void gpiod_set_raw_value(struct gpio_desc *desc, int value);
30
31/* Value get/set from sleeping context */
32int gpiod_get_value_cansleep(const struct gpio_desc *desc);
33void gpiod_set_value_cansleep(struct gpio_desc *desc, int value);
34int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc);
35void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value);
36
37int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce);
38
39int gpiod_is_active_low(const struct gpio_desc *desc);
40int gpiod_cansleep(const struct gpio_desc *desc);
41
42int gpiod_to_irq(const struct gpio_desc *desc);
43
44/* Convert between the old gpio_ and new gpiod_ interfaces */
45struct gpio_desc *gpio_to_desc(unsigned gpio);
46int desc_to_gpio(const struct gpio_desc *desc);
47struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc);
48
49#else /* CONFIG_GPIOLIB */
50
51static inline struct gpio_desc *__must_check gpiod_get(struct device *dev,
52 const char *con_id)
53{
54 return ERR_PTR(-ENOSYS);
55}
56static inline struct gpio_desc *__must_check gpiod_get_index(struct device *dev,
57 const char *con_id,
58 unsigned int idx)
59{
60 return ERR_PTR(-ENOSYS);
61}
62static inline void gpiod_put(struct gpio_desc *desc)
63{
64 might_sleep();
65
66 /* GPIO can never have been requested */
67 WARN_ON(1);
68}
69
70static inline struct gpio_desc *__must_check devm_gpiod_get(struct device *dev,
71 const char *con_id)
72{
73 return ERR_PTR(-ENOSYS);
74}
75static inline
76struct gpio_desc *__must_check devm_gpiod_get_index(struct device *dev,
77 const char *con_id,
78 unsigned int idx)
79{
80 return ERR_PTR(-ENOSYS);
81}
82static inline void devm_gpiod_put(struct device *dev, struct gpio_desc *desc)
83{
84 might_sleep();
85
86 /* GPIO can never have been requested */
87 WARN_ON(1);
88}
89
90
91static inline int gpiod_get_direction(const struct gpio_desc *desc)
92{
93 /* GPIO can never have been requested */
94 WARN_ON(1);
95 return -ENOSYS;
96}
97static inline int gpiod_direction_input(struct gpio_desc *desc)
98{
99 /* GPIO can never have been requested */
100 WARN_ON(1);
101 return -ENOSYS;
102}
103static inline int gpiod_direction_output(struct gpio_desc *desc, int value)
104{
105 /* GPIO can never have been requested */
106 WARN_ON(1);
107 return -ENOSYS;
108}
109
110
111static inline int gpiod_get_value(const struct gpio_desc *desc)
112{
113 /* GPIO can never have been requested */
114 WARN_ON(1);
115 return 0;
116}
117static inline void gpiod_set_value(struct gpio_desc *desc, int value)
118{
119 /* GPIO can never have been requested */
120 WARN_ON(1);
121}
122static inline int gpiod_get_raw_value(const struct gpio_desc *desc)
123{
124 /* GPIO can never have been requested */
125 WARN_ON(1);
126 return 0;
127}
128static inline void gpiod_set_raw_value(struct gpio_desc *desc, int value)
129{
130 /* GPIO can never have been requested */
131 WARN_ON(1);
132}
133
134static inline int gpiod_get_value_cansleep(const struct gpio_desc *desc)
135{
136 /* GPIO can never have been requested */
137 WARN_ON(1);
138 return 0;
139}
140static inline void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
141{
142 /* GPIO can never have been requested */
143 WARN_ON(1);
144}
145static inline int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
146{
147 /* GPIO can never have been requested */
148 WARN_ON(1);
149 return 0;
150}
151static inline void gpiod_set_raw_value_cansleep(struct gpio_desc *desc,
152 int value)
153{
154 /* GPIO can never have been requested */
155 WARN_ON(1);
156}
157
158static inline int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
159{
160 /* GPIO can never have been requested */
161 WARN_ON(1);
162 return -ENOSYS;
163}
164
165static inline int gpiod_is_active_low(const struct gpio_desc *desc)
166{
167 /* GPIO can never have been requested */
168 WARN_ON(1);
169 return 0;
170}
171static inline int gpiod_cansleep(const struct gpio_desc *desc)
172{
173 /* GPIO can never have been requested */
174 WARN_ON(1);
175 return 0;
176}
177
178static inline int gpiod_to_irq(const struct gpio_desc *desc)
179{
180 /* GPIO can never have been requested */
181 WARN_ON(1);
182 return -EINVAL;
183}
184
185static inline struct gpio_desc *gpio_to_desc(unsigned gpio)
186{
187 return ERR_PTR(-EINVAL);
188}
189static inline int desc_to_gpio(const struct gpio_desc *desc)
190{
191 /* GPIO can never have been requested */
192 WARN_ON(1);
193 return -EINVAL;
194}
195static inline struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
196{
197 /* GPIO can never have been requested */
198 WARN_ON(1);
199 return ERR_PTR(-ENODEV);
200}
201
202
203#endif /* CONFIG_GPIOLIB */
204
205#if IS_ENABLED(CONFIG_GPIOLIB) && IS_ENABLED(CONFIG_GPIO_SYSFS)
206
207int gpiod_export(struct gpio_desc *desc, bool direction_may_change);
208int gpiod_export_link(struct device *dev, const char *name,
209 struct gpio_desc *desc);
210int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value);
211void gpiod_unexport(struct gpio_desc *desc);
212
213#else /* CONFIG_GPIOLIB && CONFIG_GPIO_SYSFS */
214
215static inline int gpiod_export(struct gpio_desc *desc,
216 bool direction_may_change)
217{
218 return -ENOSYS;
219}
220
221static inline int gpiod_export_link(struct device *dev, const char *name,
222 struct gpio_desc *desc)
223{
224 return -ENOSYS;
225}
226
227static inline int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
228{
229 return -ENOSYS;
230}
231
232static inline void gpiod_unexport(struct gpio_desc *desc)
233{
234}
235
236#endif /* CONFIG_GPIOLIB && CONFIG_GPIO_SYSFS */
237
238#endif
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
new file mode 100644
index 000000000000..5dc172c72f0f
--- /dev/null
+++ b/include/linux/gpio/driver.h
@@ -0,0 +1,127 @@
1#ifndef __LINUX_GPIO_DRIVER_H
2#define __LINUX_GPIO_DRIVER_H
3
4#include <linux/types.h>
5
6struct device;
7struct gpio_desc;
8
9/**
10 * struct gpio_chip - abstract a GPIO controller
11 * @label: for diagnostics
12 * @dev: optional device providing the GPIOs
13 * @owner: helps prevent removal of modules exporting active GPIOs
14 * @list: links gpio_chips together for traversal
15 * @request: optional hook for chip-specific activation, such as
16 * enabling module power and clock; may sleep
17 * @free: optional hook for chip-specific deactivation, such as
18 * disabling module power and clock; may sleep
19 * @get_direction: returns direction for signal "offset", 0=out, 1=in,
20 * (same as GPIOF_DIR_XXX), or negative error
21 * @direction_input: configures signal "offset" as input, or returns error
22 * @direction_output: configures signal "offset" as output, or returns error
23 * @get: returns value for signal "offset"; for output signals this
24 * returns either the value actually sensed, or zero
25 * @set: assigns output value for signal "offset"
26 * @set_debounce: optional hook for setting debounce time for specified gpio in
27 * interrupt triggered gpio chips
28 * @to_irq: optional hook supporting non-static gpio_to_irq() mappings;
29 * implementation may not sleep
30 * @dbg_show: optional routine to show contents in debugfs; default code
31 * will be used when this is omitted, but custom code can show extra
32 * state (such as pullup/pulldown configuration).
33 * @base: identifies the first GPIO number handled by this chip; or, if
34 * negative during registration, requests dynamic ID allocation.
35 * @ngpio: the number of GPIOs handled by this controller; the last GPIO
36 * handled is (base + ngpio - 1).
37 * @desc: array of ngpio descriptors. Private.
38 * @can_sleep: flag must be set iff get()/set() methods sleep, as they
39 * must while accessing GPIO expander chips over I2C or SPI
40 * @names: if set, must be an array of strings to use as alternative
41 * names for the GPIOs in this chip. Any entry in the array
42 * may be NULL if there is no alias for the GPIO, however the
43 * array must be @ngpio entries long. A name can include a single printk
44 * format specifier for an unsigned int. It is substituted by the actual
45 * number of the gpio.
46 *
47 * A gpio_chip can help platforms abstract various sources of GPIOs so
48 * they can all be accessed through a common programing interface.
49 * Example sources would be SOC controllers, FPGAs, multifunction
50 * chips, dedicated GPIO expanders, and so on.
51 *
52 * Each chip controls a number of signals, identified in method calls
53 * by "offset" values in the range 0..(@ngpio - 1). When those signals
54 * are referenced through calls like gpio_get_value(gpio), the offset
55 * is calculated by subtracting @base from the gpio number.
56 */
57struct gpio_chip {
58 const char *label;
59 struct device *dev;
60 struct module *owner;
61 struct list_head list;
62
63 int (*request)(struct gpio_chip *chip,
64 unsigned offset);
65 void (*free)(struct gpio_chip *chip,
66 unsigned offset);
67 int (*get_direction)(struct gpio_chip *chip,
68 unsigned offset);
69 int (*direction_input)(struct gpio_chip *chip,
70 unsigned offset);
71 int (*direction_output)(struct gpio_chip *chip,
72 unsigned offset, int value);
73 int (*get)(struct gpio_chip *chip,
74 unsigned offset);
75 void (*set)(struct gpio_chip *chip,
76 unsigned offset, int value);
77 int (*set_debounce)(struct gpio_chip *chip,
78 unsigned offset,
79 unsigned debounce);
80
81 int (*to_irq)(struct gpio_chip *chip,
82 unsigned offset);
83
84 void (*dbg_show)(struct seq_file *s,
85 struct gpio_chip *chip);
86 int base;
87 u16 ngpio;
88 struct gpio_desc *desc;
89 const char *const *names;
90 unsigned can_sleep:1;
91 unsigned exported:1;
92
93#if defined(CONFIG_OF_GPIO)
94 /*
95 * If CONFIG_OF is enabled, then all GPIO controllers described in the
96 * device tree automatically may have an OF translation
97 */
98 struct device_node *of_node;
99 int of_gpio_n_cells;
100 int (*of_xlate)(struct gpio_chip *gc,
101 const struct of_phandle_args *gpiospec, u32 *flags);
102#endif
103#ifdef CONFIG_PINCTRL
104 /*
105 * If CONFIG_PINCTRL is enabled, then gpio controllers can optionally
106 * describe the actual pin range which they serve in an SoC. This
107 * information would be used by pinctrl subsystem to configure
108 * corresponding pins for gpio usage.
109 */
110 struct list_head pin_ranges;
111#endif
112};
113
114extern const char *gpiochip_is_requested(struct gpio_chip *chip,
115 unsigned offset);
116
117/* add/remove chips */
118extern int gpiochip_add(struct gpio_chip *chip);
119extern int __must_check gpiochip_remove(struct gpio_chip *chip);
120extern struct gpio_chip *gpiochip_find(void *data,
121 int (*match)(struct gpio_chip *chip, void *data));
122
123/* lock/unlock as IRQ */
124int gpiod_lock_as_irq(struct gpio_desc *desc);
125void gpiod_unlock_as_irq(struct gpio_desc *desc);
126
127#endif
generated by cgit v1.2.2 (git 2.25.0) at 2026-01-24 14:03:05 -0500