include/asm-generic/gpio.h

   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 #include <linux/pinctrl/pinctrl.h>
   9
  10 #ifdef CONFIG_GPIOLIB
  11
  12 #include <linux/compiler.h>
  13
  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).
  17  *
  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.
  21  *
  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.
  25  */
  26
  27 #ifndef ARCH_NR_GPIOS
  28 #define ARCH_NR_GPIOS           256
  29 #endif
  30
  31 /*
  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.
  35  *
  36  * Invalid GPIO numbers are useful for indicating no-such-GPIO in
  37  * platform data and other tables.
  38  */
  39
  40 static inline bool gpio_is_valid(int number)
  41 {
  42         return number >= 0 && number < ARCH_NR_GPIOS;
  43 }
  44
  45 struct device;
  46 struct gpio;
  47 struct seq_file;
  48 struct module;
  49 struct device_node;
  50 struct gpio_desc;
  51
  52 /**
  53  * struct gpio_chip - abstract a GPIO controller
  54  * @label: for diagnostics
  55  * @dev: optional device providing the GPIOs
  56  * @owner: helps prevent removal of modules exporting active GPIOs
  57  * @list: links gpio_chips together for traversal
  58  * @request: optional hook for chip-specific activation, such as
  59  *      enabling module power and clock; may sleep
  60  * @free: optional hook for chip-specific deactivation, such as
  61  *      disabling module power and clock; may sleep
  62  * @get_direction: returns direction for signal "offset", 0=out, 1=in,
  63  *      (same as GPIOF_DIR_XXX), or negative error
  64  * @direction_input: configures signal "offset" as input, or returns error
  65  * @get: returns value for signal "offset"; for output signals this
  66  *      returns either the value actually sensed, or zero
  67  * @direction_output: configures signal "offset" as output, or returns error
  68  * @set_debounce: optional hook for setting debounce time for specified gpio in
  69  *      interrupt triggered gpio chips
  70  * @set: assigns output value for signal "offset"
  71  * @to_irq: optional hook supporting non-static gpio_to_irq() mappings;
  72  *      implementation may not sleep
  73  * @dbg_show: optional routine to show contents in debugfs; default code
  74  *      will be used when this is omitted, but custom code can show extra
  75  *      state (such as pullup/pulldown configuration).
  76  * @base: identifies the first GPIO number handled by this chip; or, if
  77  *      negative during registration, requests dynamic ID allocation.
  78  * @ngpio: the number of GPIOs handled by this controller; the last GPIO
  79  *      handled is (base + ngpio - 1).
  80  * @desc: array of ngpio descriptors. Private.
  81  * @can_sleep: flag must be set iff get()/set() methods sleep, as they
  82  *      must while accessing GPIO expander chips over I2C or SPI
  83  * @names: if set, must be an array of strings to use as alternative
  84  *      names for the GPIOs in this chip. Any entry in the array
  85  *      may be NULL if there is no alias for the GPIO, however the
  86  *      array must be @ngpio entries long.  A name can include a single printk
  87  *      format specifier for an unsigned int.  It is substituted by the actual
  88  *      number of the gpio.
  89  *
  90  * A gpio_chip can help platforms abstract various sources of GPIOs so
  91  * they can all be accessed through a common programing interface.
  92  * Example sources would be SOC controllers, FPGAs, multifunction
  93  * chips, dedicated GPIO expanders, and so on.
  94  *
  95  * Each chip controls a number of signals, identified in method calls
  96  * by "offset" values in the range 0..(@ngpio - 1).  When those signals
  97  * are referenced through calls like gpio_get_value(gpio), the offset
  98  * is calculated by subtracting @base from the gpio number.
  99  */
 100 struct gpio_chip {
 101         const char              *label;
 102         struct device           *dev;
 103         struct module           *owner;
 104         struct list_head        list;
 105
 106         int                     (*request)(struct gpio_chip *chip,
 107                                                 unsigned offset);
 108         void                    (*free)(struct gpio_chip *chip,
 109                                                 unsigned offset);
 110         int                     (*get_direction)(struct gpio_chip *chip,
 111                                                 unsigned offset);
 112         int                     (*direction_input)(struct gpio_chip *chip,
 113                                                 unsigned offset);
 114         int                     (*get)(struct gpio_chip *chip,
 115                                                 unsigned offset);
 116         int                     (*direction_output)(struct gpio_chip *chip,
 117                                                 unsigned offset, int value);
 118         int                     (*set_debounce)(struct gpio_chip *chip,
 119                                                 unsigned offset, unsigned debounce);
 120
 121         void                    (*set)(struct gpio_chip *chip,
 122                                                 unsigned offset, int value);
 123
 124         int                     (*to_irq)(struct gpio_chip *chip,
 125                                                 unsigned offset);
 126
 127         void                    (*dbg_show)(struct seq_file *s,
 128                                                 struct gpio_chip *chip);
 129         int                     base;
 130         u16                     ngpio;
 131         struct gpio_desc        *desc;
 132         const char              *const *names;
 133         unsigned                can_sleep:1;
 134         unsigned                exported:1;
 135
 136 #if defined(CONFIG_OF_GPIO)
 137         /*
 138          * If CONFIG_OF is enabled, then all GPIO controllers described in the
 139          * device tree automatically may have an OF translation
 140          */
 141         struct device_node *of_node;
 142         int of_gpio_n_cells;
 143         int (*of_xlate)(struct gpio_chip *gc,
 144                         const struct of_phandle_args *gpiospec, u32 *flags);
 145 #endif
 146 #ifdef CONFIG_PINCTRL
 147         /*
 148          * If CONFIG_PINCTRL is enabled, then gpio controllers can optionally
 149          * describe the actual pin range which they serve in an SoC. This
 150          * information would be used by pinctrl subsystem to configure
 151          * corresponding pins for gpio usage.
 152          */
 153         struct list_head pin_ranges;
 154 #endif
 155 };
 156
 157 extern const char *gpiochip_is_requested(struct gpio_chip *chip,
 158                         unsigned offset);
 159 extern struct gpio_chip *gpio_to_chip(unsigned gpio);
 160
 161 /* add/remove chips */
 162 extern int gpiochip_add(struct gpio_chip *chip);
 163 extern int __must_check gpiochip_remove(struct gpio_chip *chip);
 164 extern struct gpio_chip *gpiochip_find(void *data,
 165                                         int (*match)(struct gpio_chip *chip,
 166                                                      void *data));
 167
 168
 169 /* Always use the library code for GPIO management calls,
 170  * or when sleeping may be involved.
 171  */
 172 extern int gpio_request(unsigned gpio, const char *label);
 173 extern void gpio_free(unsigned gpio);
 174
 175 extern int gpio_direction_input(unsigned gpio);
 176 extern int gpio_direction_output(unsigned gpio, int value);
 177
 178 extern int gpio_set_debounce(unsigned gpio, unsigned debounce);
 179
 180 extern int gpio_get_value_cansleep(unsigned gpio);
 181 extern void gpio_set_value_cansleep(unsigned gpio, int value);
 182
 183
 184 /* A platform's <asm/gpio.h> code may want to inline the I/O calls when
 185  * the GPIO is constant and refers to some always-present controller,
 186  * giving direct access to chip registers and tight bitbanging loops.
 187  */
 188 extern int __gpio_get_value(unsigned gpio);
 189 extern void __gpio_set_value(unsigned gpio, int value);
 190
 191 extern int __gpio_cansleep(unsigned gpio);
 192
 193 extern int __gpio_to_irq(unsigned gpio);
 194
 195 extern int gpio_request_one(unsigned gpio, unsigned long flags, const char *label);
 196 extern int gpio_request_array(const struct gpio *array, size_t num);
 197 extern void gpio_free_array(const 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 #ifdef CONFIG_PINCTRL
 214
 215 /**
 216  * struct gpio_pin_range - pin range controlled by a gpio chip
 217  * @head: list for maintaining set of pin ranges, used internally
 218  * @pctldev: pinctrl device which handles corresponding pins
 219  * @range: actual range of pins controlled by a gpio controller
 220  */
 221
 222 struct gpio_pin_range {
 223         struct list_head node;
 224         struct pinctrl_dev *pctldev;
 225         struct pinctrl_gpio_range range;
 226 };
 227
 228 int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
 229                            unsigned int gpio_offset, unsigned int pin_offset,
 230                            unsigned int npins);
 231 void gpiochip_remove_pin_ranges(struct gpio_chip *chip);
 232
 233 #else
 234
 235 static inline int
 236 gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
 237                        unsigned int gpio_offset, unsigned int pin_offset,
 238                        unsigned int npins)
 239 {
 240         return 0;
 241 }
 242
 243 static inline void
 244 gpiochip_remove_pin_ranges(struct gpio_chip *chip)
 245 {
 246 }
 247
 248 #endif /* CONFIG_PINCTRL */
 249
 250 #else   /* !CONFIG_GPIOLIB */
 251
 252 static inline bool gpio_is_valid(int number)
 253 {
 254         /* only non-negative numbers are valid */
 255         return number >= 0;
 256 }
 257
 258 /* platforms that don't directly support access to GPIOs through I2C, SPI,
 259  * or other blocking infrastructure can use these wrappers.
 260  */
 261
 262 static inline int gpio_cansleep(unsigned gpio)
 263 {
 264         return 0;
 265 }
 266
 267 static inline int gpio_get_value_cansleep(unsigned gpio)
 268 {
 269         might_sleep();
 270         return __gpio_get_value(gpio);
 271 }
 272
 273 static inline void gpio_set_value_cansleep(unsigned gpio, int value)
 274 {
 275         might_sleep();
 276         __gpio_set_value(gpio, value);
 277 }
 278
 279 #endif /* !CONFIG_GPIOLIB */
 280
 281 #ifndef CONFIG_GPIO_SYSFS
 282
 283 struct device;
 284
 285 /* sysfs support is only available with gpiolib, where it's optional */
 286
 287 static inline int gpio_export(unsigned gpio, bool direction_may_change)
 288 {
 289         return -ENOSYS;
 290 }
 291
 292 static inline int gpio_export_link(struct device *dev, const char *name,
 293                                 unsigned gpio)
 294 {
 295         return -ENOSYS;
 296 }
 297
 298 static inline int gpio_sysfs_set_active_low(unsigned gpio, int value)
 299 {
 300         return -ENOSYS;
 301 }
 302
 303 static inline void gpio_unexport(unsigned gpio)
 304 {
 305 }
 306 #endif  /* CONFIG_GPIO_SYSFS */
 307
 308 #endif /* _ASM_GENERIC_GPIO_H */