include/linux/gpio/driver.h

   1 #ifndef __LINUX_GPIO_DRIVER_H
   2 #define __LINUX_GPIO_DRIVER_H
   3
   4 #include <linux/types.h>
   5
   6 struct device;
   7 struct gpio_desc;
   8 struct seq_file;
   9
  10 /**
  11  * struct gpio_chip - abstract a GPIO controller
  12  * @label: for diagnostics
  13  * @dev: optional device providing the GPIOs
  14  * @owner: helps prevent removal of modules exporting active GPIOs
  15  * @list: links gpio_chips together for traversal
  16  * @request: optional hook for chip-specific activation, such as
  17  *      enabling module power and clock; may sleep
  18  * @free: optional hook for chip-specific deactivation, such as
  19  *      disabling module power and clock; may sleep
  20  * @get_direction: returns direction for signal "offset", 0=out, 1=in,
  21  *      (same as GPIOF_DIR_XXX), or negative error
  22  * @direction_input: configures signal "offset" as input, or returns error
  23  * @direction_output: configures signal "offset" as output, or returns error
  24  * @get: returns value for signal "offset"; for output signals this
  25  *      returns either the value actually sensed, or zero
  26  * @set: assigns output value for signal "offset"
  27  * @set_debounce: optional hook for setting debounce time for specified gpio in
  28  *      interrupt triggered gpio chips
  29  * @to_irq: optional hook supporting non-static gpio_to_irq() mappings;
  30  *      implementation may not sleep
  31  * @dbg_show: optional routine to show contents in debugfs; default code
  32  *      will be used when this is omitted, but custom code can show extra
  33  *      state (such as pullup/pulldown configuration).
  34  * @base: identifies the first GPIO number handled by this chip; or, if
  35  *      negative during registration, requests dynamic ID allocation.
  36  * @ngpio: the number of GPIOs handled by this controller; the last GPIO
  37  *      handled is (base + ngpio - 1).
  38  * @desc: array of ngpio descriptors. Private.
  39  * @names: if set, must be an array of strings to use as alternative
  40  *      names for the GPIOs in this chip. Any entry in the array
  41  *      may be NULL if there is no alias for the GPIO, however the
  42  *      array must be @ngpio entries long.  A name can include a single printk
  43  *      format specifier for an unsigned int.  It is substituted by the actual
  44  *      number of the gpio.
  45  * @can_sleep: flag must be set iff get()/set() methods sleep, as they
  46  *      must while accessing GPIO expander chips over I2C or SPI
  47  * @exported: flags if the gpiochip is exported for use from sysfs. Private.
  48  *
  49  * A gpio_chip can help platforms abstract various sources of GPIOs so
  50  * they can all be accessed through a common programing interface.
  51  * Example sources would be SOC controllers, FPGAs, multifunction
  52  * chips, dedicated GPIO expanders, and so on.
  53  *
  54  * Each chip controls a number of signals, identified in method calls
  55  * by "offset" values in the range 0..(@ngpio - 1).  When those signals
  56  * are referenced through calls like gpio_get_value(gpio), the offset
  57  * is calculated by subtracting @base from the gpio number.
  58  */
  59 struct gpio_chip {
  60         const char              *label;
  61         struct device           *dev;
  62         struct module           *owner;
  63         struct list_head        list;
  64
  65         int                     (*request)(struct gpio_chip *chip,
  66                                                 unsigned offset);
  67         void                    (*free)(struct gpio_chip *chip,
  68                                                 unsigned offset);
  69         int                     (*get_direction)(struct gpio_chip *chip,
  70                                                 unsigned offset);
  71         int                     (*direction_input)(struct gpio_chip *chip,
  72                                                 unsigned offset);
  73         int                     (*direction_output)(struct gpio_chip *chip,
  74                                                 unsigned offset, int value);
  75         int                     (*get)(struct gpio_chip *chip,
  76                                                 unsigned offset);
  77         void                    (*set)(struct gpio_chip *chip,
  78                                                 unsigned offset, int value);
  79         int                     (*set_debounce)(struct gpio_chip *chip,
  80                                                 unsigned offset,
  81                                                 unsigned debounce);
  82
  83         int                     (*to_irq)(struct gpio_chip *chip,
  84                                                 unsigned offset);
  85
  86         void                    (*dbg_show)(struct seq_file *s,
  87                                                 struct gpio_chip *chip);
  88         int                     base;
  89         u16                     ngpio;
  90         struct gpio_desc        *desc;
  91         const char              *const *names;
  92         bool                    can_sleep;
  93         bool                    exported;
  94
  95 #if defined(CONFIG_OF_GPIO)
  96         /*
  97          * If CONFIG_OF is enabled, then all GPIO controllers described in the
  98          * device tree automatically may have an OF translation
  99          */
 100         struct device_node *of_node;
 101         int of_gpio_n_cells;
 102         int (*of_xlate)(struct gpio_chip *gc,
 103                         const struct of_phandle_args *gpiospec, u32 *flags);
 104 #endif
 105 #ifdef CONFIG_PINCTRL
 106         /*
 107          * If CONFIG_PINCTRL is enabled, then gpio controllers can optionally
 108          * describe the actual pin range which they serve in an SoC. This
 109          * information would be used by pinctrl subsystem to configure
 110          * corresponding pins for gpio usage.
 111          */
 112         struct list_head pin_ranges;
 113 #endif
 114 };
 115
 116 extern const char *gpiochip_is_requested(struct gpio_chip *chip,
 117                         unsigned offset);
 118
 119 /* add/remove chips */
 120 extern int gpiochip_add(struct gpio_chip *chip);
 121 extern int __must_check gpiochip_remove(struct gpio_chip *chip);
 122 extern struct gpio_chip *gpiochip_find(void *data,
 123                               int (*match)(struct gpio_chip *chip, void *data));
 124
 125 /* lock/unlock as IRQ */
 126 int gpiod_lock_as_irq(struct gpio_desc *desc);
 127 void gpiod_unlock_as_irq(struct gpio_desc *desc);
 128
 129 /**
 130  * Lookup table for associating GPIOs to specific devices and functions using
 131  * platform data.
 132  */
 133 struct gpiod_lookup {
 134         struct list_head list;
 135         /*
 136          * name of the chip the GPIO belongs to
 137          */
 138         const char *chip_label;
 139         /*
 140          * hardware number (i.e. relative to the chip) of the GPIO
 141          */
 142         u16 chip_hwnum;
 143         /*
 144          * name of device that can claim this GPIO
 145          */
 146         const char *dev_id;
 147         /*
 148          * name of the GPIO from the device's point of view
 149          */
 150         const char *con_id;
 151         /*
 152          * index of the GPIO in case several GPIOs share the same name
 153          */
 154         unsigned int idx;
 155         /*
 156          * mask of GPIOF_* values
 157          */
 158         unsigned long flags;
 159 };
 160
 161 /*
 162  * Simple definition of a single GPIO under a con_id
 163  */
 164 #define GPIO_LOOKUP(_chip_label, _chip_hwnum, _dev_id, _con_id, _flags) \
 165         GPIO_LOOKUP_IDX(_chip_label, _chip_hwnum, _dev_id, _con_id, 0, _flags)
 166
 167 /*
 168  * Use this macro if you need to have several GPIOs under the same con_id.
 169  * Each GPIO needs to use a different index and can be accessed using
 170  * gpiod_get_index()
 171  */
 172 #define GPIO_LOOKUP_IDX(_chip_label, _chip_hwnum, _dev_id, _con_id, _idx, \
 173                         _flags)                                           \
 174 {                                                                         \
 175         .chip_label = _chip_label,                                        \
 176         .chip_hwnum = _chip_hwnum,                                        \
 177         .dev_id = _dev_id,                                                \
 178         .con_id = _con_id,                                                \
 179         .idx = _idx,                                                      \
 180         .flags = _flags,                                                  \
 181 }
 182
 183 void gpiod_add_table(struct gpiod_lookup *table, size_t size);
 184
 185 #endif