include/linux/gpio/driver.h

   1 #ifndef __LINUX_GPIO_DRIVER_H
   2 #define __LINUX_GPIO_DRIVER_H
   3
   4 #include <linux/types.h>
   5 #include <linux/module.h>
   6 #include <linux/irq.h>
   7 #include <linux/irqchip/chained_irq.h>
   8 #include <linux/irqdomain.h>
   9
  10 struct device;
  11 struct gpio_desc;
  12 struct of_phandle_args;
  13 struct device_node;
  14 struct seq_file;
  15
  16 #ifdef CONFIG_GPIOLIB
  17
  18 /**
  19  * struct gpio_chip - abstract a GPIO controller
  20  * @label: for diagnostics
  21  * @dev: optional device providing the GPIOs
  22  * @owner: helps prevent removal of modules exporting active GPIOs
  23  * @list: links gpio_chips together for traversal
  24  * @request: optional hook for chip-specific activation, such as
  25  *      enabling module power and clock; may sleep
  26  * @free: optional hook for chip-specific deactivation, such as
  27  *      disabling module power and clock; may sleep
  28  * @get_direction: returns direction for signal "offset", 0=out, 1=in,
  29  *      (same as GPIOF_DIR_XXX), or negative error
  30  * @direction_input: configures signal "offset" as input, or returns error
  31  * @direction_output: configures signal "offset" as output, or returns error
  32  * @get: returns value for signal "offset"; for output signals this
  33  *      returns either the value actually sensed, or zero
  34  * @set: assigns output value for signal "offset"
  35  * @set_debounce: optional hook for setting debounce time for specified gpio in
  36  *      interrupt triggered gpio chips
  37  * @to_irq: optional hook supporting non-static gpio_to_irq() mappings;
  38  *      implementation may not sleep
  39  * @dbg_show: optional routine to show contents in debugfs; default code
  40  *      will be used when this is omitted, but custom code can show extra
  41  *      state (such as pullup/pulldown configuration).
  42  * @base: identifies the first GPIO number handled by this chip; or, if
  43  *      negative during registration, requests dynamic ID allocation.
  44  * @ngpio: the number of GPIOs handled by this controller; the last GPIO
  45  *      handled is (base + ngpio - 1).
  46  * @desc: array of ngpio descriptors. Private.
  47  * @names: if set, must be an array of strings to use as alternative
  48  *      names for the GPIOs in this chip. Any entry in the array
  49  *      may be NULL if there is no alias for the GPIO, however the
  50  *      array must be @ngpio entries long.  A name can include a single printk
  51  *      format specifier for an unsigned int.  It is substituted by the actual
  52  *      number of the gpio.
  53  * @can_sleep: flag must be set iff get()/set() methods sleep, as they
  54  *      must while accessing GPIO expander chips over I2C or SPI. This
  55  *      implies that if the chip supports IRQs, these IRQs need to be threaded
  56  *      as the chip access may sleep when e.g. reading out the IRQ status
  57  *      registers.
  58  * @exported: flags if the gpiochip is exported for use from sysfs. Private.
  59  *
  60  * A gpio_chip can help platforms abstract various sources of GPIOs so
  61  * they can all be accessed through a common programing interface.
  62  * Example sources would be SOC controllers, FPGAs, multifunction
  63  * chips, dedicated GPIO expanders, and so on.
  64  *
  65  * Each chip controls a number of signals, identified in method calls
  66  * by "offset" values in the range 0..(@ngpio - 1).  When those signals
  67  * are referenced through calls like gpio_get_value(gpio), the offset
  68  * is calculated by subtracting @base from the gpio number.
  69  */
  70 struct gpio_chip {
  71         const char              *label;
  72         struct device           *dev;
  73         struct module           *owner;
  74         struct list_head        list;
  75
  76         int                     (*request)(struct gpio_chip *chip,
  77                                                 unsigned offset);
  78         void                    (*free)(struct gpio_chip *chip,
  79                                                 unsigned offset);
  80         int                     (*get_direction)(struct gpio_chip *chip,
  81                                                 unsigned offset);
  82         int                     (*direction_input)(struct gpio_chip *chip,
  83                                                 unsigned offset);
  84         int                     (*direction_output)(struct gpio_chip *chip,
  85                                                 unsigned offset, int value);
  86         int                     (*get)(struct gpio_chip *chip,
  87                                                 unsigned offset);
  88         void                    (*set)(struct gpio_chip *chip,
  89                                                 unsigned offset, int value);
  90         int                     (*set_debounce)(struct gpio_chip *chip,
  91                                                 unsigned offset,
  92                                                 unsigned debounce);
  93
  94         int                     (*to_irq)(struct gpio_chip *chip,
  95                                                 unsigned offset);
  96
  97         void                    (*dbg_show)(struct seq_file *s,
  98                                                 struct gpio_chip *chip);
  99         int                     base;
 100         u16                     ngpio;
 101         struct gpio_desc        *desc;
 102         const char              *const *names;
 103         bool                    can_sleep;
 104         bool                    exported;
 105
 106 #ifdef CONFIG_GPIOLIB_IRQCHIP
 107         /*
 108          * With CONFIG_GPIO_IRQCHIP we get an irqchip inside the gpiolib
 109          * to handle IRQs for most practical cases.
 110          */
 111         struct irq_chip         *irqchip;
 112         struct irq_domain       *irqdomain;
 113         unsigned int            irq_base;
 114         irq_flow_handler_t      irq_handler;
 115         unsigned int            irq_default_type;
 116 #endif
 117
 118 #if defined(CONFIG_OF_GPIO)
 119         /*
 120          * If CONFIG_OF is enabled, then all GPIO controllers described in the
 121          * device tree automatically may have an OF translation
 122          */
 123         struct device_node *of_node;
 124         int of_gpio_n_cells;
 125         int (*of_xlate)(struct gpio_chip *gc,
 126                         const struct of_phandle_args *gpiospec, u32 *flags);
 127 #endif
 128 #ifdef CONFIG_PINCTRL
 129         /*
 130          * If CONFIG_PINCTRL is enabled, then gpio controllers can optionally
 131          * describe the actual pin range which they serve in an SoC. This
 132          * information would be used by pinctrl subsystem to configure
 133          * corresponding pins for gpio usage.
 134          */
 135         struct list_head pin_ranges;
 136 #endif
 137 };
 138
 139 extern const char *gpiochip_is_requested(struct gpio_chip *chip,
 140                         unsigned offset);
 141
 142 /* add/remove chips */
 143 extern int gpiochip_add(struct gpio_chip *chip);
 144 extern int gpiochip_remove(struct gpio_chip *chip);
 145 extern struct gpio_chip *gpiochip_find(void *data,
 146                               int (*match)(struct gpio_chip *chip, void *data));
 147
 148 /* lock/unlock as IRQ */
 149 int gpio_lock_as_irq(struct gpio_chip *chip, unsigned int offset);
 150 void gpio_unlock_as_irq(struct gpio_chip *chip, unsigned int offset);
 151
 152 struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc);
 153
 154 #ifdef CONFIG_GPIOLIB_IRQCHIP
 155
 156 void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip,
 157                 struct irq_chip *irqchip,
 158                 int parent_irq,
 159                 irq_flow_handler_t parent_handler);
 160
 161 int gpiochip_irqchip_add(struct gpio_chip *gpiochip,
 162                 struct irq_chip *irqchip,
 163                 unsigned int first_irq,
 164                 irq_flow_handler_t handler,
 165                 unsigned int type);
 166
 167 #endif /* CONFIG_GPIO_IRQCHIP */
 168
 169 int gpiochip_request_own_desc(struct gpio_desc *desc, const char *label);
 170 void gpiochip_free_own_desc(struct gpio_desc *desc);
 171
 172 #else /* CONFIG_GPIOLIB */
 173
 174 static inline struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
 175 {
 176         /* GPIO can never have been requested */
 177         WARN_ON(1);
 178         return ERR_PTR(-ENODEV);
 179 }
 180
 181 #endif /* CONFIG_GPIOLIB */
 182
 183 #endif