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Diffstat (limited to 'include/linux/gpio/driver.h')
| -rw-r--r-- | include/linux/gpio/driver.h | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h new file mode 100644 index 00000000000..656a27efb2c --- /dev/null +++ b/include/linux/gpio/driver.h @@ -0,0 +1,184 @@ +#ifndef __LINUX_GPIO_DRIVER_H +#define __LINUX_GPIO_DRIVER_H + +#include <linux/types.h> + +struct device; +struct gpio_desc; +struct seq_file; + +/** + * struct gpio_chip - abstract a GPIO controller + * @label: for diagnostics + * @dev: optional device providing the GPIOs + * @owner: helps prevent removal of modules exporting active GPIOs + * @list: links gpio_chips together for traversal + * @request: optional hook for chip-specific activation, such as + * enabling module power and clock; may sleep + * @free: optional hook for chip-specific deactivation, such as + * disabling module power and clock; may sleep + * @get_direction: returns direction for signal "offset", 0=out, 1=in, + * (same as GPIOF_DIR_XXX), or negative error + * @direction_input: configures signal "offset" as input, or returns error + * @direction_output: configures signal "offset" as output, or returns error + * @get: returns value for signal "offset"; for output signals this + * returns either the value actually sensed, or zero + * @set: assigns output value for signal "offset" + * @set_debounce: optional hook for setting debounce time for specified gpio in + * interrupt triggered gpio chips + * @to_irq: optional hook supporting non-static gpio_to_irq() mappings; + * implementation may not sleep + * @dbg_show: optional routine to show contents in debugfs; default code + * will be used when this is omitted, but custom code can show extra + * state (such as pullup/pulldown configuration). + * @base: identifies the first GPIO number handled by this chip; or, if + * negative during registration, requests dynamic ID allocation. + * @ngpio: the number of GPIOs handled by this controller; the last GPIO + * handled is (base + ngpio - 1). + * @desc: array of ngpio descriptors. Private. + * @can_sleep: flag must be set iff get()/set() methods sleep, as they + * must while accessing GPIO expander chips over I2C or SPI + * @names: if set, must be an array of strings to use as alternative + * names for the GPIOs in this chip. Any entry in the array + * may be NULL if there is no alias for the GPIO, however the + * array must be @ngpio entries long. A name can include a single printk + * format specifier for an unsigned int. It is substituted by the actual + * number of the gpio. + * + * A gpio_chip can help platforms abstract various sources of GPIOs so + * they can all be accessed through a common programing interface. + * Example sources would be SOC controllers, FPGAs, multifunction + * chips, dedicated GPIO expanders, and so on. + * + * Each chip controls a number of signals, identified in method calls + * by "offset" values in the range 0..(@ngpio - 1). When those signals + * are referenced through calls like gpio_get_value(gpio), the offset + * is calculated by subtracting @base from the gpio number. + */ +struct gpio_chip { + const char *label; + struct device *dev; + struct module *owner; + struct list_head list; + + int (*request)(struct gpio_chip *chip, + unsigned offset); + void (*free)(struct gpio_chip *chip, + unsigned offset); + int (*get_direction)(struct gpio_chip *chip, + unsigned offset); + int (*direction_input)(struct gpio_chip *chip, + unsigned offset); + int (*direction_output)(struct gpio_chip *chip, + unsigned offset, int value); + int (*get)(struct gpio_chip *chip, + unsigned offset); + void (*set)(struct gpio_chip *chip, + unsigned offset, int value); + int (*set_debounce)(struct gpio_chip *chip, + unsigned offset, + unsigned debounce); + + int (*to_irq)(struct gpio_chip *chip, + unsigned offset); + + void (*dbg_show)(struct seq_file *s, + struct gpio_chip *chip); + int base; + u16 ngpio; + struct gpio_desc *desc; + const char *const *names; + unsigned can_sleep:1; + unsigned exported:1; + +#if defined(CONFIG_OF_GPIO) + /* + * If CONFIG_OF is enabled, then all GPIO controllers described in the + * device tree automatically may have an OF translation + */ + struct device_node *of_node; + int of_gpio_n_cells; + int (*of_xlate)(struct gpio_chip *gc, + const struct of_phandle_args *gpiospec, u32 *flags); +#endif +#ifdef CONFIG_PINCTRL + /* + * If CONFIG_PINCTRL is enabled, then gpio controllers can optionally + * describe the actual pin range which they serve in an SoC. This + * information would be used by pinctrl subsystem to configure + * corresponding pins for gpio usage. + */ + struct list_head pin_ranges; +#endif +}; + +extern const char *gpiochip_is_requested(struct gpio_chip *chip, + unsigned offset); + +/* add/remove chips */ +extern int gpiochip_add(struct gpio_chip *chip); +extern int __must_check gpiochip_remove(struct gpio_chip *chip); +extern struct gpio_chip *gpiochip_find(void *data, + int (*match)(struct gpio_chip *chip, void *data)); + +/* lock/unlock as IRQ */ +int gpiod_lock_as_irq(struct gpio_desc *desc); +void gpiod_unlock_as_irq(struct gpio_desc *desc); + +/** + * Lookup table for associating GPIOs to specific devices and functions using + * platform data. + */ +struct gpiod_lookup { + struct list_head list; + /* + * name of the chip the GPIO belongs to + */ + const char *chip_label; + /* + * hardware number (i.e. relative to the chip) of the GPIO + */ + u16 chip_hwnum; + /* + * name of device that can claim this GPIO + */ + const char *dev_id; + /* + * name of the GPIO from the device's point of view + */ + const char *con_id; + /* + * index of the GPIO in case several GPIOs share the same name + */ + unsigned int idx; + /* + * mask of GPIOF_* values + */ + unsigned long flags; +}; + +/* + * Simple definition of a single GPIO under a con_id + */ +#define GPIO_LOOKUP(_chip_label, _chip_hwnum, _dev_id, _con_id, _flags) \ + GPIO_LOOKUP_IDX(_chip_label, _chip_hwnum, _dev_id, _con_id, 0, _flags) + +/* + * Use this macro if you need to have several GPIOs under the same con_id. + * Each GPIO needs to use a different index and can be accessed using + * gpiod_get_index() + */ +#define GPIO_LOOKUP_IDX(_chip_label, _chip_hwnum, _dev_id, _con_id, _idx, \ + _flags) \ +{ \ + .chip_label = _chip_label, \ + .chip_hwnum = _chip_hwnum, \ + .dev_id = _dev_id, \ + .con_id = _con_id, \ + .idx = _idx, \ + .flags = _flags, \ +} + +void gpiod_add_table(struct gpiod_lookup *table, size_t size); + +#endif |