xref: /openbmc/linux/include/linux/gpio/driver.h (revision 64ff2c8e)

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_GPIO_DRIVER_H
#define __LINUX_GPIO_DRIVER_H

#include <linux/device.h>
#include <linux/types.h>
#include <linux/irq.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/irqdomain.h>
#include <linux/lockdep.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/pinctrl/pinconf-generic.h>

struct gpio_desc;
struct of_phandle_args;
struct device_node;
struct seq_file;
struct gpio_device;
struct module;

#ifdef CONFIG_GPIOLIB

#ifdef CONFIG_GPIOLIB_IRQCHIP
/**
 * struct gpio_irq_chip - GPIO interrupt controller
 */
struct gpio_irq_chip {
	/**
	 * @chip:
	 *
	 * GPIO IRQ chip implementation, provided by GPIO driver.
	 */
	struct irq_chip *chip;

	/**
	 * @domain:
	 *
	 * Interrupt translation domain; responsible for mapping between GPIO
	 * hwirq number and Linux IRQ number.
	 */
	struct irq_domain *domain;

	/**
	 * @domain_ops:
	 *
	 * Table of interrupt domain operations for this IRQ chip.
	 */
	const struct irq_domain_ops *domain_ops;

	/**
	 * @handler:
	 *
	 * The IRQ handler to use (often a predefined IRQ core function) for
	 * GPIO IRQs, provided by GPIO driver.
	 */
	irq_flow_handler_t handler;

	/**
	 * @default_type:
	 *
	 * Default IRQ triggering type applied during GPIO driver
	 * initialization, provided by GPIO driver.
	 */
	unsigned int default_type;

	/**
	 * @lock_key:
	 *
	 * Per GPIO IRQ chip lockdep class.
	 */
	struct lock_class_key *lock_key;

	/**
	 * @parent_handler:
	 *
	 * The interrupt handler for the GPIO chip's parent interrupts, may be
	 * NULL if the parent interrupts are nested rather than cascaded.
	 */
	irq_flow_handler_t parent_handler;

	/**
	 * @parent_handler_data:
	 *
	 * Data associated, and passed to, the handler for the parent
	 * interrupt.
	 */
	void *parent_handler_data;

	/**
	 * @num_parents:
	 *
	 * The number of interrupt parents of a GPIO chip.
	 */
	unsigned int num_parents;

	/**
	 * @parents:
	 *
	 * A list of interrupt parents of a GPIO chip. This is owned by the
	 * driver, so the core will only reference this list, not modify it.
	 */
	unsigned int *parents;

	/**
	 * @map:
	 *
	 * A list of interrupt parents for each line of a GPIO chip.
	 */
	unsigned int *map;

	/**
	 * @threaded:
	 *
	 * True if set the interrupt handling uses nested threads.
	 */
	bool threaded;

	/**
	 * @need_valid_mask:
	 *
	 * If set core allocates @valid_mask with all bits set to one.
	 */
	bool need_valid_mask;

	/**
	 * @valid_mask:
	 *
	 * If not %NULL holds bitmask of GPIOs which are valid to be included
	 * in IRQ domain of the chip.
	 */
	unsigned long *valid_mask;

	/**
	 * @first:
	 *
	 * Required for static IRQ allocation. If set, irq_domain_add_simple()
	 * will allocate and map all IRQs during initialization.
	 */
	unsigned int first;
};

static inline struct gpio_irq_chip *to_gpio_irq_chip(struct irq_chip *chip)
{
	return container_of(chip, struct gpio_irq_chip, chip);
}
#endif

/**
 * struct gpio_chip - abstract a GPIO controller
 * @label: a functional name for the GPIO device, such as a part
 *	number or the name of the SoC IP-block implementing it.
 * @gpiodev: the internal state holder, opaque struct
 * @parent: optional parent device providing the GPIOs
 * @owner: helps prevent removal of modules exporting active GPIOs
 * @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", 0=low, 1=high, or negative error
 * @get_multiple: reads values for multiple signals defined by "mask" and
 *	stores them in "bits", returns 0 on success or negative error
 * @set: assigns output value for signal "offset"
 * @set_multiple: assigns output values for multiple signals defined by "mask"
 * @set_config: optional hook for all kinds of settings. Uses the same
 *	packed config format as generic pinconf.
 * @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.
 *	DEPRECATION: providing anything non-negative and nailing the base
 *	offset of GPIO chips is deprecated. Please pass -1 as base to
 *	let gpiolib select the chip base in all possible cases. We want to
 *	get rid of the static GPIO number space in the long run.
 * @ngpio: the number of GPIOs handled by this controller; the last GPIO
 *	handled is (base + ngpio - 1).
 * @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.
 * @can_sleep: flag must be set iff get()/set() methods sleep, as they
 *	must while accessing GPIO expander chips over I2C or SPI. This
 *	implies that if the chip supports IRQs, these IRQs need to be threaded
 *	as the chip access may sleep when e.g. reading out the IRQ status
 *	registers.
 * @read_reg: reader function for generic GPIO
 * @write_reg: writer function for generic GPIO
 * @be_bits: if the generic GPIO has big endian bit order (bit 31 is representing
 *	line 0, bit 30 is line 1 ... bit 0 is line 31) this is set to true by the
 *	generic GPIO core. It is for internal housekeeping only.
 * @reg_dat: data (in) register for generic GPIO
 * @reg_set: output set register (out=high) for generic GPIO
 * @reg_clr: output clear register (out=low) for generic GPIO
 * @reg_dir: direction setting register for generic GPIO
 * @bgpio_bits: number of register bits used for a generic GPIO i.e.
 *	<register width> * 8
 * @bgpio_lock: used to lock chip->bgpio_data. Also, this is needed to keep
 *	shadowed and real data registers writes together.
 * @bgpio_data:	shadowed data register for generic GPIO to clear/set bits
 *	safely.
 * @bgpio_dir: shadowed direction register for generic GPIO to clear/set
 *	direction safely.
 *
 * 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 gpio_device	*gpiodev;
	struct device		*parent;
	struct module		*owner;

	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);
	int			(*get_multiple)(struct gpio_chip *chip,
						unsigned long *mask,
						unsigned long *bits);
	void			(*set)(struct gpio_chip *chip,
						unsigned offset, int value);
	void			(*set_multiple)(struct gpio_chip *chip,
						unsigned long *mask,
						unsigned long *bits);
	int			(*set_config)(struct gpio_chip *chip,
					      unsigned offset,
					      unsigned long config);
	int			(*to_irq)(struct gpio_chip *chip,
						unsigned offset);

	void			(*dbg_show)(struct seq_file *s,
						struct gpio_chip *chip);
	int			base;
	u16			ngpio;
	const char		*const *names;
	bool			can_sleep;

#if IS_ENABLED(CONFIG_GPIO_GENERIC)
	unsigned long (*read_reg)(void __iomem *reg);
	void (*write_reg)(void __iomem *reg, unsigned long data);
	bool be_bits;
	void __iomem *reg_dat;
	void __iomem *reg_set;
	void __iomem *reg_clr;
	void __iomem *reg_dir;
	int bgpio_bits;
	spinlock_t bgpio_lock;
	unsigned long bgpio_data;
	unsigned long bgpio_dir;
#endif

#ifdef CONFIG_GPIOLIB_IRQCHIP
	/*
	 * With CONFIG_GPIOLIB_IRQCHIP we get an irqchip inside the gpiolib
	 * to handle IRQs for most practical cases.
	 */

	/**
	 * @irq:
	 *
	 * Integrates interrupt chip functionality with the GPIO chip. Can be
	 * used to handle IRQs for most practical cases.
	 */
	struct gpio_irq_chip irq;
#endif

#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
	 */

	/**
	 * @of_node:
	 *
	 * Pointer to a device tree node representing this GPIO controller.
	 */
	struct device_node *of_node;

	/**
	 * @of_gpio_n_cells:
	 *
	 * Number of cells used to form the GPIO specifier.
	 */
	unsigned int of_gpio_n_cells;

	/**
	 * @of_xlate:
	 *
	 * Callback to translate a device tree GPIO specifier into a chip-
	 * relative GPIO number and flags.
	 */
	int (*of_xlate)(struct gpio_chip *gc,
			const struct of_phandle_args *gpiospec, u32 *flags);
#endif
};

extern const char *gpiochip_is_requested(struct gpio_chip *chip,
			unsigned offset);

/* add/remove chips */
extern int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
				      struct lock_class_key *lock_key);

/**
 * gpiochip_add_data() - register a gpio_chip
 * @chip: the chip to register, with chip->base initialized
 * @data: driver-private data associated with this chip
 *
 * Context: potentially before irqs will work
 *
 * When gpiochip_add_data() is called very early during boot, so that GPIOs
 * can be freely used, the chip->parent device must be registered before
 * the gpio framework's arch_initcall().  Otherwise sysfs initialization
 * for GPIOs will fail rudely.
 *
 * gpiochip_add_data() must only be called after gpiolib initialization,
 * ie after core_initcall().
 *
 * If chip->base is negative, this requests dynamic assignment of
 * a range of valid GPIOs.
 *
 * Returns:
 * A negative errno if the chip can't be registered, such as because the
 * chip->base is invalid or already associated with a different chip.
 * Otherwise it returns zero as a success code.
 */
#ifdef CONFIG_LOCKDEP
#define gpiochip_add_data(chip, data) ({		\
		static struct lock_class_key key;	\
		gpiochip_add_data_with_key(chip, data, &key);	\
	})
#else
#define gpiochip_add_data(chip, data) gpiochip_add_data_with_key(chip, data, NULL)
#endif

static inline int gpiochip_add(struct gpio_chip *chip)
{
	return gpiochip_add_data(chip, NULL);
}
extern void gpiochip_remove(struct gpio_chip *chip);
extern int devm_gpiochip_add_data(struct device *dev, struct gpio_chip *chip,
				  void *data);
extern void devm_gpiochip_remove(struct device *dev, 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 gpiochip_lock_as_irq(struct gpio_chip *chip, unsigned int offset);
void gpiochip_unlock_as_irq(struct gpio_chip *chip, unsigned int offset);
bool gpiochip_line_is_irq(struct gpio_chip *chip, unsigned int offset);

/* Line status inquiry for drivers */
bool gpiochip_line_is_open_drain(struct gpio_chip *chip, unsigned int offset);
bool gpiochip_line_is_open_source(struct gpio_chip *chip, unsigned int offset);

/* Sleep persistence inquiry for drivers */
bool gpiochip_line_is_persistent(struct gpio_chip *chip, unsigned int offset);

/* get driver data */
void *gpiochip_get_data(struct gpio_chip *chip);

struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc);

struct bgpio_pdata {
	const char *label;
	int base;
	int ngpio;
};

#if IS_ENABLED(CONFIG_GPIO_GENERIC)

int bgpio_init(struct gpio_chip *gc, struct device *dev,
	       unsigned long sz, void __iomem *dat, void __iomem *set,
	       void __iomem *clr, void __iomem *dirout, void __iomem *dirin,
	       unsigned long flags);

#define BGPIOF_BIG_ENDIAN		BIT(0)
#define BGPIOF_UNREADABLE_REG_SET	BIT(1) /* reg_set is unreadable */
#define BGPIOF_UNREADABLE_REG_DIR	BIT(2) /* reg_dir is unreadable */
#define BGPIOF_BIG_ENDIAN_BYTE_ORDER	BIT(3)
#define BGPIOF_READ_OUTPUT_REG_SET	BIT(4) /* reg_set stores output value */
#define BGPIOF_NO_OUTPUT		BIT(5) /* only input */

#endif

#ifdef CONFIG_GPIOLIB_IRQCHIP

int gpiochip_irq_map(struct irq_domain *d, unsigned int irq,
		     irq_hw_number_t hwirq);
void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq);

void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip,
		struct irq_chip *irqchip,
		unsigned int parent_irq,
		irq_flow_handler_t parent_handler);

void gpiochip_set_nested_irqchip(struct gpio_chip *gpiochip,
		struct irq_chip *irqchip,
		unsigned int parent_irq);

int gpiochip_irqchip_add_key(struct gpio_chip *gpiochip,
			     struct irq_chip *irqchip,
			     unsigned int first_irq,
			     irq_flow_handler_t handler,
			     unsigned int type,
			     bool threaded,
			     struct lock_class_key *lock_key);

bool gpiochip_irqchip_irq_valid(const struct gpio_chip *gpiochip,
				unsigned int offset);

#ifdef CONFIG_LOCKDEP

/*
 * Lockdep requires that each irqchip instance be created with a
 * unique key so as to avoid unnecessary warnings. This upfront
 * boilerplate static inlines provides such a key for each
 * unique instance.
 */
static inline int gpiochip_irqchip_add(struct gpio_chip *gpiochip,
				       struct irq_chip *irqchip,
				       unsigned int first_irq,
				       irq_flow_handler_t handler,
				       unsigned int type)
{
	static struct lock_class_key key;

	return gpiochip_irqchip_add_key(gpiochip, irqchip, first_irq,
					handler, type, false, &key);
}

static inline int gpiochip_irqchip_add_nested(struct gpio_chip *gpiochip,
			  struct irq_chip *irqchip,
			  unsigned int first_irq,
			  irq_flow_handler_t handler,
			  unsigned int type)
{

	static struct lock_class_key key;

	return gpiochip_irqchip_add_key(gpiochip, irqchip, first_irq,
					handler, type, true, &key);
}
#else
static inline int gpiochip_irqchip_add(struct gpio_chip *gpiochip,
				       struct irq_chip *irqchip,
				       unsigned int first_irq,
				       irq_flow_handler_t handler,
				       unsigned int type)
{
	return gpiochip_irqchip_add_key(gpiochip, irqchip, first_irq,
					handler, type, false, NULL);
}

static inline int gpiochip_irqchip_add_nested(struct gpio_chip *gpiochip,
			  struct irq_chip *irqchip,
			  unsigned int first_irq,
			  irq_flow_handler_t handler,
			  unsigned int type)
{
	return gpiochip_irqchip_add_key(gpiochip, irqchip, first_irq,
					handler, type, true, NULL);
}
#endif /* CONFIG_LOCKDEP */

#endif /* CONFIG_GPIOLIB_IRQCHIP */

int gpiochip_generic_request(struct gpio_chip *chip, unsigned offset);
void gpiochip_generic_free(struct gpio_chip *chip, unsigned offset);
int gpiochip_generic_config(struct gpio_chip *chip, unsigned offset,
			    unsigned long config);

#ifdef CONFIG_PINCTRL

/**
 * struct gpio_pin_range - pin range controlled by a gpio chip
 * @node: list for maintaining set of pin ranges, used internally
 * @pctldev: pinctrl device which handles corresponding pins
 * @range: actual range of pins controlled by a gpio controller
 */
struct gpio_pin_range {
	struct list_head node;
	struct pinctrl_dev *pctldev;
	struct pinctrl_gpio_range range;
};

int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
			   unsigned int gpio_offset, unsigned int pin_offset,
			   unsigned int npins);
int gpiochip_add_pingroup_range(struct gpio_chip *chip,
			struct pinctrl_dev *pctldev,
			unsigned int gpio_offset, const char *pin_group);
void gpiochip_remove_pin_ranges(struct gpio_chip *chip);

#else

static inline int
gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
		       unsigned int gpio_offset, unsigned int pin_offset,
		       unsigned int npins)
{
	return 0;
}
static inline int
gpiochip_add_pingroup_range(struct gpio_chip *chip,
			struct pinctrl_dev *pctldev,
			unsigned int gpio_offset, const char *pin_group)
{
	return 0;
}

static inline void
gpiochip_remove_pin_ranges(struct gpio_chip *chip)
{
}

#endif /* CONFIG_PINCTRL */

struct gpio_desc *gpiochip_request_own_desc(struct gpio_chip *chip, u16 hwnum,
					    const char *label);
void gpiochip_free_own_desc(struct gpio_desc *desc);

#else /* CONFIG_GPIOLIB */

static inline struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
{
	/* GPIO can never have been requested */
	WARN_ON(1);
	return ERR_PTR(-ENODEV);
}

#endif /* CONFIG_GPIOLIB */

#endif