xref: /kernel/linux/linux-6.6/include/linux/reset-controller.h (revision 62306a36)

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

#include <linux/list.h>

struct reset_controller_dev;

/**
 * struct reset_control_ops - reset controller driver callbacks
 *
 * @reset: for self-deasserting resets, does all necessary
 *         things to reset the device
 * @assert: manually assert the reset line, if supported
 * @deassert: manually deassert the reset line, if supported
 * @status: return the status of the reset line, if supported
 */
struct reset_control_ops {
	int (*reset)(struct reset_controller_dev *rcdev, unsigned long id);
	int (*assert)(struct reset_controller_dev *rcdev, unsigned long id);
	int (*deassert)(struct reset_controller_dev *rcdev, unsigned long id);
	int (*status)(struct reset_controller_dev *rcdev, unsigned long id);
};

struct module;
struct device_node;
struct of_phandle_args;

/**
 * struct reset_control_lookup - represents a single lookup entry
 *
 * @list: internal list of all reset lookup entries
 * @provider: name of the reset controller device controlling this reset line
 * @index: ID of the reset controller in the reset controller device
 * @dev_id: name of the device associated with this reset line
 * @con_id: name of the reset line (can be NULL)
 */
struct reset_control_lookup {
	struct list_head list;
	const char *provider;
	unsigned int index;
	const char *dev_id;
	const char *con_id;
};

#define RESET_LOOKUP(_provider, _index, _dev_id, _con_id)		\
	{								\
		.provider = _provider,					\
		.index = _index,					\
		.dev_id = _dev_id,					\
		.con_id = _con_id,					\
	}

/**
 * struct reset_controller_dev - reset controller entity that might
 *                               provide multiple reset controls
 * @ops: a pointer to device specific struct reset_control_ops
 * @owner: kernel module of the reset controller driver
 * @list: internal list of reset controller devices
 * @reset_control_head: head of internal list of requested reset controls
 * @dev: corresponding driver model device struct
 * @of_node: corresponding device tree node as phandle target
 * @of_reset_n_cells: number of cells in reset line specifiers
 * @of_xlate: translation function to translate from specifier as found in the
 *            device tree to id as given to the reset control ops, defaults
 *            to :c:func:`of_reset_simple_xlate`.
 * @nr_resets: number of reset controls in this reset controller device
 */
struct reset_controller_dev {
	const struct reset_control_ops *ops;
	struct module *owner;
	struct list_head list;
	struct list_head reset_control_head;
	struct device *dev;
	struct device_node *of_node;
	int of_reset_n_cells;
	int (*of_xlate)(struct reset_controller_dev *rcdev,
			const struct of_phandle_args *reset_spec);
	unsigned int nr_resets;
};

#if IS_ENABLED(CONFIG_RESET_CONTROLLER)
int reset_controller_register(struct reset_controller_dev *rcdev);
void reset_controller_unregister(struct reset_controller_dev *rcdev);

struct device;
int devm_reset_controller_register(struct device *dev,
				   struct reset_controller_dev *rcdev);

void reset_controller_add_lookup(struct reset_control_lookup *lookup,
				 unsigned int num_entries);
#else
static inline int reset_controller_register(struct reset_controller_dev *rcdev)
{
	return 0;
}

static inline void reset_controller_unregister(struct reset_controller_dev *rcdev)
{
}

static inline int devm_reset_controller_register(struct device *dev,
						 struct reset_controller_dev *rcdev)
{
	return 0;
}

static inline void reset_controller_add_lookup(struct reset_control_lookup *lookup,
					       unsigned int num_entries)
{
}
#endif

#endif