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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Definitions for the Linux I2C OF component prober
*
* Copyright (C) 2024 Google LLC
*/
#ifndef _LINUX_I2C_OF_PROBER_H
#define _LINUX_I2C_OF_PROBER_H
#include <linux/kconfig.h>
#include <linux/types.h>
struct device;
struct device_node;
/**
* struct i2c_of_probe_ops - I2C OF component prober callbacks
*
* A set of callbacks to be used by i2c_of_probe_component().
*
* All callbacks are optional. Callbacks are called only once per run, and are
* used in the order they are defined in this structure.
*
* All callbacks that have return values shall return %0 on success,
* or a negative error number on failure.
*
* The @dev parameter passed to the callbacks is the same as @dev passed to
* i2c_of_probe_component(). It should only be used for dev_printk() calls
* and nothing else, especially not managed device resource (devres) APIs.
*/
struct i2c_of_probe_ops {
/**
* @enable: Retrieve and enable resources so that the components respond to probes.
*
* It is OK for this callback to return -EPROBE_DEFER since the intended use includes
* retrieving resources and enables them. Resources should be reverted to their initial
* state and released before returning if this fails.
*/
int (*enable)(struct device *dev, struct device_node *bus_node, void *data);
/**
* @cleanup_early: Release exclusive resources prior to calling probe() on a
* detected component.
*
* Only called if a matching component is actually found. If none are found,
* resources that would have been released in this callback should be released in
* @free_resourcs_late instead.
*/
void (*cleanup_early)(struct device *dev, void *data);
/**
* @cleanup: Opposite of @enable to balance refcounts and free resources after probing.
*
* Should check if resources were already freed by @cleanup_early.
*/
void (*cleanup)(struct device *dev, void *data);
};
/**
* struct i2c_of_probe_cfg - I2C OF component prober configuration
* @ops: Callbacks for the prober to use.
* @type: A string to match the device node name prefix to probe for.
*/
struct i2c_of_probe_cfg {
const struct i2c_of_probe_ops *ops;
const char *type;
};
#if IS_ENABLED(CONFIG_OF_DYNAMIC)
int i2c_of_probe_component(struct device *dev, const struct i2c_of_probe_cfg *cfg, void *ctx);
/**
* DOC: I2C OF component prober simple helpers
*
* Components such as trackpads are commonly connected to a devices baseboard
* with a 6-pin ribbon cable. That gives at most one voltage supply and one
* GPIO (commonly a "enable" or "reset" line) besides the I2C bus, interrupt
* pin, and common ground. Touchscreens, while integrated into the display
* panel's connection, typically have the same set of connections.
*
* A simple set of helpers are provided here for use with the I2C OF component
* prober. This implementation targets such components, allowing for at most
* one regulator supply.
*
* The following helpers are provided:
* * i2c_of_probe_simple_enable()
* * i2c_of_probe_simple_cleanup_early()
* * i2c_of_probe_simple_cleanup()
*/
/**
* struct i2c_of_probe_simple_opts - Options for simple I2C component prober callbacks
* @res_node_compatible: Compatible string of device node to retrieve resources from.
* @supply_name: Name of regulator supply.
* @gpio_name: Name of GPIO. NULL if no GPIO line is used. Empty string ("") if GPIO
* line is unnamed.
* @post_power_on_delay_ms: Delay after regulators are powered on. Passed to msleep().
* @post_gpio_config_delay_ms: Delay after GPIO is configured. Passed to msleep().
* @gpio_assert_to_enable: %true if GPIO should be asserted, i.e. set to logical high,
* to enable the component.
*
* This describes power sequences common for the class of components supported by the
* simple component prober:
* * @gpio_name is configured to the non-active setting according to @gpio_assert_to_enable.
* * @supply_name regulator supply is enabled.
* * Wait for @post_power_on_delay_ms to pass.
* * @gpio_name is configured to the active setting according to @gpio_assert_to_enable.
* * Wait for @post_gpio_config_delay_ms to pass.
*/
struct i2c_of_probe_simple_opts {
const char *res_node_compatible;
const char *supply_name;
const char *gpio_name;
unsigned int post_power_on_delay_ms;
unsigned int post_gpio_config_delay_ms;
bool gpio_assert_to_enable;
};
struct gpio_desc;
struct regulator;
struct i2c_of_probe_simple_ctx {
/* public: provided by user before helpers are used. */
const struct i2c_of_probe_simple_opts *opts;
/* private: internal fields for helpers. */
struct regulator *supply;
struct gpio_desc *gpiod;
};
int i2c_of_probe_simple_enable(struct device *dev, struct device_node *bus_node, void *data);
void i2c_of_probe_simple_cleanup_early(struct device *dev, void *data);
void i2c_of_probe_simple_cleanup(struct device *dev, void *data);
extern struct i2c_of_probe_ops i2c_of_probe_simple_ops;
#endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
#endif /* _LINUX_I2C_OF_PROBER_H */
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