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