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/* SPDX-License-Identifier: GPL-2.0 */
/*
* I2C Address Translator
*
* Copyright (c) 2019,2022 Luca Ceresoli <luca@lucaceresoli.net>
* Copyright (c) 2022,2023 Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
*
* Based on i2c-mux.h
*/
#ifndef _LINUX_I2C_ATR_H
#define _LINUX_I2C_ATR_H
#include <linux/i2c.h>
#include <linux/types.h>
struct device;
struct fwnode_handle;
struct i2c_atr;
/**
* struct i2c_atr_ops - Callbacks from ATR to the device driver.
* @attach_client: Notify the driver of a new device connected on a child
* bus, with the alias assigned to it. The driver must
* configure the hardware to use the alias.
* @detach_client: Notify the driver of a device getting disconnected. The
* driver must configure the hardware to stop using the
* alias.
*
* All these functions return 0 on success, a negative error code otherwise.
*/
struct i2c_atr_ops {
int (*attach_client)(struct i2c_atr *atr, u32 chan_id,
const struct i2c_client *client, u16 alias);
void (*detach_client)(struct i2c_atr *atr, u32 chan_id,
const struct i2c_client *client);
};
/**
* i2c_atr_new() - Allocate and initialize an I2C ATR helper.
* @parent: The parent (upstream) adapter
* @dev: The device acting as an ATR
* @ops: Driver-specific callbacks
* @max_adapters: Maximum number of child adapters
*
* The new ATR helper is connected to the parent adapter but has no child
* adapters. Call i2c_atr_add_adapter() to add some.
*
* Call i2c_atr_delete() to remove.
*
* Return: pointer to the new ATR helper object, or ERR_PTR
*/
struct i2c_atr *i2c_atr_new(struct i2c_adapter *parent, struct device *dev,
const struct i2c_atr_ops *ops, int max_adapters);
/**
* i2c_atr_delete - Delete an I2C ATR helper.
* @atr: I2C ATR helper to be deleted.
*
* Precondition: all the adapters added with i2c_atr_add_adapter() must be
* removed by calling i2c_atr_del_adapter().
*/
void i2c_atr_delete(struct i2c_atr *atr);
/**
* i2c_atr_add_adapter - Create a child ("downstream") I2C bus.
* @atr: The I2C ATR
* @chan_id: Index of the new adapter (0 .. max_adapters-1). This value is
* passed to the callbacks in `struct i2c_atr_ops`.
* @adapter_parent: The device used as the parent of the new i2c adapter, or NULL
* to use the i2c-atr device as the parent.
* @bus_handle: The fwnode handle that points to the adapter's i2c
* peripherals, or NULL.
*
* After calling this function a new i2c bus will appear. Adding and removing
* devices on the downstream bus will result in calls to the
* &i2c_atr_ops->attach_client and &i2c_atr_ops->detach_client callbacks for the
* driver to assign an alias to the device.
*
* The adapter's fwnode is set to @bus_handle, or if @bus_handle is NULL the
* function looks for a child node whose 'reg' property matches the chan_id
* under the i2c-atr device's 'i2c-atr' node.
*
* Call i2c_atr_del_adapter() to remove the adapter.
*
* Return: 0 on success, a negative error code otherwise.
*/
int i2c_atr_add_adapter(struct i2c_atr *atr, u32 chan_id,
struct device *adapter_parent,
struct fwnode_handle *bus_handle);
/**
* i2c_atr_del_adapter - Remove a child ("downstream") I2C bus added by
* i2c_atr_add_adapter(). If no I2C bus has been added
* this function is a no-op.
* @atr: The I2C ATR
* @chan_id: Index of the adapter to be removed (0 .. max_adapters-1)
*/
void i2c_atr_del_adapter(struct i2c_atr *atr, u32 chan_id);
/**
* i2c_atr_set_driver_data - Set private driver data to the i2c-atr instance.
* @atr: The I2C ATR
* @data: Pointer to the data to store
*/
void i2c_atr_set_driver_data(struct i2c_atr *atr, void *data);
/**
* i2c_atr_get_driver_data - Get the stored drive data.
* @atr: The I2C ATR
*
* Return: Pointer to the stored data
*/
void *i2c_atr_get_driver_data(struct i2c_atr *atr);
#endif /* _LINUX_I2C_ATR_H */