/* SPDX-License-Identifier: GPL-2.0 */ /* * I2C Address Translator * * Copyright (c) 2019,2022 Luca Ceresoli <[email protected]> * Copyright (c) 2022,2023 Tomi Valkeinen <[email protected]> * * 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 { … }; /** * 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 */
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