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Diffstat (limited to 'include/linux/i2c-atr.h')
| -rw-r--r-- | include/linux/i2c-atr.h | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/include/linux/i2c-atr.h b/include/linux/i2c-atr.h new file mode 100644 index 000000000..4d5da161c --- /dev/null +++ b/include/linux/i2c-atr.h @@ -0,0 +1,116 @@ +/* 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 */ |