1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | /* |
3 | * I2C Address Translator |
4 | * |
5 | * Copyright (c) 2019,2022 Luca Ceresoli <luca@lucaceresoli.net> |
6 | * Copyright (c) 2022,2023 Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> |
7 | * |
8 | * Based on i2c-mux.h |
9 | */ |
10 | |
11 | #ifndef _LINUX_I2C_ATR_H |
12 | #define _LINUX_I2C_ATR_H |
13 | |
14 | #include <linux/i2c.h> |
15 | #include <linux/types.h> |
16 | |
17 | struct device; |
18 | struct fwnode_handle; |
19 | struct i2c_atr; |
20 | |
21 | /** |
22 | * struct i2c_atr_ops - Callbacks from ATR to the device driver. |
23 | * @attach_client: Notify the driver of a new device connected on a child |
24 | * bus, with the alias assigned to it. The driver must |
25 | * configure the hardware to use the alias. |
26 | * @detach_client: Notify the driver of a device getting disconnected. The |
27 | * driver must configure the hardware to stop using the |
28 | * alias. |
29 | * |
30 | * All these functions return 0 on success, a negative error code otherwise. |
31 | */ |
32 | struct i2c_atr_ops { |
33 | int (*attach_client)(struct i2c_atr *atr, u32 chan_id, |
34 | const struct i2c_client *client, u16 alias); |
35 | void (*detach_client)(struct i2c_atr *atr, u32 chan_id, |
36 | const struct i2c_client *client); |
37 | }; |
38 | |
39 | /** |
40 | * i2c_atr_new() - Allocate and initialize an I2C ATR helper. |
41 | * @parent: The parent (upstream) adapter |
42 | * @dev: The device acting as an ATR |
43 | * @ops: Driver-specific callbacks |
44 | * @max_adapters: Maximum number of child adapters |
45 | * |
46 | * The new ATR helper is connected to the parent adapter but has no child |
47 | * adapters. Call i2c_atr_add_adapter() to add some. |
48 | * |
49 | * Call i2c_atr_delete() to remove. |
50 | * |
51 | * Return: pointer to the new ATR helper object, or ERR_PTR |
52 | */ |
53 | struct i2c_atr *i2c_atr_new(struct i2c_adapter *parent, struct device *dev, |
54 | const struct i2c_atr_ops *ops, int max_adapters); |
55 | |
56 | /** |
57 | * i2c_atr_delete - Delete an I2C ATR helper. |
58 | * @atr: I2C ATR helper to be deleted. |
59 | * |
60 | * Precondition: all the adapters added with i2c_atr_add_adapter() must be |
61 | * removed by calling i2c_atr_del_adapter(). |
62 | */ |
63 | void i2c_atr_delete(struct i2c_atr *atr); |
64 | |
65 | /** |
66 | * i2c_atr_add_adapter - Create a child ("downstream") I2C bus. |
67 | * @atr: The I2C ATR |
68 | * @chan_id: Index of the new adapter (0 .. max_adapters-1). This value is |
69 | * passed to the callbacks in `struct i2c_atr_ops`. |
70 | * @adapter_parent: The device used as the parent of the new i2c adapter, or NULL |
71 | * to use the i2c-atr device as the parent. |
72 | * @bus_handle: The fwnode handle that points to the adapter's i2c |
73 | * peripherals, or NULL. |
74 | * |
75 | * After calling this function a new i2c bus will appear. Adding and removing |
76 | * devices on the downstream bus will result in calls to the |
77 | * &i2c_atr_ops->attach_client and &i2c_atr_ops->detach_client callbacks for the |
78 | * driver to assign an alias to the device. |
79 | * |
80 | * The adapter's fwnode is set to @bus_handle, or if @bus_handle is NULL the |
81 | * function looks for a child node whose 'reg' property matches the chan_id |
82 | * under the i2c-atr device's 'i2c-atr' node. |
83 | * |
84 | * Call i2c_atr_del_adapter() to remove the adapter. |
85 | * |
86 | * Return: 0 on success, a negative error code otherwise. |
87 | */ |
88 | int i2c_atr_add_adapter(struct i2c_atr *atr, u32 chan_id, |
89 | struct device *adapter_parent, |
90 | struct fwnode_handle *bus_handle); |
91 | |
92 | /** |
93 | * i2c_atr_del_adapter - Remove a child ("downstream") I2C bus added by |
94 | * i2c_atr_add_adapter(). If no I2C bus has been added |
95 | * this function is a no-op. |
96 | * @atr: The I2C ATR |
97 | * @chan_id: Index of the adapter to be removed (0 .. max_adapters-1) |
98 | */ |
99 | void i2c_atr_del_adapter(struct i2c_atr *atr, u32 chan_id); |
100 | |
101 | /** |
102 | * i2c_atr_set_driver_data - Set private driver data to the i2c-atr instance. |
103 | * @atr: The I2C ATR |
104 | * @data: Pointer to the data to store |
105 | */ |
106 | void i2c_atr_set_driver_data(struct i2c_atr *atr, void *data); |
107 | |
108 | /** |
109 | * i2c_atr_get_driver_data - Get the stored drive data. |
110 | * @atr: The I2C ATR |
111 | * |
112 | * Return: Pointer to the stored data |
113 | */ |
114 | void *i2c_atr_get_driver_data(struct i2c_atr *atr); |
115 | |
116 | #endif /* _LINUX_I2C_ATR_H */ |
117 | |