projects / linux.git / blame
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| a076a860 LC |
1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| 2 | /* | |
| 3 | * I2C Address Translator | |
| 4 | * | |
| 5 | * Copyright (c) 2019,2022 Luca Ceresoli <[email protected]> | |
| 6 | * Copyright (c) 2022,2023 Tomi Valkeinen <[email protected]> | |
| 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 */ |