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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
e4991ecd WS |
2 | /* |
3 | * Linux I2C core slave support code | |
4 | * | |
5 | * Copyright (C) 2014 by Wolfram Sang <wsa@sang-engineering.com> | |
e4991ecd WS |
6 | */ |
7 | ||
8 | #include <dt-bindings/i2c/i2c.h> | |
9 | #include <linux/acpi.h> | |
10 | #include <linux/device.h> | |
11 | #include <linux/err.h> | |
12 | #include <linux/i2c.h> | |
13 | #include <linux/of.h> | |
14 | ||
15 | #include "i2c-core.h" | |
16 | ||
17 | int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb) | |
18 | { | |
19 | int ret; | |
20 | ||
1b1be3bf | 21 | if (WARN(IS_ERR_OR_NULL(client) || !slave_cb, "insufficient data\n")) |
e4991ecd | 22 | return -EINVAL; |
e4991ecd WS |
23 | |
24 | if (!(client->flags & I2C_CLIENT_SLAVE)) | |
25 | dev_warn(&client->dev, "%s: client slave flag not set. You might see address collisions\n", | |
26 | __func__); | |
27 | ||
28 | if (!(client->flags & I2C_CLIENT_TEN)) { | |
29 | /* Enforce stricter address checking */ | |
30 | ret = i2c_check_7bit_addr_validity_strict(client->addr); | |
31 | if (ret) { | |
32 | dev_err(&client->dev, "%s: invalid address\n", __func__); | |
33 | return ret; | |
34 | } | |
35 | } | |
36 | ||
37 | if (!client->adapter->algo->reg_slave) { | |
38 | dev_err(&client->dev, "%s: not supported by adapter\n", __func__); | |
39 | return -EOPNOTSUPP; | |
40 | } | |
41 | ||
42 | client->slave_cb = slave_cb; | |
43 | ||
3f3a89e1 | 44 | i2c_lock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER); |
e4991ecd | 45 | ret = client->adapter->algo->reg_slave(client); |
3f3a89e1 | 46 | i2c_unlock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER); |
e4991ecd WS |
47 | |
48 | if (ret) { | |
49 | client->slave_cb = NULL; | |
50 | dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret); | |
51 | } | |
52 | ||
53 | return ret; | |
54 | } | |
55 | EXPORT_SYMBOL_GPL(i2c_slave_register); | |
56 | ||
57 | int i2c_slave_unregister(struct i2c_client *client) | |
58 | { | |
59 | int ret; | |
60 | ||
8808981b WS |
61 | if (IS_ERR_OR_NULL(client)) |
62 | return -EINVAL; | |
63 | ||
e4991ecd WS |
64 | if (!client->adapter->algo->unreg_slave) { |
65 | dev_err(&client->dev, "%s: not supported by adapter\n", __func__); | |
66 | return -EOPNOTSUPP; | |
67 | } | |
68 | ||
3f3a89e1 | 69 | i2c_lock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER); |
e4991ecd | 70 | ret = client->adapter->algo->unreg_slave(client); |
3f3a89e1 | 71 | i2c_unlock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER); |
e4991ecd WS |
72 | |
73 | if (ret == 0) | |
74 | client->slave_cb = NULL; | |
75 | else | |
76 | dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret); | |
77 | ||
78 | return ret; | |
79 | } | |
80 | EXPORT_SYMBOL_GPL(i2c_slave_unregister); | |
81 | ||
82 | /** | |
83 | * i2c_detect_slave_mode - detect operation mode | |
84 | * @dev: The device owning the bus | |
85 | * | |
86 | * This checks the device nodes for an I2C slave by checking the address | |
87 | * used in the reg property. If the address match the I2C_OWN_SLAVE_ADDRESS | |
88 | * flag this means the device is configured to act as a I2C slave and it will | |
89 | * be listening at that address. | |
90 | * | |
91 | * Returns true if an I2C own slave address is detected, otherwise returns | |
92 | * false. | |
93 | */ | |
94 | bool i2c_detect_slave_mode(struct device *dev) | |
95 | { | |
96 | if (IS_BUILTIN(CONFIG_OF) && dev->of_node) { | |
97 | struct device_node *child; | |
98 | u32 reg; | |
99 | ||
100 | for_each_child_of_node(dev->of_node, child) { | |
101 | of_property_read_u32(child, "reg", ®); | |
102 | if (reg & I2C_OWN_SLAVE_ADDRESS) { | |
103 | of_node_put(child); | |
104 | return true; | |
105 | } | |
106 | } | |
107 | } else if (IS_BUILTIN(CONFIG_ACPI) && ACPI_HANDLE(dev)) { | |
108 | dev_dbg(dev, "ACPI slave is not supported yet\n"); | |
109 | } | |
110 | return false; | |
111 | } | |
112 | EXPORT_SYMBOL_GPL(i2c_detect_slave_mode); |