1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Linux I2C core slave support code |
4 | * |
5 | * Copyright (C) 2014 by Wolfram Sang <wsa@sang-engineering.com> |
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 | #define CREATE_TRACE_POINTS |
18 | #include <trace/events/i2c_slave.h> |
19 | |
20 | int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb) |
21 | { |
22 | int ret; |
23 | |
24 | if (WARN(IS_ERR_OR_NULL(client) || !slave_cb, "insufficient data\n" )) |
25 | return -EINVAL; |
26 | |
27 | if (!(client->flags & I2C_CLIENT_SLAVE)) |
28 | dev_warn(&client->dev, "%s: client slave flag not set. You might see address collisions\n" , |
29 | __func__); |
30 | |
31 | if (!(client->flags & I2C_CLIENT_TEN)) { |
32 | /* Enforce stricter address checking */ |
33 | ret = i2c_check_7bit_addr_validity_strict(addr: client->addr); |
34 | if (ret) { |
35 | dev_err(&client->dev, "%s: invalid address\n" , __func__); |
36 | return ret; |
37 | } |
38 | } |
39 | |
40 | if (!client->adapter->algo->reg_slave) { |
41 | dev_err(&client->dev, "%s: not supported by adapter\n" , __func__); |
42 | return -EOPNOTSUPP; |
43 | } |
44 | |
45 | client->slave_cb = slave_cb; |
46 | |
47 | i2c_lock_bus(adapter: client->adapter, I2C_LOCK_ROOT_ADAPTER); |
48 | ret = client->adapter->algo->reg_slave(client); |
49 | i2c_unlock_bus(adapter: client->adapter, I2C_LOCK_ROOT_ADAPTER); |
50 | |
51 | if (ret) { |
52 | client->slave_cb = NULL; |
53 | dev_err(&client->dev, "%s: adapter returned error %d\n" , __func__, ret); |
54 | } |
55 | |
56 | return ret; |
57 | } |
58 | EXPORT_SYMBOL_GPL(i2c_slave_register); |
59 | |
60 | int i2c_slave_unregister(struct i2c_client *client) |
61 | { |
62 | int ret; |
63 | |
64 | if (IS_ERR_OR_NULL(ptr: client)) |
65 | return -EINVAL; |
66 | |
67 | if (!client->adapter->algo->unreg_slave) { |
68 | dev_err(&client->dev, "%s: not supported by adapter\n" , __func__); |
69 | return -EOPNOTSUPP; |
70 | } |
71 | |
72 | i2c_lock_bus(adapter: client->adapter, I2C_LOCK_ROOT_ADAPTER); |
73 | ret = client->adapter->algo->unreg_slave(client); |
74 | i2c_unlock_bus(adapter: client->adapter, I2C_LOCK_ROOT_ADAPTER); |
75 | |
76 | if (ret == 0) |
77 | client->slave_cb = NULL; |
78 | else |
79 | dev_err(&client->dev, "%s: adapter returned error %d\n" , __func__, ret); |
80 | |
81 | return ret; |
82 | } |
83 | EXPORT_SYMBOL_GPL(i2c_slave_unregister); |
84 | |
85 | int i2c_slave_event(struct i2c_client *client, |
86 | enum i2c_slave_event event, u8 *val) |
87 | { |
88 | int ret = client->slave_cb(client, event, val); |
89 | |
90 | if (trace_i2c_slave_enabled()) |
91 | trace_i2c_slave(client, event, val, cb_ret: ret); |
92 | |
93 | return ret; |
94 | } |
95 | EXPORT_SYMBOL_GPL(i2c_slave_event); |
96 | |
97 | /** |
98 | * i2c_detect_slave_mode - detect operation mode |
99 | * @dev: The device owning the bus |
100 | * |
101 | * This checks the device nodes for an I2C slave by checking the address |
102 | * used in the reg property. If the address match the I2C_OWN_SLAVE_ADDRESS |
103 | * flag this means the device is configured to act as a I2C slave and it will |
104 | * be listening at that address. |
105 | * |
106 | * Returns true if an I2C own slave address is detected, otherwise returns |
107 | * false. |
108 | */ |
109 | bool i2c_detect_slave_mode(struct device *dev) |
110 | { |
111 | if (IS_BUILTIN(CONFIG_OF) && dev->of_node) { |
112 | struct device_node *child; |
113 | u32 reg; |
114 | |
115 | for_each_child_of_node(dev->of_node, child) { |
116 | of_property_read_u32(np: child, propname: "reg" , out_value: ®); |
117 | if (reg & I2C_OWN_SLAVE_ADDRESS) { |
118 | of_node_put(node: child); |
119 | return true; |
120 | } |
121 | } |
122 | } else if (IS_BUILTIN(CONFIG_ACPI) && ACPI_HANDLE(dev)) { |
123 | dev_dbg(dev, "ACPI slave is not supported yet\n" ); |
124 | } |
125 | return false; |
126 | } |
127 | EXPORT_SYMBOL_GPL(i2c_detect_slave_mode); |
128 | |