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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
17int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb)
18{
19 int ret;
20
21 if (WARN(IS_ERR_OR_NULL(client) || !slave_cb, "insufficient data\n"))
22 return -EINVAL;
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
44 i2c_lock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER);
45 ret = client->adapter->algo->reg_slave(client);
46 i2c_unlock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER);
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}
55EXPORT_SYMBOL_GPL(i2c_slave_register);
56
57int i2c_slave_unregister(struct i2c_client *client)
58{
59 int ret;
60
61 if (IS_ERR_OR_NULL(client))
62 return -EINVAL;
63
64 if (!client->adapter->algo->unreg_slave) {
65 dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
66 return -EOPNOTSUPP;
67 }
68
69 i2c_lock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER);
70 ret = client->adapter->algo->unreg_slave(client);
71 i2c_unlock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER);
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}
80EXPORT_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 */
94bool 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}
112EXPORT_SYMBOL_GPL(i2c_detect_slave_mode);
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
20int 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(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(client->adapter, I2C_LOCK_ROOT_ADAPTER);
48 ret = client->adapter->algo->reg_slave(client);
49 i2c_unlock_bus(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}
58EXPORT_SYMBOL_GPL(i2c_slave_register);
59
60int i2c_slave_unregister(struct i2c_client *client)
61{
62 int ret;
63
64 if (IS_ERR_OR_NULL(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(client->adapter, I2C_LOCK_ROOT_ADAPTER);
73 ret = client->adapter->algo->unreg_slave(client);
74 i2c_unlock_bus(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}
83EXPORT_SYMBOL_GPL(i2c_slave_unregister);
84
85int 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, ret);
92
93 return ret;
94}
95EXPORT_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 */
109bool 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(child, "reg", ®);
117 if (reg & I2C_OWN_SLAVE_ADDRESS) {
118 of_node_put(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}
127EXPORT_SYMBOL_GPL(i2c_detect_slave_mode);