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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 | // SPDX-License-Identifier: GPL-2.0-or-later /* * Linux I2C core slave support code * * Copyright (C) 2014 by Wolfram Sang <wsa@sang-engineering.com> */ #include <dt-bindings/i2c/i2c.h> #include <linux/acpi.h> #include <linux/device.h> #include <linux/err.h> #include <linux/i2c.h> #include <linux/of.h> #include "i2c-core.h" #define CREATE_TRACE_POINTS #include <trace/events/i2c_slave.h> int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb) { int ret; if (WARN(IS_ERR_OR_NULL(client) || !slave_cb, "insufficient data\n")) return -EINVAL; if (!(client->flags & I2C_CLIENT_SLAVE)) dev_warn(&client->dev, "%s: client slave flag not set. You might see address collisions\n", __func__); if (!(client->flags & I2C_CLIENT_TEN)) { /* Enforce stricter address checking */ ret = i2c_check_7bit_addr_validity_strict(client->addr); if (ret) { dev_err(&client->dev, "%s: invalid address\n", __func__); return ret; } } if (!client->adapter->algo->reg_slave) { dev_err(&client->dev, "%s: not supported by adapter\n", __func__); return -EOPNOTSUPP; } client->slave_cb = slave_cb; i2c_lock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER); ret = client->adapter->algo->reg_slave(client); i2c_unlock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER); if (ret) { client->slave_cb = NULL; dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret); } return ret; } EXPORT_SYMBOL_GPL(i2c_slave_register); int i2c_slave_unregister(struct i2c_client *client) { int ret; if (IS_ERR_OR_NULL(client)) return -EINVAL; if (!client->adapter->algo->unreg_slave) { dev_err(&client->dev, "%s: not supported by adapter\n", __func__); return -EOPNOTSUPP; } i2c_lock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER); ret = client->adapter->algo->unreg_slave(client); i2c_unlock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER); if (ret == 0) client->slave_cb = NULL; else dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret); return ret; } EXPORT_SYMBOL_GPL(i2c_slave_unregister); int i2c_slave_event(struct i2c_client *client, enum i2c_slave_event event, u8 *val) { int ret = client->slave_cb(client, event, val); if (trace_i2c_slave_enabled()) trace_i2c_slave(client, event, val, ret); return ret; } EXPORT_SYMBOL_GPL(i2c_slave_event); /** * i2c_detect_slave_mode - detect operation mode * @dev: The device owning the bus * * This checks the device nodes for an I2C slave by checking the address * used in the reg property. If the address match the I2C_OWN_SLAVE_ADDRESS * flag this means the device is configured to act as a I2C slave and it will * be listening at that address. * * Returns true if an I2C own slave address is detected, otherwise returns * false. */ bool i2c_detect_slave_mode(struct device *dev) { if (IS_BUILTIN(CONFIG_OF) && dev->of_node) { struct device_node *child; u32 reg; for_each_child_of_node(dev->of_node, child) { of_property_read_u32(child, "reg", ®); if (reg & I2C_OWN_SLAVE_ADDRESS) { of_node_put(child); return true; } } } else if (IS_BUILTIN(CONFIG_ACPI) && ACPI_HANDLE(dev)) { dev_dbg(dev, "ACPI slave is not supported yet\n"); } return false; } EXPORT_SYMBOL_GPL(i2c_detect_slave_mode); |