projects / mirror_ubuntu-bionic-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| e4991ecd WS |
1 | /* |
| 2 | * Linux I2C core slave support code | |
| 3 | * | |
| 4 | * Copyright (C) 2014 by Wolfram Sang <wsa@sang-engineering.com> | |
| 5 | * | |
| 6 | * This program is free software; you can redistribute it and/or modify it | |
| 7 | * under the terms of the GNU General Public License as published by the Free | |
| 8 | * Software Foundation; either version 2 of the License, or (at your option) | |
| 9 | * any later version. | |
| 10 | */ | |
| 11 | ||
| 12 | #include <dt-bindings/i2c/i2c.h> | |
| 13 | #include <linux/acpi.h> | |
| 14 | #include <linux/device.h> | |
| 15 | #include <linux/err.h> | |
| 16 | #include <linux/i2c.h> | |
| 17 | #include <linux/of.h> | |
| 18 | ||
| 19 | #include "i2c-core.h" | |
| 20 | ||
| 21 | int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb) | |
| 22 | { | |
| 23 | int ret; | |
| 24 | ||
| 25 | if (!client || !slave_cb) { | |
| 26 | WARN(1, "insufficient data\n"); | |
| 27 | return -EINVAL; | |
| 28 | } | |
| 29 | ||
| 30 | if (!(client->flags & I2C_CLIENT_SLAVE)) | |
| 31 | dev_warn(&client->dev, "%s: client slave flag not set. You might see address collisions\n", | |
| 32 | __func__); | |
| 33 | ||
| 34 | if (!(client->flags & I2C_CLIENT_TEN)) { | |
| 35 | /* Enforce stricter address checking */ | |
| 36 | ret = i2c_check_7bit_addr_validity_strict(client->addr); | |
| 37 | if (ret) { | |
| 38 | dev_err(&client->dev, "%s: invalid address\n", __func__); | |
| 39 | return ret; | |
| 40 | } | |
| 41 | } | |
| 42 | ||
| 43 | if (!client->adapter->algo->reg_slave) { | |
| 44 | dev_err(&client->dev, "%s: not supported by adapter\n", __func__); | |
| 45 | return -EOPNOTSUPP; | |
| 46 | } | |
| 47 | ||
| 48 | client->slave_cb = slave_cb; | |
| 49 | ||
| 50 | i2c_lock_adapter(client->adapter); | |
| 51 | ret = client->adapter->algo->reg_slave(client); | |
| 52 | i2c_unlock_adapter(client->adapter); | |
| 53 | ||
| 54 | if (ret) { | |
| 55 | client->slave_cb = NULL; | |
| 56 | dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret); | |
| 57 | } | |
| 58 | ||
| 59 | return ret; | |
| 60 | } | |
| 61 | EXPORT_SYMBOL_GPL(i2c_slave_register); | |
| 62 | ||
| 63 | int i2c_slave_unregister(struct i2c_client *client) | |
| 64 | { | |
| 65 | int ret; | |
| 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_adapter(client->adapter); | |
| 73 | ret = client->adapter->algo->unreg_slave(client); | |
| 74 | i2c_unlock_adapter(client->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 | /** | |
| 86 | * i2c_detect_slave_mode - detect operation mode | |
| 87 | * @dev: The device owning the bus | |
| 88 | * | |
| 89 | * This checks the device nodes for an I2C slave by checking the address | |
| 90 | * used in the reg property. If the address match the I2C_OWN_SLAVE_ADDRESS | |
| 91 | * flag this means the device is configured to act as a I2C slave and it will | |
| 92 | * be listening at that address. | |
| 93 | * | |
| 94 | * Returns true if an I2C own slave address is detected, otherwise returns | |
| 95 | * false. | |
| 96 | */ | |
| 97 | bool i2c_detect_slave_mode(struct device *dev) | |
| 98 | { | |
| 99 | if (IS_BUILTIN(CONFIG_OF) && dev->of_node) { | |
| 100 | struct device_node *child; | |
| 101 | u32 reg; | |
| 102 | ||
| 103 | for_each_child_of_node(dev->of_node, child) { | |
| 104 | of_property_read_u32(child, "reg", ®); | |
| 105 | if (reg & I2C_OWN_SLAVE_ADDRESS) { | |
| 106 | of_node_put(child); | |
| 107 | return true; | |
| 108 | } | |
| 109 | } | |
| 110 | } else if (IS_BUILTIN(CONFIG_ACPI) && ACPI_HANDLE(dev)) { | |
| 111 | dev_dbg(dev, "ACPI slave is not supported yet\n"); | |
| 112 | } | |
| 113 | return false; | |
| 114 | } | |
| 115 | EXPORT_SYMBOL_GPL(i2c_detect_slave_mode); |