cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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i2c-core-slave.c (3273B)

      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", &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);