linux/drivers/i2c/i2c-core-slave.c
Thomas Gleixner 2874c5fd28 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00

112 lines
2.8 KiB
C

// 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"
int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb)
{
int ret;
if (!client || !slave_cb) {
WARN(1, "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 (!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);
/**
* 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", &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);