117 lines
3.1 KiB
C
117 lines
3.1 KiB
C
|
/*
|
||
|
|
* Linux I2C core slave support code
|
||
|
|
*
|
||
|
|
* Copyright (C) 2014 by Wolfram Sang <wsa@sang-engineering.com>
|
||
|
|
*
|
||
|
|
* 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.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#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 (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);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* 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);
|