116 lines
3.0 KiB
C
116 lines
3.0 KiB
C
/*
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* Linux I2C core slave support code
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*
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* Copyright (C) 2014 by Wolfram Sang <wsa@sang-engineering.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*/
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#include <dt-bindings/i2c/i2c.h>
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#include <linux/acpi.h>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/i2c.h>
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#include <linux/of.h>
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#include "i2c-core.h"
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int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb)
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{
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int ret;
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if (!client || !slave_cb) {
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WARN(1, "insufficient data\n");
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return -EINVAL;
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}
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if (!(client->flags & I2C_CLIENT_SLAVE))
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dev_warn(&client->dev, "%s: client slave flag not set. You might see address collisions\n",
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__func__);
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if (!(client->flags & I2C_CLIENT_TEN)) {
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/* Enforce stricter address checking */
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ret = i2c_check_7bit_addr_validity_strict(client->addr);
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if (ret) {
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dev_err(&client->dev, "%s: invalid address\n", __func__);
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return ret;
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}
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}
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if (!client->adapter->algo->reg_slave) {
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dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
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return -EOPNOTSUPP;
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}
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client->slave_cb = slave_cb;
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i2c_lock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER);
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ret = client->adapter->algo->reg_slave(client);
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i2c_unlock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER);
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if (ret) {
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client->slave_cb = NULL;
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dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);
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}
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return ret;
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}
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EXPORT_SYMBOL_GPL(i2c_slave_register);
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int i2c_slave_unregister(struct i2c_client *client)
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{
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int ret;
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if (!client->adapter->algo->unreg_slave) {
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dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
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return -EOPNOTSUPP;
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}
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i2c_lock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER);
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ret = client->adapter->algo->unreg_slave(client);
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i2c_unlock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER);
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if (ret == 0)
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client->slave_cb = NULL;
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else
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dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);
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return ret;
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}
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EXPORT_SYMBOL_GPL(i2c_slave_unregister);
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/**
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* i2c_detect_slave_mode - detect operation mode
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* @dev: The device owning the bus
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*
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* This checks the device nodes for an I2C slave by checking the address
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* used in the reg property. If the address match the I2C_OWN_SLAVE_ADDRESS
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* flag this means the device is configured to act as a I2C slave and it will
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* be listening at that address.
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*
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* Returns true if an I2C own slave address is detected, otherwise returns
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* false.
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*/
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bool i2c_detect_slave_mode(struct device *dev)
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{
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if (IS_BUILTIN(CONFIG_OF) && dev->of_node) {
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struct device_node *child;
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u32 reg;
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for_each_child_of_node(dev->of_node, child) {
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of_property_read_u32(child, "reg", ®);
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if (reg & I2C_OWN_SLAVE_ADDRESS) {
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of_node_put(child);
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return true;
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}
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}
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} else if (IS_BUILTIN(CONFIG_ACPI) && ACPI_HANDLE(dev)) {
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dev_dbg(dev, "ACPI slave is not supported yet\n");
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}
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return false;
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}
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EXPORT_SYMBOL_GPL(i2c_detect_slave_mode);
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