2874c5fd28
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>
112 lines
2.8 KiB
C
112 lines
2.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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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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#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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