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112 lines
2.9 KiB
112 lines
2.9 KiB
// 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 <[email protected]> |
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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 (WARN(IS_ERR_OR_NULL(client) || !slave_cb, "insufficient data\n")) |
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return -EINVAL; |
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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 (IS_ERR_OR_NULL(client)) |
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return -EINVAL; |
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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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