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-rw-r--r--drivers/i2c/i2c-core-slave.c127
1 files changed, 127 insertions, 0 deletions
diff --git a/drivers/i2c/i2c-core-slave.c b/drivers/i2c/i2c-core-slave.c
new file mode 100644
index 000000000..e3765e12f
--- /dev/null
+++ b/drivers/i2c/i2c-core-slave.c
@@ -0,0 +1,127 @@
+// 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"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/i2c_slave.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);
+
+int i2c_slave_event(struct i2c_client *client,
+ enum i2c_slave_event event, u8 *val)
+{
+ int ret = client->slave_cb(client, event, val);
+
+ if (trace_i2c_slave_enabled())
+ trace_i2c_slave(client, event, val, ret);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(i2c_slave_event);
+
+/**
+ * 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);