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i2c: core changes for slave support

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Finally(!), make Linux support being an I2C slave. Most of the existing
infrastructure is reused. We mainly add i2c_slave_register/unregister()
calls which tells i2c bus drivers to activate the slave mode. Then, they
also get a callback to report slave events to.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Wolfram Sang
2014-11-18 17:04:53 +01:00
committed by Wolfram Sang
parent 40ed1b4caf
commit 4b1acc4333
2 changed files with 78 additions and 0 deletions
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49
drivers/i2c/i2c-core.c
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@@ -24,6 +24,7 @@
(c) 2013 Wolfram Sang <wsa@the-dreams.de>
I2C ACPI code Copyright (C) 2014 Intel Corp
Author: Lan Tianyu <tianyu.lan@intel.com>
I2C slave support (c) 2014 by Wolfram Sang <wsa@sang-engineering.com>
*/
#include <linux/module.h>
@@ -2911,6 +2912,54 @@ trace:
}
EXPORT_SYMBOL(i2c_smbus_xfer);
int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb)
{
int ret;
if (!client || !slave_cb)
return -EINVAL;
if (!(client->flags & I2C_CLIENT_TEN)) {
/* Enforce stricter address checking */
ret = i2c_check_addr_validity(client->addr);
if (ret)
return ret;
}
if (!client->adapter->algo->reg_slave)
return -EOPNOTSUPP;
client->slave_cb = slave_cb;
i2c_lock_adapter(client->adapter);
ret = client->adapter->algo->reg_slave(client);
i2c_unlock_adapter(client->adapter);
if (ret)
client->slave_cb = NULL;
return ret;
}
EXPORT_SYMBOL_GPL(i2c_slave_register);
int i2c_slave_unregister(struct i2c_client *client)
{
int ret;
if (!client->adapter->algo->unreg_slave)
return -EOPNOTSUPP;
i2c_lock_adapter(client->adapter);
ret = client->adapter->algo->unreg_slave(client);
i2c_unlock_adapter(client->adapter);
if (ret == 0)
client->slave_cb = NULL;
return ret;
}
EXPORT_SYMBOL_GPL(i2c_slave_unregister);
MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
MODULE_DESCRIPTION("I2C-Bus main module");
MODULE_LICENSE("GPL");