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Commit 4b1acc43 authored by Wolfram Sang's avatar Wolfram Sang Committed by Wolfram Sang
Browse files

i2c: core changes for slave support 



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: default avatarWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 40ed1b4c

drivers/i2c/i2c-core.c

+49 −0
Original line number Diff line number Diff line
@@ -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 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags, 
}

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");

include/linux/i2c.h

+29 −0
Original line number Diff line number Diff line
@@ -46,6 +46,8 @@ struct i2c_client; 
struct i2c_driver;

union i2c_smbus_data;

struct i2c_board_info;

enum i2c_slave_event;

typedef int (*i2c_slave_cb_t)(struct i2c_client *, enum i2c_slave_event, u8 *);



struct module;
@@ -209,6 +211,8 @@ struct i2c_driver { 
 * @irq: indicates the IRQ generated by this device (if any)

 * @detected: member of an i2c_driver.clients list or i2c-core's

 *	userspace_devices list

 * @slave_cb: Callback when I2C slave mode of an adapter is used. The adapter

 *	calls it to pass on slave events to the slave driver.

 *

 * An i2c_client identifies a single device (i.e. chip) connected to an

 * i2c bus. The behaviour exposed to Linux is defined by the driver
@@ -224,6 +228,7 @@ struct i2c_client { 
	struct device dev;		/* the device structure		*/

	int irq;			/* irq issued by device		*/

	struct list_head detected;

	i2c_slave_cb_t slave_cb;	/* callback for slave mode	*/

};

#define to_i2c_client(d) container_of(d, struct i2c_client, dev)
@@ -246,6 +251,25 @@ static inline void i2c_set_clientdata(struct i2c_client *dev, void *data) 
	dev_set_drvdata(&dev->dev, data);

}



/* I2C slave support */



enum i2c_slave_event {

	I2C_SLAVE_REQ_READ_START,

	I2C_SLAVE_REQ_READ_END,

	I2C_SLAVE_REQ_WRITE_START,

	I2C_SLAVE_REQ_WRITE_END,

	I2C_SLAVE_STOP,

};



extern int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb);

extern int i2c_slave_unregister(struct i2c_client *client);



static inline int i2c_slave_event(struct i2c_client *client,

				  enum i2c_slave_event event, u8 *val)

{

	return client->slave_cb(client, event, val);

}



/**

 * struct i2c_board_info - template for device creation

 * @type: chip type, to initialize i2c_client.name
@@ -352,6 +376,8 @@ i2c_register_board_info(int busnum, struct i2c_board_info const *info, 
 *   into I2C transfers instead.

 * @functionality: Return the flags that this algorithm/adapter pair supports

 *   from the I2C_FUNC_* flags.

 * @reg_slave: Register given client to I2C slave mode of this adapter

 * @unreg_slave: Unregister given client from I2C slave mode of this adapter

 *

 * The following structs are for those who like to implement new bus drivers:

 * i2c_algorithm is the interface to a class of hardware solutions which can
@@ -377,6 +403,9 @@ struct i2c_algorithm { 


	/* To determine what the adapter supports */

	u32 (*functionality) (struct i2c_adapter *);



	int (*reg_slave)(struct i2c_client *client);

	int (*unreg_slave)(struct i2c_client *client);

};



/**