416 lines
17 KiB
C
416 lines
17 KiB
C
/* ------------------------------------------------------------------------- */
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/* */
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/* i2c.h - definitions for the i2c-bus interface */
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/* */
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/* ------------------------------------------------------------------------- */
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/* Copyright (C) 1995-2000 Simon G. Vogl
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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MA 02110-1301 USA. */
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/* ------------------------------------------------------------------------- */
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/* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and
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Frodo Looijaard <frodol@dds.nl> */
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#ifndef _LINUX_I2C_H
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#define _LINUX_I2C_H
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#include <linux/types.h>
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#ifdef __KERNEL__
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#include <linux/module.h>
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#include <linux/i2c-id.h>
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#include <linux/mod_devicetable.h>
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extern struct bus_type i2c_bus_type;
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extern struct device_type i2c_adapter_type;
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/* --- General options ------------------------------------------------ */
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struct i2c_msg;
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struct i2c_algorithm;
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struct i2c_adapter;
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struct i2c_client;
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struct i2c_driver;
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union i2c_smbus_data;
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struct i2c_board_info;
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/* Transfer num messages.
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*/
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extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
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int num);
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/**
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* struct i2c_driver - represent an I2C device driver
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* @class: What kind of i2c device we instantiate (for detect)
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* @attach_adapter: Callback for bus addition (deprecated)
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* @detach_adapter: Callback for bus removal (deprecated)
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* @probe: Callback for device binding
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* @remove: Callback for device unbinding
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* @shutdown: Callback for device shutdown
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* @suspend: Callback for device suspend
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* @resume: Callback for device resume
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* @alert: Alert callback, for example for the SMBus alert protocol
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* @command: Callback for bus-wide signaling (optional)
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* @driver: Device driver model driver
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* @id_table: List of I2C devices supported by this driver
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* @detect: Callback for device detection
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* @address_list: The I2C addresses to probe (for detect)
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* @clients: List of detected clients we created (for i2c-core use only)
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*
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* The driver.owner field should be set to the module owner of this driver.
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* The driver.name field should be set to the name of this driver.
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*
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* For automatic device detection, both @detect and @address_list must
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* be defined. @class should also be set, otherwise only devices forced
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* with module parameters will be created. The detect function must
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* fill at least the name field of the i2c_board_info structure it is
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* handed upon successful detection, and possibly also the flags field.
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*
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* If @detect is missing, the driver will still work fine for enumerated
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* devices. Detected devices simply won't be supported. This is expected
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* for the many I2C/SMBus devices which can't be detected reliably, and
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* the ones which can always be enumerated in practice.
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*
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* The i2c_client structure which is handed to the @detect callback is
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* not a real i2c_client. It is initialized just enough so that you can
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* call i2c_smbus_read_byte_data and friends on it. Don't do anything
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* else with it. In particular, calling dev_dbg and friends on it is
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* not allowed.
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*/
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struct i2c_driver {
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unsigned int class;
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/* Notifies the driver that a new bus has appeared or is about to be
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* removed. You should avoid using this, it will be removed in a
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* near future.
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*/
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int (*attach_adapter)(struct i2c_adapter *) __deprecated;
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int (*detach_adapter)(struct i2c_adapter *) __deprecated;
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/* Standard driver model interfaces */
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int (*probe)(struct i2c_client *, const struct i2c_device_id *);
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int (*remove)(struct i2c_client *);
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/* driver model interfaces that don't relate to enumeration */
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void (*shutdown)(struct i2c_client *);
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// int (*suspend)(struct i2c_client *, pm_message_t mesg);
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int (*resume)(struct i2c_client *);
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/* Alert callback, for example for the SMBus alert protocol.
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* The format and meaning of the data value depends on the protocol.
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* For the SMBus alert protocol, there is a single bit of data passed
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* as the alert response's low bit ("event flag").
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*/
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void (*alert)(struct i2c_client *, unsigned int data);
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/* a ioctl like command that can be used to perform specific functions
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* with the device.
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*/
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int (*command)(struct i2c_client *client, unsigned int cmd, void *arg);
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// struct device_driver driver;
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const struct i2c_device_id *id_table;
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/* Device detection callback for automatic device creation */
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// int (*detect)(struct i2c_client *, struct i2c_board_info *);
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const unsigned short *address_list;
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struct list_head clients;
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};
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#define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
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/**
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* struct i2c_client - represent an I2C slave device
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* @flags: I2C_CLIENT_TEN indicates the device uses a ten bit chip address;
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* I2C_CLIENT_PEC indicates it uses SMBus Packet Error Checking
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* @addr: Address used on the I2C bus connected to the parent adapter.
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* @name: Indicates the type of the device, usually a chip name that's
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* generic enough to hide second-sourcing and compatible revisions.
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* @adapter: manages the bus segment hosting this I2C device
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* @driver: device's driver, hence pointer to access routines
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* @dev: Driver model device node for the slave.
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* @irq: indicates the IRQ generated by this device (if any)
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* @detected: member of an i2c_driver.clients list or i2c-core's
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* userspace_devices list
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*
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* An i2c_client identifies a single device (i.e. chip) connected to an
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* i2c bus. The behaviour exposed to Linux is defined by the driver
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* managing the device.
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*/
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struct i2c_client {
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unsigned short flags; /* div., see below */
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unsigned short addr; /* chip address - NOTE: 7bit */
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/* addresses are stored in the */
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/* _LOWER_ 7 bits */
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char name[I2C_NAME_SIZE];
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struct i2c_adapter *adapter; /* the adapter we sit on */
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struct i2c_driver *driver; /* and our access routines */
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struct device dev; /* the device structure */
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int irq; /* irq issued by device */
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struct list_head detected;
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};
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#define to_i2c_client(d) container_of(d, struct i2c_client, dev)
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extern struct i2c_client *i2c_verify_client(struct device *dev);
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/**
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* struct i2c_board_info - template for device creation
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* @type: chip type, to initialize i2c_client.name
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* @flags: to initialize i2c_client.flags
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* @addr: stored in i2c_client.addr
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* @platform_data: stored in i2c_client.dev.platform_data
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* @archdata: copied into i2c_client.dev.archdata
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* @of_node: pointer to OpenFirmware device node
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* @acpi_node: ACPI device node
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* @irq: stored in i2c_client.irq
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*
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* I2C doesn't actually support hardware probing, although controllers and
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* devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's
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* a device at a given address. Drivers commonly need more information than
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* that, such as chip type, configuration, associated IRQ, and so on.
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*
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* i2c_board_info is used to build tables of information listing I2C devices
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* that are present. This information is used to grow the driver model tree.
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* For mainboards this is done statically using i2c_register_board_info();
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* bus numbers identify adapters that aren't yet available. For add-on boards,
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* i2c_new_device() does this dynamically with the adapter already known.
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*/
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struct i2c_board_info {
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char type[I2C_NAME_SIZE];
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unsigned short flags;
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unsigned short addr;
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void *platform_data;
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struct dev_archdata *archdata;
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#ifdef CONFIG_OF
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struct device_node *of_node;
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#endif
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int irq;
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};
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/**
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* I2C_BOARD_INFO - macro used to list an i2c device and its address
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* @dev_type: identifies the device type
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* @dev_addr: the device's address on the bus.
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*
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* This macro initializes essential fields of a struct i2c_board_info,
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* declaring what has been provided on a particular board. Optional
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* fields (such as associated irq, or device-specific platform_data)
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* are provided using conventional syntax.
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*/
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#define I2C_BOARD_INFO(dev_type, dev_addr) \
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.type = dev_type, .addr = (dev_addr)
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/*
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* The following structs are for those who like to implement new bus drivers:
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* i2c_algorithm is the interface to a class of hardware solutions which can
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* be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584
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* to name two of the most common.
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*/
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struct i2c_algorithm {
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/* If an adapter algorithm can't do I2C-level access, set master_xfer
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to NULL. If an adapter algorithm can do SMBus access, set
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smbus_xfer. If set to NULL, the SMBus protocol is simulated
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using common I2C messages */
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/* master_xfer should return the number of messages successfully
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processed, or a negative value on error */
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int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs,
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int num);
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int (*smbus_xfer) (struct i2c_adapter *adap, u16 addr,
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unsigned short flags, char read_write,
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u8 command, int size, union i2c_smbus_data *data);
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/* To determine what the adapter supports */
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u32 (*functionality) (struct i2c_adapter *);
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};
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/*
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* i2c_adapter is the structure used to identify a physical i2c bus along
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* with the access algorithms necessary to access it.
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*/
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struct i2c_adapter {
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struct module *owner;
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unsigned int class; /* classes to allow probing for */
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const struct i2c_algorithm *algo; /* the algorithm to access the bus */
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void *algo_data;
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/* data fields that are valid for all devices */
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// struct rt_mutex bus_lock;
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int timeout; /* in jiffies */
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int retries;
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struct device dev; /* the adapter device */
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int nr;
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char name[48];
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};
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#define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
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static inline void *i2c_get_adapdata(struct i2c_adapter *dev)
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{
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return dev_get_drvdata(&dev->dev);
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}
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static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data)
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{
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dev_set_drvdata(&dev->dev, data);
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}
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/* Adapter locking functions, exported for shared pin cases */
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void i2c_lock_adapter(struct i2c_adapter *);
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void i2c_unlock_adapter(struct i2c_adapter *);
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/*flags for the client struct: */
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#define I2C_CLIENT_PEC 0x04 /* Use Packet Error Checking */
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#define I2C_CLIENT_TEN 0x10 /* we have a ten bit chip address */
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/* Must equal I2C_M_TEN below */
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#define I2C_CLIENT_WAKE 0x80 /* for board_info; true iff can wake */
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#define I2C_CLIENT_SCCB 0x9000 /* Use Omnivision SCCB protocol */
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/* Must match I2C_M_STOP|IGNORE_NAK */
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/* i2c adapter classes (bitmask) */
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#define I2C_CLASS_HWMON (1<<0) /* lm_sensors, ... */
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#define I2C_CLASS_DDC (1<<3) /* DDC bus on graphics adapters */
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#define I2C_CLASS_SPD (1<<7) /* Memory modules */
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/* Internal numbers to terminate lists */
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#define I2C_CLIENT_END 0xfffeU
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/* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
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#define I2C_ADDRS(addr, addrs...) \
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((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
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#endif /* __KERNEL__ */
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/**
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* struct i2c_msg - an I2C transaction segment beginning with START
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* @addr: Slave address, either seven or ten bits. When this is a ten
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* bit address, I2C_M_TEN must be set in @flags and the adapter
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* must support I2C_FUNC_10BIT_ADDR.
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* @flags: I2C_M_RD is handled by all adapters. No other flags may be
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* provided unless the adapter exported the relevant I2C_FUNC_*
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* flags through i2c_check_functionality().
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* @len: Number of data bytes in @buf being read from or written to the
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* I2C slave address. For read transactions where I2C_M_RECV_LEN
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* is set, the caller guarantees that this buffer can hold up to
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* 32 bytes in addition to the initial length byte sent by the
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* slave (plus, if used, the SMBus PEC); and this value will be
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* incremented by the number of block data bytes received.
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* @buf: The buffer into which data is read, or from which it's written.
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*
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* An i2c_msg is the low level representation of one segment of an I2C
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* transaction. It is visible to drivers in the @i2c_transfer() procedure,
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* to userspace from i2c-dev, and to I2C adapter drivers through the
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* @i2c_adapter.@master_xfer() method.
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*
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* Except when I2C "protocol mangling" is used, all I2C adapters implement
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* the standard rules for I2C transactions. Each transaction begins with a
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* START. That is followed by the slave address, and a bit encoding read
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* versus write. Then follow all the data bytes, possibly including a byte
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* with SMBus PEC. The transfer terminates with a NAK, or when all those
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* bytes have been transferred and ACKed. If this is the last message in a
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* group, it is followed by a STOP. Otherwise it is followed by the next
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* @i2c_msg transaction segment, beginning with a (repeated) START.
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*
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* Alternatively, when the adapter supports I2C_FUNC_PROTOCOL_MANGLING then
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* passing certain @flags may have changed those standard protocol behaviors.
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* Those flags are only for use with broken/nonconforming slaves, and with
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* adapters which are known to support the specific mangling options they
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* need (one or more of IGNORE_NAK, NO_RD_ACK, NOSTART, and REV_DIR_ADDR).
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*/
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struct i2c_msg {
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__u16 addr; /* slave address */
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__u16 flags;
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#define I2C_M_TEN 0x0010 /* this is a ten bit chip address */
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#define I2C_M_RD 0x0001 /* read data, from slave to master */
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#define I2C_M_NOSTART 0x4000 /* if I2C_FUNC_PROTOCOL_MANGLING */
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#define I2C_M_REV_DIR_ADDR 0x2000 /* if I2C_FUNC_PROTOCOL_MANGLING */
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#define I2C_M_IGNORE_NAK 0x1000 /* if I2C_FUNC_PROTOCOL_MANGLING */
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#define I2C_M_NO_RD_ACK 0x0800 /* if I2C_FUNC_PROTOCOL_MANGLING */
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#define I2C_M_RECV_LEN 0x0400 /* length will be first received byte */
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__u16 len; /* msg length */
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__u8 *buf; /* pointer to msg data */
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};
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/* To determine what functionality is present */
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#define I2C_FUNC_I2C 0x00000001
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#define I2C_FUNC_10BIT_ADDR 0x00000002
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#define I2C_FUNC_PROTOCOL_MANGLING 0x00000004 /* I2C_M_NOSTART etc. */
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#define I2C_FUNC_SMBUS_PEC 0x00000008
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#define I2C_FUNC_SMBUS_BLOCK_PROC_CALL 0x00008000 /* SMBus 2.0 */
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#define I2C_FUNC_SMBUS_QUICK 0x00010000
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#define I2C_FUNC_SMBUS_READ_BYTE 0x00020000
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#define I2C_FUNC_SMBUS_WRITE_BYTE 0x00040000
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#define I2C_FUNC_SMBUS_READ_BYTE_DATA 0x00080000
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#define I2C_FUNC_SMBUS_WRITE_BYTE_DATA 0x00100000
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#define I2C_FUNC_SMBUS_READ_WORD_DATA 0x00200000
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#define I2C_FUNC_SMBUS_WRITE_WORD_DATA 0x00400000
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#define I2C_FUNC_SMBUS_PROC_CALL 0x00800000
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#define I2C_FUNC_SMBUS_READ_BLOCK_DATA 0x01000000
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#define I2C_FUNC_SMBUS_WRITE_BLOCK_DATA 0x02000000
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#define I2C_FUNC_SMBUS_READ_I2C_BLOCK 0x04000000 /* I2C-like block xfer */
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#define I2C_FUNC_SMBUS_WRITE_I2C_BLOCK 0x08000000 /* w/ 1-byte reg. addr. */
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#define I2C_FUNC_SMBUS_BYTE (I2C_FUNC_SMBUS_READ_BYTE | \
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I2C_FUNC_SMBUS_WRITE_BYTE)
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#define I2C_FUNC_SMBUS_BYTE_DATA (I2C_FUNC_SMBUS_READ_BYTE_DATA | \
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I2C_FUNC_SMBUS_WRITE_BYTE_DATA)
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#define I2C_FUNC_SMBUS_WORD_DATA (I2C_FUNC_SMBUS_READ_WORD_DATA | \
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I2C_FUNC_SMBUS_WRITE_WORD_DATA)
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#define I2C_FUNC_SMBUS_BLOCK_DATA (I2C_FUNC_SMBUS_READ_BLOCK_DATA | \
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I2C_FUNC_SMBUS_WRITE_BLOCK_DATA)
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#define I2C_FUNC_SMBUS_I2C_BLOCK (I2C_FUNC_SMBUS_READ_I2C_BLOCK | \
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I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)
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#define I2C_FUNC_SMBUS_EMUL (I2C_FUNC_SMBUS_QUICK | \
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I2C_FUNC_SMBUS_BYTE | \
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I2C_FUNC_SMBUS_BYTE_DATA | \
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I2C_FUNC_SMBUS_WORD_DATA | \
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I2C_FUNC_SMBUS_PROC_CALL | \
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I2C_FUNC_SMBUS_WRITE_BLOCK_DATA | \
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I2C_FUNC_SMBUS_I2C_BLOCK | \
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I2C_FUNC_SMBUS_PEC)
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/*
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* Data for SMBus Messages
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*/
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#define I2C_SMBUS_BLOCK_MAX 32 /* As specified in SMBus standard */
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union i2c_smbus_data {
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__u8 byte;
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__u16 word;
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__u8 block[I2C_SMBUS_BLOCK_MAX + 2]; /* block[0] is used for length */
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/* and one more for user-space compatibility */
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};
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/* i2c_smbus_xfer read or write markers */
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#define I2C_SMBUS_READ 1
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#define I2C_SMBUS_WRITE 0
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/* SMBus transaction types (size parameter in the above functions)
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Note: these no longer correspond to the (arbitrary) PIIX4 internal codes! */
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#define I2C_SMBUS_QUICK 0
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#define I2C_SMBUS_BYTE 1
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#define I2C_SMBUS_BYTE_DATA 2
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#define I2C_SMBUS_WORD_DATA 3
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#define I2C_SMBUS_PROC_CALL 4
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#define I2C_SMBUS_BLOCK_DATA 5
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#define I2C_SMBUS_I2C_BLOCK_BROKEN 6
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#define I2C_SMBUS_BLOCK_PROC_CALL 7 /* SMBus 2.0 */
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#define I2C_SMBUS_I2C_BLOCK_DATA 8
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#define i2c_add_adapter(x) 0
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#define i2c_del_adapter(x)
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#endif /* _LINUX_I2C_H */
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