151 lines
4.8 KiB
C
151 lines
4.8 KiB
C
/*
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* i2c.h - definitions for the barebox i2c framework
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*
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* Copyright (C) 2009 by Marc Kleine-Budde <mkl@pengutronix.de>
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*
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* This file is released under the GPLv2
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*
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* Derived from:
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* - i2c.h - i.MX I2C driver header file
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* Copyright (c) 2008, Darius Augulis <augulis.darius@gmail.com>
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* - i2c.h - definitions for the i2c-bus interface
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* Copyright (C) 1995-2000 Simon G. Vogl
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*
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*/
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#ifndef I2C_I2C_H
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#define I2C_I2C_H
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#ifndef DOXYGEN_SHOULD_SKIP_THIS
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/*
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* struct i2c_platform_data - structure of platform data for MXC I2C driver
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* @param bitrate Bus speed measured in Hz
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*
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*/
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struct i2c_platform_data {
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int bitrate;
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};
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#define I2C_NAME_SIZE 20
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#define I2C_M_RD 0x0001 /* read data, from slave to master */
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#define I2C_M_DATA_ONLY 0x0002 /* transfer data bytes only */
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#define I2C_M_TEN 0x0010 /* this is a ten bit chip address */
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#define I2C_M_IGNORE_NAK 0x1000 /* if I2C_FUNC_PROTOCOL_MANGLING */
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/**
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* struct i2c_msg - an I2C transaction segment beginning with START
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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()
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* procedure and to I2C adapter drivers through the
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* @i2c_adapter.@master_xfer() method.
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*
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* All I2C adapters implement the standard rules for I2C transactions.
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* Each transaction begins with a START. That is followed by the
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* slave address, and a bit encoding read versus write. Then follow
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* all the data bytes, The transfer terminates with a NAK, or when all
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* those bytes have been transferred and ACKed. If this is the last
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* message in a group, it is followed by a STOP. Otherwise it is
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* followed by the next @i2c_msg transaction segment, beginning with a
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* (repeated) START.
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*
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*/
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struct i2c_msg {
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__u8 *buf; /**< The buffer into which data is read, or from which it's written. */
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__u16 addr; /**< Slave address, seven bits */
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__u16 flags; /**< I2C_M_RD is handled by all adapters */
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__u16 len; /**< Number of data bytes in @buf being read from or written to the I2C slave address. */
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};
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/**
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* i2c_adapter is the structure used to identify a physical i2c bus
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* along with the access algorithms necessary to access it.
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*
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*/
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struct i2c_adapter {
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struct device_d *dev; /* ptr to device */
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int nr; /* bus number */
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int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs, int num);
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struct list_head list;
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};
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struct i2c_client {
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struct device_d dev;
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struct i2c_adapter *adapter;
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unsigned short addr;
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};
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#define to_i2c_client(a) container_of(a, struct i2c_client, dev)
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/**
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* struct i2c_board_info - template for device creation
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*
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* I2C doesn't actually support hardware probing, Drivers commonly
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* need more information than that, such as chip type, configuration,
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* and so on.
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*
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* i2c_board_info is used to build tables of information listing I2C
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* devices that are present. This information is used to grow the
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* driver model tree. For mainboards this is done statically using
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* i2c_register_board_info(); bus numbers identify adapters that
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* aren't yet available. For add-on boards, i2c_new_device() does this
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* 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]; /**< name of device */
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unsigned short addr; /**< stored in i2c_client.addr */
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void *platform_data; /**< platform data for device */
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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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#ifdef CONFIG_I2C
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extern int i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned n);
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#else
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static inline int i2c_register_board_info(int busnum,
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struct i2c_board_info const *info, unsigned n)
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{
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return 0;
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}
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#endif
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extern int i2c_add_numbered_adapter(struct i2c_adapter *adapter);
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struct i2c_adapter *i2c_get_adapter(int busnum);
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extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num);
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extern int i2c_master_send(struct i2c_client *client, const char *buf, int count);
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extern int i2c_master_recv(struct i2c_client *client, char *buf, int count);
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#define I2C_ADDR_16_BIT (1 << 31)
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extern int i2c_read_reg(struct i2c_client *client, u32 addr, u8 *buf, u16 count);
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extern int i2c_write_reg(struct i2c_client *client, u32 addr, const u8 *buf, u16 count);
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#endif /* DOXYGEN_SHOULD_SKIP_THIS */
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extern struct bus_type i2c_bus;
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static inline int i2c_register_driver(struct driver_d *drv)
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{
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drv->bus = &i2c_bus;
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return register_driver(drv);
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}
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#endif /* I2C_I2C_H */
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