0f2dd1eff9
Split `i2c.h` into three pieces to ease reuse of the generic defi-
nitions. No code is changed.
* `i2c.h` - keeps the generic definitions
* `i2c_simple.h` - holds the current, limited to one controller driver
per board, devicetree independent I2C interface
* `i2c_bus.h` - will become the devicetree compatible interface for
native I2C (e.g. non-SMBus) controllers
Change-Id: I382d45c70f9314588663e1284f264f877469c74d
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/20845
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
69 lines
2.6 KiB
C
69 lines
2.6 KiB
C
/*
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* This file is part of the coreboot project.
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*
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* Copyright (C) 2014 Google, Inc.
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*
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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; version 2 of the License.
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*
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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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*/
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#ifndef _DEVICE_I2C_H_
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#define _DEVICE_I2C_H_
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#include <stdint.h>
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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.
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* @flags: I2C_M_RD is handled by all adapters.
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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).
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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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*
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* All I2C adapters implement the standard rules for I2C transactions. Each
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* transaction begins with a START. That is followed by the slave address,
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* and a bit encoding read versus write. Then follow all the data bytes,
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* possibly including a byte with SMBus PEC. The transfer terminates with
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* a NAK, or when all those bytes have been transferred and ACKed. If this
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* is the last message in a group, it is followed by a STOP. Otherwise it
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* is 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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struct i2c_msg {
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uint16_t flags;
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#define I2C_M_RD 0x0001 /* read data, from slave to master */
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#define I2C_M_TEN 0x0010 /* this is a ten bit chip address */
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#define I2C_M_RECV_LEN 0x0400 /* length will be first received byte */
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#define I2C_M_NOSTART 0x4000 /* don't send a repeated START */
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uint16_t slave; /* slave address */
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uint16_t len; /* msg length */
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uint8_t *buf; /* pointer to msg data */
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};
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enum i2c_speed {
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I2C_SPEED_STANDARD = 100000,
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I2C_SPEED_FAST = 400000,
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I2C_SPEED_FAST_PLUS = 1000000,
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I2C_SPEED_HIGH = 3400000,
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I2C_SPEED_FAST_ULTRA = 5000000,
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};
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enum i2c_address_mode {
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I2C_MODE_7_BIT,
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I2C_MODE_10_BIT
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};
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#endif /* _DEVICE_I2C_H_ */
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