mirror of
https://github.com/AsahiLinux/u-boot
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151 lines
3.9 KiB
C
151 lines
3.9 KiB
C
/*
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* (C) Copyright 2001
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* Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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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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* 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., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*
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* The original I2C interface was
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* (C) 2000 by Paolo Scaffardi (arsenio@tin.it)
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* AIRVENT SAM s.p.a - RIMINI(ITALY)
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* but has been changed substantially.
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*/
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#ifndef _I2C_H_
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#define _I2C_H_
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/*
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* WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
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*
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* The implementation MUST NOT use static or global variables if the
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* I2C routines are used to read SDRAM configuration information
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* because this is done before the memories are initialized. Limited
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* use of stack-based variables are OK (the initial stack size is
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* limited).
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*
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* WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
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*/
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/*
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* Configuration items.
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*/
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#define I2C_RXTX_LEN 128 /* maximum tx/rx buffer length */
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#if defined(CONFIG_I2C_MULTI_BUS)
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#define CFG_MAX_I2C_BUS 2
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#define I2C_GET_BUS() i2c_get_bus_num()
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#define I2C_SET_BUS(a) i2c_set_bus_num(a)
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#else
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#define CFG_MAX_I2C_BUS 1
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#define I2C_GET_BUS() 0
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#define I2C_SET_BUS(a)
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#endif
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/* define the I2C bus number for RTC and DTT if not already done */
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#if !defined(CFG_RTC_BUS_NUM)
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#define CFG_RTC_BUS_NUM 0
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#endif
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#if !defined(CFG_DTT_BUS_NUM)
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#define CFG_DTT_BUS_NUM 0
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#endif
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#if !defined(CFG_SPD_BUS_NUM)
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#define CFG_SPD_BUS_NUM 0
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#endif
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/*
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* Initialization, must be called once on start up, may be called
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* repeatedly to change the speed and slave addresses.
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*/
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void i2c_init(int speed, int slaveaddr);
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#ifdef CFG_I2C_INIT_BOARD
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void i2c_init_board(void);
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#endif
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/*
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* Probe the given I2C chip address. Returns 0 if a chip responded,
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* not 0 on failure.
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*/
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int i2c_probe(uchar chip);
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/*
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* Read/Write interface:
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* chip: I2C chip address, range 0..127
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* addr: Memory (register) address within the chip
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* alen: Number of bytes to use for addr (typically 1, 2 for larger
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* memories, 0 for register type devices with only one
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* register)
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* buffer: Where to read/write the data
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* len: How many bytes to read/write
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*
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* Returns: 0 on success, not 0 on failure
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*/
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int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len);
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int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len);
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/*
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* Utility routines to read/write registers.
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*/
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uchar i2c_reg_read (uchar chip, uchar reg);
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void i2c_reg_write(uchar chip, uchar reg, uchar val);
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/*
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* Functions for setting the current I2C bus and its speed
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*/
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/*
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* i2c_set_bus_num:
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*
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* Change the active I2C bus. Subsequent read/write calls will
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* go to this one.
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*
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* bus - bus index, zero based
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*
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* Returns: 0 on success, not 0 on failure
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*
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*/
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int i2c_set_bus_num(unsigned int bus);
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/*
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* i2c_get_bus_num:
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*
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* Returns index of currently active I2C bus. Zero-based.
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*/
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unsigned int i2c_get_bus_num(void);
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/*
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* i2c_set_bus_speed:
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*
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* Change the speed of the active I2C bus
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*
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* speed - bus speed in Hz
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*
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* Returns: 0 on success, not 0 on failure
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*
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*/
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int i2c_set_bus_speed(unsigned int);
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/*
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* i2c_get_bus_speed:
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*
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* Returns speed of currently active I2C bus in Hz
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*/
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unsigned int i2c_get_bus_speed(void);
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#endif /* _I2C_H_ */
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