This adds an i2c bitbang interface that can coexist with processor i2c.
Signed-off-by: Dirk Eibach eibach@gdsys.de --- board/gdsys/common/Makefile | 2 +- board/gdsys/common/bb_i2c.c | 304 +++++++++++++++++++++++++++++++++++++++++++ board/gdsys/common/bb_i2c.h | 76 +++++++++++ 3 files changed, 381 insertions(+), 1 deletion(-) create mode 100644 board/gdsys/common/bb_i2c.c create mode 100644 board/gdsys/common/bb_i2c.h
diff --git a/board/gdsys/common/Makefile b/board/gdsys/common/Makefile index aa15c15..b217d97 100644 --- a/board/gdsys/common/Makefile +++ b/board/gdsys/common/Makefile @@ -31,7 +31,7 @@ LIB = $(obj)lib$(VENDOR).o
COBJS-$(CONFIG_IO) += miiphybb.o COBJS-$(CONFIG_IO64) += miiphybb.o -COBJS-$(CONFIG_IOCON) += osd.o mclink.o cmd_fpga.o +COBJS-$(CONFIG_IOCON) += osd.o mclink.o cmd_fpga.o bb_i2c.o COBJS-$(CONFIG_DLVISION_10G) += osd.o
COBJS := $(COBJS-y) diff --git a/board/gdsys/common/bb_i2c.c b/board/gdsys/common/bb_i2c.c new file mode 100644 index 0000000..a816514 --- /dev/null +++ b/board/gdsys/common/bb_i2c.c @@ -0,0 +1,304 @@ +/* + * (C) Copyright 2012 + * Dirk Eibach, Guntermann & Drunck GmbH, eibach@gdsys.de + * + * based on soft_i2c.c + * (C) Copyright 2001, 2002 + * Wolfgang Denk, DENX Software Engineering, wd@denx.de. + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + * + * This has been changed substantially by Gerald Van Baren, Custom IDEAS, + * vanbaren@cideas.com. It was heavily influenced by LiMon, written by + * Neil Russell. + */ + +#include <common.h> + +/*----------------------------------------------------------------------- + * Definitions + */ + +#define RETRIES 0 + +#define BB_I2C_ACK 0 /* PD_SDA level to ack a byte */ +#define BB_I2C_NOACK 1 /* PD_SDA level to noack a byte */ + +/*----------------------------------------------------------------------- + * Local functions + */ +static void send_reset(unsigned int bus); +static void send_start(unsigned int bus); +static void send_stop(unsigned int bus); +static void send_ack(unsigned int bus, int ack); +static int write_byte(unsigned int bus, uchar byte); +static uchar read_byte(unsigned int bus, int ack); + +/*----------------------------------------------------------------------- + * Send a reset sequence consisting of 9 clocks with the data signal high + * to clock any confused device back into an idle state. Also send a + * <stop> at the end of the sequence for belts & suspenders. + */ +static void send_reset(unsigned int bus) +{ + BB_I2C_SOFT_DECLARATIONS(bus) /* intentional without ';' */ + int j; + + BB_I2C_SCL(bus, 1); + BB_I2C_SDA(bus, 1); + BB_I2C_TRISTATE(bus); + for (j = 0; j < 9; j++) { + BB_I2C_SCL(bus, 0); + BB_I2C_DELAY(bus); + BB_I2C_DELAY(bus); + BB_I2C_SCL(bus, 1); + BB_I2C_DELAY(bus); + BB_I2C_DELAY(bus); + } + send_stop(bus); + BB_I2C_TRISTATE(bus); +} + +/*----------------------------------------------------------------------- + * START: High -> Low on SDA while SCL is High + */ +static void send_start(unsigned int bus) +{ + BB_I2C_SOFT_DECLARATIONS(bus) /* intentional without ';' */ + + BB_I2C_DELAY(bus); + BB_I2C_SDA(bus, 1); + BB_I2C_ACTIVE(bus); + BB_I2C_DELAY(bus); + BB_I2C_SCL(bus, 1); + BB_I2C_DELAY(bus); + BB_I2C_SDA(bus, 0); + BB_I2C_DELAY(bus); +} + +/*----------------------------------------------------------------------- + * STOP: Low -> High on SDA while SCL is High + */ +static void send_stop(unsigned int bus) +{ + BB_I2C_SOFT_DECLARATIONS(bus) /* intentional without ';' */ + + BB_I2C_SCL(bus, 0); + BB_I2C_DELAY(bus); + BB_I2C_SDA(bus, 0); + BB_I2C_ACTIVE(bus); + BB_I2C_DELAY(bus); + BB_I2C_SCL(bus, 1); + BB_I2C_DELAY(bus); + BB_I2C_SDA(bus, 1); + BB_I2C_DELAY(bus); + BB_I2C_TRISTATE(bus); +} + +/*----------------------------------------------------------------------- + * ack should be BB_I2C_ACK or BB_I2C_NOACK + */ +static void send_ack(unsigned int bus, int ack) +{ + BB_I2C_SOFT_DECLARATIONS(bus) /* intentional without ';' */ + + BB_I2C_SCL(bus, 0); + BB_I2C_DELAY(bus); + BB_I2C_ACTIVE(bus); + BB_I2C_SDA(bus, ack); + BB_I2C_DELAY(bus); + BB_I2C_SCL(bus, 1); + BB_I2C_DELAY(bus); + BB_I2C_DELAY(bus); + BB_I2C_SCL(bus, 0); + BB_I2C_DELAY(bus); +} + +/*----------------------------------------------------------------------- + * Send 8 bits and look for an acknowledgement. + */ +static int write_byte(unsigned int bus, uchar data) +{ + BB_I2C_SOFT_DECLARATIONS(bus) /* intentional without ';' */ + int j; + int nack; + + BB_I2C_ACTIVE(bus); + for (j = 0; j < 8; j++) { + BB_I2C_SCL(bus, 0); + BB_I2C_DELAY(bus); + BB_I2C_SDA(bus, data & 0x80); + BB_I2C_DELAY(bus); + BB_I2C_SCL(bus, 1); + BB_I2C_DELAY(bus); + BB_I2C_DELAY(bus); + + data <<= 1; + } + + /* + * Look for an <ACK>(negative logic) and return it. + */ + BB_I2C_SCL(bus, 0); + BB_I2C_DELAY(bus); + BB_I2C_SDA(bus, 1); + BB_I2C_TRISTATE(bus); + BB_I2C_DELAY(bus); + BB_I2C_SCL(bus, 1); + BB_I2C_DELAY(bus); + BB_I2C_DELAY(bus); + nack = BB_I2C_READ(bus); + BB_I2C_SCL(bus, 0); + BB_I2C_DELAY(bus); + BB_I2C_ACTIVE(bus); + + return nack; /* not a nack is an ack */ +} + +/*----------------------------------------------------------------------- + * if ack == BB_I2C_ACK, ACK the byte so can continue reading, else + * send BB_I2C_NOACK to end the read. + */ +static uchar read_byte(unsigned int bus, int ack) +{ + BB_I2C_SOFT_DECLARATIONS(bus) /* intentional without ';' */ + int data; + int j; + + /* + * Read 8 bits, MSB first. + */ + BB_I2C_TRISTATE(bus); + BB_I2C_SDA(bus, 1); + data = 0; + for (j = 0; j < 8; j++) { + BB_I2C_SCL(bus, 0); + BB_I2C_DELAY(bus); + BB_I2C_SCL(bus, 1); + BB_I2C_DELAY(bus); + data <<= 1; + data |= BB_I2C_READ(bus); + BB_I2C_DELAY(bus); + } + send_ack(bus, ack); + + return data; +} + +/*=====================================================================*/ +/* Public Functions */ +/*=====================================================================*/ + +/*----------------------------------------------------------------------- + * Initialization + */ +void bb_i2c_init(unsigned int bus, int speed, int slaveaddr) +{ + send_reset(bus); +} + +/*----------------------------------------------------------------------- + * Probe to see if a chip is present. Also good for checking for the + * completion of EEPROM writes since the chip stops responding until + * the write completes (typically 10mSec). + */ +int bb_i2c_probe(unsigned int bus, uchar addr) +{ + int rc; + + /* + * perform 1 byte write transaction with just address byte + * (fake write) + */ + send_start(bus); + rc = write_byte(bus, (addr << 1) | 0); + send_stop(bus); + + return rc ? 1 : 0; +} + +/*----------------------------------------------------------------------- + * Read bytes + */ +int bb_i2c_read(unsigned int bus, uchar chip, uint addr, int alen, + uchar *buffer, int len) +{ + int shift; + + /* + * Do the addressing portion of a write cycle to set the + * chip's address pointer. If the address length is zero, + * don't do the normal write cycle to set the address pointer, + * there is no address pointer in this chip. + */ + send_start(bus); + if (alen > 0) { + if (write_byte(bus, chip << 1)) { /* write cycle */ + send_stop(bus); + return 1; + } + shift = (alen-1) * 8; + while (alen-- > 0) { + if (write_byte(bus, addr >> shift)) + return 1; + shift -= 8; + } + + send_stop(bus); + send_start(bus); + } + /* + * Send the chip address again, this time for a read cycle. + * Then read the data. On the last byte, we do a NACK instead + * of an ACK(len == 0) to terminate the read. + */ + write_byte(bus, (chip << 1) | 1); /* read cycle */ + while (len-- > 0) + *buffer++ = read_byte(bus, len == 0); + send_stop(bus); + return 0; +} + +/*----------------------------------------------------------------------- + * Write bytes + */ +int bb_i2c_write(unsigned int bus, uchar chip, uint addr, int alen, + uchar *buffer, int len) +{ + int shift, failures = 0; + + send_start(bus); + if (write_byte(bus, chip << 1)) { /* write cycle */ + send_stop(bus); + return 1; + } + shift = (alen-1) * 8; + while (alen-- > 0) { + if (write_byte(bus, addr >> shift)) + return 1; + shift -= 8; + } + + while (len-- > 0) { + if (write_byte(bus, *buffer++)) + failures++; + } + send_stop(bus); + return failures; +} diff --git a/board/gdsys/common/bb_i2c.h b/board/gdsys/common/bb_i2c.h new file mode 100644 index 0000000..34f4c0f --- /dev/null +++ b/board/gdsys/common/bb_i2c.h @@ -0,0 +1,76 @@ +/* + * (C) Copyright 2012 + * Dirk Eibach, Guntermann & Drunck GmbH, eibach@gdsys.de + * + * based on i2c.h + * (C) Copyright 2001 + * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com. + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + * + * The original I2C interface was + * (C) 2000 by Paolo Scaffardi (arsenio@tin.it) + * AIRVENT SAM s.p.a - RIMINI(ITALY) + * but has been changed substantially. + */ + +#ifndef _BB_I2C_H_ +#define _BB_I2C_H_ + +/* + * Probe the given I2C chip address. Returns 0 if a chip responded, + * not 0 on failure. + */ +int bb_i2c_probe(unsigned int bus, uchar chip); + +/* + * Read/Write interface: + * chip: I2C chip address, range 0..127 + * addr: Memory (register) address within the chip + * alen: Number of bytes to use for addr (typically 1, 2 for larger + * memories, 0 for register type devices with only one + * register) + * buffer: Where to read/write the data + * len: How many bytes to read/write + * + * Returns: 0 on success, not 0 on failure + */ +int bb_i2c_read(unsigned int bus, uchar chip, uint addr, int alen, + uchar *buffer, int len); +int bb_i2c_write(unsigned int bus, uchar chip, uint addr, int alen, + uchar *buffer, int len); + +/* + * Utility routines to read/write registers. + */ +static inline u8 bb_i2c_reg_read(unsigned int bus, u8 addr, u8 reg) +{ + u8 buf; + + bb_i2c_read(bus, addr, reg, 1, &buf, 1); + + return buf; +} + +static inline void bb_i2c_reg_write(unsigned int bus, u8 addr, u8 reg, u8 val) +{ + bb_i2c_write(bus, addr, reg, 1, &val, 1); +} + +#endif /* _BB_I2C_H_ */