diff options
| -rw-r--r-- | sys/dev/i2c/files.i2c | 4 | ||||
| -rw-r--r-- | sys/dev/i2c/i2c_bitbang.c | 179 | ||||
| -rw-r--r-- | sys/dev/i2c/i2c_bitbang.h | 63 |
3 files changed, 245 insertions, 1 deletions
diff --git a/sys/dev/i2c/files.i2c b/sys/dev/i2c/files.i2c index 3a0b718af89..30a3a46327d 100644 --- a/sys/dev/i2c/files.i2c +++ b/sys/dev/i2c/files.i2c @@ -1,12 +1,14 @@ -# $OpenBSD: files.i2c,v 1.26 2006/01/02 19:49:26 miod Exp $ +# $OpenBSD: files.i2c,v 1.27 2006/01/13 23:56:46 grange Exp $ # $NetBSD: files.i2c,v 1.3 2003/10/20 16:24:10 briggs Exp $ define i2c {[addr = -1], [size = -1]} +define i2c_bitbang device iic: i2c attach iic at i2cbus file dev/i2c/i2c.c iic | i2cbus file dev/i2c/i2c_exec.c iic | i2cbus file dev/i2c/i2c_scan.c iic | i2cbus +file dev/i2c/i2c_bitbang.c i2c_bitbang # # I2C client devices diff --git a/sys/dev/i2c/i2c_bitbang.c b/sys/dev/i2c/i2c_bitbang.c new file mode 100644 index 00000000000..5a865b0af9c --- /dev/null +++ b/sys/dev/i2c/i2c_bitbang.c @@ -0,0 +1,179 @@ +/* $OpenBSD: i2c_bitbang.c,v 1.3 2006/01/13 23:56:46 grange Exp $ */ +/* $NetBSD: i2c_bitbang.c,v 1.1 2003/09/30 00:35:31 thorpej Exp $ */ + +/* + * Copyright (c) 2003 Wasabi Systems, Inc. + * All rights reserved. + * + * Written by Jason R. Thorpe for Wasabi Systems, Inc. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed for the NetBSD Project by + * Wasabi Systems, Inc. + * 4. The name of Wasabi Systems, Inc. may not be used to endorse + * or promote products derived from this software without specific prior + * written permission. + * + * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC + * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +/* + * Common module for bit-bang'ing an I2C bus. + */ + +#include <sys/param.h> + +#include <dev/i2c/i2cvar.h> +#include <dev/i2c/i2c_bitbang.h> + +#define BB_SET(x) ops->ibo_set_bits(v, (x)) +#define BB_DIR(x) ops->ibo_set_dir(v, (x)) +#define BB_READ ops->ibo_read_bits(v) + +#define SDA ops->ibo_bits[I2C_BIT_SDA] /* i2c signal */ +#define SCL ops->ibo_bits[I2C_BIT_SCL] /* i2c signal */ +#define OUTPUT ops->ibo_bits[I2C_BIT_OUTPUT] /* SDA is output */ +#define INPUT ops->ibo_bits[I2C_BIT_INPUT] /* SDA is input */ + +/*ARGSUSED*/ +int +i2c_bitbang_send_start(void *v, int flags, i2c_bitbang_ops_t ops) +{ + + BB_DIR(OUTPUT); + + BB_SET(SDA | SCL); + delay(5); /* bus free time (4.7 uS) */ + BB_SET( SCL); + delay(4); /* start hold time (4.0 uS) */ + BB_SET( 0); + delay(5); /* clock low time (4.7 uS) */ + + return (0); +} + +/*ARGSUSED*/ +int +i2c_bitbang_send_stop(void *v, int flags, i2c_bitbang_ops_t ops) +{ + + BB_DIR(OUTPUT); + + BB_SET( SCL); + delay(4); /* stop setup time (4.0 uS) */ + BB_SET(SDA | SCL); + + return (0); +} + +int +i2c_bitbang_initiate_xfer(void *v, i2c_addr_t addr, int flags, + i2c_bitbang_ops_t ops) +{ + int i2caddr; + + /* XXX Only support 7-bit addressing for now. */ + if ((addr & 0x78) == 0x78) + return (EINVAL); + + i2caddr = (addr << 1) | ((flags & I2C_F_READ) ? 1 : 0); + + (void) i2c_bitbang_send_start(v, flags, ops); + return (i2c_bitbang_write_byte(v, i2caddr, flags & ~I2C_F_STOP, ops)); +} + +int +i2c_bitbang_read_byte(void *v, uint8_t *valp, int flags, + i2c_bitbang_ops_t ops) +{ + int i; + uint8_t val = 0; + uint32_t bit; + + BB_DIR(INPUT); + BB_SET(SDA ); + + for (i = 0; i < 8; i++) { + val <<= 1; + BB_SET(SDA | SCL); + delay(4); /* clock high time (4.0 uS) */ + if (BB_READ & SDA) + val |= 1; + BB_SET(SDA ); + delay(5); /* clock low time (4.7 uS) */ + } + + bit = (flags & I2C_F_LAST) ? SDA : 0; + BB_DIR(OUTPUT); + BB_SET(bit ); + delay(1); /* data setup time (250 nS) */ + BB_SET(bit | SCL); + delay(4); /* clock high time (4.0 uS) */ + BB_SET(bit ); + delay(5); /* clock low time (4.7 uS) */ + + BB_DIR(INPUT); + BB_SET(SDA ); + delay(5); + + if ((flags & (I2C_F_STOP | I2C_F_LAST)) == (I2C_F_STOP | I2C_F_LAST)) + (void) i2c_bitbang_send_stop(v, flags, ops); + + *valp = val; + return (0); +} + +int +i2c_bitbang_write_byte(void *v, uint8_t val, int flags, + i2c_bitbang_ops_t ops) +{ + uint32_t bit; + uint8_t mask; + int error; + + BB_DIR(OUTPUT); + + for (mask = 0x80; mask != 0; mask >>= 1) { + bit = (val & mask) ? SDA : 0; + BB_SET(bit ); + delay(1); /* data setup time (250 nS) */ + BB_SET(bit | SCL); + delay(4); /* clock high time (4.0 uS) */ + BB_SET(bit ); + delay(5); /* clock low time (4.7 uS) */ + } + + BB_DIR(INPUT); + + BB_SET(SDA ); + delay(5); + BB_SET(SDA | SCL); + delay(4); + error = (BB_READ & SDA) ? EIO : 0; + BB_SET(SDA ); + delay(5); + + if (flags & I2C_F_STOP) + (void) i2c_bitbang_send_stop(v, flags, ops); + + return (error); +} diff --git a/sys/dev/i2c/i2c_bitbang.h b/sys/dev/i2c/i2c_bitbang.h new file mode 100644 index 00000000000..a10eb425547 --- /dev/null +++ b/sys/dev/i2c/i2c_bitbang.h @@ -0,0 +1,63 @@ +/* $OpenBSD: i2c_bitbang.h,v 1.3 2006/01/13 23:56:46 grange Exp $ */ +/* $NetBSD: i2c_bitbang.h,v 1.1 2003/09/30 00:35:31 thorpej Exp $ */ + +/* + * Copyright (c) 2003 Wasabi Systems, Inc. + * All rights reserved. + * + * Written by Jason R. Thorpe for Wasabi Systems, Inc. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed for the NetBSD Project by + * Wasabi Systems, Inc. + * 4. The name of Wasabi Systems, Inc. may not be used to endorse + * or promote products derived from this software without specific prior + * written permission. + * + * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC + * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef _DEV_I2C_I2C_BITBANG_H_ +#define _DEV_I2C_I2C_BITBANG_H_ + +#define I2C_BIT_SDA 0 /* SDA signal */ +#define I2C_BIT_SCL 1 /* SCL signal */ +#define I2C_BIT_OUTPUT 2 /* controller: SDA is output */ +#define I2C_BIT_INPUT 3 /* controller: SDA is input */ +#define I2C_NBITS 4 + +struct i2c_bitbang_ops { + void (*ibo_set_bits)(void *, uint32_t); + void (*ibo_set_dir)(void *, uint32_t); + uint32_t (*ibo_read_bits)(void *); + uint32_t ibo_bits[I2C_NBITS]; +}; + +typedef const struct i2c_bitbang_ops *i2c_bitbang_ops_t; + +int i2c_bitbang_send_start(void *, int, i2c_bitbang_ops_t); +int i2c_bitbang_send_stop(void *, int, i2c_bitbang_ops_t); +int i2c_bitbang_initiate_xfer(void *, i2c_addr_t, int, i2c_bitbang_ops_t); +int i2c_bitbang_read_byte(void *, uint8_t *, int, i2c_bitbang_ops_t); +int i2c_bitbang_write_byte(void *, uint8_t, int, i2c_bitbang_ops_t); + +#endif /* _DEV_I2C_I2C_BITBANG_H_ */ |