diff options
Diffstat (limited to 'sys/dev/iicbus/iicbb.c')
-rw-r--r-- | sys/dev/iicbus/iicbb.c | 390 |
1 files changed, 390 insertions, 0 deletions
diff --git a/sys/dev/iicbus/iicbb.c b/sys/dev/iicbus/iicbb.c new file mode 100644 index 0000000..53ecdce --- /dev/null +++ b/sys/dev/iicbus/iicbb.c @@ -0,0 +1,390 @@ +/*- + * Copyright (c) 1998, 2001 Nicolas Souchu + * All rights reserved. + * + * 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. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 THE AUTHOR OR CONTRIBUTORS 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. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +/* + * Generic I2C bit-banging code + * + * Example: + * + * iicbus + * / \ + * iicbb pcf + * | \ + * bti2c lpbb + * + * From Linux I2C generic interface + * (c) 1998 Gerd Knorr <kraxel@cs.tu-berlin.de> + * + */ + +#include <sys/param.h> +#include <sys/kernel.h> +#include <sys/systm.h> +#include <sys/module.h> +#include <sys/bus.h> +#include <sys/uio.h> + + +#include <dev/iicbus/iiconf.h> +#include <dev/iicbus/iicbus.h> + +#include <dev/smbus/smbconf.h> + +#include "iicbus_if.h" +#include "iicbb_if.h" + +struct iicbb_softc { + device_t iicbus; +}; + +static int iicbb_probe(device_t); +static int iicbb_attach(device_t); +static int iicbb_detach(device_t); +static int iicbb_print_child(device_t, device_t); + +static int iicbb_callback(device_t, int, caddr_t); +static int iicbb_start(device_t, u_char, int); +static int iicbb_stop(device_t); +static int iicbb_write(device_t, char *, int, int *, int); +static int iicbb_read(device_t, char *, int, int *, int, int); +static int iicbb_reset(device_t, u_char, u_char, u_char *); + +static device_method_t iicbb_methods[] = { + /* device interface */ + DEVMETHOD(device_probe, iicbb_probe), + DEVMETHOD(device_attach, iicbb_attach), + DEVMETHOD(device_detach, iicbb_detach), + + /* bus interface */ + DEVMETHOD(bus_print_child, iicbb_print_child), + + /* iicbus interface */ + DEVMETHOD(iicbus_callback, iicbb_callback), + DEVMETHOD(iicbus_start, iicbb_start), + DEVMETHOD(iicbus_repeated_start, iicbb_start), + DEVMETHOD(iicbus_stop, iicbb_stop), + DEVMETHOD(iicbus_write, iicbb_write), + DEVMETHOD(iicbus_read, iicbb_read), + DEVMETHOD(iicbus_reset, iicbb_reset), + + { 0, 0 } +}; + +driver_t iicbb_driver = { + "iicbb", + iicbb_methods, + sizeof(struct iicbb_softc), +}; + +devclass_t iicbb_devclass; + +static int iicbb_probe(device_t dev) +{ + device_set_desc(dev, "I2C bit-banging driver"); + + return (0); +} + +static int iicbb_attach(device_t dev) +{ + struct iicbb_softc *sc = (struct iicbb_softc *)device_get_softc(dev); + + bzero(sc, sizeof(struct iicbb_softc)); + + sc->iicbus = device_add_child(dev, "iicbus", -1); + + if (!sc->iicbus) + return (ENXIO); + + bus_generic_attach(dev); + + return (0); +} + +static int iicbb_detach(device_t dev) +{ + struct iicbb_softc *sc = (struct iicbb_softc *)device_get_softc(dev); + + if (sc->iicbus) { + bus_generic_detach(dev); + device_delete_child(dev, sc->iicbus); + } + + return (0); +} + +static int +iicbb_print_child(device_t bus, device_t dev) +{ + int error; + int retval = 0; + u_char oldaddr; + + retval += bus_print_child_header(bus, dev); + /* retrieve the interface I2C address */ + error = IICBB_RESET(device_get_parent(bus), IIC_FASTEST, 0, &oldaddr); + if (error == IIC_ENOADDR) { + retval += printf(" on %s master-only\n", + device_get_nameunit(bus)); + } else { + /* restore the address */ + IICBB_RESET(device_get_parent(bus), IIC_FASTEST, oldaddr, NULL); + + retval += printf(" on %s addr 0x%x\n", + device_get_nameunit(bus), oldaddr & 0xff); + } + + return (retval); +} + +#define IIC_DELAY 10 + +#define I2C_SETSDA(dev,val) do { \ + IICBB_SETSDA(device_get_parent(dev), val); \ + DELAY(IIC_DELAY); \ + } while (0) + +#define I2C_SETSCL(dev,val) do { \ + iicbb_setscl(dev, val, 100); \ + } while (0) + +#define I2C_SET(dev,ctrl,data) do { \ + I2C_SETSCL(dev, ctrl); \ + I2C_SETSDA(dev, data); \ + } while (0) + +#define I2C_GETSDA(dev) (IICBB_GETSDA(device_get_parent(dev))) + +#define I2C_GETSCL(dev) (IICBB_GETSCL(device_get_parent(dev))) + +static int i2c_debug = 0; +#define I2C_DEBUG(x) do { \ + if (i2c_debug) (x); \ + } while (0) + +#define I2C_LOG(format,args...) do { \ + printf(format, args); \ + } while (0) + +static void iicbb_setscl(device_t dev, int val, int timeout) +{ + int k = 0; + + IICBB_SETSCL(device_get_parent(dev), val); + DELAY(IIC_DELAY); + + while (val && !I2C_GETSCL(dev) && k++ < timeout) { + IICBB_SETSCL(device_get_parent(dev), val); + DELAY(IIC_DELAY); + } + + return; +} + +static void iicbb_one(device_t dev, int timeout) +{ + I2C_SET(dev,0,1); + I2C_SET(dev,1,1); + I2C_SET(dev,0,1); + return; +} + +static void iicbb_zero(device_t dev, int timeout) +{ + I2C_SET(dev,0,0); + I2C_SET(dev,1,0); + I2C_SET(dev,0,0); + return; +} + +/* + * Waiting for ACKNOWLEDGE. + * + * When a chip is being addressed or has received data it will issue an + * ACKNOWLEDGE pulse. Therefore the MASTER must release the DATA line + * (set it to high level) and then release the CLOCK line. + * Now it must wait for the SLAVE to pull the DATA line low. + * Actually on the bus this looks like a START condition so nothing happens + * because of the fact that the IC's that have not been addressed are doing + * nothing. + * + * When the SLAVE has pulled this line low the MASTER will take the CLOCK + * line low and then the SLAVE will release the SDA (data) line. + */ +static int iicbb_ack(device_t dev, int timeout) +{ + int noack; + int k = 0; + + I2C_SET(dev,0,1); + I2C_SET(dev,1,1); + do { + noack = I2C_GETSDA(dev); + if (!noack) + break; + DELAY(10); + k += 10; + } while (k < timeout); + + I2C_SET(dev,0,1); + I2C_DEBUG(printf("%c ",noack?'-':'+')); + + return (noack); +} + +static void iicbb_sendbyte(device_t dev, u_char data, int timeout) +{ + int i; + + for (i=7; i>=0; i--) { + if (data&(1<<i)) { + iicbb_one(dev, timeout); + } else { + iicbb_zero(dev, timeout); + } + } + I2C_DEBUG(printf("w%02x",(int)data)); + return; +} + +static u_char iicbb_readbyte(device_t dev, int last, int timeout) +{ + int i; + unsigned char data=0; + + I2C_SET(dev,0,1); + for (i=7; i>=0; i--) + { + I2C_SET(dev,1,1); + if (I2C_GETSDA(dev)) + data |= (1<<i); + I2C_SET(dev,0,1); + } + if (last) { + iicbb_one(dev, timeout); + } else { + iicbb_zero(dev, timeout); + } + I2C_DEBUG(printf("r%02x%c ",(int)data,last?'-':'+')); + return data; +} + +static int iicbb_callback(device_t dev, int index, caddr_t data) +{ + return (IICBB_CALLBACK(device_get_parent(dev), index, data)); +} + +static int iicbb_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr) +{ + return (IICBB_RESET(device_get_parent(dev), speed, addr, oldaddr)); +} + +static int iicbb_start(device_t dev, u_char slave, int timeout) +{ + int error; + + I2C_DEBUG(printf("<")); + + I2C_SET(dev,1,1); + I2C_SET(dev,1,0); + I2C_SET(dev,0,0); + + /* send address */ + iicbb_sendbyte(dev, slave, timeout); + + /* check for ack */ + if (iicbb_ack(dev, timeout)) { + error = IIC_ENOACK; + goto error; + } + + return(0); + +error: + iicbb_stop(dev); + return (error); +} + +static int iicbb_stop(device_t dev) +{ + I2C_SET(dev,0,0); + I2C_SET(dev,1,0); + I2C_SET(dev,1,1); + I2C_DEBUG(printf(">")); + return (0); +} + +static int iicbb_write(device_t dev, char * buf, int len, int *sent, + int timeout) +{ + int bytes, error = 0; + + bytes = 0; + while (len) { + /* send byte */ + iicbb_sendbyte(dev,(u_char)*buf++, timeout); + + /* check for ack */ + if (iicbb_ack(dev, timeout)) { + error = IIC_ENOACK; + goto error; + } + bytes ++; + len --; + } + +error: + *sent = bytes; + return (error); +} + +static int iicbb_read(device_t dev, char * buf, int len, int *read, + int last, int delay) +{ + int bytes; + + bytes = 0; + while (len) { + /* XXX should insert delay here */ + *buf++ = (char)iicbb_readbyte(dev, (len == 1) ? last : 0, delay); + + bytes ++; + len --; + } + + *read = bytes; + return (0); +} + +DRIVER_MODULE(iicbb, bktr, iicbb_driver, iicbb_devclass, 0, 0); +DRIVER_MODULE(iicbb, lpbb, iicbb_driver, iicbb_devclass, 0, 0); +DRIVER_MODULE(iicbb, viapm, iicbb_driver, iicbb_devclass, 0, 0); + +MODULE_DEPEND(iicbb, iicbus, IICBUS_MINVER, IICBUS_PREFVER, IICBUS_MAXVER); +MODULE_VERSION(iicbb, IICBB_MODVER); |