bf17755477
This change makes ofw_iicbus attach to iicbb(4) controllers in addition to the already supported i2c host bridges (iichb). On iicbb(4) allow the direct access of the OFW parent node by its children, so they can be directly attached to iicbb(4) node on the DTS without the need of describing the i2c bus. Approved by: adrian (mentor, implicit)
472 lines
10 KiB
C
472 lines
10 KiB
C
/*-
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* Copyright (c) 1998, 2001 Nicolas Souchu
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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/*
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* Generic I2C bit-banging code
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*
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* Example:
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*
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* iicbus
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* / \
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* iicbb pcf
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* | \
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* bti2c lpbb
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*
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* From Linux I2C generic interface
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* (c) 1998 Gerd Knorr <kraxel@cs.tu-berlin.de>
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*
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*/
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#include "opt_platform.h"
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/systm.h>
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#include <sys/module.h>
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#include <sys/bus.h>
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#include <sys/uio.h>
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#ifdef FDT
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#include <dev/ofw/ofw_bus.h>
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#include <dev/ofw/ofw_bus_subr.h>
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#include <dev/fdt/fdt_common.h>
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#endif
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#include <dev/iicbus/iiconf.h>
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#include <dev/iicbus/iicbus.h>
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#include <dev/smbus/smbconf.h>
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#include "iicbus_if.h"
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#include "iicbb_if.h"
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struct iicbb_softc {
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device_t iicbus;
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int udelay; /* signal toggle delay in usec */
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};
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static int iicbb_attach(device_t);
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static void iicbb_child_detached(device_t, device_t);
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static int iicbb_detach(device_t);
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static int iicbb_print_child(device_t, device_t);
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static int iicbb_probe(device_t);
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static int iicbb_callback(device_t, int, caddr_t);
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static int iicbb_start(device_t, u_char, int);
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static int iicbb_stop(device_t);
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static int iicbb_write(device_t, const char *, int, int *, int);
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static int iicbb_read(device_t, char *, int, int *, int, int);
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static int iicbb_reset(device_t, u_char, u_char, u_char *);
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static int iicbb_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs);
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#ifdef FDT
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static phandle_t iicbb_get_node(device_t, device_t);
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#endif
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static device_method_t iicbb_methods[] = {
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/* device interface */
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DEVMETHOD(device_probe, iicbb_probe),
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DEVMETHOD(device_attach, iicbb_attach),
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DEVMETHOD(device_detach, iicbb_detach),
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/* bus interface */
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DEVMETHOD(bus_child_detached, iicbb_child_detached),
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DEVMETHOD(bus_print_child, iicbb_print_child),
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/* iicbus interface */
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DEVMETHOD(iicbus_callback, iicbb_callback),
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DEVMETHOD(iicbus_start, iicbb_start),
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DEVMETHOD(iicbus_repeated_start, iicbb_start),
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DEVMETHOD(iicbus_stop, iicbb_stop),
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DEVMETHOD(iicbus_write, iicbb_write),
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DEVMETHOD(iicbus_read, iicbb_read),
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DEVMETHOD(iicbus_reset, iicbb_reset),
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DEVMETHOD(iicbus_transfer, iicbb_transfer),
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#ifdef FDT
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/* ofw_bus interface */
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DEVMETHOD(ofw_bus_get_node, iicbb_get_node),
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#endif
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{ 0, 0 }
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};
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driver_t iicbb_driver = {
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"iicbb",
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iicbb_methods,
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sizeof(struct iicbb_softc),
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};
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devclass_t iicbb_devclass;
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static int
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iicbb_probe(device_t dev)
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{
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device_set_desc(dev, "I2C bit-banging driver");
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return (0);
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}
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static int
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iicbb_attach(device_t dev)
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{
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struct iicbb_softc *sc = (struct iicbb_softc *)device_get_softc(dev);
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sc->iicbus = device_add_child(dev, "iicbus", -1);
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if (!sc->iicbus)
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return (ENXIO);
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sc->udelay = 10; /* 10 uS default */
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bus_generic_attach(dev);
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return (0);
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}
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static int
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iicbb_detach(device_t dev)
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{
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struct iicbb_softc *sc = (struct iicbb_softc *)device_get_softc(dev);
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device_t child;
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/*
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* We need to save child because the detach indirectly causes
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* sc->iicbus to be zeroed. Since we added the device
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* unconditionally in iicbb_attach, we need to make sure we
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* delete it here. See iicbb_child_detached. We need that
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* callback in case newbus detached our children w/o detaching
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* us (say iicbus is a module and unloaded w/o iicbb being
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* unloaded).
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*/
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child = sc->iicbus;
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bus_generic_detach(dev);
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if (child)
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device_delete_child(dev, child);
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return (0);
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}
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#ifdef FDT
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static phandle_t
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iicbb_get_node(device_t bus, device_t dev)
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{
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/* We only have one child, the I2C bus, which needs our own node. */
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return (ofw_bus_get_node(bus));
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}
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#endif
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static void
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iicbb_child_detached( device_t dev, device_t child )
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{
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struct iicbb_softc *sc = (struct iicbb_softc *)device_get_softc(dev);
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if (child == sc->iicbus)
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sc->iicbus = NULL;
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}
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static int
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iicbb_print_child(device_t bus, device_t dev)
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{
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int error;
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int retval = 0;
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u_char oldaddr;
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retval += bus_print_child_header(bus, dev);
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/* retrieve the interface I2C address */
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error = IICBB_RESET(device_get_parent(bus), IIC_FASTEST, 0, &oldaddr);
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if (error == IIC_ENOADDR) {
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retval += printf(" on %s master-only\n",
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device_get_nameunit(bus));
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} else {
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/* restore the address */
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IICBB_RESET(device_get_parent(bus), IIC_FASTEST, oldaddr, NULL);
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retval += printf(" on %s addr 0x%x\n",
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device_get_nameunit(bus), oldaddr & 0xff);
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}
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return (retval);
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}
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#define I2C_SETSDA(sc,dev,val) do { \
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IICBB_SETSDA(device_get_parent(dev), val); \
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DELAY(sc->udelay); \
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} while (0)
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#define I2C_SETSCL(dev,val) do { \
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iicbb_setscl(dev, val, 100); \
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} while (0)
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#define I2C_SET(sc,dev,ctrl,data) do { \
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I2C_SETSCL(dev, ctrl); \
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I2C_SETSDA(sc, dev, data); \
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} while (0)
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#define I2C_GETSDA(dev) (IICBB_GETSDA(device_get_parent(dev)))
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#define I2C_GETSCL(dev) (IICBB_GETSCL(device_get_parent(dev)))
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static int i2c_debug = 0;
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#define I2C_DEBUG(x) do { \
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if (i2c_debug) (x); \
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} while (0)
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#define I2C_LOG(format,args...) do { \
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printf(format, args); \
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} while (0)
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static void
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iicbb_setscl(device_t dev, int val, int timeout)
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{
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struct iicbb_softc *sc = device_get_softc(dev);
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int k = 0;
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IICBB_SETSCL(device_get_parent(dev), val);
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DELAY(sc->udelay);
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while (val && !I2C_GETSCL(dev) && k++ < timeout) {
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IICBB_SETSCL(device_get_parent(dev), val);
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DELAY(sc->udelay);
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}
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return;
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}
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static void
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iicbb_one(device_t dev, int timeout)
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{
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struct iicbb_softc *sc = device_get_softc(dev);
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I2C_SET(sc,dev,0,1);
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I2C_SET(sc,dev,1,1);
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I2C_SET(sc,dev,0,1);
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return;
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}
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static void
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iicbb_zero(device_t dev, int timeout)
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{
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struct iicbb_softc *sc = device_get_softc(dev);
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I2C_SET(sc,dev,0,0);
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I2C_SET(sc,dev,1,0);
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I2C_SET(sc,dev,0,0);
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return;
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}
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/*
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* Waiting for ACKNOWLEDGE.
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*
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* When a chip is being addressed or has received data it will issue an
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* ACKNOWLEDGE pulse. Therefore the MASTER must release the DATA line
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* (set it to high level) and then release the CLOCK line.
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* Now it must wait for the SLAVE to pull the DATA line low.
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* Actually on the bus this looks like a START condition so nothing happens
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* because of the fact that the IC's that have not been addressed are doing
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* nothing.
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*
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* When the SLAVE has pulled this line low the MASTER will take the CLOCK
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* line low and then the SLAVE will release the SDA (data) line.
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*/
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static int
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iicbb_ack(device_t dev, int timeout)
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{
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struct iicbb_softc *sc = device_get_softc(dev);
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int noack;
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int k = 0;
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I2C_SET(sc,dev,0,1);
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I2C_SET(sc,dev,1,1);
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do {
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noack = I2C_GETSDA(dev);
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if (!noack)
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break;
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DELAY(1);
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k++;
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} while (k < timeout);
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I2C_SET(sc,dev,0,1);
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I2C_DEBUG(printf("%c ",noack?'-':'+'));
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return (noack);
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}
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static void
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iicbb_sendbyte(device_t dev, u_char data, int timeout)
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{
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int i;
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for (i=7; i>=0; i--) {
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if (data&(1<<i)) {
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iicbb_one(dev, timeout);
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} else {
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iicbb_zero(dev, timeout);
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}
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}
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I2C_DEBUG(printf("w%02x",(int)data));
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return;
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}
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static u_char
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iicbb_readbyte(device_t dev, int last, int timeout)
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{
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struct iicbb_softc *sc = device_get_softc(dev);
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int i;
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unsigned char data=0;
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I2C_SET(sc,dev,0,1);
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for (i=7; i>=0; i--)
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{
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I2C_SET(sc,dev,1,1);
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if (I2C_GETSDA(dev))
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data |= (1<<i);
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I2C_SET(sc,dev,0,1);
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}
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if (last) {
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iicbb_one(dev, timeout);
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} else {
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iicbb_zero(dev, timeout);
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}
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I2C_DEBUG(printf("r%02x%c ",(int)data,last?'-':'+'));
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return data;
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}
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static int
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iicbb_callback(device_t dev, int index, caddr_t data)
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{
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return (IICBB_CALLBACK(device_get_parent(dev), index, data));
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}
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static int
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iicbb_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
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{
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return (IICBB_RESET(device_get_parent(dev), speed, addr, oldaddr));
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}
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static int
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iicbb_start(device_t dev, u_char slave, int timeout)
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{
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struct iicbb_softc *sc = device_get_softc(dev);
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int error;
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I2C_DEBUG(printf("<"));
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I2C_SET(sc,dev,1,1);
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I2C_SET(sc,dev,1,0);
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I2C_SET(sc,dev,0,0);
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/* send address */
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iicbb_sendbyte(dev, slave, timeout);
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/* check for ack */
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if (iicbb_ack(dev, timeout)) {
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error = IIC_ENOACK;
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goto error;
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}
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return(0);
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error:
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iicbb_stop(dev);
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return (error);
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}
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static int
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iicbb_stop(device_t dev)
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{
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struct iicbb_softc *sc = device_get_softc(dev);
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I2C_SET(sc,dev,0,0);
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I2C_SET(sc,dev,1,0);
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I2C_SET(sc,dev,1,1);
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I2C_DEBUG(printf(">"));
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I2C_DEBUG(printf("\n"));
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return (0);
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}
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static int
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iicbb_write(device_t dev, const char *buf, int len, int *sent, int timeout)
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{
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int bytes, error = 0;
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bytes = 0;
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while (len) {
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/* send byte */
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iicbb_sendbyte(dev,(u_char)*buf++, timeout);
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/* check for ack */
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if (iicbb_ack(dev, timeout)) {
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error = IIC_ENOACK;
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goto error;
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}
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bytes ++;
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len --;
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}
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error:
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*sent = bytes;
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return (error);
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}
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static int
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iicbb_read(device_t dev, char * buf, int len, int *read, int last, int delay)
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{
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int bytes;
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bytes = 0;
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while (len) {
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/* XXX should insert delay here */
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*buf++ = (char)iicbb_readbyte(dev, (len == 1) ? last : 0, delay);
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bytes ++;
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len --;
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}
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*read = bytes;
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return (0);
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}
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static int
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iicbb_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
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{
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int error;
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error = IICBB_PRE_XFER(device_get_parent(dev));
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if (error)
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return (error);
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error = iicbus_transfer_gen(dev, msgs, nmsgs);
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IICBB_POST_XFER(device_get_parent(dev));
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return (error);
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}
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DRIVER_MODULE(iicbus, iicbb, iicbus_driver, iicbus_devclass, 0, 0);
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MODULE_DEPEND(iicbb, iicbus, IICBUS_MINVER, IICBUS_PREFVER, IICBUS_MAXVER);
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MODULE_VERSION(iicbb, IICBB_MODVER);
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