259 lines
6.8 KiB
C
259 lines
6.8 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2019 Ian Lepore <ian@freebsd.org>
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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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#include "opt_platform.h"
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#include <sys/param.h>
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#include <sys/bus.h>
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#include <sys/kernel.h>
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#include <sys/module.h>
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#include <sys/systm.h>
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#include <dev/iicbus/iicbus.h>
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#include <dev/iicbus/iiconf.h>
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#include "iicbus_if.h"
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#include "iicmux_if.h"
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static struct chip_info {
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const char *partname;
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const char *description;
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int numchannels;
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} chip_infos[] = {
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{"ltc4305", "LTC4305 I2C Mux", 2},
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{"ltc4306", "LTC4306 I2C Mux", 4},
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};
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#define CHIP_NONE (-1)
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#define CHIP_LTC4305 0
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#define CHIP_LTC4306 1
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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/ofw/openfirm.h>
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static struct ofw_compat_data compat_data[] = {
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{"lltc,ltc4305", CHIP_LTC4305},
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{"lltc,ltc4306", CHIP_LTC4306},
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{NULL, CHIP_NONE}
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};
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IICBUS_FDT_PNP_INFO(compat_data);
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#endif
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#include <dev/iicbus/mux/iicmux.h>
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struct ltc430x_softc {
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struct iicmux_softc mux;
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bool idle_disconnect;
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};
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/*
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* The datasheet doesn't name the registers, it calls them control register 0-3.
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*/
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#define LTC430X_CTLREG_0 0
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#define LTC430X_CTLREG_1 1
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#define LTC430X_CTLREG_2 2
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#define LTC430X_CR2_ENABLE_MW (1u << 3) /* Enable mass write address. */
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#define LTC430X_CTLREG_3 3
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static int
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ltc430x_bus_select(device_t dev, int busidx, struct iic_reqbus_data *rd)
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{
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struct ltc430x_softc *sc = device_get_softc(dev);
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uint8_t busbits;
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/*
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* The iicmux caller ensures busidx is between 0 and the number of buses
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* we passed to iicmux_init_softc(), no need for validation here. If
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* the fdt data has the idle_disconnect property we idle the bus by
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* selecting no downstream buses, otherwise we just leave the current
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* bus active. The upper bits of control register 3 activate the
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* downstream buses; bit 7 is the first bus, bit 6 the second, etc.
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*/
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if (busidx == IICMUX_SELECT_IDLE) {
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if (sc->idle_disconnect)
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busbits = 0;
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else
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return (0);
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} else {
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busbits = 1u << (7 - busidx);
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}
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/*
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* We have to add the IIC_RECURSIVE flag because the iicmux core has
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* already reserved the bus for us, and iicdev_writeto() is going to try
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* to reserve it again, which is allowed with the recursive flag.
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*/
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return (iicdev_writeto(dev, LTC430X_CTLREG_3, &busbits, sizeof(busbits),
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rd->flags | IIC_RECURSIVE));
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}
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static int
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ltc430x_find_chiptype(device_t dev)
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{
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#ifdef FDT
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return (ofw_bus_search_compatible(dev, compat_data)->ocd_data);
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#else
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const char *type;
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int i;
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if (resource_string_value(device_get_name(dev), device_get_unit(dev),
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"chip_type", &type) == 0) {
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for (i = 0; i < nitems(chip_infos); ++i) {
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if (strcasecmp(type, chip_infos[i].partname) == 0) {
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return (i);
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}
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}
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}
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return (CHIP_NONE);
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#endif
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}
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static int
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ltc430x_probe(device_t dev)
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{
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int type;
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#ifdef FDT
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if (!ofw_bus_status_okay(dev))
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return (ENXIO);
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#endif
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type = ltc430x_find_chiptype(dev);
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if (type == CHIP_NONE)
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return (ENXIO);
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device_set_desc(dev, chip_infos[type].description);
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return (BUS_PROBE_DEFAULT);
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}
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static int
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ltc430x_attach(device_t dev)
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{
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struct ltc430x_softc *sc __unused;
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int chip, err, numchan, val;
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uint8_t busbits, ctlreg2;
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sc = device_get_softc(dev);
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busbits = 0;
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ctlreg2 = LTC430X_CR2_ENABLE_MW;
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/*
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* Check for the idle-disconnect and ctlreg2 options, first in FDT data,
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* then allow them to be overriden by hints data.
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*/
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#ifdef FDT
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phandle_t node;
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node = ofw_bus_get_node(dev);
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sc->idle_disconnect = OF_hasprop(node, "i2c-mux-idle-disconnect");
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if (OF_getprop(node, "freebsd,ctlreg2", &val, sizeof(val)) > 0) {
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ctlreg2 = val;
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}
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#endif
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if (resource_int_value(device_get_name(dev), device_get_unit(dev),
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"idle_disconnect", &val) == 0) {
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sc->idle_disconnect = val;
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}
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if (resource_int_value(device_get_name(dev), device_get_unit(dev),
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"ctlreg2", &val) == 0) {
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ctlreg2 = val;
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}
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/* We found the chip type when probing, so now it "can't fail". */
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if ((chip = ltc430x_find_chiptype(dev)) == CHIP_NONE) {
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device_printf(dev, "impossible: can't identify chip type\n");
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return (ENXIO);
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}
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numchan = chip_infos[chip].numchannels;
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/* Set control reg 2 with configured (or default) values. */
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iicdev_writeto(dev, LTC430X_CTLREG_2, &ctlreg2, sizeof(ctlreg2),
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IIC_WAIT);
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/* If configured for idle-disconnect, ensure we start disconnected. */
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if (sc->idle_disconnect) {
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iicdev_writeto(dev, LTC430X_CTLREG_3, &busbits, sizeof(busbits),
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IIC_WAIT);
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}
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/*
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* Invoke the iicmux framework's attach code, and if it succeeds, invoke
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* the probe and attach code of any child iicbus instances it added.
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*/
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if ((err = iicmux_attach(dev, device_get_parent(dev), numchan)) == 0)
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bus_generic_attach(dev);
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return (err);
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}
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static int
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ltc430x_detach(device_t dev)
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{
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int err;
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if ((err = iicmux_detach(dev)) != 0)
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return (err);
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return (0);
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}
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static device_method_t ltc430x_methods[] = {
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/* device methods */
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DEVMETHOD(device_probe, ltc430x_probe),
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DEVMETHOD(device_attach, ltc430x_attach),
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DEVMETHOD(device_detach, ltc430x_detach),
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/* iicmux methods */
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DEVMETHOD(iicmux_bus_select, ltc430x_bus_select),
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DEVMETHOD_END
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};
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static devclass_t ltc430x_devclass;
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DEFINE_CLASS_1(ltc430x, ltc430x_driver, ltc430x_methods,
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sizeof(struct ltc430x_softc), iicmux_driver);
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DRIVER_MODULE(ltc430x, iicbus, ltc430x_driver, ltc430x_devclass, 0, 0);
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#ifdef FDT
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DRIVER_MODULE(ofw_iicbus, ltc430x, ofw_iicbus_driver, ofw_iicbus_devclass, 0, 0);
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#else
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DRIVER_MODULE(iicbus, ltc430x, iicbus_driver, iicbus_devclass, 0, 0);
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#endif
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MODULE_DEPEND(ltc430x, iicmux, 1, 1, 1);
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MODULE_DEPEND(ltc430x, iicbus, 1, 1, 1);
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