269 lines
6.3 KiB
C
269 lines
6.3 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) Andriy Gapon
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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 FOR
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* 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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*/
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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/sysctl.h>
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#include <sys/systm.h>
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#include <machine/bus.h>
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#include <dev/iicbus/iicbus.h>
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#include <dev/iicbus/iiconf.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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#endif
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/*
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* Driver for PCF8591 I2C 8-bit ADC and DAC.
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*/
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#define CTRL_CH_SELECT_MASK 0x03
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#define CTRL_AUTOINC_EN 0x04
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#define CTRL_CH_CONFIG_MASK 0x30
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#define CTRL_CH_CONFIG_4_SINGLE 0x00
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#define CTRL_CH_CONFIG_3_DIFF 0x10
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#define CTRL_CH_CONFIG_2_SINGLE_1_DIFF 0x20
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#define CTRL_CH_CONFIG_2_DIFF 0x30
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#define CTRL_OUTPUT_EN 0x40
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struct pcf8591_softc {
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device_t sc_dev;
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int sc_ch_count;
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uint8_t sc_addr;
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uint8_t sc_cfg;
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uint8_t sc_output;
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};
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#ifdef FDT
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static struct ofw_compat_data compat_data[] = {
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{ "nxp,pcf8591", true },
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{ NULL, false }
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};
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#endif
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static int
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pcf8591_set_config(device_t dev)
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{
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struct iic_msg msg;
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uint8_t data[2];
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struct pcf8591_softc *sc;
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int error;
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sc = device_get_softc(dev);
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data[0] = sc->sc_cfg;
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data[1] = sc->sc_output;
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msg.slave = sc->sc_addr;
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msg.flags = IIC_M_WR;
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msg.len = nitems(data);
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msg.buf = data;
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error = iicbus_transfer_excl(dev, &msg, 1, IIC_INTRWAIT);
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return (error);
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}
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static int
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pcf8591_get_reading(device_t dev, uint8_t *reading)
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{
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struct iic_msg msg;
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struct pcf8591_softc *sc;
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int error;
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sc = device_get_softc(dev);
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msg.slave = sc->sc_addr;
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msg.flags = IIC_M_RD;
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msg.len = 1;
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msg.buf = reading;
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error = iicbus_transfer_excl(dev, &msg, 1, IIC_INTRWAIT);
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return (error);
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}
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static int
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pcf8591_select_channel(device_t dev, int channel)
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{
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struct pcf8591_softc *sc;
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int error;
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uint8_t unused;
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sc = device_get_softc(dev);
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if (channel >= sc->sc_ch_count)
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return (EINVAL);
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sc->sc_cfg &= ~CTRL_CH_SELECT_MASK;
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sc->sc_cfg += channel;
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error = pcf8591_set_config(dev);
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if (error != 0)
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return (error);
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/*
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* The next read is still for the old channel,
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* so do it and discard.
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*/
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error = pcf8591_get_reading(dev, &unused);
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return (error);
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}
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static int
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pcf8591_channel_sysctl(SYSCTL_HANDLER_ARGS)
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{
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device_t dev;
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int error, channel, val;
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uint8_t reading;
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dev = arg1;
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channel = arg2;
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if (req->oldptr != NULL) {
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error = pcf8591_select_channel(dev, channel);
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if (error != 0)
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return (EIO);
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error = pcf8591_get_reading(dev, &reading);
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if (error != 0)
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return (EIO);
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val = reading;
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}
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error = sysctl_handle_int(oidp, &val, 0, req);
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return (error);
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}
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static void
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pcf8591_start(void *arg)
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{
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device_t dev;
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struct pcf8591_softc *sc;
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struct sysctl_ctx_list *ctx;
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struct sysctl_oid *tree_node;
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struct sysctl_oid_list *tree;
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struct sysctl_oid *inputs_node;
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struct sysctl_oid_list *inputs;
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sc = arg;
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dev = sc->sc_dev;
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/*
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* Set initial -- and, for the time being, fixed -- configuration.
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* Channel auto-incrementi is disabled, although it could be more
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* performant and precise for bulk channel queries.
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* The inputs are configured as four single channels.
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* The output is disabled.
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*/
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sc->sc_cfg = 0;
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sc->sc_output = 0;
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sc->sc_ch_count = 4;
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(void)pcf8591_set_config(dev);
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ctx = device_get_sysctl_ctx(dev);
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tree_node = device_get_sysctl_tree(dev);
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tree = SYSCTL_CHILDREN(tree_node);
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inputs_node = SYSCTL_ADD_NODE(ctx, tree, OID_AUTO, "inputs",
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CTLTYPE_NODE, NULL, "Input channels");
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inputs = SYSCTL_CHILDREN(inputs_node);
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for (int i = 0; i < sc->sc_ch_count; i++) {
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char buf[4];
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snprintf(buf, sizeof(buf), "%d", i);
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SYSCTL_ADD_PROC(ctx, inputs, OID_AUTO, buf,
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CTLTYPE_INT | CTLFLAG_RD, dev, i,
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pcf8591_channel_sysctl, "I", "Input level from 0 to 255 "
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"(relative to Vref)");
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}
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}
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static int
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pcf8591_probe(device_t dev)
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{
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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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device_set_desc(dev, "PCF8591 8-bit ADC / DAC");
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#ifdef FDT
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if (ofw_bus_search_compatible(dev, compat_data)->ocd_data)
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return (BUS_PROBE_GENERIC);
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#endif
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return (BUS_PROBE_NOWILDCARD);
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}
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static int
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pcf8591_attach(device_t dev)
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{
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struct pcf8591_softc *sc;
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sc = device_get_softc(dev);
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sc->sc_dev = dev;
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sc->sc_addr = iicbus_get_addr(dev);
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/*
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* We have to wait until interrupts are enabled. Usually I2C read
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* and write only works when the interrupts are available.
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*/
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config_intrhook_oneshot(pcf8591_start, sc);
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return (0);
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}
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static int
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pcf8591_detach(device_t dev)
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{
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return (0);
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}
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static device_method_t pcf8591_methods[] = {
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/* Device interface */
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DEVMETHOD(device_probe, pcf8591_probe),
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DEVMETHOD(device_attach, pcf8591_attach),
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DEVMETHOD(device_detach, pcf8591_detach),
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DEVMETHOD_END
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};
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static driver_t pcf8591_driver = {
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"pcf8591",
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pcf8591_methods,
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sizeof(struct pcf8591_softc)
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};
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static devclass_t pcf8591_devclass;
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DRIVER_MODULE(pcf8591, iicbus, pcf8591_driver, pcf8591_devclass, 0, 0);
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MODULE_DEPEND(pcf8591, iicbus, IICBUS_MINVER, IICBUS_PREFVER, IICBUS_MAXVER);
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MODULE_VERSION(pcf8591, 1);
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#ifdef FDT
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IICBUS_FDT_PNP_INFO(compat_data);
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#endif
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