d082e488cb
Allow i2c bus speed to be configured via hints, FDT data, and sysctl. Implement bus speed setting for OMAP4, AM335x, and imx5/6. Fix the i2c bus speed divisors for TI OMAP4 and AM335x to give the advertised 100, 400, and 1000 KHz speeds. PR: 195009
326 lines
8.1 KiB
C
326 lines
8.1 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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* Autoconfiguration and support routines for the Philips serial I2C bus
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/module.h>
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#include <sys/mutex.h>
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#include <sys/sysctl.h>
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#include <sys/bus.h>
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#include <dev/iicbus/iiconf.h>
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#include <dev/iicbus/iicbus.h>
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#include "iicbus_if.h"
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/* See comments below for why auto-scanning is a bad idea. */
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#define SCAN_IICBUS 0
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static int
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iicbus_probe(device_t dev)
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{
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device_set_desc(dev, "Philips I2C bus");
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/* Allow other subclasses to override this driver. */
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return (BUS_PROBE_GENERIC);
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}
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#if SCAN_IICBUS
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static int
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iic_probe_device(device_t dev, u_char addr)
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{
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int count;
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char byte;
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if ((addr & 1) == 0) {
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/* is device writable? */
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if (!iicbus_start(dev, (u_char)addr, 0)) {
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iicbus_stop(dev);
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return (1);
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}
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} else {
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/* is device readable? */
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if (!iicbus_block_read(dev, (u_char)addr, &byte, 1, &count))
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return (1);
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}
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return (0);
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}
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#endif
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/*
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* We add all the devices which we know about.
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* The generic attach routine will attach them if they are alive.
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*/
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static int
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iicbus_attach(device_t dev)
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{
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#if SCAN_IICBUS
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unsigned char addr;
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#endif
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struct iicbus_softc *sc = IICBUS_SOFTC(dev);
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int strict;
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sc->dev = dev;
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mtx_init(&sc->lock, "iicbus", NULL, MTX_DEF);
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iicbus_init_frequency(dev, 0);
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iicbus_reset(dev, IIC_FASTEST, 0, NULL);
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if (resource_int_value(device_get_name(dev),
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device_get_unit(dev), "strict", &strict) == 0)
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sc->strict = strict;
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else
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sc->strict = 1;
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/* device probing is meaningless since the bus is supposed to be
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* hot-plug. Moreover, some I2C chips do not appreciate random
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* accesses like stop after start to fast, reads for less than
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* x bytes...
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*/
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#if SCAN_IICBUS
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printf("Probing for devices on iicbus%d:", device_get_unit(dev));
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/* probe any devices */
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for (addr = 16; addr < 240; addr++) {
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if (iic_probe_device(dev, (u_char)addr)) {
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printf(" <%x>", addr);
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}
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}
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printf("\n");
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#endif
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bus_generic_probe(dev);
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bus_enumerate_hinted_children(dev);
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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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iicbus_detach(device_t dev)
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{
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struct iicbus_softc *sc = IICBUS_SOFTC(dev);
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iicbus_reset(dev, IIC_FASTEST, 0, NULL);
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bus_generic_detach(dev);
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mtx_destroy(&sc->lock);
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return (0);
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}
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static int
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iicbus_print_child(device_t dev, device_t child)
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{
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struct iicbus_ivar *devi = IICBUS_IVAR(child);
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int retval = 0;
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retval += bus_print_child_header(dev, child);
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if (devi->addr != 0)
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retval += printf(" at addr %#x", devi->addr);
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retval += bus_print_child_footer(dev, child);
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return (retval);
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}
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static void
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iicbus_probe_nomatch(device_t bus, device_t child)
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{
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struct iicbus_ivar *devi = IICBUS_IVAR(child);
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device_printf(bus, "<unknown card>");
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printf(" at addr %#x\n", devi->addr);
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return;
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}
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static int
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iicbus_child_location_str(device_t bus, device_t child, char *buf,
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size_t buflen)
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{
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struct iicbus_ivar *devi = IICBUS_IVAR(child);
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snprintf(buf, buflen, "addr=%#x", devi->addr);
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return (0);
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}
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static int
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iicbus_child_pnpinfo_str(device_t bus, device_t child, char *buf,
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size_t buflen)
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{
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*buf = '\0';
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return (0);
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}
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static int
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iicbus_read_ivar(device_t bus, device_t child, int which, uintptr_t *result)
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{
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struct iicbus_ivar *devi = IICBUS_IVAR(child);
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switch (which) {
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default:
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return (EINVAL);
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case IICBUS_IVAR_ADDR:
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*result = devi->addr;
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break;
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}
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return (0);
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}
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static device_t
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iicbus_add_child(device_t dev, u_int order, const char *name, int unit)
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{
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device_t child;
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struct iicbus_ivar *devi;
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child = device_add_child_ordered(dev, order, name, unit);
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if (child == NULL)
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return (child);
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devi = malloc(sizeof(struct iicbus_ivar), M_DEVBUF, M_NOWAIT | M_ZERO);
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if (devi == NULL) {
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device_delete_child(dev, child);
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return (0);
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}
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device_set_ivars(child, devi);
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return (child);
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}
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static void
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iicbus_hinted_child(device_t bus, const char *dname, int dunit)
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{
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device_t child;
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struct iicbus_ivar *devi;
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child = BUS_ADD_CHILD(bus, 0, dname, dunit);
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devi = IICBUS_IVAR(child);
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resource_int_value(dname, dunit, "addr", &devi->addr);
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}
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int
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iicbus_generic_intr(device_t dev, int event, char *buf)
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{
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return (0);
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}
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int
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iicbus_null_callback(device_t dev, int index, caddr_t data)
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{
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return (0);
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}
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int
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iicbus_null_repeated_start(device_t dev, u_char addr)
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{
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return (IIC_ENOTSUPP);
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}
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void
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iicbus_init_frequency(device_t dev, u_int bus_freq)
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{
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struct iicbus_softc *sc = IICBUS_SOFTC(dev);
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/*
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* If a bus frequency value was passed in, use it. Otherwise initialize
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* it first to the standard i2c 100KHz frequency, then override that
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* from a hint if one exists.
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*/
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if (bus_freq > 0)
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sc->bus_freq = bus_freq;
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else {
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sc->bus_freq = 100000;
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resource_int_value(device_get_name(dev), device_get_unit(dev),
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"frequency", (int *)&sc->bus_freq);
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}
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/*
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* Set up the sysctl that allows the bus frequency to be changed.
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* It is flagged as a tunable so that the user can set the value in
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* loader(8), and that will override any other setting from any source.
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* The sysctl tunable/value is the one most directly controlled by the
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* user and thus the one that always takes precedence.
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*/
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SYSCTL_ADD_UINT(device_get_sysctl_ctx(dev),
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SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
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OID_AUTO, "frequency", CTLFLAG_RW | CTLFLAG_TUN, &sc->bus_freq,
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sc->bus_freq, "Bus frequency in Hz");
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}
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static u_int
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iicbus_get_frequency(device_t dev, u_char speed)
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{
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struct iicbus_softc *sc = IICBUS_SOFTC(dev);
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/*
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* If the frequency has not been configured for the bus, or the request
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* is specifically for SLOW speed, use the standard 100KHz rate, else
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* use the configured bus speed.
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*/
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if (sc->bus_freq == 0 || speed == IIC_SLOW)
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return (100000);
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return (sc->bus_freq);
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}
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static device_method_t iicbus_methods[] = {
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/* device interface */
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DEVMETHOD(device_probe, iicbus_probe),
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DEVMETHOD(device_attach, iicbus_attach),
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DEVMETHOD(device_detach, iicbus_detach),
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/* bus interface */
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DEVMETHOD(bus_add_child, iicbus_add_child),
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DEVMETHOD(bus_print_child, iicbus_print_child),
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DEVMETHOD(bus_probe_nomatch, iicbus_probe_nomatch),
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DEVMETHOD(bus_read_ivar, iicbus_read_ivar),
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DEVMETHOD(bus_child_pnpinfo_str, iicbus_child_pnpinfo_str),
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DEVMETHOD(bus_child_location_str, iicbus_child_location_str),
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DEVMETHOD(bus_hinted_child, iicbus_hinted_child),
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/* iicbus interface */
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DEVMETHOD(iicbus_transfer, iicbus_transfer),
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DEVMETHOD(iicbus_get_frequency, iicbus_get_frequency),
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DEVMETHOD_END
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};
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driver_t iicbus_driver = {
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"iicbus",
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iicbus_methods,
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sizeof(struct iicbus_softc),
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};
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devclass_t iicbus_devclass;
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MODULE_VERSION(iicbus, IICBUS_MODVER);
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DRIVER_MODULE(iicbus, iichb, iicbus_driver, iicbus_devclass, 0, 0);
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