317 lines
8.5 KiB
C
317 lines
8.5 KiB
C
/* $NetBSD: i2cmux.c,v 1.5 2021/04/24 23:36:54 thorpej Exp $ */
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/*-
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* Copyright (c) 2020 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jason R. Thorpe.
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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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#if defined(__i386__) || defined(__amd64__) || defined(__aarch64__)
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#include "acpica.h"
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#endif
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: i2cmux.c,v 1.5 2021/04/24 23:36:54 thorpej Exp $");
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#include <sys/types.h>
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#include <sys/device.h>
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#include <sys/kernel.h>
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#include <sys/kmem.h>
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#include <dev/fdt/fdtvar.h>
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#include <dev/i2c/i2cvar.h>
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#include <dev/i2c/i2cmuxvar.h>
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#if NACPICA > 0
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#include <dev/acpi/acpivar.h>
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#include <dev/acpi/acpi_i2c.h>
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#endif
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/*
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* i2c mux
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*
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* This works by interposing a set of virtual controllers behind the real
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* i2c controller. We provide our own acquire and release functions that
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* perform the following tasks:
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*
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* acquire -> acquire parent controller, program mux
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*
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* release -> idle mux, release parent controller
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*
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* All of the actual I/O operations are transparently passed through.
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*
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* N.B. the locking order; the generic I2C layer has already acquired
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* our virtual controller's mutex before calling our acquire function,
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* and we will then acquire the real controller's mutex when we acquire
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* the bus, so the order is:
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*
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* mux virtual controller -> parent controller
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*
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* These are common routines used by various i2c mux controller
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* implementations (gpio, pin mux, i2c device, etc.).
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*/
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/*****************************************************************************/
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static int
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iicmux_acquire_bus(void * const v, int const flags)
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{
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struct iicmux_bus * const bus = v;
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struct iicmux_softc * const sc = bus->mux;
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int error;
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error = iic_acquire_bus(sc->sc_i2c_parent, flags);
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if (error) {
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return error;
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}
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error = sc->sc_config->acquire_bus(bus, flags);
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if (error) {
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iic_release_bus(sc->sc_i2c_parent, flags);
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}
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return error;
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}
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static void
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iicmux_release_bus(void * const v, int const flags)
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{
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struct iicmux_bus * const bus = v;
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struct iicmux_softc * const sc = bus->mux;
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sc->sc_config->release_bus(bus, flags);
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iic_release_bus(sc->sc_i2c_parent, flags);
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}
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static int
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iicmux_exec(void * const v, i2c_op_t const op, i2c_addr_t const addr,
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const void * const cmdbuf, size_t const cmdlen, void * const databuf,
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size_t const datalen, int const flags)
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{
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struct iicmux_bus * const bus = v;
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struct iicmux_softc * const sc = bus->mux;
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return iic_exec(sc->sc_i2c_parent, op, addr, cmdbuf, cmdlen,
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databuf, datalen, flags);
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}
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/*****************************************************************************/
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static int
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iicmux_count_children(struct iicmux_softc * const sc)
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{
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char name[32];
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int child, count;
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restart:
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for (child = OF_child(sc->sc_i2c_mux_phandle), count = 0; child;
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child = OF_peer(child)) {
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if (OF_getprop(child, "name", name, sizeof(name)) <= 0) {
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continue;
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}
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if (strcmp(name, "i2c-mux") == 0) {
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/*
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* The node we encountered is the acutal parent
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* of the i2c bus children. Stash its phandle
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* and restart the enumeration.
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*/
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sc->sc_i2c_mux_phandle = child;
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goto restart;
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}
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count++;
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}
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return count;
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}
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/* XXX iicbus_print() should be able to do this. */
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static int
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iicmux_print(void * const aux, const char * const pnp)
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{
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i2c_tag_t const tag = aux;
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struct iicmux_bus * const bus = tag->ic_cookie;
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int rv;
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rv = iicbus_print(aux, pnp);
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aprint_normal(" bus %d", bus->busidx);
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return rv;
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}
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static void
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iicmux_attach_bus(struct iicmux_softc * const sc,
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uintptr_t const handle, enum i2c_cookie_type handletype, int const busidx)
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{
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struct iicmux_bus * const bus = &sc->sc_busses[busidx];
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bus->mux = sc;
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bus->busidx = busidx;
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bus->handle = handle;
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bus->handletype = handletype;
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bus->bus_data = sc->sc_config->get_bus_info(bus);
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if (bus->bus_data == NULL) {
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aprint_error_dev(sc->sc_dev,
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"unable to get info for bus %d\n", busidx);
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return;
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}
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iic_tag_init(&bus->controller);
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bus->controller.ic_cookie = bus;
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bus->controller.ic_acquire_bus = iicmux_acquire_bus;
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bus->controller.ic_release_bus = iicmux_release_bus;
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bus->controller.ic_exec = iicmux_exec;
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switch (handletype) {
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case I2C_COOKIE_OF:
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fdtbus_register_i2c_controller(&bus->controller,
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(int)bus->handle);
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fdtbus_attach_i2cbus(sc->sc_dev, (int)bus->handle,
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&bus->controller, iicmux_print);
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break;
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#if NACPICA > 0
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case I2C_COOKIE_ACPI: {
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struct acpi_devnode *ad = acpi_match_node((ACPI_HANDLE)handle);
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KASSERT(ad != NULL);
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struct i2cbus_attach_args iba = {
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.iba_tag = &bus->controller,
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.iba_child_devices = acpi_enter_i2c_devs(NULL, ad)
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};
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config_found(sc->sc_dev, &iba, iicbus_print, CFARG_EOL);
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} break;
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#endif
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default:
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aprint_error_dev(sc->sc_dev, "unknown handle type\n");
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break;
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}
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}
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static void
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iicmux_attach_fdt(struct iicmux_softc * const sc)
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{
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/*
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* We start out assuming that the i2c bus nodes are children of
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* our own node. We'll adjust later if we encounter an "i2c-mux"
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* node when counting our children. If we encounter such a node,
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* then it's that node that is the parent of the i2c bus children.
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*/
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sc->sc_i2c_mux_phandle = (int)sc->sc_handle;
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sc->sc_nbusses = iicmux_count_children(sc);
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if (sc->sc_nbusses == 0) {
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return;
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}
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sc->sc_busses = kmem_zalloc(sizeof(*sc->sc_busses) * sc->sc_nbusses,
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KM_SLEEP);
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int child, idx;
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for (child = OF_child(sc->sc_i2c_mux_phandle), idx = 0; child;
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child = OF_peer(child), idx++) {
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KASSERT(idx < sc->sc_nbusses);
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iicmux_attach_bus(sc, child, I2C_COOKIE_OF, idx);
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}
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}
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#if NACPICA > 0
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static void
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iicmux_attach_acpi(struct iicmux_softc * const sc)
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{
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ACPI_HANDLE hdl = (ACPI_HANDLE)sc->sc_handle;
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struct acpi_devnode *devnode, *ad;
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int idx;
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devnode = acpi_match_node(hdl);
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KASSERT(devnode != NULL);
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/* Count child busses */
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sc->sc_nbusses = 0;
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SIMPLEQ_FOREACH(ad, &devnode->ad_child_head, ad_child_list) {
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if (ad->ad_devinfo->Type != ACPI_TYPE_DEVICE ||
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!acpi_device_present(ad->ad_handle)) {
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continue;
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}
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sc->sc_nbusses++;
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}
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sc->sc_busses = kmem_zalloc(sizeof(*sc->sc_busses) * sc->sc_nbusses,
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KM_SLEEP);
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/* Attach child busses */
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idx = 0;
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SIMPLEQ_FOREACH(ad, &devnode->ad_child_head, ad_child_list) {
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if (ad->ad_devinfo->Type != ACPI_TYPE_DEVICE ||
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!acpi_device_present(ad->ad_handle)) {
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continue;
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}
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iicmux_attach_bus(sc, (uintptr_t)ad->ad_handle,
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I2C_COOKIE_ACPI, idx);
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idx++;
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}
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}
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#endif
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void
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iicmux_attach(struct iicmux_softc * const sc)
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{
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/*
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* We expect sc->sc_handle, sc->sc_config, and sc->sc_i2c_parent
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* to be initialized by the front-end.
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*/
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KASSERT(sc->sc_handle > 0);
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KASSERT(sc->sc_config != NULL);
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KASSERT(sc->sc_i2c_parent != NULL);
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/*
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* Gather up all of the various bits of information needed
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* for this particular type of i2c mux.
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*/
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sc->sc_mux_data = sc->sc_config->get_mux_info(sc);
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if (sc->sc_mux_data == NULL) {
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aprint_error_dev(sc->sc_dev, "unable to get info for mux\n");
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return;
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}
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/*
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* Do configuration method (OF, ACPI) specific setup.
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*/
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switch (sc->sc_handletype) {
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case I2C_COOKIE_OF:
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iicmux_attach_fdt(sc);
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break;
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#if NACPICA > 0
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case I2C_COOKIE_ACPI:
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iicmux_attach_acpi(sc);
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break;
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#endif
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default:
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aprint_error_dev(sc->sc_dev, "could not configure mux: "
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"handle type %u not supported\n", sc->sc_handletype);
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break;
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}
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}
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