Add a bus multiplexer device
This patch set adds a bus multiplexer and the necessary infrastructure in the I2C code to allow it to work. These are common on systems with lots of I2C devices, like an IPMI BMC. -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEE/Q1c5nzg9ZpmiCaGYfOMkJGb/4EFAmCdnpcACgkQYfOMkJGb /4EG7BAAkUB1QbYzUChbTqVwrjxBcYmcSSdehKcZlACr9oIjwH/EutKdve/qt+fE xCHkxQAo1s+cFMoV0aFlE0UuwSxR42JwuALQcbz0UNGk0uJsgglVS65qqpwQkbiO pRnbW7ZjOxVpcjwvP9RvOIaBabUnEvNqrA7SUqs5+yPZVfhi0NqJ0DHZuvv/5L9c DV96Adv2UIKA1vqw6aOBULWm5J5zRN+6IjacZ2Qd7xQplilUcJQ5ZqiYskHF9LuT NuXoBMk5Dqqy01LYDdnjwxHAUEG31hIhtoaWgqW9AIlPuHUSxesZNsy/3BKZzWhD JX5WfKwkAzWx5pfVbmRzNSG8XqHR5nJqOdaJdWsSl2MGgjQ1/MtoIV/uLMozSVu3 5arQ7frhCXA2Dy1ozPiqIhrdiNlOHDKRTsu468o5eyxzAf+FclVPPZoKsQttaOA9 eNu+RNFY/nKCW8iAOPdSV4gQ9QwvUv3Z91lVOQjEiBbll3Iix/3r0/bZmQRArLzY 6WX0hVrhGIqdCFv5aVar0uFZz1n/G6nv3RBo6a6C72Tf+8KvjMrfA/mAXmQLJ/o1 j0s7G65lE9blyRmg7aBrfASTBPsT+JocIqeLMdMLIVxAAJLhpnQtjSRILmPy9zjl TMicA5MEC4BlXqGTJNoMTlOVyG7iC5VZ5qkeFPe1q5A/b5HxwyM= =IamZ -----END PGP SIGNATURE----- Merge remote-tracking branch 'remotes/cminyard/tags/for-qemu-6.1-v1' into staging Add a bus multiplexer device This patch set adds a bus multiplexer and the necessary infrastructure in the I2C code to allow it to work. These are common on systems with lots of I2C devices, like an IPMI BMC. # gpg: Signature made Thu 13 May 2021 22:48:07 BST # gpg: using RSA key FD0D5CE67CE0F59A6688268661F38C90919BFF81 # gpg: Good signature from "Corey Minyard <cminyard@mvista.com>" [unknown] # gpg: aka "Corey Minyard <minyard@acm.org>" [unknown] # gpg: aka "Corey Minyard <corey@minyard.net>" [unknown] # gpg: aka "Corey Minyard <minyard@mvista.com>" [unknown] # gpg: WARNING: This key is not certified with a trusted signature! # gpg: There is no indication that the signature belongs to the owner. # Primary key fingerprint: FD0D 5CE6 7CE0 F59A 6688 2686 61F3 8C90 919B FF81 * remotes/cminyard/tags/for-qemu-6.1-v1: hw/i2c: add pca954x i2c-mux switch hw/i2c: move search to i2c_scan_bus method hw/i2c: add match method for device search hw/i2c: name I2CNode list in I2CBus Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Peter Maydell
commit
499063d00a
@ -2024,6 +2024,12 @@ S: Maintained
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F: hw/net/tulip.c
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F: hw/net/tulip.h
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pca954x
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M: Patrick Venture <venture@google.com>
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S: Maintained
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F: hw/i2c/i2c_mux_pca954x.c
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F: include/hw/i2c/i2c_mux_pca954x.h
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Generic Loader
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M: Alistair Francis <alistair@alistair23.me>
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S: Maintained
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@ -28,3 +28,7 @@ config IMX_I2C
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config MPC_I2C
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bool
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select I2C
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config PCA954X
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bool
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select I2C
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@ -77,6 +77,30 @@ int i2c_bus_busy(I2CBus *bus)
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return !QLIST_EMPTY(&bus->current_devs);
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}
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bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast,
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I2CNodeList *current_devs)
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{
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BusChild *kid;
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QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
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DeviceState *qdev = kid->child;
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I2CSlave *candidate = I2C_SLAVE(qdev);
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I2CSlaveClass *sc = I2C_SLAVE_GET_CLASS(candidate);
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if (sc->match_and_add(candidate, address, broadcast, current_devs)) {
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if (!broadcast) {
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return true;
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}
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}
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}
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/*
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* If broadcast was true, and the list was full or empty, return true. If
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* broadcast was false, return false.
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*/
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return broadcast;
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}
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/* TODO: Make this handle multiple masters. */
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/*
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* Start or continue an i2c transaction. When this is called for the
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@ -93,7 +117,6 @@ int i2c_bus_busy(I2CBus *bus)
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*/
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int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv)
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{
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BusChild *kid;
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I2CSlaveClass *sc;
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I2CNode *node;
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bool bus_scanned = false;
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@ -115,18 +138,8 @@ int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv)
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* terminating the previous transaction.
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*/
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if (QLIST_EMPTY(&bus->current_devs)) {
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QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
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DeviceState *qdev = kid->child;
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I2CSlave *candidate = I2C_SLAVE(qdev);
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if ((candidate->address == address) || (bus->broadcast)) {
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node = g_malloc(sizeof(struct I2CNode));
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node->elt = candidate;
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QLIST_INSERT_HEAD(&bus->current_devs, node, next);
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if (!bus->broadcast) {
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break;
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}
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}
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}
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/* Disregard whether devices were found. */
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(void)i2c_scan_bus(bus, address, bus->broadcast, &bus->current_devs);
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bus_scanned = true;
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}
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@ -290,12 +303,28 @@ I2CSlave *i2c_slave_create_simple(I2CBus *bus, const char *name, uint8_t addr)
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return dev;
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}
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static bool i2c_slave_match(I2CSlave *candidate, uint8_t address,
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bool broadcast, I2CNodeList *current_devs)
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{
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if ((candidate->address == address) || (broadcast)) {
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I2CNode *node = g_malloc(sizeof(struct I2CNode));
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node->elt = candidate;
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QLIST_INSERT_HEAD(current_devs, node, next);
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return true;
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}
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/* Not found and not broadcast. */
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return false;
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}
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static void i2c_slave_class_init(ObjectClass *klass, void *data)
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{
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DeviceClass *k = DEVICE_CLASS(klass);
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I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass);
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set_bit(DEVICE_CATEGORY_MISC, k->categories);
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k->bus_type = TYPE_I2C_BUS;
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device_class_set_props(k, i2c_props);
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sc->match_and_add = i2c_slave_match;
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}
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static const TypeInfo i2c_slave_type_info = {
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290
hw/i2c/i2c_mux_pca954x.c
Normal file
290
hw/i2c/i2c_mux_pca954x.c
Normal file
@ -0,0 +1,290 @@
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/*
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* I2C multiplexer for PCA954x series of I2C multiplexer/switch chips.
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*
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* Copyright 2021 Google LLC
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*/
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#include "qemu/osdep.h"
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#include "qapi/error.h"
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#include "hw/i2c/i2c.h"
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#include "hw/i2c/i2c_mux_pca954x.h"
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#include "hw/i2c/smbus_slave.h"
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#include "hw/qdev-core.h"
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#include "hw/sysbus.h"
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#include "qemu/log.h"
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#include "qemu/module.h"
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#include "qemu/queue.h"
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#include "qom/object.h"
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#include "trace.h"
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#define PCA9548_CHANNEL_COUNT 8
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#define PCA9546_CHANNEL_COUNT 4
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/*
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* struct Pca954xChannel - The i2c mux device will have N of these states
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* that own the i2c channel bus.
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* @bus: The owned channel bus.
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* @enabled: Is this channel active?
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*/
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typedef struct Pca954xChannel {
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SysBusDevice parent;
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I2CBus *bus;
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bool enabled;
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} Pca954xChannel;
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#define TYPE_PCA954X_CHANNEL "pca954x-channel"
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#define PCA954X_CHANNEL(obj) \
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OBJECT_CHECK(Pca954xChannel, (obj), TYPE_PCA954X_CHANNEL)
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/*
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* struct Pca954xState - The pca954x state object.
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* @control: The value written to the mux control.
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* @channel: The set of i2c channel buses that act as channels which own the
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* i2c children.
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*/
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typedef struct Pca954xState {
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SMBusDevice parent;
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uint8_t control;
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/* The channel i2c buses. */
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Pca954xChannel channel[PCA9548_CHANNEL_COUNT];
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} Pca954xState;
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/*
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* struct Pca954xClass - The pca954x class object.
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* @nchans: The number of i2c channels this device has.
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*/
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typedef struct Pca954xClass {
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SMBusDeviceClass parent;
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uint8_t nchans;
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} Pca954xClass;
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#define TYPE_PCA954X "pca954x"
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OBJECT_DECLARE_TYPE(Pca954xState, Pca954xClass, PCA954X)
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/*
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* For each channel, if it's enabled, recursively call match on those children.
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*/
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static bool pca954x_match(I2CSlave *candidate, uint8_t address,
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bool broadcast,
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I2CNodeList *current_devs)
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{
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Pca954xState *mux = PCA954X(candidate);
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Pca954xClass *mc = PCA954X_GET_CLASS(mux);
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int i;
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/* They are talking to the mux itself (or all devices enabled). */
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if ((candidate->address == address) || broadcast) {
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I2CNode *node = g_malloc(sizeof(struct I2CNode));
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node->elt = candidate;
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QLIST_INSERT_HEAD(current_devs, node, next);
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if (!broadcast) {
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return true;
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}
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}
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for (i = 0; i < mc->nchans; i++) {
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if (!mux->channel[i].enabled) {
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continue;
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}
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if (i2c_scan_bus(mux->channel[i].bus, address, broadcast,
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current_devs)) {
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if (!broadcast) {
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return true;
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}
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}
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}
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/* If we arrived here we didn't find a match, return broadcast. */
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return broadcast;
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}
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static void pca954x_enable_channel(Pca954xState *s, uint8_t enable_mask)
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{
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Pca954xClass *mc = PCA954X_GET_CLASS(s);
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int i;
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/*
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* For each channel, check if their bit is set in enable_mask and if yes,
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* enable it, otherwise disable, hide it.
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*/
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for (i = 0; i < mc->nchans; i++) {
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if (enable_mask & (1 << i)) {
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s->channel[i].enabled = true;
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} else {
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s->channel[i].enabled = false;
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}
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}
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}
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static void pca954x_write(Pca954xState *s, uint8_t data)
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{
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s->control = data;
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pca954x_enable_channel(s, data);
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trace_pca954x_write_bytes(data);
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}
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static int pca954x_write_data(SMBusDevice *d, uint8_t *buf, uint8_t len)
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{
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Pca954xState *s = PCA954X(d);
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if (len == 0) {
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qemu_log_mask(LOG_GUEST_ERROR, "%s: writing empty data\n", __func__);
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return -1;
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}
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/*
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* len should be 1, because they write one byte to enable/disable channels.
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*/
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if (len > 1) {
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qemu_log_mask(LOG_GUEST_ERROR,
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"%s: extra data after channel selection mask\n",
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__func__);
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return -1;
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}
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pca954x_write(s, buf[0]);
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return 0;
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}
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static uint8_t pca954x_read_byte(SMBusDevice *d)
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{
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Pca954xState *s = PCA954X(d);
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uint8_t data = s->control;
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trace_pca954x_read_data(data);
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return data;
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}
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static void pca954x_enter_reset(Object *obj, ResetType type)
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{
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Pca954xState *s = PCA954X(obj);
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/* Reset will disable all channels. */
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pca954x_write(s, 0);
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}
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I2CBus *pca954x_i2c_get_bus(I2CSlave *mux, uint8_t channel)
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{
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Pca954xClass *pc = PCA954X_GET_CLASS(mux);
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Pca954xState *pca954x = PCA954X(mux);
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g_assert(channel < pc->nchans);
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return I2C_BUS(qdev_get_child_bus(DEVICE(&pca954x->channel[channel]),
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"i2c-bus"));
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}
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static void pca954x_channel_init(Object *obj)
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{
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Pca954xChannel *s = PCA954X_CHANNEL(obj);
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s->bus = i2c_init_bus(DEVICE(s), "i2c-bus");
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/* Start all channels as disabled. */
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s->enabled = false;
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}
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static void pca954x_channel_class_init(ObjectClass *klass, void *data)
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{
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DeviceClass *dc = DEVICE_CLASS(klass);
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dc->desc = "Pca954x Channel";
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}
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static void pca9546_class_init(ObjectClass *klass, void *data)
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{
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Pca954xClass *s = PCA954X_CLASS(klass);
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s->nchans = PCA9546_CHANNEL_COUNT;
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}
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static void pca9548_class_init(ObjectClass *klass, void *data)
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{
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Pca954xClass *s = PCA954X_CLASS(klass);
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s->nchans = PCA9548_CHANNEL_COUNT;
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}
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static void pca954x_realize(DeviceState *dev, Error **errp)
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{
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Pca954xState *s = PCA954X(dev);
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Pca954xClass *c = PCA954X_GET_CLASS(s);
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int i;
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/* SMBus modules. Cannot fail. */
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for (i = 0; i < c->nchans; i++) {
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sysbus_realize(SYS_BUS_DEVICE(&s->channel[i]), &error_abort);
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}
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}
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static void pca954x_init(Object *obj)
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{
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Pca954xState *s = PCA954X(obj);
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Pca954xClass *c = PCA954X_GET_CLASS(obj);
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int i;
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/* Only initialize the children we expect. */
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for (i = 0; i < c->nchans; i++) {
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object_initialize_child(obj, "channel[*]", &s->channel[i],
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TYPE_PCA954X_CHANNEL);
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}
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}
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static void pca954x_class_init(ObjectClass *klass, void *data)
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{
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I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass);
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ResettableClass *rc = RESETTABLE_CLASS(klass);
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DeviceClass *dc = DEVICE_CLASS(klass);
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SMBusDeviceClass *k = SMBUS_DEVICE_CLASS(klass);
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sc->match_and_add = pca954x_match;
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rc->phases.enter = pca954x_enter_reset;
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dc->desc = "Pca954x i2c-mux";
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dc->realize = pca954x_realize;
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k->write_data = pca954x_write_data;
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k->receive_byte = pca954x_read_byte;
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}
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static const TypeInfo pca954x_info[] = {
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{
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.name = TYPE_PCA954X,
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.parent = TYPE_SMBUS_DEVICE,
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.instance_size = sizeof(Pca954xState),
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.instance_init = pca954x_init,
|
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.class_size = sizeof(Pca954xClass),
|
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.class_init = pca954x_class_init,
|
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.abstract = true,
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},
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{
|
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.name = TYPE_PCA9546,
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.parent = TYPE_PCA954X,
|
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.class_init = pca9546_class_init,
|
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},
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{
|
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.name = TYPE_PCA9548,
|
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.parent = TYPE_PCA954X,
|
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.class_init = pca9548_class_init,
|
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},
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{
|
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.name = TYPE_PCA954X_CHANNEL,
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.parent = TYPE_SYS_BUS_DEVICE,
|
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.class_init = pca954x_channel_class_init,
|
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.instance_size = sizeof(Pca954xChannel),
|
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.instance_init = pca954x_channel_init,
|
||||
}
|
||||
};
|
||||
|
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DEFINE_TYPES(pca954x_info)
|
||||
@ -14,4 +14,5 @@ i2c_ss.add(when: 'CONFIG_SMBUS_EEPROM', if_true: files('smbus_eeprom.c'))
|
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i2c_ss.add(when: 'CONFIG_VERSATILE_I2C', if_true: files('versatile_i2c.c'))
|
||||
i2c_ss.add(when: 'CONFIG_OMAP', if_true: files('omap_i2c.c'))
|
||||
i2c_ss.add(when: 'CONFIG_PPC4XX', if_true: files('ppc4xx_i2c.c'))
|
||||
i2c_ss.add(when: 'CONFIG_PCA954X', if_true: files('i2c_mux_pca954x.c'))
|
||||
softmmu_ss.add_all(when: 'CONFIG_I2C', if_true: i2c_ss)
|
||||
|
||||
@ -26,3 +26,8 @@ npcm7xx_smbus_recv_byte(const char *id, uint8_t value) "%s recv byte: 0x%02x"
|
||||
npcm7xx_smbus_stop(const char *id) "%s stopping"
|
||||
npcm7xx_smbus_nack(const char *id) "%s nacking"
|
||||
npcm7xx_smbus_recv_fifo(const char *id, uint8_t received, uint8_t expected) "%s recv fifo: received %u, expected %u"
|
||||
|
||||
# i2c-mux-pca954x.c
|
||||
|
||||
pca954x_write_bytes(uint8_t value) "PCA954X write data: 0x%02x"
|
||||
pca954x_read_data(uint8_t value) "PCA954X read data: 0x%02x"
|
||||
|
||||
@ -16,6 +16,7 @@ enum i2c_event {
|
||||
I2C_NACK /* Masker NACKed a receive byte. */
|
||||
};
|
||||
|
||||
typedef struct I2CNodeList I2CNodeList;
|
||||
|
||||
#define TYPE_I2C_SLAVE "i2c-slave"
|
||||
OBJECT_DECLARE_TYPE(I2CSlave, I2CSlaveClass,
|
||||
@ -39,6 +40,16 @@ struct I2CSlaveClass {
|
||||
* return code is not used and should be zero.
|
||||
*/
|
||||
int (*event)(I2CSlave *s, enum i2c_event event);
|
||||
|
||||
/*
|
||||
* Check if this device matches the address provided. Returns bool of
|
||||
* true if it matches (or broadcast), and updates the device list, false
|
||||
* otherwise.
|
||||
*
|
||||
* If broadcast is true, match should add the device and return true.
|
||||
*/
|
||||
bool (*match_and_add)(I2CSlave *candidate, uint8_t address, bool broadcast,
|
||||
I2CNodeList *current_devs);
|
||||
};
|
||||
|
||||
struct I2CSlave {
|
||||
@ -58,9 +69,11 @@ struct I2CNode {
|
||||
QLIST_ENTRY(I2CNode) next;
|
||||
};
|
||||
|
||||
typedef QLIST_HEAD(I2CNodeList, I2CNode) I2CNodeList;
|
||||
|
||||
struct I2CBus {
|
||||
BusState qbus;
|
||||
QLIST_HEAD(, I2CNode) current_devs;
|
||||
I2CNodeList current_devs;
|
||||
uint8_t saved_address;
|
||||
bool broadcast;
|
||||
};
|
||||
@ -74,6 +87,8 @@ void i2c_nack(I2CBus *bus);
|
||||
int i2c_send_recv(I2CBus *bus, uint8_t *data, bool send);
|
||||
int i2c_send(I2CBus *bus, uint8_t data);
|
||||
uint8_t i2c_recv(I2CBus *bus);
|
||||
bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast,
|
||||
I2CNodeList *current_devs);
|
||||
|
||||
/**
|
||||
* Create an I2C slave device on the heap.
|
||||
|
||||
19
include/hw/i2c/i2c_mux_pca954x.h
Normal file
19
include/hw/i2c/i2c_mux_pca954x.h
Normal file
@ -0,0 +1,19 @@
|
||||
#ifndef QEMU_I2C_MUX_PCA954X
|
||||
#define QEMU_I2C_MUX_PCA954X
|
||||
|
||||
#include "hw/i2c/i2c.h"
|
||||
|
||||
#define TYPE_PCA9546 "pca9546"
|
||||
#define TYPE_PCA9548 "pca9548"
|
||||
|
||||
/**
|
||||
* Retrieves the i2c bus associated with the specified channel on this i2c
|
||||
* mux.
|
||||
* @mux: an i2c mux device.
|
||||
* @channel: the i2c channel requested
|
||||
*
|
||||
* Returns: a pointer to the associated i2c bus.
|
||||
*/
|
||||
I2CBus *pca954x_i2c_get_bus(I2CSlave *mux, uint8_t channel);
|
||||
|
||||
#endif
|
||||
Loading…
Reference in New Issue
Block a user