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-rw-r--r--Documentation/ABI/testing/sysfs-class-mux16
-rw-r--r--Documentation/driver-model/devres.txt5
-rw-r--r--MAINTAINERS3
-rw-r--r--drivers/Kconfig2
-rw-r--r--drivers/Makefile1
-rw-r--r--drivers/mux/Kconfig16
-rw-r--r--drivers/mux/Makefile5
-rw-r--r--drivers/mux/mux-core.c547
-rw-r--r--include/linux/mux/consumer.h32
-rw-r--r--include/linux/mux/driver.h108
10 files changed, 735 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-mux b/Documentation/ABI/testing/sysfs-class-mux
new file mode 100644
index 000000000000..8715f9c7bd4f
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-mux
@@ -0,0 +1,16 @@
+What: /sys/class/mux/
+Date: April 2017
+KernelVersion: 4.13
+Contact: Peter Rosin <peda@axentia.se>
+Description:
+ The mux/ class sub-directory belongs to the Generic MUX
+ Framework and provides a sysfs interface for using MUX
+ controllers.
+
+What: /sys/class/mux/muxchipN/
+Date: April 2017
+KernelVersion: 4.13
+Contact: Peter Rosin <peda@axentia.se>
+Description:
+ A /sys/class/mux/muxchipN directory is created for each
+ probed MUX chip where N is a simple enumeration.
diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
index af08b4cd7968..40e4787c399c 100644
--- a/Documentation/driver-model/devres.txt
+++ b/Documentation/driver-model/devres.txt
@@ -337,6 +337,11 @@ MEM
MFD
devm_mfd_add_devices()
+MUX
+ devm_mux_chip_alloc()
+ devm_mux_chip_register()
+ devm_mux_control_get()
+
PER-CPU MEM
devm_alloc_percpu()
devm_free_percpu()
diff --git a/MAINTAINERS b/MAINTAINERS
index b2cc32caabb9..a507bb4316ce 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8719,8 +8719,11 @@ F: include/linux/spi/mmc_spi.h
MULTIPLEXER SUBSYSTEM
M: Peter Rosin <peda@axentia.se>
S: Maintained
+F: Documentation/ABI/testing/mux/sysfs-class-mux*
F: Documentation/devicetree/bindings/mux/
F: include/linux/dt-bindings/mux/
+F: include/linux/mux/
+F: drivers/mux/
MULTISOUND SOUND DRIVER
M: Andrew Veliath <andrewtv@usa.net>
diff --git a/drivers/Kconfig b/drivers/Kconfig
index ba2901e76769..505c676fa9c7 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -206,4 +206,6 @@ source "drivers/fsi/Kconfig"
source "drivers/tee/Kconfig"
+source "drivers/mux/Kconfig"
+
endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index cfabd141dba2..dfdcda00bfe3 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -181,3 +181,4 @@ obj-$(CONFIG_NVMEM) += nvmem/
obj-$(CONFIG_FPGA) += fpga/
obj-$(CONFIG_FSI) += fsi/
obj-$(CONFIG_TEE) += tee/
+obj-$(CONFIG_MULTIPLEXER) += mux/
diff --git a/drivers/mux/Kconfig b/drivers/mux/Kconfig
new file mode 100644
index 000000000000..23ab2cde83b1
--- /dev/null
+++ b/drivers/mux/Kconfig
@@ -0,0 +1,16 @@
+#
+# Multiplexer devices
+#
+
+menuconfig MULTIPLEXER
+ tristate "Multiplexer subsystem"
+ help
+ Multiplexer controller subsystem. Multiplexers are used in a
+ variety of settings, and this subsystem abstracts their use
+ so that the rest of the kernel sees a common interface. When
+ multiple parallel multiplexers are controlled by one single
+ multiplexer controller, this subsystem also coordinates the
+ multiplexer accesses.
+
+ To compile the subsystem as a module, choose M here: the module will
+ be called mux-core.
diff --git a/drivers/mux/Makefile b/drivers/mux/Makefile
new file mode 100644
index 000000000000..09f0299e109d
--- /dev/null
+++ b/drivers/mux/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for multiplexer devices.
+#
+
+obj-$(CONFIG_MULTIPLEXER) += mux-core.o
diff --git a/drivers/mux/mux-core.c b/drivers/mux/mux-core.c
new file mode 100644
index 000000000000..90b8995f07cb
--- /dev/null
+++ b/drivers/mux/mux-core.c
@@ -0,0 +1,547 @@
+/*
+ * Multiplexer subsystem
+ *
+ * Copyright (C) 2017 Axentia Technologies AB
+ *
+ * Author: Peter Rosin <peda@axentia.se>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#define pr_fmt(fmt) "mux-core: " fmt
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/idr.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mux/consumer.h>
+#include <linux/mux/driver.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/slab.h>
+
+/*
+ * The idle-as-is "state" is not an actual state that may be selected, it
+ * only implies that the state should not be changed. So, use that state
+ * as indication that the cached state of the multiplexer is unknown.
+ */
+#define MUX_CACHE_UNKNOWN MUX_IDLE_AS_IS
+
+static struct class mux_class = {
+ .name = "mux",
+ .owner = THIS_MODULE,
+};
+
+static DEFINE_IDA(mux_ida);
+
+static int __init mux_init(void)
+{
+ ida_init(&mux_ida);
+ return class_register(&mux_class);
+}
+
+static void __exit mux_exit(void)
+{
+ class_register(&mux_class);
+ ida_destroy(&mux_ida);
+}
+
+static void mux_chip_release(struct device *dev)
+{
+ struct mux_chip *mux_chip = to_mux_chip(dev);
+
+ ida_simple_remove(&mux_ida, mux_chip->id);
+ kfree(mux_chip);
+}
+
+static struct device_type mux_type = {
+ .name = "mux-chip",
+ .release = mux_chip_release,
+};
+
+/**
+ * mux_chip_alloc() - Allocate a mux-chip.
+ * @dev: The parent device implementing the mux interface.
+ * @controllers: The number of mux controllers to allocate for this chip.
+ * @sizeof_priv: Size of extra memory area for private use by the caller.
+ *
+ * After allocating the mux-chip with the desired number of mux controllers
+ * but before registering the chip, the mux driver is required to configure
+ * the number of valid mux states in the mux_chip->mux[N].states members and
+ * the desired idle state in the returned mux_chip->mux[N].idle_state members.
+ * The default idle state is MUX_IDLE_AS_IS. The mux driver also needs to
+ * provide a pointer to the operations struct in the mux_chip->ops member
+ * before registering the mux-chip with mux_chip_register.
+ *
+ * Return: A pointer to the new mux-chip, or an ERR_PTR with a negative errno.
+ */
+struct mux_chip *mux_chip_alloc(struct device *dev,
+ unsigned int controllers, size_t sizeof_priv)
+{
+ struct mux_chip *mux_chip;
+ int i;
+
+ if (WARN_ON(!dev || !controllers))
+ return ERR_PTR(-EINVAL);
+
+ mux_chip = kzalloc(sizeof(*mux_chip) +
+ controllers * sizeof(*mux_chip->mux) +
+ sizeof_priv, GFP_KERNEL);
+ if (!mux_chip)
+ return ERR_PTR(-ENOMEM);
+
+ mux_chip->mux = (struct mux_control *)(mux_chip + 1);
+ mux_chip->dev.class = &mux_class;
+ mux_chip->dev.type = &mux_type;
+ mux_chip->dev.parent = dev;
+ mux_chip->dev.of_node = dev->of_node;
+ dev_set_drvdata(&mux_chip->dev, mux_chip);
+
+ mux_chip->id = ida_simple_get(&mux_ida, 0, 0, GFP_KERNEL);
+ if (mux_chip->id < 0) {
+ int err = mux_chip->id;
+
+ pr_err("muxchipX failed to get a device id\n");
+ kfree(mux_chip);
+ return ERR_PTR(err);
+ }
+ dev_set_name(&mux_chip->dev, "muxchip%d", mux_chip->id);
+
+ mux_chip->controllers = controllers;
+ for (i = 0; i < controllers; ++i) {
+ struct mux_control *mux = &mux_chip->mux[i];
+
+ mux->chip = mux_chip;
+ sema_init(&mux->lock, 1);
+ mux->cached_state = MUX_CACHE_UNKNOWN;
+ mux->idle_state = MUX_IDLE_AS_IS;
+ }
+
+ device_initialize(&mux_chip->dev);
+
+ return mux_chip;
+}
+EXPORT_SYMBOL_GPL(mux_chip_alloc);
+
+static int mux_control_set(struct mux_control *mux, int state)
+{
+ int ret = mux->chip->ops->set(mux, state);
+
+ mux->cached_state = ret < 0 ? MUX_CACHE_UNKNOWN : state;
+
+ return ret;
+}
+
+/**
+ * mux_chip_register() - Register a mux-chip, thus readying the controllers
+ * for use.
+ * @mux_chip: The mux-chip to register.
+ *
+ * Do not retry registration of the same mux-chip on failure. You should
+ * instead put it away with mux_chip_free() and allocate a new one, if you
+ * for some reason would like to retry registration.
+ *
+ * Return: Zero on success or a negative errno on error.
+ */
+int mux_chip_register(struct mux_chip *mux_chip)
+{
+ int i;
+ int ret;
+
+ for (i = 0; i < mux_chip->controllers; ++i) {
+ struct mux_control *mux = &mux_chip->mux[i];
+
+ if (mux->idle_state == mux->cached_state)
+ continue;
+
+ ret = mux_control_set(mux, mux->idle_state);
+ if (ret < 0) {
+ dev_err(&mux_chip->dev, "unable to set idle state\n");
+ return ret;
+ }
+ }
+
+ ret = device_add(&mux_chip->dev);
+ if (ret < 0)
+ dev_err(&mux_chip->dev,
+ "device_add failed in %s: %d\n", __func__, ret);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(mux_chip_register);
+
+/**
+ * mux_chip_unregister() - Take the mux-chip off-line.
+ * @mux_chip: The mux-chip to unregister.
+ *
+ * mux_chip_unregister() reverses the effects of mux_chip_register().
+ * But not completely, you should not try to call mux_chip_register()
+ * on a mux-chip that has been registered before.
+ */
+void mux_chip_unregister(struct mux_chip *mux_chip)
+{
+ device_del(&mux_chip->dev);
+}
+EXPORT_SYMBOL_GPL(mux_chip_unregister);
+
+/**
+ * mux_chip_free() - Free the mux-chip for good.
+ * @mux_chip: The mux-chip to free.
+ *
+ * mux_chip_free() reverses the effects of mux_chip_alloc().
+ */
+void mux_chip_free(struct mux_chip *mux_chip)
+{
+ if (!mux_chip)
+ return;
+
+ put_device(&mux_chip->dev);
+}
+EXPORT_SYMBOL_GPL(mux_chip_free);
+
+static void devm_mux_chip_release(struct device *dev, void *res)
+{
+ struct mux_chip *mux_chip = *(struct mux_chip **)res;
+
+ mux_chip_free(mux_chip);
+}
+
+/**
+ * devm_mux_chip_alloc() - Resource-managed version of mux_chip_alloc().
+ * @dev: The parent device implementing the mux interface.
+ * @controllers: The number of mux controllers to allocate for this chip.
+ * @sizeof_priv: Size of extra memory area for private use by the caller.
+ *
+ * See mux_chip_alloc() for more details.
+ *
+ * Return: A pointer to the new mux-chip, or an ERR_PTR with a negative errno.
+ */
+struct mux_chip *devm_mux_chip_alloc(struct device *dev,
+ unsigned int controllers,
+ size_t sizeof_priv)
+{
+ struct mux_chip **ptr, *mux_chip;
+
+ ptr = devres_alloc(devm_mux_chip_release, sizeof(*ptr), GFP_KERNEL);
+ if (!ptr)
+ return ERR_PTR(-ENOMEM);
+
+ mux_chip = mux_chip_alloc(dev, controllers, sizeof_priv);
+ if (IS_ERR(mux_chip)) {
+ devres_free(ptr);
+ return mux_chip;
+ }
+
+ *ptr = mux_chip;
+ devres_add(dev, ptr);
+
+ return mux_chip;
+}
+EXPORT_SYMBOL_GPL(devm_mux_chip_alloc);
+
+static void devm_mux_chip_reg_release(struct device *dev, void *res)
+{
+ struct mux_chip *mux_chip = *(struct mux_chip **)res;
+
+ mux_chip_unregister(mux_chip);
+}
+
+/**
+ * devm_mux_chip_register() - Resource-managed version mux_chip_register().
+ * @dev: The parent device implementing the mux interface.
+ * @mux_chip: The mux-chip to register.
+ *
+ * See mux_chip_register() for more details.
+ *
+ * Return: Zero on success or a negative errno on error.
+ */
+int devm_mux_chip_register(struct device *dev,
+ struct mux_chip *mux_chip)
+{
+ struct mux_chip **ptr;
+ int res;
+
+ ptr = devres_alloc(devm_mux_chip_reg_release, sizeof(*ptr), GFP_KERNEL);
+ if (!ptr)
+ return -ENOMEM;
+
+ res = mux_chip_register(mux_chip);
+ if (res) {
+ devres_free(ptr);
+ return res;
+ }
+
+ *ptr = mux_chip;
+ devres_add(dev, ptr);
+
+ return res;
+}
+EXPORT_SYMBOL_GPL(devm_mux_chip_register);
+
+/**
+ * mux_control_states() - Query the number of multiplexer states.
+ * @mux: The mux-control to query.
+ *
+ * Return: The number of multiplexer states.
+ */
+unsigned int mux_control_states(struct mux_control *mux)
+{
+ return mux->states;
+}
+EXPORT_SYMBOL_GPL(mux_control_states);
+
+/*
+ * The mux->lock must be down when calling this function.
+ */
+static int __mux_control_select(struct mux_control *mux, int state)
+{
+ int ret;
+
+ if (WARN_ON(state < 0 || state >= mux->states))
+ return -EINVAL;
+
+ if (mux->cached_state == state)
+ return 0;
+
+ ret = mux_control_set(mux, state);
+ if (ret >= 0)
+ return 0;
+
+ /* The mux update failed, try to revert if appropriate... */
+ if (mux->idle_state != MUX_IDLE_AS_IS)
+ mux_control_set(mux, mux->idle_state);
+
+ return ret;
+}
+
+/**
+ * mux_control_select() - Select the given multiplexer state.
+ * @mux: The mux-control to request a change of state from.
+ * @state: The new requested state.
+ *
+ * On successfully selecting the mux-control state, it will be locked until
+ * there is a call to mux_control_deselect(). If the mux-control is already
+ * selected when mux_control_select() is called, the caller will be blocked
+ * until mux_control_deselect() is called (by someone else).
+ *
+ * Therefore, make sure to call mux_control_deselect() when the operation is
+ * complete and the mux-control is free for others to use, but do not call
+ * mux_control_deselect() if mux_control_select() fails.
+ *
+ * Return: 0 when the mux-control state has the requested state or a negative
+ * errno on error.
+ */
+int mux_control_select(struct mux_control *mux, unsigned int state)
+{
+ int ret;
+
+ ret = down_killable(&mux->lock);
+ if (ret < 0)
+ return ret;
+
+ ret = __mux_control_select(mux, state);
+
+ if (ret < 0)
+ up(&mux->lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(mux_control_select);
+
+/**
+ * mux_control_try_select() - Try to select the given multiplexer state.
+ * @mux: The mux-control to request a change of state from.
+ * @state: The new requested state.
+ *
+ * On successfully selecting the mux-control state, it will be locked until
+ * mux_control_deselect() called.
+ *
+ * Therefore, make sure to call mux_control_deselect() when the operation is
+ * complete and the mux-control is free for others to use, but do not call
+ * mux_control_deselect() if mux_control_try_select() fails.
+ *
+ * Return: 0 when the mux-control state has the requested state or a negative
+ * errno on error. Specifically -EBUSY if the mux-control is contended.
+ */
+int mux_control_try_select(struct mux_control *mux, unsigned int state)
+{
+ int ret;
+
+ if (down_trylock(&mux->lock))
+ return -EBUSY;
+
+ ret = __mux_control_select(mux, state);
+
+ if (ret < 0)
+ up(&mux->lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(mux_control_try_select);
+
+/**
+ * mux_control_deselect() - Deselect the previously selected multiplexer state.
+ * @mux: The mux-control to deselect.
+ *
+ * It is required that a single call is made to mux_control_deselect() for
+ * each and every successful call made to either of mux_control_select() or
+ * mux_control_try_select().
+ *
+ * Return: 0 on success and a negative errno on error. An error can only
+ * occur if the mux has an idle state. Note that even if an error occurs, the
+ * mux-control is unlocked and is thus free for the next access.
+ */
+int mux_control_deselect(struct mux_control *mux)
+{
+ int ret = 0;
+
+ if (mux->idle_state != MUX_IDLE_AS_IS &&
+ mux->idle_state != mux->cached_state)
+ ret = mux_control_set(mux, mux->idle_state);
+
+ up(&mux->lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(mux_control_deselect);
+
+static int of_dev_node_match(struct device *dev, const void *data)
+{
+ return dev->of_node == data;
+}
+
+static struct mux_chip *of_find_mux_chip_by_node(struct device_node *np)
+{
+ struct device *dev;
+
+ dev = class_find_device(&mux_class, NULL, np, of_dev_node_match);
+
+ return dev ? to_mux_chip(dev) : NULL;
+}
+
+/**
+ * mux_control_get() - Get the mux-control for a device.
+ * @dev: The device that needs a mux-control.
+ * @mux_name: The name identifying the mux-control.
+ *
+ * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno.
+ */
+struct mux_control *mux_control_get(struct device *dev, const char *mux_name)
+{
+ struct device_node *np = dev->of_node;
+ struct of_phandle_args args;
+ struct mux_chip *mux_chip;
+ unsigned int controller;
+ int index = 0;
+ int ret;
+
+ if (mux_name) {
+ index = of_property_match_string(np, "mux-control-names",
+ mux_name);
+ if (index < 0) {
+ dev_err(dev, "mux controller '%s' not found\n",
+ mux_name);
+ return ERR_PTR(index);
+ }
+ }
+
+ ret = of_parse_phandle_with_args(np,
+ "mux-controls", "#mux-control-cells",
+ index, &args);
+ if (ret) {
+ dev_err(dev, "%s: failed to get mux-control %s(%i)\n",
+ np->full_name, mux_name ?: "", index);
+ return ERR_PTR(ret);
+ }
+
+ mux_chip = of_find_mux_chip_by_node(args.np);
+ of_node_put(args.np);
+ if (!mux_chip)
+ return ERR_PTR(-EPROBE_DEFER);
+
+ if (args.args_count > 1 ||
+ (!args.args_count && (mux_chip->controllers > 1))) {
+ dev_err(dev, "%s: wrong #mux-control-cells for %s\n",
+ np->full_name, args.np->full_name);
+ return ERR_PTR(-EINVAL);
+ }
+
+ controller = 0;
+ if (args.args_count)
+ controller = args.args[0];
+
+ if (controller >= mux_chip->controllers) {
+ dev_err(dev, "%s: bad mux controller %u specified in %s\n",
+ np->full_name, controller, args.np->full_name);
+ return ERR_PTR(-EINVAL);
+ }
+
+ get_device(&mux_chip->dev);
+ return &mux_chip->mux[controller];
+}
+EXPORT_SYMBOL_GPL(mux_control_get);
+
+/**
+ * mux_control_put() - Put away the mux-control for good.
+ * @mux: The mux-control to put away.
+ *
+ * mux_control_put() reverses the effects of mux_control_get().
+ */
+void mux_control_put(struct mux_control *mux)
+{
+ put_device(&mux->chip->dev);
+}
+EXPORT_SYMBOL_GPL(mux_control_put);
+
+static void devm_mux_control_release(struct device *dev, void *res)
+{
+ struct mux_control *mux = *(struct mux_control **)res;
+
+ mux_control_put(mux);
+}
+
+/**
+ * devm_mux_control_get() - Get the mux-control for a device, with resource
+ * management.
+ * @dev: The device that needs a mux-control.
+ * @mux_name: The name identifying the mux-control.
+ *
+ * Return: Pointer to the mux-control, or an ERR_PTR with a negative errno.
+ */
+struct mux_control *devm_mux_control_get(struct device *dev,
+ const char *mux_name)
+{
+ struct mux_control **ptr, *mux;
+
+ ptr = devres_alloc(devm_mux_control_release, sizeof(*ptr), GFP_KERNEL);
+ if (!ptr)
+ return ERR_PTR(-ENOMEM);
+
+ mux = mux_control_get(dev, mux_name);
+ if (IS_ERR(mux)) {
+ devres_free(ptr);
+ return mux;
+ }
+
+ *ptr = mux;
+ devres_add(dev, ptr);
+
+ return mux;
+}
+EXPORT_SYMBOL_GPL(devm_mux_control_get);
+
+/*
+ * Using subsys_initcall instead of module_init here to try to ensure - for
+ * the non-modular case - that the subsystem is initialized when mux consumers
+ * and mux controllers start to use it.
+ * For the modular case, the ordering is ensured with module dependencies.
+ */
+subsys_initcall(mux_init);
+module_exit(mux_exit);
+
+MODULE_DESCRIPTION("Multiplexer subsystem");
+MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/mux/consumer.h b/include/linux/mux/consumer.h
new file mode 100644
index 000000000000..5577e1b773c4
--- /dev/null
+++ b/include/linux/mux/consumer.h
@@ -0,0 +1,32 @@
+/*
+ * mux/consumer.h - definitions for the multiplexer consumer interface
+ *
+ * Copyright (C) 2017 Axentia Technologies AB
+ *
+ * Author: Peter Rosin <peda@axentia.se>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _LINUX_MUX_CONSUMER_H
+#define _LINUX_MUX_CONSUMER_H
+
+struct device;
+struct mux_control;
+
+unsigned int mux_control_states(struct mux_control *mux);
+int __must_check mux_control_select(struct mux_control *mux,
+ unsigned int state);
+int __must_check mux_control_try_select(struct mux_control *mux,
+ unsigned int state);
+int mux_control_deselect(struct mux_control *mux);
+
+struct mux_control *mux_control_get(struct device *dev, const char *mux_name);
+void mux_control_put(struct mux_control *mux);
+
+struct mux_control *devm_mux_control_get(struct device *dev,
+ const char *mux_name);
+
+#endif /* _LINUX_MUX_CONSUMER_H */
diff --git a/include/linux/mux/driver.h b/include/linux/mux/driver.h
new file mode 100644
index 000000000000..35c3579c3304
--- /dev/null
+++ b/include/linux/mux/driver.h
@@ -0,0 +1,108 @@
+/*
+ * mux/driver.h - definitions for the multiplexer driver interface
+ *
+ * Copyright (C) 2017 Axentia Technologies AB
+ *
+ * Author: Peter Rosin <peda@axentia.se>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _LINUX_MUX_DRIVER_H
+#define _LINUX_MUX_DRIVER_H
+
+#include <dt-bindings/mux/mux.h>
+#include <linux/device.h>
+#include <linux/semaphore.h>
+
+struct mux_chip;
+struct mux_control;
+
+/**
+ * struct mux_control_ops - Mux controller operations for a mux chip.
+ * @set: Set the state of the given mux controller.
+ */
+struct mux_control_ops {
+ int (*set)(struct mux_control *mux, int state);
+};
+
+/**
+ * struct mux_control - Represents a mux controller.
+ * @lock: Protects the mux controller state.
+ * @chip: The mux chip that is handling this mux controller.
+ * @cached_state: The current mux controller state, or -1 if none.
+ * @states: The number of mux controller states.
+ * @idle_state: The mux controller state to use when inactive, or one
+ * of MUX_IDLE_AS_IS and MUX_IDLE_DISCONNECT.
+ *
+ * Mux drivers may only change @states and @idle_state, and may only do so
+ * between allocation and registration of the mux controller. Specifically,
+ * @cached_state is internal to the mux core and should never be written by
+ * mux drivers.
+ */
+struct mux_control {
+ struct semaphore lock; /* protects the state of the mux */
+
+ struct mux_chip *chip;
+ int cached_state;
+
+ unsigned int states;
+ int idle_state;
+};
+
+/**
+ * struct mux_chip - Represents a chip holding mux controllers.
+ * @controllers: Number of mux controllers handled by the chip.
+ * @mux: Array of mux controllers that are handled.
+ * @dev: Device structure.
+ * @id: Used to identify the device internally.
+ * @ops: Mux controller operations.
+ */
+struct mux_chip {
+ unsigned int controllers;
+ struct mux_control *mux;
+ struct device dev;
+ int id;
+
+ const struct mux_control_ops *ops;
+};
+
+#define to_mux_chip(x) container_of((x), struct mux_chip, dev)
+
+/**
+ * mux_chip_priv() - Get the extra memory reserved by mux_chip_alloc().
+ * @mux_chip: The mux-chip to get the private memory from.
+ *
+ * Return: Pointer to the private memory reserved by the allocator.
+ */
+static inline void *mux_chip_priv(struct mux_chip *mux_chip)
+{
+ return &mux_chip->mux[mux_chip->controllers];
+}
+
+struct mux_chip *mux_chip_alloc(struct device *dev,
+ unsigned int controllers, size_t sizeof_priv);
+int mux_chip_register(struct mux_chip *mux_chip);
+void mux_chip_unregister(struct mux_chip *mux_chip);
+void mux_chip_free(struct mux_chip *mux_chip);
+
+struct mux_chip *devm_mux_chip_alloc(struct device *dev,
+ unsigned int controllers,
+ size_t sizeof_priv);
+int devm_mux_chip_register(struct device *dev, struct mux_chip *mux_chip);
+
+/**
+ * mux_control_get_index() - Get the index of the given mux controller
+ * @mux: The mux-control to get the index for.
+ *
+ * Return: The index of the mux controller within the mux chip the mux
+ * controller is a part of.
+ */
+static inline unsigned int mux_control_get_index(struct mux_control *mux)
+{
+ return mux - mux->chip->mux;
+}
+
+#endif /* _LINUX_MUX_DRIVER_H */