usb: typec: Add support for retimers

Introduce a retimer device class and associated functions that register
and use retimer "switch" devices. These operate in a manner similar to
the "mode-switch" and help configure retimers that exist between the
Type-C connector and host controller(s).

Type C ports can be linked to retimers using firmware node device
references (again, in a manner similar to "mode-switch").

There are no new sysfs files being created; there is the new retimer
class directory, but there are no class-specific files being created
there.

Signed-off-by: Prashant Malani <pmalani@chromium.org>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20220711072333.2064341-2-pmalani@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Prashant Malani 2022-07-11 07:22:55 +00:00 committed by Greg Kroah-Hartman
parent 69bb3520db
commit ddaf8d96f9
6 changed files with 238 additions and 2 deletions

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@ -1,6 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_TYPEC) += typec.o
typec-y := class.o mux.o bus.o pd.o
typec-y := class.o mux.o bus.o pd.o retimer.o
typec-$(CONFIG_ACPI) += port-mapper.o
obj-$(CONFIG_TYPEC) += altmodes/
obj-$(CONFIG_TYPEC_TCPM) += tcpm/

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@ -2299,10 +2299,14 @@ static int __init typec_init(void)
if (ret)
goto err_unregister_bus;
ret = class_register(&typec_class);
ret = class_register(&retimer_class);
if (ret)
goto err_unregister_mux_class;
ret = class_register(&typec_class);
if (ret)
goto err_unregister_retimer_class;
ret = usb_power_delivery_init();
if (ret)
goto err_unregister_class;
@ -2312,6 +2316,9 @@ static int __init typec_init(void)
err_unregister_class:
class_unregister(&typec_class);
err_unregister_retimer_class:
class_unregister(&retimer_class);
err_unregister_mux_class:
class_unregister(&typec_mux_class);

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@ -76,6 +76,7 @@ extern const struct device_type typec_port_dev_type;
#define is_typec_port(dev) ((dev)->type == &typec_port_dev_type)
extern struct class typec_mux_class;
extern struct class retimer_class;
extern struct class typec_class;
#if defined(CONFIG_ACPI)

168
drivers/usb/typec/retimer.c Normal file
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@ -0,0 +1,168 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2022 Google LLC
*
* USB Type-C Retimer support.
* Author: Prashant Malani <pmalani@chromium.org>
*
*/
#include <linux/device.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/property.h>
#include <linux/slab.h>
#include "class.h"
#include "retimer.h"
static bool dev_name_ends_with(struct device *dev, const char *suffix)
{
const char *name = dev_name(dev);
const int name_len = strlen(name);
const int suffix_len = strlen(suffix);
if (suffix_len > name_len)
return false;
return strcmp(name + (name_len - suffix_len), suffix) == 0;
}
static int retimer_fwnode_match(struct device *dev, const void *fwnode)
{
return dev_fwnode(dev) == fwnode && dev_name_ends_with(dev, "-retimer");
}
static void *typec_retimer_match(struct fwnode_handle *fwnode, const char *id, void *data)
{
struct device *dev = class_find_device(&retimer_class, NULL, fwnode,
retimer_fwnode_match);
return dev ? to_typec_retimer(dev) : ERR_PTR(-EPROBE_DEFER);
}
/**
* fwnode_typec_retimer_get - Find USB Type-C retimer.
* @fwnode: The caller device node.
*
* Finds a retimer linked to the caller. This function is primarily meant for the
* Type-C drivers. Returns a reference to the retimer on success, NULL if no
* matching connection was found, or ERR_PTR(-EPROBE_DEFER) when a connection
* was found but the retimer has not been enumerated yet.
*/
struct typec_retimer *fwnode_typec_retimer_get(struct fwnode_handle *fwnode)
{
struct typec_retimer *retimer;
retimer = fwnode_connection_find_match(fwnode, "retimer-switch", NULL, typec_retimer_match);
if (!IS_ERR_OR_NULL(retimer))
WARN_ON(!try_module_get(retimer->dev.parent->driver->owner));
return retimer;
}
EXPORT_SYMBOL_GPL(fwnode_typec_retimer_get);
/**
* typec_retimer_put - Release handle to a retimer.
* @retimer: USB Type-C Connector Retimer.
*
* Decrements reference count for @retimer.
*/
void typec_retimer_put(struct typec_retimer *retimer)
{
if (!IS_ERR_OR_NULL(retimer)) {
module_put(retimer->dev.parent->driver->owner);
put_device(&retimer->dev);
}
}
EXPORT_SYMBOL_GPL(typec_retimer_put);
int typec_retimer_set(struct typec_retimer *retimer, struct typec_retimer_state *state)
{
if (IS_ERR_OR_NULL(retimer))
return 0;
return retimer->set(retimer, state);
}
EXPORT_SYMBOL_GPL(typec_retimer_set);
static void typec_retimer_release(struct device *dev)
{
kfree(to_typec_retimer(dev));
}
static const struct device_type typec_retimer_dev_type = {
.name = "typec_retimer",
.release = typec_retimer_release,
};
/**
* typec_retimer_register - Register a retimer device.
* @parent: Parent device.
* @desc: Retimer description.
*
* Some USB Type-C connectors have their physical lines routed through retimers before they
* reach muxes or host controllers. In some cases (for example: using alternate modes)
* these retimers need to be reconfigured appropriately. This function registers retimer
* switches which route and potentially modify the signals on the Type C physical lines
* enroute to the host controllers.
*/
struct typec_retimer *
typec_retimer_register(struct device *parent, const struct typec_retimer_desc *desc)
{
struct typec_retimer *retimer;
int ret;
if (!desc || !desc->set)
return ERR_PTR(-EINVAL);
retimer = kzalloc(sizeof(*retimer), GFP_KERNEL);
if (!retimer)
return ERR_PTR(-ENOMEM);
retimer->set = desc->set;
device_initialize(&retimer->dev);
retimer->dev.parent = parent;
retimer->dev.fwnode = desc->fwnode;
retimer->dev.class = &retimer_class;
retimer->dev.type = &typec_retimer_dev_type;
retimer->dev.driver_data = desc->drvdata;
dev_set_name(&retimer->dev, "%s-retimer",
desc->name ? desc->name : dev_name(parent));
ret = device_add(&retimer->dev);
if (ret) {
dev_err(parent, "failed to register retimer (%d)\n", ret);
put_device(&retimer->dev);
return ERR_PTR(ret);
}
return retimer;
}
EXPORT_SYMBOL_GPL(typec_retimer_register);
/**
* typec_retimer_unregister - Unregister retimer device.
* @retimer: USB Type-C Connector retimer.
*
* Unregister retimer that was registered with typec_retimer_register().
*/
void typec_retimer_unregister(struct typec_retimer *retimer)
{
if (!IS_ERR_OR_NULL(retimer))
device_unregister(&retimer->dev);
}
EXPORT_SYMBOL_GPL(typec_retimer_unregister);
void *typec_retimer_get_drvdata(struct typec_retimer *retimer)
{
return dev_get_drvdata(&retimer->dev);
}
EXPORT_SYMBOL_GPL(typec_retimer_get_drvdata);
struct class retimer_class = {
.name = "retimer",
.owner = THIS_MODULE,
};

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@ -0,0 +1,15 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __USB_TYPEC_RETIMER__
#define __USB_TYPEC_RETIMER__
#include <linux/usb/typec_retimer.h>
struct typec_retimer {
struct device dev;
typec_retimer_set_fn_t set;
};
#define to_typec_retimer(_dev_) container_of(_dev_, struct typec_retimer, dev)
#endif /* __USB_TYPEC_RETIMER__ */

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@ -0,0 +1,45 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __USB_TYPEC_RETIMER
#define __USB_TYPEC_RETIMER
#include <linux/property.h>
#include <linux/usb/typec.h>
struct device;
struct typec_retimer;
struct typec_altmode;
struct fwnode_handle;
struct typec_retimer_state {
struct typec_altmode *alt;
unsigned long mode;
void *data;
};
typedef int (*typec_retimer_set_fn_t)(struct typec_retimer *retimer,
struct typec_retimer_state *state);
struct typec_retimer_desc {
struct fwnode_handle *fwnode;
typec_retimer_set_fn_t set;
const char *name;
void *drvdata;
};
struct typec_retimer *fwnode_typec_retimer_get(struct fwnode_handle *fwnode);
void typec_retimer_put(struct typec_retimer *retimer);
int typec_retimer_set(struct typec_retimer *retimer, struct typec_retimer_state *state);
static inline struct typec_retimer *typec_retimer_get(struct device *dev)
{
return fwnode_typec_retimer_get(dev_fwnode(dev));
}
struct typec_retimer *
typec_retimer_register(struct device *parent, const struct typec_retimer_desc *desc);
void typec_retimer_unregister(struct typec_retimer *retimer);
void *typec_retimer_get_drvdata(struct typec_retimer *retimer);
#endif /* __USB_TYPEC_RETIMER */