Commit ddaf8d96 authored by Prashant Malani's avatar Prashant Malani Committed by Greg Kroah-Hartman
Browse files

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: default avatarPrashant Malani <pmalani@chromium.org>
Acked-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20220711072333.2064341-2-pmalani@chromium.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 69bb3520

drivers/usb/typec/Makefile

+1 −1
Original line number Diff line number Diff line 
# 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/

drivers/usb/typec/class.c

+8 −1
Original line number Diff line number Diff line
@@ -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);

drivers/usb/typec/class.h

+1 −0
Original line number Diff line number Diff line
@@ -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)

drivers/usb/typec/retimer.c

0 → 100644
+168 −0
Original line number Diff line number Diff line 
// 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,

};

drivers/usb/typec/retimer.h

0 → 100644
+15 −0
Original line number Diff line number Diff line 
/* 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__ */