From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6A785EA2 for ; Thu, 30 Jun 2022 08:18:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1656577089; x=1688113089; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=NkhpkOsbzxMVNebOoJQwylDN7LDEukV9qRSiQGkoqq0=; b=SnSImmrvepKA7TLP2OZYSe2RgrJiocx2NgHCKUx9P5g5zY0UQYgZ2Cpe y8qIOW4XHEdI2gJRLhzSuyJ4Ti3TwRZLxNMOUQgBay+kgsodVBmbSafL3 Vb/QdfTvi1+zY2SiIMH97bN5ac2CyBuaoFG5C3P4P2GP7Q2otM0TeftNJ NgmYRJkHT9zJ3okBY28MFS0PHJHV9d5BVSpSfWjwB6NKx/nt8FGgdxLap doGcBuF/HTmjJBeCHHcgff1E8Z3TmjFrJmZY700ODo4YRmGKjK+35Z17R IU9enYWJWy3jBwFjoYmfk0VwsU9hGyX7OWtaaLAmDpIfn1mF6GqjF4gE6 w==; X-IronPort-AV: E=McAfee;i="6400,9594,10393"; a="283380851" X-IronPort-AV: E=Sophos;i="5.92,233,1650956400"; d="scan'208";a="283380851" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Jun 2022 01:18:05 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.92,233,1650956400"; d="scan'208";a="733543157" Received: from kuha.fi.intel.com ([10.237.72.185]) by fmsmga001.fm.intel.com with SMTP; 30 Jun 2022 01:18:00 -0700 Received: by kuha.fi.intel.com (sSMTP sendmail emulation); Thu, 30 Jun 2022 11:17:59 +0300 Date: Thu, 30 Jun 2022 11:17:59 +0300 From: Heikki Krogerus To: Prashant Malani Cc: linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, chrome-platform@lists.linux.dev, bleung@chromium.org, Daisuke Nojiri , "Dustin L. Howett" , Greg Kroah-Hartman , Guenter Roeck , "Gustavo A. R. Silva" , Kees Cook , Sebastian Reichel , Mika Westerberg Subject: Re: [PATCH 1/9] usb: typec: Add support for retimers Message-ID: References: <20220629233314.3540377-1-pmalani@chromium.org> <20220629233314.3540377-2-pmalani@chromium.org> Precedence: bulk X-Mailing-List: chrome-platform@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220629233314.3540377-2-pmalani@chromium.org> On Wed, Jun 29, 2022 at 11:32:19PM +0000, Prashant Malani wrote: > 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"). > > Signed-off-by: Prashant Malani Cool! This looks really good to me. I'll add Mika here, just to keep him in the loop. Thunderbolt/USB4 can control the same physical retimers over the SBU line. Right now there is no conflict, but I think we want to later be able to use these devices to upgrade the retimer firmware, and that is something that the Thunderbolt/USB4 already does. So let's keep an eye on this. I wonder, would it make sense to later make the thunderbolt_retimer devices also part of the device class that's introduced here? I think that way it would be easier to later figure out which thunderbolt_retimer and which retimer_switch represent the same physical retimer. And perhaps it would also be more clear for the user space to have a single device class for the retimers? Maybe the device class could be named just "retimer", and the device type could then be named "typec_retimer" instead of "retimer_switch"? thanks, > --- > drivers/usb/typec/Makefile | 2 +- > drivers/usb/typec/class.c | 9 +- > drivers/usb/typec/class.h | 1 + > drivers/usb/typec/retimer.c | 168 ++++++++++++++++++++++++++++++ > drivers/usb/typec/retimer.h | 15 +++ > include/linux/usb/typec_retimer.h | 45 ++++++++ > 6 files changed, 238 insertions(+), 2 deletions(-) > create mode 100644 drivers/usb/typec/retimer.c > create mode 100644 drivers/usb/typec/retimer.h > create mode 100644 include/linux/usb/typec_retimer.h > > diff --git a/drivers/usb/typec/Makefile b/drivers/usb/typec/Makefile > index 2f174cd3e5df..4955d9af0811 100644 > --- a/drivers/usb/typec/Makefile > +++ b/drivers/usb/typec/Makefile > @@ -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/ > diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c > index bbc46b14f99a..2fa0b3718d23 100644 > --- a/drivers/usb/typec/class.c > +++ b/drivers/usb/typec/class.c > @@ -2299,10 +2299,14 @@ static int __init typec_init(void) > if (ret) > goto err_unregister_bus; > > - ret = class_register(&typec_class); > + ret = class_register(&typec_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(&typec_retimer_class); > + > err_unregister_mux_class: > class_unregister(&typec_mux_class); > > diff --git a/drivers/usb/typec/class.h b/drivers/usb/typec/class.h > index b531f9853bc0..1bb1da124109 100644 > --- a/drivers/usb/typec/class.h > +++ b/drivers/usb/typec/class.h > @@ -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 typec_retimer_class; > extern struct class typec_class; > > #if defined(CONFIG_ACPI) > diff --git a/drivers/usb/typec/retimer.c b/drivers/usb/typec/retimer.c > new file mode 100644 > index 000000000000..2fa0aeb9363c > --- /dev/null > +++ b/drivers/usb/typec/retimer.c > @@ -0,0 +1,168 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright 2022 Google LLC > + * > + * USB Type-C Retimer support. > + * Author: Prashant Malani > + * > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > + > +#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(&typec_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 = "retimer_switch", > + .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 = &typec_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 typec_retimer_class = { > + .name = "typec_retimer", > + .owner = THIS_MODULE, > +}; > diff --git a/drivers/usb/typec/retimer.h b/drivers/usb/typec/retimer.h > new file mode 100644 > index 000000000000..fa15951d4846 > --- /dev/null > +++ b/drivers/usb/typec/retimer.h > @@ -0,0 +1,15 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > + > +#ifndef __USB_TYPEC_RETIMER__ > +#define __USB_TYPEC_RETIMER__ > + > +#include > + > +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__ */ > diff --git a/include/linux/usb/typec_retimer.h b/include/linux/usb/typec_retimer.h > new file mode 100644 > index 000000000000..5e036b3360e2 > --- /dev/null > +++ b/include/linux/usb/typec_retimer.h > @@ -0,0 +1,45 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > + > +#ifndef __USB_TYPEC_RETIMER > +#define __USB_TYPEC_RETIMER > + > +#include > +#include > + > +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 */ > -- > 2.37.0.rc0.161.g10f37bed90-goog -- heikki