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[35.185.214.157]) by smtp.gmail.com with ESMTPSA id h14-20020a170902f7ce00b0016be0d5483asm7514953plw.252.2022.07.06.10.16.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 06 Jul 2022 10:16:46 -0700 (PDT) From: Prashant Malani To: linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, chrome-platform@lists.linux.dev Cc: bleung@chromium.org, heikki.krogerus@linux.intel.com, Prashant Malani , Daisuke Nojiri , "Dustin L. Howett" , Greg Kroah-Hartman , Guenter Roeck , "Gustavo A. R. Silva" , Kees Cook , Sebastian Reichel , Tzung-Bi Shih Subject: [PATCH v2 1/9] usb: typec: Add support for retimers Date: Wed, 6 Jul 2022 17:15:05 +0000 Message-Id: <20220706171601.807042-2-pmalani@chromium.org> X-Mailer: git-send-email 2.37.0.rc0.161.g10f37bed90-goog In-Reply-To: <20220706171601.807042-1-pmalani@chromium.org> References: <20220706171601.807042-1-pmalani@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org 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 --- Changes since v11: - Change class name to "retimer" - Change device type to "typec_retimer". 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..9062836bb638 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(&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); diff --git a/drivers/usb/typec/class.h b/drivers/usb/typec/class.h index b531f9853bc0..43fcf9e37a8c 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 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..051eaa7d2899 --- /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(&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, +}; 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 */