diff options
Diffstat (limited to 'drivers/usb/typec/retimer.c')
| -rw-r--r-- | drivers/usb/typec/retimer.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/drivers/usb/typec/retimer.c b/drivers/usb/typec/retimer.c new file mode 100644 index 000000000..ee94dbbe4 --- /dev/null +++ b/drivers/usb/typec/retimer.c @@ -0,0 +1,173 @@ +// 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 device_match_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; + + if (id && !fwnode_property_present(fwnode, id)) + return NULL; + + 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, +}; |