1*ddaf8d96SPrashant Malani // SPDX-License-Identifier: GPL-2.0 2*ddaf8d96SPrashant Malani /* 3*ddaf8d96SPrashant Malani * Copyright 2022 Google LLC 4*ddaf8d96SPrashant Malani * 5*ddaf8d96SPrashant Malani * USB Type-C Retimer support. 6*ddaf8d96SPrashant Malani * Author: Prashant Malani <pmalani@chromium.org> 7*ddaf8d96SPrashant Malani * 8*ddaf8d96SPrashant Malani */ 9*ddaf8d96SPrashant Malani 10*ddaf8d96SPrashant Malani #include <linux/device.h> 11*ddaf8d96SPrashant Malani #include <linux/list.h> 12*ddaf8d96SPrashant Malani #include <linux/module.h> 13*ddaf8d96SPrashant Malani #include <linux/mutex.h> 14*ddaf8d96SPrashant Malani #include <linux/property.h> 15*ddaf8d96SPrashant Malani #include <linux/slab.h> 16*ddaf8d96SPrashant Malani 17*ddaf8d96SPrashant Malani #include "class.h" 18*ddaf8d96SPrashant Malani #include "retimer.h" 19*ddaf8d96SPrashant Malani 20*ddaf8d96SPrashant Malani static bool dev_name_ends_with(struct device *dev, const char *suffix) 21*ddaf8d96SPrashant Malani { 22*ddaf8d96SPrashant Malani const char *name = dev_name(dev); 23*ddaf8d96SPrashant Malani const int name_len = strlen(name); 24*ddaf8d96SPrashant Malani const int suffix_len = strlen(suffix); 25*ddaf8d96SPrashant Malani 26*ddaf8d96SPrashant Malani if (suffix_len > name_len) 27*ddaf8d96SPrashant Malani return false; 28*ddaf8d96SPrashant Malani 29*ddaf8d96SPrashant Malani return strcmp(name + (name_len - suffix_len), suffix) == 0; 30*ddaf8d96SPrashant Malani } 31*ddaf8d96SPrashant Malani 32*ddaf8d96SPrashant Malani static int retimer_fwnode_match(struct device *dev, const void *fwnode) 33*ddaf8d96SPrashant Malani { 34*ddaf8d96SPrashant Malani return dev_fwnode(dev) == fwnode && dev_name_ends_with(dev, "-retimer"); 35*ddaf8d96SPrashant Malani } 36*ddaf8d96SPrashant Malani 37*ddaf8d96SPrashant Malani static void *typec_retimer_match(struct fwnode_handle *fwnode, const char *id, void *data) 38*ddaf8d96SPrashant Malani { 39*ddaf8d96SPrashant Malani struct device *dev = class_find_device(&retimer_class, NULL, fwnode, 40*ddaf8d96SPrashant Malani retimer_fwnode_match); 41*ddaf8d96SPrashant Malani 42*ddaf8d96SPrashant Malani return dev ? to_typec_retimer(dev) : ERR_PTR(-EPROBE_DEFER); 43*ddaf8d96SPrashant Malani } 44*ddaf8d96SPrashant Malani 45*ddaf8d96SPrashant Malani /** 46*ddaf8d96SPrashant Malani * fwnode_typec_retimer_get - Find USB Type-C retimer. 47*ddaf8d96SPrashant Malani * @fwnode: The caller device node. 48*ddaf8d96SPrashant Malani * 49*ddaf8d96SPrashant Malani * Finds a retimer linked to the caller. This function is primarily meant for the 50*ddaf8d96SPrashant Malani * Type-C drivers. Returns a reference to the retimer on success, NULL if no 51*ddaf8d96SPrashant Malani * matching connection was found, or ERR_PTR(-EPROBE_DEFER) when a connection 52*ddaf8d96SPrashant Malani * was found but the retimer has not been enumerated yet. 53*ddaf8d96SPrashant Malani */ 54*ddaf8d96SPrashant Malani struct typec_retimer *fwnode_typec_retimer_get(struct fwnode_handle *fwnode) 55*ddaf8d96SPrashant Malani { 56*ddaf8d96SPrashant Malani struct typec_retimer *retimer; 57*ddaf8d96SPrashant Malani 58*ddaf8d96SPrashant Malani retimer = fwnode_connection_find_match(fwnode, "retimer-switch", NULL, typec_retimer_match); 59*ddaf8d96SPrashant Malani if (!IS_ERR_OR_NULL(retimer)) 60*ddaf8d96SPrashant Malani WARN_ON(!try_module_get(retimer->dev.parent->driver->owner)); 61*ddaf8d96SPrashant Malani 62*ddaf8d96SPrashant Malani return retimer; 63*ddaf8d96SPrashant Malani } 64*ddaf8d96SPrashant Malani EXPORT_SYMBOL_GPL(fwnode_typec_retimer_get); 65*ddaf8d96SPrashant Malani 66*ddaf8d96SPrashant Malani /** 67*ddaf8d96SPrashant Malani * typec_retimer_put - Release handle to a retimer. 68*ddaf8d96SPrashant Malani * @retimer: USB Type-C Connector Retimer. 69*ddaf8d96SPrashant Malani * 70*ddaf8d96SPrashant Malani * Decrements reference count for @retimer. 71*ddaf8d96SPrashant Malani */ 72*ddaf8d96SPrashant Malani void typec_retimer_put(struct typec_retimer *retimer) 73*ddaf8d96SPrashant Malani { 74*ddaf8d96SPrashant Malani if (!IS_ERR_OR_NULL(retimer)) { 75*ddaf8d96SPrashant Malani module_put(retimer->dev.parent->driver->owner); 76*ddaf8d96SPrashant Malani put_device(&retimer->dev); 77*ddaf8d96SPrashant Malani } 78*ddaf8d96SPrashant Malani } 79*ddaf8d96SPrashant Malani EXPORT_SYMBOL_GPL(typec_retimer_put); 80*ddaf8d96SPrashant Malani 81*ddaf8d96SPrashant Malani int typec_retimer_set(struct typec_retimer *retimer, struct typec_retimer_state *state) 82*ddaf8d96SPrashant Malani { 83*ddaf8d96SPrashant Malani if (IS_ERR_OR_NULL(retimer)) 84*ddaf8d96SPrashant Malani return 0; 85*ddaf8d96SPrashant Malani 86*ddaf8d96SPrashant Malani return retimer->set(retimer, state); 87*ddaf8d96SPrashant Malani } 88*ddaf8d96SPrashant Malani EXPORT_SYMBOL_GPL(typec_retimer_set); 89*ddaf8d96SPrashant Malani 90*ddaf8d96SPrashant Malani static void typec_retimer_release(struct device *dev) 91*ddaf8d96SPrashant Malani { 92*ddaf8d96SPrashant Malani kfree(to_typec_retimer(dev)); 93*ddaf8d96SPrashant Malani } 94*ddaf8d96SPrashant Malani 95*ddaf8d96SPrashant Malani static const struct device_type typec_retimer_dev_type = { 96*ddaf8d96SPrashant Malani .name = "typec_retimer", 97*ddaf8d96SPrashant Malani .release = typec_retimer_release, 98*ddaf8d96SPrashant Malani }; 99*ddaf8d96SPrashant Malani 100*ddaf8d96SPrashant Malani /** 101*ddaf8d96SPrashant Malani * typec_retimer_register - Register a retimer device. 102*ddaf8d96SPrashant Malani * @parent: Parent device. 103*ddaf8d96SPrashant Malani * @desc: Retimer description. 104*ddaf8d96SPrashant Malani * 105*ddaf8d96SPrashant Malani * Some USB Type-C connectors have their physical lines routed through retimers before they 106*ddaf8d96SPrashant Malani * reach muxes or host controllers. In some cases (for example: using alternate modes) 107*ddaf8d96SPrashant Malani * these retimers need to be reconfigured appropriately. This function registers retimer 108*ddaf8d96SPrashant Malani * switches which route and potentially modify the signals on the Type C physical lines 109*ddaf8d96SPrashant Malani * enroute to the host controllers. 110*ddaf8d96SPrashant Malani */ 111*ddaf8d96SPrashant Malani struct typec_retimer * 112*ddaf8d96SPrashant Malani typec_retimer_register(struct device *parent, const struct typec_retimer_desc *desc) 113*ddaf8d96SPrashant Malani { 114*ddaf8d96SPrashant Malani struct typec_retimer *retimer; 115*ddaf8d96SPrashant Malani int ret; 116*ddaf8d96SPrashant Malani 117*ddaf8d96SPrashant Malani if (!desc || !desc->set) 118*ddaf8d96SPrashant Malani return ERR_PTR(-EINVAL); 119*ddaf8d96SPrashant Malani 120*ddaf8d96SPrashant Malani retimer = kzalloc(sizeof(*retimer), GFP_KERNEL); 121*ddaf8d96SPrashant Malani if (!retimer) 122*ddaf8d96SPrashant Malani return ERR_PTR(-ENOMEM); 123*ddaf8d96SPrashant Malani 124*ddaf8d96SPrashant Malani retimer->set = desc->set; 125*ddaf8d96SPrashant Malani 126*ddaf8d96SPrashant Malani device_initialize(&retimer->dev); 127*ddaf8d96SPrashant Malani retimer->dev.parent = parent; 128*ddaf8d96SPrashant Malani retimer->dev.fwnode = desc->fwnode; 129*ddaf8d96SPrashant Malani retimer->dev.class = &retimer_class; 130*ddaf8d96SPrashant Malani retimer->dev.type = &typec_retimer_dev_type; 131*ddaf8d96SPrashant Malani retimer->dev.driver_data = desc->drvdata; 132*ddaf8d96SPrashant Malani dev_set_name(&retimer->dev, "%s-retimer", 133*ddaf8d96SPrashant Malani desc->name ? desc->name : dev_name(parent)); 134*ddaf8d96SPrashant Malani 135*ddaf8d96SPrashant Malani ret = device_add(&retimer->dev); 136*ddaf8d96SPrashant Malani if (ret) { 137*ddaf8d96SPrashant Malani dev_err(parent, "failed to register retimer (%d)\n", ret); 138*ddaf8d96SPrashant Malani put_device(&retimer->dev); 139*ddaf8d96SPrashant Malani return ERR_PTR(ret); 140*ddaf8d96SPrashant Malani } 141*ddaf8d96SPrashant Malani 142*ddaf8d96SPrashant Malani return retimer; 143*ddaf8d96SPrashant Malani } 144*ddaf8d96SPrashant Malani EXPORT_SYMBOL_GPL(typec_retimer_register); 145*ddaf8d96SPrashant Malani 146*ddaf8d96SPrashant Malani /** 147*ddaf8d96SPrashant Malani * typec_retimer_unregister - Unregister retimer device. 148*ddaf8d96SPrashant Malani * @retimer: USB Type-C Connector retimer. 149*ddaf8d96SPrashant Malani * 150*ddaf8d96SPrashant Malani * Unregister retimer that was registered with typec_retimer_register(). 151*ddaf8d96SPrashant Malani */ 152*ddaf8d96SPrashant Malani void typec_retimer_unregister(struct typec_retimer *retimer) 153*ddaf8d96SPrashant Malani { 154*ddaf8d96SPrashant Malani if (!IS_ERR_OR_NULL(retimer)) 155*ddaf8d96SPrashant Malani device_unregister(&retimer->dev); 156*ddaf8d96SPrashant Malani } 157*ddaf8d96SPrashant Malani EXPORT_SYMBOL_GPL(typec_retimer_unregister); 158*ddaf8d96SPrashant Malani 159*ddaf8d96SPrashant Malani void *typec_retimer_get_drvdata(struct typec_retimer *retimer) 160*ddaf8d96SPrashant Malani { 161*ddaf8d96SPrashant Malani return dev_get_drvdata(&retimer->dev); 162*ddaf8d96SPrashant Malani } 163*ddaf8d96SPrashant Malani EXPORT_SYMBOL_GPL(typec_retimer_get_drvdata); 164*ddaf8d96SPrashant Malani 165*ddaf8d96SPrashant Malani struct class retimer_class = { 166*ddaf8d96SPrashant Malani .name = "retimer", 167*ddaf8d96SPrashant Malani .owner = THIS_MODULE, 168*ddaf8d96SPrashant Malani }; 169