usb/core/phy.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * A wrapper for multiple PHYs which passes all phy_* function calls to
   4  * multiple (actual) PHY devices. This is comes handy when initializing
   5  * all PHYs on a HCD and to keep them all in the same state.
   6  *
   7  * Copyright (C) 2018 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
   8  */
   9
  10 #include <linux/device.h>
  11 #include <linux/list.h>
  12 #include <linux/phy/phy.h>
  13 #include <linux/of.h>
  14
  15 #include "phy.h"
  16
  17 struct usb_phy_roothub {
  18         struct phy              *phy;
  19         struct list_head        list;
  20 };
  21
  22 static int usb_phy_roothub_add_phy(struct device *dev, int index,
  23                                    struct list_head *list)
  24 {
  25         struct usb_phy_roothub *roothub_entry;
  26         struct phy *phy = devm_of_phy_get_by_index(dev, dev->of_node, index);
  27
  28         if (IS_ERR_OR_NULL(phy)) {
  29                 if (!phy || PTR_ERR(phy) == -ENODEV)
  30                         return 0;
  31                 else
  32                         return PTR_ERR(phy);
  33         }
  34
  35         roothub_entry = devm_kzalloc(dev, sizeof(*roothub_entry), GFP_KERNEL);
  36         if (!roothub_entry)
  37                 return -ENOMEM;
  38
  39         INIT_LIST_HEAD(&roothub_entry->list);
  40
  41         roothub_entry->phy = phy;
  42
  43         list_add_tail(&roothub_entry->list, list);
  44
  45         return 0;
  46 }
  47
  48 struct usb_phy_roothub *usb_phy_roothub_alloc(struct device *dev)
  49 {
  50         struct usb_phy_roothub *phy_roothub;
  51         int i, num_phys, err;
  52
  53         if (!IS_ENABLED(CONFIG_GENERIC_PHY))
  54                 return NULL;
  55
  56         num_phys = of_count_phandle_with_args(dev->of_node, "phys",
  57                                               "#phy-cells");
  58         if (num_phys <= 0)
  59                 return NULL;
  60
  61         phy_roothub = devm_kzalloc(dev, sizeof(*phy_roothub), GFP_KERNEL);
  62         if (!phy_roothub)
  63                 return ERR_PTR(-ENOMEM);
  64
  65         INIT_LIST_HEAD(&phy_roothub->list);
  66
  67         for (i = 0; i < num_phys; i++) {
  68                 err = usb_phy_roothub_add_phy(dev, i, &phy_roothub->list);
  69                 if (err)
  70                         return ERR_PTR(err);
  71         }
  72
  73         return phy_roothub;
  74 }
  75 EXPORT_SYMBOL_GPL(usb_phy_roothub_alloc);
  76
  77 int usb_phy_roothub_init(struct usb_phy_roothub *phy_roothub)
  78 {
  79         struct usb_phy_roothub *roothub_entry;
  80         struct list_head *head;
  81         int err;
  82
  83         if (!phy_roothub)
  84                 return 0;
  85
  86         head = &phy_roothub->list;
  87
  88         list_for_each_entry(roothub_entry, head, list) {
  89                 err = phy_init(roothub_entry->phy);
  90                 if (err)
  91                         goto err_exit_phys;
  92         }
  93
  94         return 0;
  95
  96 err_exit_phys:
  97         list_for_each_entry_continue_reverse(roothub_entry, head, list)
  98                 phy_exit(roothub_entry->phy);
  99
 100         return err;
 101 }
 102 EXPORT_SYMBOL_GPL(usb_phy_roothub_init);
 103
 104 int usb_phy_roothub_exit(struct usb_phy_roothub *phy_roothub)
 105 {
 106         struct usb_phy_roothub *roothub_entry;
 107         struct list_head *head;
 108         int err, ret = 0;
 109
 110         if (!phy_roothub)
 111                 return 0;
 112
 113         head = &phy_roothub->list;
 114
 115         list_for_each_entry(roothub_entry, head, list) {
 116                 err = phy_exit(roothub_entry->phy);
 117                 if (err)
 118                         ret = err;
 119         }
 120
 121         return ret;
 122 }
 123 EXPORT_SYMBOL_GPL(usb_phy_roothub_exit);
 124
 125 int usb_phy_roothub_power_on(struct usb_phy_roothub *phy_roothub)
 126 {
 127         struct usb_phy_roothub *roothub_entry;
 128         struct list_head *head;
 129         int err;
 130
 131         if (!phy_roothub)
 132                 return 0;
 133
 134         head = &phy_roothub->list;
 135
 136         list_for_each_entry(roothub_entry, head, list) {
 137                 err = phy_power_on(roothub_entry->phy);
 138                 if (err)
 139                         goto err_out;
 140         }
 141
 142         return 0;
 143
 144 err_out:
 145         list_for_each_entry_continue_reverse(roothub_entry, head, list)
 146                 phy_power_off(roothub_entry->phy);
 147
 148         return err;
 149 }
 150 EXPORT_SYMBOL_GPL(usb_phy_roothub_power_on);
 151
 152 void usb_phy_roothub_power_off(struct usb_phy_roothub *phy_roothub)
 153 {
 154         struct usb_phy_roothub *roothub_entry;
 155
 156         if (!phy_roothub)
 157                 return;
 158
 159         list_for_each_entry_reverse(roothub_entry, &phy_roothub->list, list)
 160                 phy_power_off(roothub_entry->phy);
 161 }
 162 EXPORT_SYMBOL_GPL(usb_phy_roothub_power_off);
 163
 164 int usb_phy_roothub_suspend(struct device *controller_dev,
 165                             struct usb_phy_roothub *phy_roothub)
 166 {
 167         usb_phy_roothub_power_off(phy_roothub);
 168
 169         /* keep the PHYs initialized so the device can wake up the system */
 170         if (device_may_wakeup(controller_dev))
 171                 return 0;
 172
 173         return usb_phy_roothub_exit(phy_roothub);
 174 }
 175 EXPORT_SYMBOL_GPL(usb_phy_roothub_suspend);
 176
 177 int usb_phy_roothub_resume(struct device *controller_dev,
 178                            struct usb_phy_roothub *phy_roothub)
 179 {
 180         int err;
 181
 182         /* if the device can't wake up the system _exit was called */
 183         if (!device_may_wakeup(controller_dev)) {
 184                 err = usb_phy_roothub_init(phy_roothub);
 185                 if (err)
 186                         return err;
 187         }
 188
 189         err = usb_phy_roothub_power_on(phy_roothub);
 190
 191         /* undo _init if _power_on failed */
 192         if (err && !device_may_wakeup(controller_dev))
 193                 usb_phy_roothub_exit(phy_roothub);
 194
 195         return err;
 196 }
 197 EXPORT_SYMBOL_GPL(usb_phy_roothub_resume);