drivers/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 <[email protected]>
   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;
  27
  28         phy = devm_of_phy_get_by_index(dev, dev->of_node, index);
  29         if (IS_ERR(phy)) {
  30                 if (PTR_ERR(phy) == -ENODEV)
  31                         return 0;
  32                 else
  33                         return PTR_ERR(phy);
  34         }
  35
  36         roothub_entry = devm_kzalloc(dev, sizeof(*roothub_entry), GFP_KERNEL);
  37         if (!roothub_entry)
  38                 return -ENOMEM;
  39
  40         INIT_LIST_HEAD(&roothub_entry->list);
  41
  42         roothub_entry->phy = phy;
  43
  44         list_add_tail(&roothub_entry->list, list);
  45
  46         return 0;
  47 }
  48
  49 struct usb_phy_roothub *usb_phy_roothub_alloc(struct device *dev)
  50 {
  51         struct usb_phy_roothub *phy_roothub;
  52         int i, num_phys, err;
  53
  54         if (!IS_ENABLED(CONFIG_GENERIC_PHY))
  55                 return NULL;
  56
  57         num_phys = of_count_phandle_with_args(dev->of_node, "phys",
  58                                               "#phy-cells");
  59         if (num_phys <= 0)
  60                 return NULL;
  61
  62         phy_roothub = devm_kzalloc(dev, sizeof(*phy_roothub), GFP_KERNEL);
  63         if (!phy_roothub)
  64                 return ERR_PTR(-ENOMEM);
  65
  66         INIT_LIST_HEAD(&phy_roothub->list);
  67
  68         for (i = 0; i < num_phys; i++) {
  69                 err = usb_phy_roothub_add_phy(dev, i, &phy_roothub->list);
  70                 if (err)
  71                         return ERR_PTR(err);
  72         }
  73
  74         return phy_roothub;
  75 }
  76 EXPORT_SYMBOL_GPL(usb_phy_roothub_alloc);
  77
  78 int usb_phy_roothub_init(struct usb_phy_roothub *phy_roothub)
  79 {
  80         struct usb_phy_roothub *roothub_entry;
  81         struct list_head *head;
  82         int err;
  83
  84         if (!phy_roothub)
  85                 return 0;
  86
  87         head = &phy_roothub->list;
  88
  89         list_for_each_entry(roothub_entry, head, list) {
  90                 err = phy_init(roothub_entry->phy);
  91                 if (err)
  92                         goto err_exit_phys;
  93         }
  94
  95         return 0;
  96
  97 err_exit_phys:
  98         list_for_each_entry_continue_reverse(roothub_entry, head, list)
  99                 phy_exit(roothub_entry->phy);
 100
 101         return err;
 102 }
 103 EXPORT_SYMBOL_GPL(usb_phy_roothub_init);
 104
 105 int usb_phy_roothub_exit(struct usb_phy_roothub *phy_roothub)
 106 {
 107         struct usb_phy_roothub *roothub_entry;
 108         struct list_head *head;
 109         int err, ret = 0;
 110
 111         if (!phy_roothub)
 112                 return 0;
 113
 114         head = &phy_roothub->list;
 115
 116         list_for_each_entry(roothub_entry, head, list) {
 117                 err = phy_exit(roothub_entry->phy);
 118                 if (err)
 119                         ret = err;
 120         }
 121
 122         return ret;
 123 }
 124 EXPORT_SYMBOL_GPL(usb_phy_roothub_exit);
 125
 126 int usb_phy_roothub_power_on(struct usb_phy_roothub *phy_roothub)
 127 {
 128         struct usb_phy_roothub *roothub_entry;
 129         struct list_head *head;
 130         int err;
 131
 132         if (!phy_roothub)
 133                 return 0;
 134
 135         head = &phy_roothub->list;
 136
 137         list_for_each_entry(roothub_entry, head, list) {
 138                 err = phy_power_on(roothub_entry->phy);
 139                 if (err)
 140                         goto err_out;
 141         }
 142
 143         return 0;
 144
 145 err_out:
 146         list_for_each_entry_continue_reverse(roothub_entry, head, list)
 147                 phy_power_off(roothub_entry->phy);
 148
 149         return err;
 150 }
 151 EXPORT_SYMBOL_GPL(usb_phy_roothub_power_on);
 152
 153 void usb_phy_roothub_power_off(struct usb_phy_roothub *phy_roothub)
 154 {
 155         struct usb_phy_roothub *roothub_entry;
 156
 157         if (!phy_roothub)
 158                 return;
 159
 160         list_for_each_entry_reverse(roothub_entry, &phy_roothub->list, list)
 161                 phy_power_off(roothub_entry->phy);
 162 }
 163 EXPORT_SYMBOL_GPL(usb_phy_roothub_power_off);
 164
 165 int usb_phy_roothub_suspend(struct device *controller_dev,
 166                             struct usb_phy_roothub *phy_roothub)
 167 {
 168         usb_phy_roothub_power_off(phy_roothub);
 169
 170         /* keep the PHYs initialized so the device can wake up the system */
 171         if (device_may_wakeup(controller_dev))
 172                 return 0;
 173
 174         return usb_phy_roothub_exit(phy_roothub);
 175 }
 176 EXPORT_SYMBOL_GPL(usb_phy_roothub_suspend);
 177
 178 int usb_phy_roothub_resume(struct device *controller_dev,
 179                            struct usb_phy_roothub *phy_roothub)
 180 {
 181         int err;
 182
 183         /* if the device can't wake up the system _exit was called */
 184         if (!device_may_wakeup(controller_dev)) {
 185                 err = usb_phy_roothub_init(phy_roothub);
 186                 if (err)
 187                         return err;
 188         }
 189
 190         err = usb_phy_roothub_power_on(phy_roothub);
 191
 192         /* undo _init if _power_on failed */
 193         if (err && !device_may_wakeup(controller_dev))
 194                 usb_phy_roothub_exit(phy_roothub);
 195
 196         return err;
 197 }
 198 EXPORT_SYMBOL_GPL(usb_phy_roothub_resume);