drivers/usb/misc/usb4604.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Driver for SMSC USB4604 USB HSIC 4-port 2.0 hub controller driver
   4  * Based on usb3503 driver
   5  *
   6  * Copyright (c) 2012-2013 Dongjin Kim (tobetter@gmail.com)
   7  * Copyright (c) 2016 Linaro Ltd.
   8  */
   9
  10 #include <linux/i2c.h>
  11 #include <linux/delay.h>
  12 #include <linux/slab.h>
  13 #include <linux/module.h>
  14 #include <linux/gpio/consumer.h>
  15
  16 enum usb4604_mode {
  17         USB4604_MODE_UNKNOWN,
  18         USB4604_MODE_HUB,
  19         USB4604_MODE_STANDBY,
  20 };
  21
  22 struct usb4604 {
  23         enum usb4604_mode       mode;
  24         struct device           *dev;
  25         struct gpio_desc        *gpio_reset;
  26 };
  27
  28 static void usb4604_reset(struct usb4604 *hub, int state)
  29 {
  30         gpiod_set_value_cansleep(hub->gpio_reset, state);
  31
  32         /* Wait for i2c logic to come up */
  33         if (state)
  34                 msleep(250);
  35 }
  36
  37 static int usb4604_connect(struct usb4604 *hub)
  38 {
  39         struct device *dev = hub->dev;
  40         struct i2c_client *client = to_i2c_client(dev);
  41         int err;
  42         u8 connect_cmd[] = { 0xaa, 0x55, 0x00 };
  43
  44         usb4604_reset(hub, 1);
  45
  46         err = i2c_master_send(client, connect_cmd, ARRAY_SIZE(connect_cmd));
  47         if (err < 0) {
  48                 usb4604_reset(hub, 0);
  49                 return err;
  50         }
  51
  52         hub->mode = USB4604_MODE_HUB;
  53         dev_dbg(dev, "switched to HUB mode\n");
  54
  55         return 0;
  56 }
  57
  58 static int usb4604_switch_mode(struct usb4604 *hub, enum usb4604_mode mode)
  59 {
  60         struct device *dev = hub->dev;
  61         int err = 0;
  62
  63         switch (mode) {
  64         case USB4604_MODE_HUB:
  65                 err = usb4604_connect(hub);
  66                 break;
  67
  68         case USB4604_MODE_STANDBY:
  69                 usb4604_reset(hub, 0);
  70                 dev_dbg(dev, "switched to STANDBY mode\n");
  71                 break;
  72
  73         default:
  74                 dev_err(dev, "unknown mode is requested\n");
  75                 err = -EINVAL;
  76                 break;
  77         }
  78
  79         return err;
  80 }
  81
  82 static int usb4604_probe(struct usb4604 *hub)
  83 {
  84         struct device *dev = hub->dev;
  85         struct device_node *np = dev->of_node;
  86         struct gpio_desc *gpio;
  87         u32 mode = USB4604_MODE_HUB;
  88
  89         gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
  90         if (IS_ERR(gpio))
  91                 return PTR_ERR(gpio);
  92         hub->gpio_reset = gpio;
  93
  94         if (of_property_read_u32(np, "initial-mode", &hub->mode))
  95                 hub->mode = mode;
  96
  97         return usb4604_switch_mode(hub, hub->mode);
  98 }
  99
 100 static int usb4604_i2c_probe(struct i2c_client *i2c,
 101                              const struct i2c_device_id *id)
 102 {
 103         struct usb4604 *hub;
 104
 105         hub = devm_kzalloc(&i2c->dev, sizeof(*hub), GFP_KERNEL);
 106         if (!hub)
 107                 return -ENOMEM;
 108
 109         i2c_set_clientdata(i2c, hub);
 110         hub->dev = &i2c->dev;
 111
 112         return usb4604_probe(hub);
 113 }
 114
 115 static int __maybe_unused usb4604_i2c_suspend(struct device *dev)
 116 {
 117         struct i2c_client *client = to_i2c_client(dev);
 118         struct usb4604 *hub = i2c_get_clientdata(client);
 119
 120         usb4604_switch_mode(hub, USB4604_MODE_STANDBY);
 121
 122         return 0;
 123 }
 124
 125 static int __maybe_unused usb4604_i2c_resume(struct device *dev)
 126 {
 127         struct i2c_client *client = to_i2c_client(dev);
 128         struct usb4604 *hub = i2c_get_clientdata(client);
 129
 130         usb4604_switch_mode(hub, hub->mode);
 131
 132         return 0;
 133 }
 134
 135 static SIMPLE_DEV_PM_OPS(usb4604_i2c_pm_ops, usb4604_i2c_suspend,
 136                 usb4604_i2c_resume);
 137
 138 static const struct i2c_device_id usb4604_id[] = {
 139         { "usb4604", 0 },
 140         { }
 141 };
 142 MODULE_DEVICE_TABLE(i2c, usb4604_id);
 143
 144 #ifdef CONFIG_OF
 145 static const struct of_device_id usb4604_of_match[] = {
 146         { .compatible = "smsc,usb4604" },
 147         {}
 148 };
 149 MODULE_DEVICE_TABLE(of, usb4604_of_match);
 150 #endif
 151
 152 static struct i2c_driver usb4604_i2c_driver = {
 153         .driver = {
 154                 .name = "usb4604",
 155                 .pm = pm_ptr(&usb4604_i2c_pm_ops),
 156                 .of_match_table = of_match_ptr(usb4604_of_match),
 157         },
 158         .probe          = usb4604_i2c_probe,
 159         .id_table       = usb4604_id,
 160 };
 161 module_i2c_driver(usb4604_i2c_driver);
 162
 163 MODULE_DESCRIPTION("USB4604 USB HUB driver");
 164 MODULE_LICENSE("GPL v2");