1 /* 2 * Driver for SMSC USB4604 USB HSIC 4-port 2.0 hub controller driver 3 * Based on usb3503 driver 4 * 5 * Copyright (c) 2012-2013 Dongjin Kim (tobetter@gmail.com) 6 * Copyright (c) 2016 Linaro Ltd. 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 */ 18 19 #include <linux/i2c.h> 20 #include <linux/delay.h> 21 #include <linux/slab.h> 22 #include <linux/module.h> 23 #include <linux/gpio/consumer.h> 24 25 enum usb4604_mode { 26 USB4604_MODE_UNKNOWN, 27 USB4604_MODE_HUB, 28 USB4604_MODE_STANDBY, 29 }; 30 31 struct usb4604 { 32 enum usb4604_mode mode; 33 struct device *dev; 34 struct gpio_desc *gpio_reset; 35 }; 36 37 static void usb4604_reset(struct usb4604 *hub, int state) 38 { 39 gpiod_set_value_cansleep(hub->gpio_reset, state); 40 41 /* Wait for i2c logic to come up */ 42 if (state) 43 msleep(250); 44 } 45 46 static int usb4604_connect(struct usb4604 *hub) 47 { 48 struct device *dev = hub->dev; 49 struct i2c_client *client = to_i2c_client(dev); 50 int err; 51 u8 connect_cmd[] = { 0xaa, 0x55, 0x00 }; 52 53 usb4604_reset(hub, 1); 54 55 err = i2c_master_send(client, connect_cmd, ARRAY_SIZE(connect_cmd)); 56 if (err < 0) { 57 usb4604_reset(hub, 0); 58 return err; 59 } 60 61 hub->mode = USB4604_MODE_HUB; 62 dev_dbg(dev, "switched to HUB mode\n"); 63 64 return 0; 65 } 66 67 static int usb4604_switch_mode(struct usb4604 *hub, enum usb4604_mode mode) 68 { 69 struct device *dev = hub->dev; 70 int err = 0; 71 72 switch (mode) { 73 case USB4604_MODE_HUB: 74 err = usb4604_connect(hub); 75 break; 76 77 case USB4604_MODE_STANDBY: 78 usb4604_reset(hub, 0); 79 dev_dbg(dev, "switched to STANDBY mode\n"); 80 break; 81 82 default: 83 dev_err(dev, "unknown mode is requested\n"); 84 err = -EINVAL; 85 break; 86 } 87 88 return err; 89 } 90 91 static int usb4604_probe(struct usb4604 *hub) 92 { 93 struct device *dev = hub->dev; 94 struct device_node *np = dev->of_node; 95 struct gpio_desc *gpio; 96 u32 mode = USB4604_MODE_HUB; 97 98 gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW); 99 if (IS_ERR(gpio)) 100 return PTR_ERR(gpio); 101 hub->gpio_reset = gpio; 102 103 if (of_property_read_u32(np, "initial-mode", &hub->mode)) 104 hub->mode = mode; 105 106 return usb4604_switch_mode(hub, hub->mode); 107 } 108 109 static int usb4604_i2c_probe(struct i2c_client *i2c, 110 const struct i2c_device_id *id) 111 { 112 struct usb4604 *hub; 113 114 hub = devm_kzalloc(&i2c->dev, sizeof(*hub), GFP_KERNEL); 115 if (!hub) 116 return -ENOMEM; 117 118 i2c_set_clientdata(i2c, hub); 119 hub->dev = &i2c->dev; 120 121 return usb4604_probe(hub); 122 } 123 124 #ifdef CONFIG_PM_SLEEP 125 static int usb4604_i2c_suspend(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, USB4604_MODE_STANDBY); 131 132 return 0; 133 } 134 135 static int usb4604_i2c_resume(struct device *dev) 136 { 137 struct i2c_client *client = to_i2c_client(dev); 138 struct usb4604 *hub = i2c_get_clientdata(client); 139 140 usb4604_switch_mode(hub, hub->mode); 141 142 return 0; 143 } 144 #endif 145 146 static SIMPLE_DEV_PM_OPS(usb4604_i2c_pm_ops, usb4604_i2c_suspend, 147 usb4604_i2c_resume); 148 149 static const struct i2c_device_id usb4604_id[] = { 150 { "usb4604", 0 }, 151 { } 152 }; 153 MODULE_DEVICE_TABLE(i2c, usb4604_id); 154 155 #ifdef CONFIG_OF 156 static const struct of_device_id usb4604_of_match[] = { 157 { .compatible = "smsc,usb4604" }, 158 {} 159 }; 160 MODULE_DEVICE_TABLE(of, usb4604_of_match); 161 #endif 162 163 static struct i2c_driver usb4604_i2c_driver = { 164 .driver = { 165 .name = "usb4604", 166 .pm = &usb4604_i2c_pm_ops, 167 .of_match_table = of_match_ptr(usb4604_of_match), 168 }, 169 .probe = usb4604_i2c_probe, 170 .id_table = usb4604_id, 171 }; 172 module_i2c_driver(usb4604_i2c_driver); 173 174 MODULE_DESCRIPTION("USB4604 USB HUB driver"); 175 MODULE_LICENSE("GPL v2"); 176