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 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License as published by 11 * the Free Software Foundation; either version 2 of the License, or 12 * (at your option) any later version. 13 * 14 * This program is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 * GNU General Public License for more details. 18 */ 19 20 #include <linux/i2c.h> 21 #include <linux/delay.h> 22 #include <linux/slab.h> 23 #include <linux/module.h> 24 #include <linux/gpio/consumer.h> 25 26 enum usb4604_mode { 27 USB4604_MODE_UNKNOWN, 28 USB4604_MODE_HUB, 29 USB4604_MODE_STANDBY, 30 }; 31 32 struct usb4604 { 33 enum usb4604_mode mode; 34 struct device *dev; 35 struct gpio_desc *gpio_reset; 36 }; 37 38 static void usb4604_reset(struct usb4604 *hub, int state) 39 { 40 gpiod_set_value_cansleep(hub->gpio_reset, state); 41 42 /* Wait for i2c logic to come up */ 43 if (state) 44 msleep(250); 45 } 46 47 static int usb4604_connect(struct usb4604 *hub) 48 { 49 struct device *dev = hub->dev; 50 struct i2c_client *client = to_i2c_client(dev); 51 int err; 52 u8 connect_cmd[] = { 0xaa, 0x55, 0x00 }; 53 54 usb4604_reset(hub, 1); 55 56 err = i2c_master_send(client, connect_cmd, ARRAY_SIZE(connect_cmd)); 57 if (err < 0) { 58 usb4604_reset(hub, 0); 59 return err; 60 } 61 62 hub->mode = USB4604_MODE_HUB; 63 dev_dbg(dev, "switched to HUB mode\n"); 64 65 return 0; 66 } 67 68 static int usb4604_switch_mode(struct usb4604 *hub, enum usb4604_mode mode) 69 { 70 struct device *dev = hub->dev; 71 int err = 0; 72 73 switch (mode) { 74 case USB4604_MODE_HUB: 75 err = usb4604_connect(hub); 76 break; 77 78 case USB4604_MODE_STANDBY: 79 usb4604_reset(hub, 0); 80 dev_dbg(dev, "switched to STANDBY mode\n"); 81 break; 82 83 default: 84 dev_err(dev, "unknown mode is requested\n"); 85 err = -EINVAL; 86 break; 87 } 88 89 return err; 90 } 91 92 static int usb4604_probe(struct usb4604 *hub) 93 { 94 struct device *dev = hub->dev; 95 struct device_node *np = dev->of_node; 96 struct gpio_desc *gpio; 97 u32 mode = USB4604_MODE_HUB; 98 99 gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW); 100 if (IS_ERR(gpio)) 101 return PTR_ERR(gpio); 102 hub->gpio_reset = gpio; 103 104 if (of_property_read_u32(np, "initial-mode", &hub->mode)) 105 hub->mode = mode; 106 107 return usb4604_switch_mode(hub, hub->mode); 108 } 109 110 static int usb4604_i2c_probe(struct i2c_client *i2c, 111 const struct i2c_device_id *id) 112 { 113 struct usb4604 *hub; 114 115 hub = devm_kzalloc(&i2c->dev, sizeof(*hub), GFP_KERNEL); 116 if (!hub) 117 return -ENOMEM; 118 119 i2c_set_clientdata(i2c, hub); 120 hub->dev = &i2c->dev; 121 122 return usb4604_probe(hub); 123 } 124 125 #ifdef CONFIG_PM_SLEEP 126 static int usb4604_i2c_suspend(struct device *dev) 127 { 128 struct i2c_client *client = to_i2c_client(dev); 129 struct usb4604 *hub = i2c_get_clientdata(client); 130 131 usb4604_switch_mode(hub, USB4604_MODE_STANDBY); 132 133 return 0; 134 } 135 136 static int usb4604_i2c_resume(struct device *dev) 137 { 138 struct i2c_client *client = to_i2c_client(dev); 139 struct usb4604 *hub = i2c_get_clientdata(client); 140 141 usb4604_switch_mode(hub, hub->mode); 142 143 return 0; 144 } 145 #endif 146 147 static SIMPLE_DEV_PM_OPS(usb4604_i2c_pm_ops, usb4604_i2c_suspend, 148 usb4604_i2c_resume); 149 150 static const struct i2c_device_id usb4604_id[] = { 151 { "usb4604", 0 }, 152 { } 153 }; 154 MODULE_DEVICE_TABLE(i2c, usb4604_id); 155 156 #ifdef CONFIG_OF 157 static const struct of_device_id usb4604_of_match[] = { 158 { .compatible = "smsc,usb4604" }, 159 {} 160 }; 161 MODULE_DEVICE_TABLE(of, usb4604_of_match); 162 #endif 163 164 static struct i2c_driver usb4604_i2c_driver = { 165 .driver = { 166 .name = "usb4604", 167 .pm = &usb4604_i2c_pm_ops, 168 .of_match_table = of_match_ptr(usb4604_of_match), 169 }, 170 .probe = usb4604_i2c_probe, 171 .id_table = usb4604_id, 172 }; 173 module_i2c_driver(usb4604_i2c_driver); 174 175 MODULE_DESCRIPTION("USB4604 USB HUB driver"); 176 MODULE_LICENSE("GPL v2"); 177