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 { 102 struct usb4604 *hub; 103 104 hub = devm_kzalloc(&i2c->dev, sizeof(*hub), GFP_KERNEL); 105 if (!hub) 106 return -ENOMEM; 107 108 i2c_set_clientdata(i2c, hub); 109 hub->dev = &i2c->dev; 110 111 return usb4604_probe(hub); 112 } 113 114 static int __maybe_unused usb4604_i2c_suspend(struct device *dev) 115 { 116 struct i2c_client *client = to_i2c_client(dev); 117 struct usb4604 *hub = i2c_get_clientdata(client); 118 119 usb4604_switch_mode(hub, USB4604_MODE_STANDBY); 120 121 return 0; 122 } 123 124 static int __maybe_unused usb4604_i2c_resume(struct device *dev) 125 { 126 struct i2c_client *client = to_i2c_client(dev); 127 struct usb4604 *hub = i2c_get_clientdata(client); 128 129 usb4604_switch_mode(hub, hub->mode); 130 131 return 0; 132 } 133 134 static SIMPLE_DEV_PM_OPS(usb4604_i2c_pm_ops, usb4604_i2c_suspend, 135 usb4604_i2c_resume); 136 137 static const struct i2c_device_id usb4604_id[] = { 138 { "usb4604", 0 }, 139 { } 140 }; 141 MODULE_DEVICE_TABLE(i2c, usb4604_id); 142 143 #ifdef CONFIG_OF 144 static const struct of_device_id usb4604_of_match[] = { 145 { .compatible = "smsc,usb4604" }, 146 {} 147 }; 148 MODULE_DEVICE_TABLE(of, usb4604_of_match); 149 #endif 150 151 static struct i2c_driver usb4604_i2c_driver = { 152 .driver = { 153 .name = "usb4604", 154 .pm = pm_ptr(&usb4604_i2c_pm_ops), 155 .of_match_table = of_match_ptr(usb4604_of_match), 156 }, 157 .probe = usb4604_i2c_probe, 158 .id_table = usb4604_id, 159 }; 160 module_i2c_driver(usb4604_i2c_driver); 161 162 MODULE_DESCRIPTION("USB4604 USB HUB driver"); 163 MODULE_LICENSE("GPL v2"); 164