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
usb4604_reset(struct usb4604 * hub,int state)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
usb4604_connect(struct usb4604 * hub)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
usb4604_switch_mode(struct usb4604 * hub,enum usb4604_mode mode)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
usb4604_probe(struct usb4604 * hub)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
usb4604_i2c_probe(struct i2c_client * i2c)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
usb4604_i2c_suspend(struct device * dev)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
usb4604_i2c_resume(struct device * dev)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_new = 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