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