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
16enum usb4604_mode {
17	USB4604_MODE_UNKNOWN,
18	USB4604_MODE_HUB,
19	USB4604_MODE_STANDBY,
20};
21
22struct usb4604 {
23	enum usb4604_mode	mode;
24	struct device		*dev;
25	struct gpio_desc	*gpio_reset;
26};
27
28static 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
37static 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
58static 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
82static 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
100static 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
114static 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
124static 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
134static SIMPLE_DEV_PM_OPS(usb4604_i2c_pm_ops, usb4604_i2c_suspend,
135		usb4604_i2c_resume);
136
137static const struct i2c_device_id usb4604_id[] = {
138	{ "usb4604", 0 },
139	{ }
140};
141MODULE_DEVICE_TABLE(i2c, usb4604_id);
142
143#ifdef CONFIG_OF
144static const struct of_device_id usb4604_of_match[] = {
145	{ .compatible = "smsc,usb4604" },
146	{}
147};
148MODULE_DEVICE_TABLE(of, usb4604_of_match);
149#endif
150
151static 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};
160module_i2c_driver(usb4604_i2c_driver);
161
162MODULE_DESCRIPTION("USB4604 USB HUB driver");
163MODULE_LICENSE("GPL v2");
164