1 // SPDX-License-Identifier: GPL-2.0
2 /**
3 * drivers/extcon/extcon-tusb320.c - TUSB320 extcon driver
4 *
5 * Copyright (C) 2020 National Instruments Corporation
6 * Author: Michael Auchter <michael.auchter@ni.com>
7 */
8
9 #include <linux/extcon-provider.h>
10 #include <linux/i2c.h>
11 #include <linux/init.h>
12 #include <linux/interrupt.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/regmap.h>
16
17 #define TUSB320_REG9 0x9
18 #define TUSB320_REG9_ATTACHED_STATE_SHIFT 6
19 #define TUSB320_REG9_ATTACHED_STATE_MASK 0x3
20 #define TUSB320_REG9_CABLE_DIRECTION BIT(5)
21 #define TUSB320_REG9_INTERRUPT_STATUS BIT(4)
22 #define TUSB320_ATTACHED_STATE_NONE 0x0
23 #define TUSB320_ATTACHED_STATE_DFP 0x1
24 #define TUSB320_ATTACHED_STATE_UFP 0x2
25 #define TUSB320_ATTACHED_STATE_ACC 0x3
26
27 struct tusb320_priv {
28 struct device *dev;
29 struct regmap *regmap;
30 struct extcon_dev *edev;
31 };
32
33 static const char * const tusb_attached_states[] = {
34 [TUSB320_ATTACHED_STATE_NONE] = "not attached",
35 [TUSB320_ATTACHED_STATE_DFP] = "downstream facing port",
36 [TUSB320_ATTACHED_STATE_UFP] = "upstream facing port",
37 [TUSB320_ATTACHED_STATE_ACC] = "accessory",
38 };
39
40 static const unsigned int tusb320_extcon_cable[] = {
41 EXTCON_USB,
42 EXTCON_USB_HOST,
43 EXTCON_NONE,
44 };
45
tusb320_check_signature(struct tusb320_priv * priv)46 static int tusb320_check_signature(struct tusb320_priv *priv)
47 {
48 static const char sig[] = { '\0', 'T', 'U', 'S', 'B', '3', '2', '0' };
49 unsigned val;
50 int i, ret;
51
52 for (i = 0; i < sizeof(sig); i++) {
53 ret = regmap_read(priv->regmap, sizeof(sig) - 1 - i, &val);
54 if (ret < 0)
55 return ret;
56 if (val != sig[i]) {
57 dev_err(priv->dev, "signature mismatch!\n");
58 return -ENODEV;
59 }
60 }
61
62 return 0;
63 }
64
tusb320_irq_handler(int irq,void * dev_id)65 static irqreturn_t tusb320_irq_handler(int irq, void *dev_id)
66 {
67 struct tusb320_priv *priv = dev_id;
68 int state, polarity;
69 unsigned reg;
70
71 if (regmap_read(priv->regmap, TUSB320_REG9, ®)) {
72 dev_err(priv->dev, "error during i2c read!\n");
73 return IRQ_NONE;
74 }
75
76 if (!(reg & TUSB320_REG9_INTERRUPT_STATUS))
77 return IRQ_NONE;
78
79 state = (reg >> TUSB320_REG9_ATTACHED_STATE_SHIFT) &
80 TUSB320_REG9_ATTACHED_STATE_MASK;
81 polarity = !!(reg & TUSB320_REG9_CABLE_DIRECTION);
82
83 dev_dbg(priv->dev, "attached state: %s, polarity: %d\n",
84 tusb_attached_states[state], polarity);
85
86 extcon_set_state(priv->edev, EXTCON_USB,
87 state == TUSB320_ATTACHED_STATE_UFP);
88 extcon_set_state(priv->edev, EXTCON_USB_HOST,
89 state == TUSB320_ATTACHED_STATE_DFP);
90 extcon_set_property(priv->edev, EXTCON_USB,
91 EXTCON_PROP_USB_TYPEC_POLARITY,
92 (union extcon_property_value)polarity);
93 extcon_set_property(priv->edev, EXTCON_USB_HOST,
94 EXTCON_PROP_USB_TYPEC_POLARITY,
95 (union extcon_property_value)polarity);
96 extcon_sync(priv->edev, EXTCON_USB);
97 extcon_sync(priv->edev, EXTCON_USB_HOST);
98
99 regmap_write(priv->regmap, TUSB320_REG9, reg);
100
101 return IRQ_HANDLED;
102 }
103
104 static const struct regmap_config tusb320_regmap_config = {
105 .reg_bits = 8,
106 .val_bits = 8,
107 };
108
tusb320_extcon_probe(struct i2c_client * client,const struct i2c_device_id * id)109 static int tusb320_extcon_probe(struct i2c_client *client,
110 const struct i2c_device_id *id)
111 {
112 struct tusb320_priv *priv;
113 int ret;
114
115 priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
116 if (!priv)
117 return -ENOMEM;
118 priv->dev = &client->dev;
119
120 priv->regmap = devm_regmap_init_i2c(client, &tusb320_regmap_config);
121 if (IS_ERR(priv->regmap))
122 return PTR_ERR(priv->regmap);
123
124 ret = tusb320_check_signature(priv);
125 if (ret)
126 return ret;
127
128 priv->edev = devm_extcon_dev_allocate(priv->dev, tusb320_extcon_cable);
129 if (IS_ERR(priv->edev)) {
130 dev_err(priv->dev, "failed to allocate extcon device\n");
131 return PTR_ERR(priv->edev);
132 }
133
134 ret = devm_extcon_dev_register(priv->dev, priv->edev);
135 if (ret < 0) {
136 dev_err(priv->dev, "failed to register extcon device\n");
137 return ret;
138 }
139
140 extcon_set_property_capability(priv->edev, EXTCON_USB,
141 EXTCON_PROP_USB_TYPEC_POLARITY);
142 extcon_set_property_capability(priv->edev, EXTCON_USB_HOST,
143 EXTCON_PROP_USB_TYPEC_POLARITY);
144
145 /* update initial state */
146 tusb320_irq_handler(client->irq, priv);
147
148 ret = devm_request_threaded_irq(priv->dev, client->irq, NULL,
149 tusb320_irq_handler,
150 IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
151 client->name, priv);
152
153 return ret;
154 }
155
156 static const struct of_device_id tusb320_extcon_dt_match[] = {
157 { .compatible = "ti,tusb320", },
158 { }
159 };
160 MODULE_DEVICE_TABLE(of, tusb320_extcon_dt_match);
161
162 static struct i2c_driver tusb320_extcon_driver = {
163 .probe = tusb320_extcon_probe,
164 .driver = {
165 .name = "extcon-tusb320",
166 .of_match_table = tusb320_extcon_dt_match,
167 },
168 };
169
tusb320_init(void)170 static int __init tusb320_init(void)
171 {
172 return i2c_add_driver(&tusb320_extcon_driver);
173 }
174 subsys_initcall(tusb320_init);
175
tusb320_exit(void)176 static void __exit tusb320_exit(void)
177 {
178 i2c_del_driver(&tusb320_extcon_driver);
179 }
180 module_exit(tusb320_exit);
181
182 MODULE_AUTHOR("Michael Auchter <michael.auchter@ni.com>");
183 MODULE_DESCRIPTION("TI TUSB320 extcon driver");
184 MODULE_LICENSE("GPL v2");
185