1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Driver for Goodix touchscreens that use the i2c-hid protocol.
4  *
5  * Copyright 2020 Google LLC
6  */
7 
8 #include <linux/delay.h>
9 #include <linux/device.h>
10 #include <linux/gpio/consumer.h>
11 #include <linux/i2c.h>
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/of.h>
15 #include <linux/pm.h>
16 #include <linux/regulator/consumer.h>
17 
18 #include "i2c-hid.h"
19 
20 struct goodix_i2c_hid_timing_data {
21 	unsigned int post_gpio_reset_delay_ms;
22 	unsigned int post_power_delay_ms;
23 };
24 
25 struct i2c_hid_of_goodix {
26 	struct i2chid_ops ops;
27 
28 	struct regulator *vdd;
29 	struct gpio_desc *reset_gpio;
30 	const struct goodix_i2c_hid_timing_data *timings;
31 };
32 
33 static int goodix_i2c_hid_power_up(struct i2chid_ops *ops)
34 {
35 	struct i2c_hid_of_goodix *ihid_goodix =
36 		container_of(ops, struct i2c_hid_of_goodix, ops);
37 	int ret;
38 
39 	ret = regulator_enable(ihid_goodix->vdd);
40 	if (ret)
41 		return ret;
42 
43 	if (ihid_goodix->timings->post_power_delay_ms)
44 		msleep(ihid_goodix->timings->post_power_delay_ms);
45 
46 	gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 0);
47 	if (ihid_goodix->timings->post_gpio_reset_delay_ms)
48 		msleep(ihid_goodix->timings->post_gpio_reset_delay_ms);
49 
50 	return 0;
51 }
52 
53 static void goodix_i2c_hid_power_down(struct i2chid_ops *ops)
54 {
55 	struct i2c_hid_of_goodix *ihid_goodix =
56 		container_of(ops, struct i2c_hid_of_goodix, ops);
57 
58 	gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1);
59 	regulator_disable(ihid_goodix->vdd);
60 }
61 
62 static int i2c_hid_of_goodix_probe(struct i2c_client *client,
63 				   const struct i2c_device_id *id)
64 {
65 	struct i2c_hid_of_goodix *ihid_goodix;
66 
67 	ihid_goodix = devm_kzalloc(&client->dev, sizeof(*ihid_goodix),
68 				   GFP_KERNEL);
69 	if (!ihid_goodix)
70 		return -ENOMEM;
71 
72 	ihid_goodix->ops.power_up = goodix_i2c_hid_power_up;
73 	ihid_goodix->ops.power_down = goodix_i2c_hid_power_down;
74 
75 	/* Start out with reset asserted */
76 	ihid_goodix->reset_gpio =
77 		devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
78 	if (IS_ERR(ihid_goodix->reset_gpio))
79 		return PTR_ERR(ihid_goodix->reset_gpio);
80 
81 	ihid_goodix->vdd = devm_regulator_get(&client->dev, "vdd");
82 	if (IS_ERR(ihid_goodix->vdd))
83 		return PTR_ERR(ihid_goodix->vdd);
84 
85 	ihid_goodix->timings = device_get_match_data(&client->dev);
86 
87 	return i2c_hid_core_probe(client, &ihid_goodix->ops, 0x0001);
88 }
89 
90 static const struct goodix_i2c_hid_timing_data goodix_gt7375p_timing_data = {
91 	.post_power_delay_ms = 10,
92 	.post_gpio_reset_delay_ms = 180,
93 };
94 
95 static const struct of_device_id goodix_i2c_hid_of_match[] = {
96 	{ .compatible = "goodix,gt7375p", .data = &goodix_gt7375p_timing_data },
97 	{ }
98 };
99 MODULE_DEVICE_TABLE(of, goodix_i2c_hid_of_match);
100 
101 static struct i2c_driver goodix_i2c_hid_ts_driver = {
102 	.driver = {
103 		.name	= "i2c_hid_of_goodix",
104 		.pm	= &i2c_hid_core_pm,
105 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
106 		.of_match_table = of_match_ptr(goodix_i2c_hid_of_match),
107 	},
108 	.probe		= i2c_hid_of_goodix_probe,
109 	.remove		= i2c_hid_core_remove,
110 	.shutdown	= i2c_hid_core_shutdown,
111 };
112 module_i2c_driver(goodix_i2c_hid_ts_driver);
113 
114 MODULE_AUTHOR("Douglas Anderson <dianders@chromium.org>");
115 MODULE_DESCRIPTION("Goodix i2c-hid touchscreen driver");
116 MODULE_LICENSE("GPL v2");
117