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 regulator *vddio;
30 	struct gpio_desc *reset_gpio;
31 	const struct goodix_i2c_hid_timing_data *timings;
32 };
33 
34 static int goodix_i2c_hid_power_up(struct i2chid_ops *ops)
35 {
36 	struct i2c_hid_of_goodix *ihid_goodix =
37 		container_of(ops, struct i2c_hid_of_goodix, ops);
38 	int ret;
39 
40 	ret = regulator_enable(ihid_goodix->vdd);
41 	if (ret)
42 		return ret;
43 
44 	ret = regulator_enable(ihid_goodix->vddio);
45 	if (ret)
46 		return ret;
47 
48 	if (ihid_goodix->timings->post_power_delay_ms)
49 		msleep(ihid_goodix->timings->post_power_delay_ms);
50 
51 	gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 0);
52 	if (ihid_goodix->timings->post_gpio_reset_delay_ms)
53 		msleep(ihid_goodix->timings->post_gpio_reset_delay_ms);
54 
55 	return 0;
56 }
57 
58 static void goodix_i2c_hid_power_down(struct i2chid_ops *ops)
59 {
60 	struct i2c_hid_of_goodix *ihid_goodix =
61 		container_of(ops, struct i2c_hid_of_goodix, ops);
62 
63 	gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1);
64 	regulator_disable(ihid_goodix->vddio);
65 	regulator_disable(ihid_goodix->vdd);
66 }
67 
68 static int i2c_hid_of_goodix_probe(struct i2c_client *client)
69 {
70 	struct i2c_hid_of_goodix *ihid_goodix;
71 
72 	ihid_goodix = devm_kzalloc(&client->dev, sizeof(*ihid_goodix),
73 				   GFP_KERNEL);
74 	if (!ihid_goodix)
75 		return -ENOMEM;
76 
77 	ihid_goodix->ops.power_up = goodix_i2c_hid_power_up;
78 	ihid_goodix->ops.power_down = goodix_i2c_hid_power_down;
79 
80 	/* Start out with reset asserted */
81 	ihid_goodix->reset_gpio =
82 		devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
83 	if (IS_ERR(ihid_goodix->reset_gpio))
84 		return PTR_ERR(ihid_goodix->reset_gpio);
85 
86 	ihid_goodix->vdd = devm_regulator_get(&client->dev, "vdd");
87 	if (IS_ERR(ihid_goodix->vdd))
88 		return PTR_ERR(ihid_goodix->vdd);
89 
90 	ihid_goodix->vddio = devm_regulator_get(&client->dev, "mainboard-vddio");
91 	if (IS_ERR(ihid_goodix->vddio))
92 		return PTR_ERR(ihid_goodix->vddio);
93 
94 	ihid_goodix->timings = device_get_match_data(&client->dev);
95 
96 	return i2c_hid_core_probe(client, &ihid_goodix->ops, 0x0001, 0);
97 }
98 
99 static const struct goodix_i2c_hid_timing_data goodix_gt7375p_timing_data = {
100 	.post_power_delay_ms = 10,
101 	.post_gpio_reset_delay_ms = 180,
102 };
103 
104 static const struct of_device_id goodix_i2c_hid_of_match[] = {
105 	{ .compatible = "goodix,gt7375p", .data = &goodix_gt7375p_timing_data },
106 	{ }
107 };
108 MODULE_DEVICE_TABLE(of, goodix_i2c_hid_of_match);
109 
110 static struct i2c_driver goodix_i2c_hid_ts_driver = {
111 	.driver = {
112 		.name	= "i2c_hid_of_goodix",
113 		.pm	= &i2c_hid_core_pm,
114 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
115 		.of_match_table = of_match_ptr(goodix_i2c_hid_of_match),
116 	},
117 	.probe_new	= i2c_hid_of_goodix_probe,
118 	.remove		= i2c_hid_core_remove,
119 	.shutdown	= i2c_hid_core_shutdown,
120 };
121 module_i2c_driver(goodix_i2c_hid_ts_driver);
122 
123 MODULE_AUTHOR("Douglas Anderson <dianders@chromium.org>");
124 MODULE_DESCRIPTION("Goodix i2c-hid touchscreen driver");
125 MODULE_LICENSE("GPL v2");
126