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 	bool no_reset_during_suspend;
32 	const struct goodix_i2c_hid_timing_data *timings;
33 };
34 
goodix_i2c_hid_power_up(struct i2chid_ops * ops)35 static int goodix_i2c_hid_power_up(struct i2chid_ops *ops)
36 {
37 	struct i2c_hid_of_goodix *ihid_goodix =
38 		container_of(ops, struct i2c_hid_of_goodix, ops);
39 	int ret;
40 
41 	/*
42 	 * We assert reset GPIO here (instead of during power-down) to ensure
43 	 * the device will have a clean state after powering up, just like the
44 	 * normal scenarios will have.
45 	 */
46 	if (ihid_goodix->no_reset_during_suspend)
47 		gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1);
48 
49 	ret = regulator_enable(ihid_goodix->vdd);
50 	if (ret)
51 		return ret;
52 
53 	ret = regulator_enable(ihid_goodix->vddio);
54 	if (ret)
55 		return ret;
56 
57 	if (ihid_goodix->timings->post_power_delay_ms)
58 		msleep(ihid_goodix->timings->post_power_delay_ms);
59 
60 	gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 0);
61 	if (ihid_goodix->timings->post_gpio_reset_delay_ms)
62 		msleep(ihid_goodix->timings->post_gpio_reset_delay_ms);
63 
64 	return 0;
65 }
66 
goodix_i2c_hid_power_down(struct i2chid_ops * ops)67 static void goodix_i2c_hid_power_down(struct i2chid_ops *ops)
68 {
69 	struct i2c_hid_of_goodix *ihid_goodix =
70 		container_of(ops, struct i2c_hid_of_goodix, ops);
71 
72 	if (!ihid_goodix->no_reset_during_suspend)
73 		gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1);
74 
75 	regulator_disable(ihid_goodix->vddio);
76 	regulator_disable(ihid_goodix->vdd);
77 }
78 
i2c_hid_of_goodix_probe(struct i2c_client * client)79 static int i2c_hid_of_goodix_probe(struct i2c_client *client)
80 {
81 	struct i2c_hid_of_goodix *ihid_goodix;
82 
83 	ihid_goodix = devm_kzalloc(&client->dev, sizeof(*ihid_goodix),
84 				   GFP_KERNEL);
85 	if (!ihid_goodix)
86 		return -ENOMEM;
87 
88 	ihid_goodix->ops.power_up = goodix_i2c_hid_power_up;
89 	ihid_goodix->ops.power_down = goodix_i2c_hid_power_down;
90 
91 	/* Start out with reset asserted */
92 	ihid_goodix->reset_gpio =
93 		devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
94 	if (IS_ERR(ihid_goodix->reset_gpio))
95 		return PTR_ERR(ihid_goodix->reset_gpio);
96 
97 	ihid_goodix->vdd = devm_regulator_get(&client->dev, "vdd");
98 	if (IS_ERR(ihid_goodix->vdd))
99 		return PTR_ERR(ihid_goodix->vdd);
100 
101 	ihid_goodix->vddio = devm_regulator_get(&client->dev, "mainboard-vddio");
102 	if (IS_ERR(ihid_goodix->vddio))
103 		return PTR_ERR(ihid_goodix->vddio);
104 
105 	ihid_goodix->no_reset_during_suspend =
106 		of_property_read_bool(client->dev.of_node, "goodix,no-reset-during-suspend");
107 
108 	ihid_goodix->timings = device_get_match_data(&client->dev);
109 
110 	return i2c_hid_core_probe(client, &ihid_goodix->ops, 0x0001, 0);
111 }
112 
113 static const struct goodix_i2c_hid_timing_data goodix_gt7375p_timing_data = {
114 	.post_power_delay_ms = 10,
115 	.post_gpio_reset_delay_ms = 180,
116 };
117 
118 static const struct of_device_id goodix_i2c_hid_of_match[] = {
119 	{ .compatible = "goodix,gt7375p", .data = &goodix_gt7375p_timing_data },
120 	{ }
121 };
122 MODULE_DEVICE_TABLE(of, goodix_i2c_hid_of_match);
123 
124 static struct i2c_driver goodix_i2c_hid_ts_driver = {
125 	.driver = {
126 		.name	= "i2c_hid_of_goodix",
127 		.pm	= &i2c_hid_core_pm,
128 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
129 		.of_match_table = of_match_ptr(goodix_i2c_hid_of_match),
130 	},
131 	.probe		= i2c_hid_of_goodix_probe,
132 	.remove		= i2c_hid_core_remove,
133 	.shutdown	= i2c_hid_core_shutdown,
134 };
135 module_i2c_driver(goodix_i2c_hid_ts_driver);
136 
137 MODULE_AUTHOR("Douglas Anderson <dianders@chromium.org>");
138 MODULE_DESCRIPTION("Goodix i2c-hid touchscreen driver");
139 MODULE_LICENSE("GPL v2");
140