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
20struct goodix_i2c_hid_timing_data {
21	unsigned int post_gpio_reset_delay_ms;
22	unsigned int post_power_delay_ms;
23};
24
25struct 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
35static 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
67static 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
79static 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
113static 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
118static const struct of_device_id goodix_i2c_hid_of_match[] = {
119	{ .compatible = "goodix,gt7375p", .data = &goodix_gt7375p_timing_data },
120	{ }
121};
122MODULE_DEVICE_TABLE(of, goodix_i2c_hid_of_match);
123
124static 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};
135module_i2c_driver(goodix_i2c_hid_ts_driver);
136
137MODULE_AUTHOR("Douglas Anderson <dianders@chromium.org>");
138MODULE_DESCRIPTION("Goodix i2c-hid touchscreen driver");
139MODULE_LICENSE("GPL v2");
140