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
goodix_i2c_hid_power_up(struct i2chid_ops * ops)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
goodix_i2c_hid_power_down(struct i2chid_ops * ops)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
i2c_hid_of_goodix_probe(struct i2c_client * client,const struct i2c_device_id * id)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