1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Driver for Elan 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 elan_i2c_hid_chip_data {
21 unsigned int post_gpio_reset_on_delay_ms;
22 unsigned int post_gpio_reset_off_delay_ms;
23 unsigned int post_power_delay_ms;
24 u16 hid_descriptor_address;
25 const char *main_supply_name;
26 };
27
28 struct i2c_hid_of_elan {
29 struct i2chid_ops ops;
30
31 struct regulator *vcc33;
32 struct regulator *vccio;
33 struct gpio_desc *reset_gpio;
34 const struct elan_i2c_hid_chip_data *chip_data;
35 };
36
elan_i2c_hid_power_up(struct i2chid_ops * ops)37 static int elan_i2c_hid_power_up(struct i2chid_ops *ops)
38 {
39 struct i2c_hid_of_elan *ihid_elan =
40 container_of(ops, struct i2c_hid_of_elan, ops);
41 int ret;
42
43 if (ihid_elan->vcc33) {
44 ret = regulator_enable(ihid_elan->vcc33);
45 if (ret)
46 return ret;
47 }
48
49 ret = regulator_enable(ihid_elan->vccio);
50 if (ret) {
51 regulator_disable(ihid_elan->vcc33);
52 return ret;
53 }
54
55 if (ihid_elan->chip_data->post_power_delay_ms)
56 msleep(ihid_elan->chip_data->post_power_delay_ms);
57
58 gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0);
59 if (ihid_elan->chip_data->post_gpio_reset_on_delay_ms)
60 msleep(ihid_elan->chip_data->post_gpio_reset_on_delay_ms);
61
62 return 0;
63 }
64
elan_i2c_hid_power_down(struct i2chid_ops * ops)65 static void elan_i2c_hid_power_down(struct i2chid_ops *ops)
66 {
67 struct i2c_hid_of_elan *ihid_elan =
68 container_of(ops, struct i2c_hid_of_elan, ops);
69
70 gpiod_set_value_cansleep(ihid_elan->reset_gpio, 1);
71 if (ihid_elan->chip_data->post_gpio_reset_off_delay_ms)
72 msleep(ihid_elan->chip_data->post_gpio_reset_off_delay_ms);
73
74 regulator_disable(ihid_elan->vccio);
75 if (ihid_elan->vcc33)
76 regulator_disable(ihid_elan->vcc33);
77 }
78
i2c_hid_of_elan_probe(struct i2c_client * client)79 static int i2c_hid_of_elan_probe(struct i2c_client *client)
80 {
81 struct i2c_hid_of_elan *ihid_elan;
82
83 ihid_elan = devm_kzalloc(&client->dev, sizeof(*ihid_elan), GFP_KERNEL);
84 if (!ihid_elan)
85 return -ENOMEM;
86
87 ihid_elan->ops.power_up = elan_i2c_hid_power_up;
88 ihid_elan->ops.power_down = elan_i2c_hid_power_down;
89
90 /* Start out with reset asserted */
91 ihid_elan->reset_gpio =
92 devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
93 if (IS_ERR(ihid_elan->reset_gpio))
94 return PTR_ERR(ihid_elan->reset_gpio);
95
96 ihid_elan->vccio = devm_regulator_get(&client->dev, "vccio");
97 if (IS_ERR(ihid_elan->vccio))
98 return PTR_ERR(ihid_elan->vccio);
99
100 ihid_elan->chip_data = device_get_match_data(&client->dev);
101
102 if (ihid_elan->chip_data->main_supply_name) {
103 ihid_elan->vcc33 = devm_regulator_get(&client->dev,
104 ihid_elan->chip_data->main_supply_name);
105 if (IS_ERR(ihid_elan->vcc33))
106 return PTR_ERR(ihid_elan->vcc33);
107 }
108
109 return i2c_hid_core_probe(client, &ihid_elan->ops,
110 ihid_elan->chip_data->hid_descriptor_address, 0);
111 }
112
113 static const struct elan_i2c_hid_chip_data elan_ekth6915_chip_data = {
114 .post_power_delay_ms = 1,
115 .post_gpio_reset_on_delay_ms = 300,
116 .hid_descriptor_address = 0x0001,
117 .main_supply_name = "vcc33",
118 };
119
120 static const struct elan_i2c_hid_chip_data ilitek_ili9882t_chip_data = {
121 .post_power_delay_ms = 1,
122 .post_gpio_reset_on_delay_ms = 200,
123 .post_gpio_reset_off_delay_ms = 65,
124 .hid_descriptor_address = 0x0001,
125 /*
126 * this touchscreen is tightly integrated with the panel and assumes
127 * that the relevant power rails (other than the IO rail) have already
128 * been turned on by the panel driver because we're a panel follower.
129 */
130 .main_supply_name = NULL,
131 };
132
133 static const struct elan_i2c_hid_chip_data ilitek_ili2901_chip_data = {
134 .post_power_delay_ms = 10,
135 .post_gpio_reset_on_delay_ms = 100,
136 .hid_descriptor_address = 0x0001,
137 .main_supply_name = "vcc33",
138 };
139
140 static const struct of_device_id elan_i2c_hid_of_match[] = {
141 { .compatible = "elan,ekth6915", .data = &elan_ekth6915_chip_data },
142 { .compatible = "ilitek,ili9882t", .data = &ilitek_ili9882t_chip_data },
143 { .compatible = "ilitek,ili2901", .data = &ilitek_ili2901_chip_data },
144 { }
145 };
146 MODULE_DEVICE_TABLE(of, elan_i2c_hid_of_match);
147
148 static struct i2c_driver elan_i2c_hid_ts_driver = {
149 .driver = {
150 .name = "i2c_hid_of_elan",
151 .pm = &i2c_hid_core_pm,
152 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
153 .of_match_table = of_match_ptr(elan_i2c_hid_of_match),
154 },
155 .probe = i2c_hid_of_elan_probe,
156 .remove = i2c_hid_core_remove,
157 .shutdown = i2c_hid_core_shutdown,
158 };
159 module_i2c_driver(elan_i2c_hid_ts_driver);
160
161 MODULE_AUTHOR("Douglas Anderson <dianders@chromium.org>");
162 MODULE_DESCRIPTION("Elan i2c-hid touchscreen driver");
163 MODULE_LICENSE("GPL");
164