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
20struct 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
28struct 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
37static 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(regulator: ihid_elan->vcc33);
45 if (ret)
46 return ret;
47 }
48
49 ret = regulator_enable(regulator: ihid_elan->vccio);
50 if (ret) {
51 regulator_disable(regulator: ihid_elan->vcc33);
52 return ret;
53 }
54
55 if (ihid_elan->chip_data->post_power_delay_ms)
56 msleep(msecs: ihid_elan->chip_data->post_power_delay_ms);
57
58 gpiod_set_value_cansleep(desc: ihid_elan->reset_gpio, value: 0);
59 if (ihid_elan->chip_data->post_gpio_reset_on_delay_ms)
60 msleep(msecs: ihid_elan->chip_data->post_gpio_reset_on_delay_ms);
61
62 return 0;
63}
64
65static 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(desc: ihid_elan->reset_gpio, value: 1);
71 if (ihid_elan->chip_data->post_gpio_reset_off_delay_ms)
72 msleep(msecs: ihid_elan->chip_data->post_gpio_reset_off_delay_ms);
73
74 regulator_disable(regulator: ihid_elan->vccio);
75 if (ihid_elan->vcc33)
76 regulator_disable(regulator: ihid_elan->vcc33);
77}
78
79static 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(dev: &client->dev, size: 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(dev: &client->dev, con_id: "reset", flags: GPIOD_OUT_HIGH);
93 if (IS_ERR(ptr: ihid_elan->reset_gpio))
94 return PTR_ERR(ptr: ihid_elan->reset_gpio);
95
96 ihid_elan->vccio = devm_regulator_get(dev: &client->dev, id: "vccio");
97 if (IS_ERR(ptr: ihid_elan->vccio))
98 return PTR_ERR(ptr: ihid_elan->vccio);
99
100 ihid_elan->chip_data = device_get_match_data(dev: &client->dev);
101
102 if (ihid_elan->chip_data->main_supply_name) {
103 ihid_elan->vcc33 = devm_regulator_get(dev: &client->dev,
104 id: ihid_elan->chip_data->main_supply_name);
105 if (IS_ERR(ptr: ihid_elan->vcc33))
106 return PTR_ERR(ptr: ihid_elan->vcc33);
107 }
108
109 return i2c_hid_core_probe(client, ops: &ihid_elan->ops,
110 hid_descriptor_address: ihid_elan->chip_data->hid_descriptor_address, quirks: 0);
111}
112
113static 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
120static 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
133static 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
140static 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};
146MODULE_DEVICE_TABLE(of, elan_i2c_hid_of_match);
147
148static 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};
159module_i2c_driver(elan_i2c_hid_ts_driver);
160
161MODULE_AUTHOR("Douglas Anderson <dianders@chromium.org>");
162MODULE_DESCRIPTION("Elan i2c-hid touchscreen driver");
163MODULE_LICENSE("GPL");
164

source code of linux/drivers/hid/i2c-hid/i2c-hid-of-elan.c