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(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
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(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
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(&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
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