1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Driver for ChipOne icn8318 i2c touchscreen controller
4 *
5 * Copyright (c) 2015 Red Hat Inc.
6 *
7 * Red Hat authors:
8 * Hans de Goede <hdegoede@redhat.com>
9 */
10
11#include <linux/gpio/consumer.h>
12#include <linux/interrupt.h>
13#include <linux/i2c.h>
14#include <linux/input.h>
15#include <linux/input/mt.h>
16#include <linux/input/touchscreen.h>
17#include <linux/module.h>
18#include <linux/of.h>
19
20#define ICN8318_REG_POWER 4
21#define ICN8318_REG_TOUCHDATA 16
22
23#define ICN8318_POWER_ACTIVE 0
24#define ICN8318_POWER_MONITOR 1
25#define ICN8318_POWER_HIBERNATE 2
26
27#define ICN8318_MAX_TOUCHES 5
28
29struct icn8318_touch {
30 __u8 slot;
31 __be16 x;
32 __be16 y;
33 __u8 pressure; /* Seems more like finger width then pressure really */
34 __u8 event;
35/* The difference between 2 and 3 is unclear */
36#define ICN8318_EVENT_NO_DATA 1 /* No finger seen yet since wakeup */
37#define ICN8318_EVENT_UPDATE1 2 /* New or updated coordinates */
38#define ICN8318_EVENT_UPDATE2 3 /* New or updated coordinates */
39#define ICN8318_EVENT_END 4 /* Finger lifted */
40} __packed;
41
42struct icn8318_touch_data {
43 __u8 softbutton;
44 __u8 touch_count;
45 struct icn8318_touch touches[ICN8318_MAX_TOUCHES];
46} __packed;
47
48struct icn8318_data {
49 struct i2c_client *client;
50 struct input_dev *input;
51 struct gpio_desc *wake_gpio;
52 struct touchscreen_properties prop;
53};
54
55static int icn8318_read_touch_data(struct i2c_client *client,
56 struct icn8318_touch_data *touch_data)
57{
58 u8 reg = ICN8318_REG_TOUCHDATA;
59 struct i2c_msg msg[2] = {
60 {
61 .addr = client->addr,
62 .len = 1,
63 .buf = &reg
64 },
65 {
66 .addr = client->addr,
67 .flags = I2C_M_RD,
68 .len = sizeof(struct icn8318_touch_data),
69 .buf = (u8 *)touch_data
70 }
71 };
72
73 return i2c_transfer(adap: client->adapter, msgs: msg, num: 2);
74}
75
76static inline bool icn8318_touch_active(u8 event)
77{
78 return (event == ICN8318_EVENT_UPDATE1) ||
79 (event == ICN8318_EVENT_UPDATE2);
80}
81
82static irqreturn_t icn8318_irq(int irq, void *dev_id)
83{
84 struct icn8318_data *data = dev_id;
85 struct device *dev = &data->client->dev;
86 struct icn8318_touch_data touch_data;
87 int i, ret;
88
89 ret = icn8318_read_touch_data(client: data->client, touch_data: &touch_data);
90 if (ret < 0) {
91 dev_err(dev, "Error reading touch data: %d\n", ret);
92 return IRQ_HANDLED;
93 }
94
95 if (touch_data.softbutton) {
96 /*
97 * Other data is invalid when a softbutton is pressed.
98 * This needs some extra devicetree bindings to map the icn8318
99 * softbutton codes to evdev codes. Currently no known devices
100 * use this.
101 */
102 return IRQ_HANDLED;
103 }
104
105 if (touch_data.touch_count > ICN8318_MAX_TOUCHES) {
106 dev_warn(dev, "Too much touches %d > %d\n",
107 touch_data.touch_count, ICN8318_MAX_TOUCHES);
108 touch_data.touch_count = ICN8318_MAX_TOUCHES;
109 }
110
111 for (i = 0; i < touch_data.touch_count; i++) {
112 struct icn8318_touch *touch = &touch_data.touches[i];
113 bool act = icn8318_touch_active(event: touch->event);
114
115 input_mt_slot(dev: data->input, slot: touch->slot);
116 input_mt_report_slot_state(dev: data->input, MT_TOOL_FINGER, active: act);
117 if (!act)
118 continue;
119
120 touchscreen_report_pos(input: data->input, prop: &data->prop,
121 be16_to_cpu(touch->x),
122 be16_to_cpu(touch->y), multitouch: true);
123 }
124
125 input_mt_sync_frame(dev: data->input);
126 input_sync(dev: data->input);
127
128 return IRQ_HANDLED;
129}
130
131static int icn8318_start(struct input_dev *dev)
132{
133 struct icn8318_data *data = input_get_drvdata(dev);
134
135 enable_irq(irq: data->client->irq);
136 gpiod_set_value_cansleep(desc: data->wake_gpio, value: 1);
137
138 return 0;
139}
140
141static void icn8318_stop(struct input_dev *dev)
142{
143 struct icn8318_data *data = input_get_drvdata(dev);
144
145 disable_irq(irq: data->client->irq);
146 i2c_smbus_write_byte_data(client: data->client, ICN8318_REG_POWER,
147 ICN8318_POWER_HIBERNATE);
148 gpiod_set_value_cansleep(desc: data->wake_gpio, value: 0);
149}
150
151static int icn8318_suspend(struct device *dev)
152{
153 struct icn8318_data *data = i2c_get_clientdata(to_i2c_client(dev));
154
155 mutex_lock(&data->input->mutex);
156 if (input_device_enabled(dev: data->input))
157 icn8318_stop(dev: data->input);
158 mutex_unlock(lock: &data->input->mutex);
159
160 return 0;
161}
162
163static int icn8318_resume(struct device *dev)
164{
165 struct icn8318_data *data = i2c_get_clientdata(to_i2c_client(dev));
166
167 mutex_lock(&data->input->mutex);
168 if (input_device_enabled(dev: data->input))
169 icn8318_start(dev: data->input);
170 mutex_unlock(lock: &data->input->mutex);
171
172 return 0;
173}
174
175static DEFINE_SIMPLE_DEV_PM_OPS(icn8318_pm_ops, icn8318_suspend, icn8318_resume);
176
177static int icn8318_probe(struct i2c_client *client)
178{
179 struct device *dev = &client->dev;
180 struct icn8318_data *data;
181 struct input_dev *input;
182 int error;
183
184 if (!client->irq) {
185 dev_err(dev, "Error no irq specified\n");
186 return -EINVAL;
187 }
188
189 data = devm_kzalloc(dev, size: sizeof(*data), GFP_KERNEL);
190 if (!data)
191 return -ENOMEM;
192
193 data->wake_gpio = devm_gpiod_get(dev, con_id: "wake", flags: GPIOD_OUT_LOW);
194 if (IS_ERR(ptr: data->wake_gpio))
195 return dev_err_probe(dev, err: PTR_ERR(ptr: data->wake_gpio), fmt: "Error getting wake gpio\n");
196
197 input = devm_input_allocate_device(dev);
198 if (!input)
199 return -ENOMEM;
200
201 input->name = client->name;
202 input->id.bustype = BUS_I2C;
203 input->open = icn8318_start;
204 input->close = icn8318_stop;
205 input->dev.parent = dev;
206
207 input_set_capability(dev: input, EV_ABS, ABS_MT_POSITION_X);
208 input_set_capability(dev: input, EV_ABS, ABS_MT_POSITION_Y);
209
210 touchscreen_parse_properties(input, multitouch: true, prop: &data->prop);
211 if (!input_abs_get_max(dev: input, ABS_MT_POSITION_X) ||
212 !input_abs_get_max(dev: input, ABS_MT_POSITION_Y)) {
213 dev_err(dev, "Error touchscreen-size-x and/or -y missing\n");
214 return -EINVAL;
215 }
216
217 error = input_mt_init_slots(dev: input, ICN8318_MAX_TOUCHES,
218 INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
219 if (error)
220 return error;
221
222 data->client = client;
223 data->input = input;
224 input_set_drvdata(dev: input, data);
225
226 error = devm_request_threaded_irq(dev, irq: client->irq, NULL, thread_fn: icn8318_irq,
227 IRQF_ONESHOT, devname: client->name, dev_id: data);
228 if (error) {
229 dev_err(dev, "Error requesting irq: %d\n", error);
230 return error;
231 }
232
233 /* Stop device till opened */
234 icn8318_stop(dev: data->input);
235
236 error = input_register_device(input);
237 if (error)
238 return error;
239
240 i2c_set_clientdata(client, data);
241
242 return 0;
243}
244
245static const struct of_device_id icn8318_of_match[] = {
246 { .compatible = "chipone,icn8318" },
247 { }
248};
249MODULE_DEVICE_TABLE(of, icn8318_of_match);
250
251/* This is useless for OF-enabled devices, but it is needed by I2C subsystem */
252static const struct i2c_device_id icn8318_i2c_id[] = {
253 { },
254};
255MODULE_DEVICE_TABLE(i2c, icn8318_i2c_id);
256
257static struct i2c_driver icn8318_driver = {
258 .driver = {
259 .name = "chipone_icn8318",
260 .pm = pm_sleep_ptr(&icn8318_pm_ops),
261 .of_match_table = icn8318_of_match,
262 },
263 .probe = icn8318_probe,
264 .id_table = icn8318_i2c_id,
265};
266
267module_i2c_driver(icn8318_driver);
268
269MODULE_DESCRIPTION("ChipOne icn8318 I2C Touchscreen Driver");
270MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
271MODULE_LICENSE("GPL");
272

source code of linux/drivers/input/touchscreen/chipone_icn8318.c