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(client->adapter, msg, 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(data->client, &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(touch->event);
114
115		input_mt_slot(data->input, touch->slot);
116		input_mt_report_slot_state(data->input, MT_TOOL_FINGER, act);
117		if (!act)
118			continue;
119
120		touchscreen_report_pos(data->input, &data->prop,
121				       be16_to_cpu(touch->x),
122				       be16_to_cpu(touch->y), true);
123	}
124
125	input_mt_sync_frame(data->input);
126	input_sync(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(data->client->irq);
136	gpiod_set_value_cansleep(data->wake_gpio, 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(data->client->irq);
146	i2c_smbus_write_byte_data(data->client, ICN8318_REG_POWER,
147				  ICN8318_POWER_HIBERNATE);
148	gpiod_set_value_cansleep(data->wake_gpio, 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(data->input))
157		icn8318_stop(data->input);
158	mutex_unlock(&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(data->input))
169		icn8318_start(data->input);
170	mutex_unlock(&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, sizeof(*data), GFP_KERNEL);
190	if (!data)
191		return -ENOMEM;
192
193	data->wake_gpio = devm_gpiod_get(dev, "wake", GPIOD_OUT_LOW);
194	if (IS_ERR(data->wake_gpio))
195		return dev_err_probe(dev, PTR_ERR(data->wake_gpio), "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(input, EV_ABS, ABS_MT_POSITION_X);
208	input_set_capability(input, EV_ABS, ABS_MT_POSITION_Y);
209
210	touchscreen_parse_properties(input, true, &data->prop);
211	if (!input_abs_get_max(input, ABS_MT_POSITION_X) ||
212	    !input_abs_get_max(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(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(input, data);
225
226	error = devm_request_threaded_irq(dev, client->irq, NULL, icn8318_irq,
227					  IRQF_ONESHOT, client->name, 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(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