1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Driver for Novatek NT11205 i2c touchscreen controller as found
4 * on the Acer Iconia One 7 B1-750 tablet.
5 *
6 * Copyright (c) 2023 Hans de Goede <hdegoede@redhat.com>
7 */
8
9#include <linux/delay.h>
10#include <linux/gpio/consumer.h>
11#include <linux/interrupt.h>
12#include <linux/i2c.h>
13#include <linux/input.h>
14#include <linux/input/mt.h>
15#include <linux/input/touchscreen.h>
16#include <linux/module.h>
17
18#include <asm/unaligned.h>
19
20#define NVT_TS_TOUCH_START		0x00
21#define NVT_TS_TOUCH_SIZE		6
22
23#define NVT_TS_PARAMETERS_START		0x78
24/* These are offsets from NVT_TS_PARAMETERS_START */
25#define NVT_TS_PARAMS_WIDTH		0x04
26#define NVT_TS_PARAMS_HEIGHT		0x06
27#define NVT_TS_PARAMS_MAX_TOUCH		0x09
28#define NVT_TS_PARAMS_MAX_BUTTONS	0x0a
29#define NVT_TS_PARAMS_IRQ_TYPE		0x0b
30#define NVT_TS_PARAMS_WAKE_TYPE		0x0c
31#define NVT_TS_PARAMS_CHIP_ID		0x0e
32#define NVT_TS_PARAMS_SIZE		0x0f
33
34#define NVT_TS_SUPPORTED_WAKE_TYPE	0x05
35#define NVT_TS_SUPPORTED_CHIP_ID	0x05
36
37#define NVT_TS_MAX_TOUCHES		10
38#define NVT_TS_MAX_SIZE			4096
39
40#define NVT_TS_TOUCH_INVALID		0xff
41#define NVT_TS_TOUCH_SLOT_SHIFT		3
42#define NVT_TS_TOUCH_TYPE_MASK		GENMASK(2, 0)
43#define NVT_TS_TOUCH_NEW		1
44#define NVT_TS_TOUCH_UPDATE		2
45#define NVT_TS_TOUCH_RELEASE		3
46
47static const int nvt_ts_irq_type[4] = {
48	IRQF_TRIGGER_RISING,
49	IRQF_TRIGGER_FALLING,
50	IRQF_TRIGGER_LOW,
51	IRQF_TRIGGER_HIGH
52};
53
54struct nvt_ts_data {
55	struct i2c_client *client;
56	struct input_dev *input;
57	struct gpio_desc *reset_gpio;
58	struct touchscreen_properties prop;
59	int max_touches;
60	u8 buf[NVT_TS_TOUCH_SIZE * NVT_TS_MAX_TOUCHES];
61};
62
63static int nvt_ts_read_data(struct i2c_client *client, u8 reg, u8 *data, int count)
64{
65	struct i2c_msg msg[2] = {
66		{
67			.addr = client->addr,
68			.len = 1,
69			.buf = &reg,
70		},
71		{
72			.addr = client->addr,
73			.flags = I2C_M_RD,
74			.len = count,
75			.buf = data,
76		}
77	};
78	int ret;
79
80	ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
81	if (ret != ARRAY_SIZE(msg)) {
82		dev_err(&client->dev, "Error reading from 0x%02x: %d\n", reg, ret);
83		return (ret < 0) ? ret : -EIO;
84	}
85
86	return 0;
87}
88
89static irqreturn_t nvt_ts_irq(int irq, void *dev_id)
90{
91	struct nvt_ts_data *data = dev_id;
92	struct device *dev = &data->client->dev;
93	int i, error, slot, x, y;
94	bool active;
95	u8 *touch;
96
97	error = nvt_ts_read_data(data->client, NVT_TS_TOUCH_START, data->buf,
98				 data->max_touches * NVT_TS_TOUCH_SIZE);
99	if (error)
100		return IRQ_HANDLED;
101
102	for (i = 0; i < data->max_touches; i++) {
103		touch = &data->buf[i * NVT_TS_TOUCH_SIZE];
104
105		if (touch[0] == NVT_TS_TOUCH_INVALID)
106			continue;
107
108		slot = touch[0] >> NVT_TS_TOUCH_SLOT_SHIFT;
109		if (slot < 1 || slot > data->max_touches) {
110			dev_warn(dev, "slot %d out of range, ignoring\n", slot);
111			continue;
112		}
113
114		switch (touch[0] & NVT_TS_TOUCH_TYPE_MASK) {
115		case NVT_TS_TOUCH_NEW:
116		case NVT_TS_TOUCH_UPDATE:
117			active = true;
118			break;
119		case NVT_TS_TOUCH_RELEASE:
120			active = false;
121			break;
122		default:
123			dev_warn(dev, "slot %d unknown state %d\n", slot, touch[0] & 7);
124			continue;
125		}
126
127		slot--;
128		x = (touch[1] << 4) | (touch[3] >> 4);
129		y = (touch[2] << 4) | (touch[3] & 0x0f);
130
131		input_mt_slot(data->input, slot);
132		input_mt_report_slot_state(data->input, MT_TOOL_FINGER, active);
133		touchscreen_report_pos(data->input, &data->prop, x, y, true);
134	}
135
136	input_mt_sync_frame(data->input);
137	input_sync(data->input);
138
139	return IRQ_HANDLED;
140}
141
142static int nvt_ts_start(struct input_dev *dev)
143{
144	struct nvt_ts_data *data = input_get_drvdata(dev);
145
146	enable_irq(data->client->irq);
147	gpiod_set_value_cansleep(data->reset_gpio, 0);
148
149	return 0;
150}
151
152static void nvt_ts_stop(struct input_dev *dev)
153{
154	struct nvt_ts_data *data = input_get_drvdata(dev);
155
156	disable_irq(data->client->irq);
157	gpiod_set_value_cansleep(data->reset_gpio, 1);
158}
159
160static int nvt_ts_suspend(struct device *dev)
161{
162	struct nvt_ts_data *data = i2c_get_clientdata(to_i2c_client(dev));
163
164	mutex_lock(&data->input->mutex);
165	if (input_device_enabled(data->input))
166		nvt_ts_stop(data->input);
167	mutex_unlock(&data->input->mutex);
168
169	return 0;
170}
171
172static int nvt_ts_resume(struct device *dev)
173{
174	struct nvt_ts_data *data = i2c_get_clientdata(to_i2c_client(dev));
175
176	mutex_lock(&data->input->mutex);
177	if (input_device_enabled(data->input))
178		nvt_ts_start(data->input);
179	mutex_unlock(&data->input->mutex);
180
181	return 0;
182}
183
184static DEFINE_SIMPLE_DEV_PM_OPS(nvt_ts_pm_ops, nvt_ts_suspend, nvt_ts_resume);
185
186static int nvt_ts_probe(struct i2c_client *client)
187{
188	struct device *dev = &client->dev;
189	int error, width, height, irq_type;
190	struct nvt_ts_data *data;
191	struct input_dev *input;
192
193	if (!client->irq) {
194		dev_err(dev, "Error no irq specified\n");
195		return -EINVAL;
196	}
197
198	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
199	if (!data)
200		return -ENOMEM;
201
202	data->client = client;
203	i2c_set_clientdata(client, data);
204
205	data->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
206	error = PTR_ERR_OR_ZERO(data->reset_gpio);
207	if (error) {
208		dev_err(dev, "failed to request reset GPIO: %d\n", error);
209		return error;
210	}
211
212	/* Wait for controller to come out of reset before params read */
213	msleep(100);
214	error = nvt_ts_read_data(data->client, NVT_TS_PARAMETERS_START,
215				 data->buf, NVT_TS_PARAMS_SIZE);
216	gpiod_set_value_cansleep(data->reset_gpio, 1); /* Put back in reset */
217	if (error)
218		return error;
219
220	width  = get_unaligned_be16(&data->buf[NVT_TS_PARAMS_WIDTH]);
221	height = get_unaligned_be16(&data->buf[NVT_TS_PARAMS_HEIGHT]);
222	data->max_touches = data->buf[NVT_TS_PARAMS_MAX_TOUCH];
223	irq_type = data->buf[NVT_TS_PARAMS_IRQ_TYPE];
224
225	if (width > NVT_TS_MAX_SIZE || height >= NVT_TS_MAX_SIZE ||
226	    data->max_touches > NVT_TS_MAX_TOUCHES ||
227	    irq_type >= ARRAY_SIZE(nvt_ts_irq_type) ||
228	    data->buf[NVT_TS_PARAMS_WAKE_TYPE] != NVT_TS_SUPPORTED_WAKE_TYPE ||
229	    data->buf[NVT_TS_PARAMS_CHIP_ID] != NVT_TS_SUPPORTED_CHIP_ID) {
230		dev_err(dev, "Unsupported touchscreen parameters: %*ph\n",
231			NVT_TS_PARAMS_SIZE, data->buf);
232		return -EIO;
233	}
234
235	dev_dbg(dev, "Detected %dx%d touchscreen with %d max touches\n",
236		width, height, data->max_touches);
237
238	if (data->buf[NVT_TS_PARAMS_MAX_BUTTONS])
239		dev_warn(dev, "Touchscreen buttons are not supported\n");
240
241	input = devm_input_allocate_device(dev);
242	if (!input)
243		return -ENOMEM;
244
245	input->name = client->name;
246	input->id.bustype = BUS_I2C;
247	input->open = nvt_ts_start;
248	input->close = nvt_ts_stop;
249
250	input_set_abs_params(input, ABS_MT_POSITION_X, 0, width - 1, 0, 0);
251	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, height - 1, 0, 0);
252	touchscreen_parse_properties(input, true, &data->prop);
253
254	error = input_mt_init_slots(input, data->max_touches,
255				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
256	if (error)
257		return error;
258
259	data->input = input;
260	input_set_drvdata(input, data);
261
262	error = devm_request_threaded_irq(dev, client->irq, NULL, nvt_ts_irq,
263					  IRQF_ONESHOT | IRQF_NO_AUTOEN |
264						nvt_ts_irq_type[irq_type],
265					  client->name, data);
266	if (error) {
267		dev_err(dev, "failed to request irq: %d\n", error);
268		return error;
269	}
270
271	error = input_register_device(input);
272	if (error) {
273		dev_err(dev, "failed to register input device: %d\n", error);
274		return error;
275	}
276
277	return 0;
278}
279
280static const struct i2c_device_id nvt_ts_i2c_id[] = {
281	{ "NVT-ts" },
282	{ }
283};
284MODULE_DEVICE_TABLE(i2c, nvt_ts_i2c_id);
285
286static struct i2c_driver nvt_ts_driver = {
287	.driver = {
288		.name	= "novatek-nvt-ts",
289		.pm	= pm_sleep_ptr(&nvt_ts_pm_ops),
290	},
291	.probe = nvt_ts_probe,
292	.id_table = nvt_ts_i2c_id,
293};
294
295module_i2c_driver(nvt_ts_driver);
296
297MODULE_DESCRIPTION("Novatek NT11205 touchscreen driver");
298MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
299MODULE_LICENSE("GPL");
300