1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *  Atmel AT42QT1070 QTouch Sensor Controller
4 *
5 *  Copyright (C) 2011 Atmel
6 *
7 *  Authors: Bo Shen <voice.shen@atmel.com>
8 *
9 *  Base on AT42QT2160 driver by:
10 *  Raphael Derosso Pereira <raphaelpereira@gmail.com>
11 *  Copyright (C) 2009
12 */
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/i2c.h>
16#include <linux/input.h>
17#include <linux/slab.h>
18#include <linux/irq.h>
19#include <linux/interrupt.h>
20#include <linux/jiffies.h>
21#include <linux/delay.h>
22
23/* Address for each register */
24#define CHIP_ID            0x00
25#define QT1070_CHIP_ID     0x2E
26
27#define FW_VERSION         0x01
28#define QT1070_FW_VERSION  0x15
29
30#define DET_STATUS         0x02
31
32#define KEY_STATUS         0x03
33
34/* Calibrate */
35#define CALIBRATE_CMD      0x38
36#define QT1070_CAL_TIME    200
37
38/* Reset */
39#define RESET              0x39
40#define QT1070_RESET_TIME  255
41
42/* AT42QT1070 support up to 7 keys */
43static const unsigned short qt1070_key2code[] = {
44	KEY_0, KEY_1, KEY_2, KEY_3,
45	KEY_4, KEY_5, KEY_6,
46};
47
48struct qt1070_data {
49	struct i2c_client *client;
50	struct input_dev *input;
51	unsigned int irq;
52	unsigned short keycodes[ARRAY_SIZE(qt1070_key2code)];
53	u8 last_keys;
54};
55
56static int qt1070_read(struct i2c_client *client, u8 reg)
57{
58	int ret;
59
60	ret = i2c_smbus_read_byte_data(client, reg);
61	if (ret < 0)
62		dev_err(&client->dev,
63			"can not read register, returned %d\n", ret);
64
65	return ret;
66}
67
68static int qt1070_write(struct i2c_client *client, u8 reg, u8 data)
69{
70	int ret;
71
72	ret = i2c_smbus_write_byte_data(client, reg, data);
73	if (ret < 0)
74		dev_err(&client->dev,
75			"can not write register, returned %d\n", ret);
76
77	return ret;
78}
79
80static bool qt1070_identify(struct i2c_client *client)
81{
82	int id, ver;
83
84	/* Read Chip ID */
85	id = qt1070_read(client, CHIP_ID);
86	if (id != QT1070_CHIP_ID) {
87		dev_err(&client->dev, "ID %d not supported\n", id);
88		return false;
89	}
90
91	/* Read firmware version */
92	ver = qt1070_read(client, FW_VERSION);
93	if (ver < 0) {
94		dev_err(&client->dev, "could not read the firmware version\n");
95		return false;
96	}
97
98	dev_info(&client->dev, "AT42QT1070 firmware version %x\n", ver);
99
100	return true;
101}
102
103static irqreturn_t qt1070_interrupt(int irq, void *dev_id)
104{
105	struct qt1070_data *data = dev_id;
106	struct i2c_client *client = data->client;
107	struct input_dev *input = data->input;
108	int i;
109	u8 new_keys, keyval, mask = 0x01;
110
111	/* Read the detected status register, thus clearing interrupt */
112	qt1070_read(client, DET_STATUS);
113
114	/* Read which key changed */
115	new_keys = qt1070_read(client, KEY_STATUS);
116
117	for (i = 0; i < ARRAY_SIZE(qt1070_key2code); i++) {
118		keyval = new_keys & mask;
119		if ((data->last_keys & mask) != keyval)
120			input_report_key(input, data->keycodes[i], keyval);
121		mask <<= 1;
122	}
123	input_sync(input);
124
125	data->last_keys = new_keys;
126	return IRQ_HANDLED;
127}
128
129static int qt1070_probe(struct i2c_client *client)
130{
131	struct qt1070_data *data;
132	struct input_dev *input;
133	int i;
134	int err;
135
136	err = i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE);
137	if (!err) {
138		dev_err(&client->dev, "%s adapter not supported\n",
139			dev_driver_string(&client->adapter->dev));
140		return -ENODEV;
141	}
142
143	if (!client->irq) {
144		dev_err(&client->dev, "please assign the irq to this device\n");
145		return -EINVAL;
146	}
147
148	/* Identify the qt1070 chip */
149	if (!qt1070_identify(client))
150		return -ENODEV;
151
152	data = devm_kzalloc(&client->dev, sizeof(struct qt1070_data),
153			    GFP_KERNEL);
154	if (!data)
155		return -ENOMEM;
156
157	input = devm_input_allocate_device(&client->dev);
158	if (!input)
159		return -ENOMEM;
160
161	data->client = client;
162	data->input = input;
163	data->irq = client->irq;
164
165	input->name = "AT42QT1070 QTouch Sensor";
166	input->id.bustype = BUS_I2C;
167
168	/* Add the keycode */
169	input->keycode = data->keycodes;
170	input->keycodesize = sizeof(data->keycodes[0]);
171	input->keycodemax = ARRAY_SIZE(qt1070_key2code);
172
173	__set_bit(EV_KEY, input->evbit);
174
175	for (i = 0; i < ARRAY_SIZE(qt1070_key2code); i++) {
176		data->keycodes[i] = qt1070_key2code[i];
177		__set_bit(qt1070_key2code[i], input->keybit);
178	}
179
180	/* Calibrate device */
181	qt1070_write(client, CALIBRATE_CMD, 1);
182	msleep(QT1070_CAL_TIME);
183
184	/* Soft reset */
185	qt1070_write(client, RESET, 1);
186	msleep(QT1070_RESET_TIME);
187
188	err = devm_request_threaded_irq(&client->dev, client->irq,
189					NULL, qt1070_interrupt,
190					IRQF_TRIGGER_NONE | IRQF_ONESHOT,
191					client->dev.driver->name, data);
192	if (err) {
193		dev_err(&client->dev, "fail to request irq\n");
194		return err;
195	}
196
197	/* Register the input device */
198	err = input_register_device(data->input);
199	if (err) {
200		dev_err(&client->dev, "Failed to register input device\n");
201		return err;
202	}
203
204	i2c_set_clientdata(client, data);
205
206	/* Read to clear the chang line */
207	qt1070_read(client, DET_STATUS);
208
209	return 0;
210}
211
212static int qt1070_suspend(struct device *dev)
213{
214	struct i2c_client *client = to_i2c_client(dev);
215	struct qt1070_data *data = i2c_get_clientdata(client);
216
217	if (device_may_wakeup(dev))
218		enable_irq_wake(data->irq);
219
220	return 0;
221}
222
223static int qt1070_resume(struct device *dev)
224{
225	struct i2c_client *client = to_i2c_client(dev);
226	struct qt1070_data *data = i2c_get_clientdata(client);
227
228	if (device_may_wakeup(dev))
229		disable_irq_wake(data->irq);
230
231	return 0;
232}
233
234static DEFINE_SIMPLE_DEV_PM_OPS(qt1070_pm_ops, qt1070_suspend, qt1070_resume);
235
236static const struct i2c_device_id qt1070_id[] = {
237	{ "qt1070", 0 },
238	{ },
239};
240MODULE_DEVICE_TABLE(i2c, qt1070_id);
241
242#ifdef CONFIG_OF
243static const struct of_device_id qt1070_of_match[] = {
244	{ .compatible = "qt1070", },
245	{ },
246};
247MODULE_DEVICE_TABLE(of, qt1070_of_match);
248#endif
249
250static struct i2c_driver qt1070_driver = {
251	.driver	= {
252		.name	= "qt1070",
253		.of_match_table = of_match_ptr(qt1070_of_match),
254		.pm	= pm_sleep_ptr(&qt1070_pm_ops),
255	},
256	.id_table	= qt1070_id,
257	.probe		= qt1070_probe,
258};
259
260module_i2c_driver(qt1070_driver);
261
262MODULE_AUTHOR("Bo Shen <voice.shen@atmel.com>");
263MODULE_DESCRIPTION("Driver for AT42QT1070 QTouch sensor");
264MODULE_LICENSE("GPL");
265