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 
29 struct 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 
42 struct icn8318_touch_data {
43 	__u8 softbutton;
44 	__u8 touch_count;
45 	struct icn8318_touch touches[ICN8318_MAX_TOUCHES];
46 } __packed;
47 
48 struct 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 
55 static 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 
76 static inline bool icn8318_touch_active(u8 event)
77 {
78 	return (event == ICN8318_EVENT_UPDATE1) ||
79 	       (event == ICN8318_EVENT_UPDATE2);
80 }
81 
82 static 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 
131 static 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 
141 static 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 
151 static 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 
163 static 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 
175 static DEFINE_SIMPLE_DEV_PM_OPS(icn8318_pm_ops, icn8318_suspend, icn8318_resume);
176 
177 static 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 		error = PTR_ERR(data->wake_gpio);
196 		if (error != -EPROBE_DEFER)
197 			dev_err(dev, "Error getting wake gpio: %d\n", error);
198 		return error;
199 	}
200 
201 	input = devm_input_allocate_device(dev);
202 	if (!input)
203 		return -ENOMEM;
204 
205 	input->name = client->name;
206 	input->id.bustype = BUS_I2C;
207 	input->open = icn8318_start;
208 	input->close = icn8318_stop;
209 	input->dev.parent = dev;
210 
211 	input_set_capability(input, EV_ABS, ABS_MT_POSITION_X);
212 	input_set_capability(input, EV_ABS, ABS_MT_POSITION_Y);
213 
214 	touchscreen_parse_properties(input, true, &data->prop);
215 	if (!input_abs_get_max(input, ABS_MT_POSITION_X) ||
216 	    !input_abs_get_max(input, ABS_MT_POSITION_Y)) {
217 		dev_err(dev, "Error touchscreen-size-x and/or -y missing\n");
218 		return -EINVAL;
219 	}
220 
221 	error = input_mt_init_slots(input, ICN8318_MAX_TOUCHES,
222 				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
223 	if (error)
224 		return error;
225 
226 	data->client = client;
227 	data->input = input;
228 	input_set_drvdata(input, data);
229 
230 	error = devm_request_threaded_irq(dev, client->irq, NULL, icn8318_irq,
231 					  IRQF_ONESHOT, client->name, data);
232 	if (error) {
233 		dev_err(dev, "Error requesting irq: %d\n", error);
234 		return error;
235 	}
236 
237 	/* Stop device till opened */
238 	icn8318_stop(data->input);
239 
240 	error = input_register_device(input);
241 	if (error)
242 		return error;
243 
244 	i2c_set_clientdata(client, data);
245 
246 	return 0;
247 }
248 
249 static const struct of_device_id icn8318_of_match[] = {
250 	{ .compatible = "chipone,icn8318" },
251 	{ }
252 };
253 MODULE_DEVICE_TABLE(of, icn8318_of_match);
254 
255 /* This is useless for OF-enabled devices, but it is needed by I2C subsystem */
256 static const struct i2c_device_id icn8318_i2c_id[] = {
257 	{ },
258 };
259 MODULE_DEVICE_TABLE(i2c, icn8318_i2c_id);
260 
261 static struct i2c_driver icn8318_driver = {
262 	.driver = {
263 		.name	= "chipone_icn8318",
264 		.pm	= pm_sleep_ptr(&icn8318_pm_ops),
265 		.of_match_table = icn8318_of_match,
266 	},
267 	.probe_new = icn8318_probe,
268 	.id_table = icn8318_i2c_id,
269 };
270 
271 module_i2c_driver(icn8318_driver);
272 
273 MODULE_DESCRIPTION("ChipOne icn8318 I2C Touchscreen Driver");
274 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
275 MODULE_LICENSE("GPL");
276