1 /*
2  * Driver for ChipOne icn8318 i2c touchscreen controller
3  *
4  * Copyright (c) 2015 Red Hat Inc.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * Red Hat authors:
12  * Hans de Goede <hdegoede@redhat.com>
13  */
14 
15 #include <linux/gpio/consumer.h>
16 #include <linux/interrupt.h>
17 #include <linux/i2c.h>
18 #include <linux/input.h>
19 #include <linux/input/mt.h>
20 #include <linux/input/touchscreen.h>
21 #include <linux/module.h>
22 #include <linux/of.h>
23 
24 #define ICN8318_REG_POWER		4
25 #define ICN8318_REG_TOUCHDATA		16
26 
27 #define ICN8318_POWER_ACTIVE		0
28 #define ICN8318_POWER_MONITOR		1
29 #define ICN8318_POWER_HIBERNATE		2
30 
31 #define ICN8318_MAX_TOUCHES		5
32 
33 struct icn8318_touch {
34 	__u8 slot;
35 	__be16 x;
36 	__be16 y;
37 	__u8 pressure;	/* Seems more like finger width then pressure really */
38 	__u8 event;
39 /* The difference between 2 and 3 is unclear */
40 #define ICN8318_EVENT_NO_DATA	1 /* No finger seen yet since wakeup */
41 #define ICN8318_EVENT_UPDATE1	2 /* New or updated coordinates */
42 #define ICN8318_EVENT_UPDATE2	3 /* New or updated coordinates */
43 #define ICN8318_EVENT_END	4 /* Finger lifted */
44 } __packed;
45 
46 struct icn8318_touch_data {
47 	__u8 softbutton;
48 	__u8 touch_count;
49 	struct icn8318_touch touches[ICN8318_MAX_TOUCHES];
50 } __packed;
51 
52 struct icn8318_data {
53 	struct i2c_client *client;
54 	struct input_dev *input;
55 	struct gpio_desc *wake_gpio;
56 	struct touchscreen_properties prop;
57 };
58 
59 static int icn8318_read_touch_data(struct i2c_client *client,
60 				   struct icn8318_touch_data *touch_data)
61 {
62 	u8 reg = ICN8318_REG_TOUCHDATA;
63 	struct i2c_msg msg[2] = {
64 		{
65 			.addr = client->addr,
66 			.len = 1,
67 			.buf = &reg
68 		},
69 		{
70 			.addr = client->addr,
71 			.flags = I2C_M_RD,
72 			.len = sizeof(struct icn8318_touch_data),
73 			.buf = (u8 *)touch_data
74 		}
75 	};
76 
77 	return i2c_transfer(client->adapter, msg, 2);
78 }
79 
80 static inline bool icn8318_touch_active(u8 event)
81 {
82 	return (event == ICN8318_EVENT_UPDATE1) ||
83 	       (event == ICN8318_EVENT_UPDATE2);
84 }
85 
86 static irqreturn_t icn8318_irq(int irq, void *dev_id)
87 {
88 	struct icn8318_data *data = dev_id;
89 	struct device *dev = &data->client->dev;
90 	struct icn8318_touch_data touch_data;
91 	int i, ret;
92 
93 	ret = icn8318_read_touch_data(data->client, &touch_data);
94 	if (ret < 0) {
95 		dev_err(dev, "Error reading touch data: %d\n", ret);
96 		return IRQ_HANDLED;
97 	}
98 
99 	if (touch_data.softbutton) {
100 		/*
101 		 * Other data is invalid when a softbutton is pressed.
102 		 * This needs some extra devicetree bindings to map the icn8318
103 		 * softbutton codes to evdev codes. Currently no known devices
104 		 * use this.
105 		 */
106 		return IRQ_HANDLED;
107 	}
108 
109 	if (touch_data.touch_count > ICN8318_MAX_TOUCHES) {
110 		dev_warn(dev, "Too much touches %d > %d\n",
111 			 touch_data.touch_count, ICN8318_MAX_TOUCHES);
112 		touch_data.touch_count = ICN8318_MAX_TOUCHES;
113 	}
114 
115 	for (i = 0; i < touch_data.touch_count; i++) {
116 		struct icn8318_touch *touch = &touch_data.touches[i];
117 		bool act = icn8318_touch_active(touch->event);
118 
119 		input_mt_slot(data->input, touch->slot);
120 		input_mt_report_slot_state(data->input, MT_TOOL_FINGER, act);
121 		if (!act)
122 			continue;
123 
124 		touchscreen_report_pos(data->input, &data->prop,
125 				       be16_to_cpu(touch->x),
126 				       be16_to_cpu(touch->y), true);
127 	}
128 
129 	input_mt_sync_frame(data->input);
130 	input_sync(data->input);
131 
132 	return IRQ_HANDLED;
133 }
134 
135 static int icn8318_start(struct input_dev *dev)
136 {
137 	struct icn8318_data *data = input_get_drvdata(dev);
138 
139 	enable_irq(data->client->irq);
140 	gpiod_set_value_cansleep(data->wake_gpio, 1);
141 
142 	return 0;
143 }
144 
145 static void icn8318_stop(struct input_dev *dev)
146 {
147 	struct icn8318_data *data = input_get_drvdata(dev);
148 
149 	disable_irq(data->client->irq);
150 	i2c_smbus_write_byte_data(data->client, ICN8318_REG_POWER,
151 				  ICN8318_POWER_HIBERNATE);
152 	gpiod_set_value_cansleep(data->wake_gpio, 0);
153 }
154 
155 #ifdef CONFIG_PM_SLEEP
156 static int icn8318_suspend(struct device *dev)
157 {
158 	struct icn8318_data *data = i2c_get_clientdata(to_i2c_client(dev));
159 
160 	mutex_lock(&data->input->mutex);
161 	if (data->input->users)
162 		icn8318_stop(data->input);
163 	mutex_unlock(&data->input->mutex);
164 
165 	return 0;
166 }
167 
168 static int icn8318_resume(struct device *dev)
169 {
170 	struct icn8318_data *data = i2c_get_clientdata(to_i2c_client(dev));
171 
172 	mutex_lock(&data->input->mutex);
173 	if (data->input->users)
174 		icn8318_start(data->input);
175 	mutex_unlock(&data->input->mutex);
176 
177 	return 0;
178 }
179 #endif
180 
181 static SIMPLE_DEV_PM_OPS(icn8318_pm_ops, icn8318_suspend, icn8318_resume);
182 
183 static int icn8318_probe(struct i2c_client *client,
184 			 const struct i2c_device_id *id)
185 {
186 	struct device *dev = &client->dev;
187 	struct icn8318_data *data;
188 	struct input_dev *input;
189 	int error;
190 
191 	if (!client->irq) {
192 		dev_err(dev, "Error no irq specified\n");
193 		return -EINVAL;
194 	}
195 
196 	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
197 	if (!data)
198 		return -ENOMEM;
199 
200 	data->wake_gpio = devm_gpiod_get(dev, "wake", GPIOD_OUT_LOW);
201 	if (IS_ERR(data->wake_gpio)) {
202 		error = PTR_ERR(data->wake_gpio);
203 		if (error != -EPROBE_DEFER)
204 			dev_err(dev, "Error getting wake gpio: %d\n", error);
205 		return error;
206 	}
207 
208 	input = devm_input_allocate_device(dev);
209 	if (!input)
210 		return -ENOMEM;
211 
212 	input->name = client->name;
213 	input->id.bustype = BUS_I2C;
214 	input->open = icn8318_start;
215 	input->close = icn8318_stop;
216 	input->dev.parent = dev;
217 
218 	input_set_capability(input, EV_ABS, ABS_MT_POSITION_X);
219 	input_set_capability(input, EV_ABS, ABS_MT_POSITION_Y);
220 
221 	touchscreen_parse_properties(input, true, &data->prop);
222 	if (!input_abs_get_max(input, ABS_MT_POSITION_X) ||
223 	    !input_abs_get_max(input, ABS_MT_POSITION_Y)) {
224 		dev_err(dev, "Error touchscreen-size-x and/or -y missing\n");
225 		return -EINVAL;
226 	}
227 
228 	error = input_mt_init_slots(input, ICN8318_MAX_TOUCHES,
229 				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
230 	if (error)
231 		return error;
232 
233 	data->client = client;
234 	data->input = input;
235 	input_set_drvdata(input, data);
236 
237 	error = devm_request_threaded_irq(dev, client->irq, NULL, icn8318_irq,
238 					  IRQF_ONESHOT, client->name, data);
239 	if (error) {
240 		dev_err(dev, "Error requesting irq: %d\n", error);
241 		return error;
242 	}
243 
244 	/* Stop device till opened */
245 	icn8318_stop(data->input);
246 
247 	error = input_register_device(input);
248 	if (error)
249 		return error;
250 
251 	i2c_set_clientdata(client, data);
252 
253 	return 0;
254 }
255 
256 static const struct of_device_id icn8318_of_match[] = {
257 	{ .compatible = "chipone,icn8318" },
258 	{ }
259 };
260 MODULE_DEVICE_TABLE(of, icn8318_of_match);
261 
262 /* This is useless for OF-enabled devices, but it is needed by I2C subsystem */
263 static const struct i2c_device_id icn8318_i2c_id[] = {
264 	{ },
265 };
266 MODULE_DEVICE_TABLE(i2c, icn8318_i2c_id);
267 
268 static struct i2c_driver icn8318_driver = {
269 	.driver = {
270 		.name	= "chipone_icn8318",
271 		.pm	= &icn8318_pm_ops,
272 		.of_match_table = icn8318_of_match,
273 	},
274 	.probe = icn8318_probe,
275 	.id_table = icn8318_i2c_id,
276 };
277 
278 module_i2c_driver(icn8318_driver);
279 
280 MODULE_DESCRIPTION("ChipOne icn8318 I2C Touchscreen Driver");
281 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
282 MODULE_LICENSE("GPL");
283