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
 33struct 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
 46struct icn8318_touch_data {
 47	__u8 softbutton;
 48	__u8 touch_count;
 49	struct icn8318_touch touches[ICN8318_MAX_TOUCHES];
 50} __packed;
 51
 52struct 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
 59static 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
 80static inline bool icn8318_touch_active(u8 event)
 81{
 82	return (event == ICN8318_EVENT_UPDATE1) ||
 83	       (event == ICN8318_EVENT_UPDATE2);
 84}
 85
 86static 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
135static 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
145static 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
156static 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
168static 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
181static SIMPLE_DEV_PM_OPS(icn8318_pm_ops, icn8318_suspend, icn8318_resume);
182
183static 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
256static const struct of_device_id icn8318_of_match[] = {
257	{ .compatible = "chipone,icn8318" },
258	{ }
259};
260MODULE_DEVICE_TABLE(of, icn8318_of_match);
261
262/* This is useless for OF-enabled devices, but it is needed by I2C subsystem */
263static const struct i2c_device_id icn8318_i2c_id[] = {
264	{ },
265};
266MODULE_DEVICE_TABLE(i2c, icn8318_i2c_id);
267
268static 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
278module_i2c_driver(icn8318_driver);
279
280MODULE_DESCRIPTION("ChipOne icn8318 I2C Touchscreen Driver");
281MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
282MODULE_LICENSE("GPL");