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/module.h>
 21#include <linux/of.h>
 22
 23#define ICN8318_REG_POWER		4
 24#define ICN8318_REG_TOUCHDATA		16
 25
 26#define ICN8318_POWER_ACTIVE		0
 27#define ICN8318_POWER_MONITOR		1
 28#define ICN8318_POWER_HIBERNATE		2
 29
 30#define ICN8318_MAX_TOUCHES		5
 31
 32struct icn8318_touch {
 33	__u8 slot;
 34	__be16 x;
 35	__be16 y;
 36	__u8 pressure;	/* Seems more like finger width then pressure really */
 37	__u8 event;
 38/* The difference between 2 and 3 is unclear */
 39#define ICN8318_EVENT_NO_DATA	1 /* No finger seen yet since wakeup */
 40#define ICN8318_EVENT_UPDATE1	2 /* New or updated coordinates */
 41#define ICN8318_EVENT_UPDATE2	3 /* New or updated coordinates */
 42#define ICN8318_EVENT_END	4 /* Finger lifted */
 43} __packed;
 44
 45struct icn8318_touch_data {
 46	__u8 softbutton;
 47	__u8 touch_count;
 48	struct icn8318_touch touches[ICN8318_MAX_TOUCHES];
 49} __packed;
 50
 51struct icn8318_data {
 52	struct i2c_client *client;
 53	struct input_dev *input;
 54	struct gpio_desc *wake_gpio;
 55	u32 max_x;
 56	u32 max_y;
 57	bool invert_x;
 58	bool invert_y;
 59	bool swap_x_y;
 60};
 61
 62static int icn8318_read_touch_data(struct i2c_client *client,
 63				   struct icn8318_touch_data *touch_data)
 64{
 65	u8 reg = ICN8318_REG_TOUCHDATA;
 66	struct i2c_msg msg[2] = {
 67		{
 68			.addr = client->addr,
 69			.len = 1,
 70			.buf = &reg
 71		},
 72		{
 73			.addr = client->addr,
 74			.flags = I2C_M_RD,
 75			.len = sizeof(struct icn8318_touch_data),
 76			.buf = (u8 *)touch_data
 77		}
 78	};
 79
 80	return i2c_transfer(client->adapter, msg, 2);
 81}
 82
 83static inline bool icn8318_touch_active(u8 event)
 84{
 85	return (event == ICN8318_EVENT_UPDATE1) ||
 86	       (event == ICN8318_EVENT_UPDATE2);
 87}
 88
 89static irqreturn_t icn8318_irq(int irq, void *dev_id)
 90{
 91	struct icn8318_data *data = dev_id;
 92	struct device *dev = &data->client->dev;
 93	struct icn8318_touch_data touch_data;
 94	int i, ret, x, y;
 95
 96	ret = icn8318_read_touch_data(data->client, &touch_data);
 97	if (ret < 0) {
 98		dev_err(dev, "Error reading touch data: %d\n", ret);
 99		return IRQ_HANDLED;
100	}
101
102	if (touch_data.softbutton) {
103		/*
104		 * Other data is invalid when a softbutton is pressed.
105		 * This needs some extra devicetree bindings to map the icn8318
106		 * softbutton codes to evdev codes. Currently no known devices
107		 * use this.
108		 */
109		return IRQ_HANDLED;
110	}
111
112	if (touch_data.touch_count > ICN8318_MAX_TOUCHES) {
113		dev_warn(dev, "Too much touches %d > %d\n",
114			 touch_data.touch_count, ICN8318_MAX_TOUCHES);
115		touch_data.touch_count = ICN8318_MAX_TOUCHES;
116	}
117
118	for (i = 0; i < touch_data.touch_count; i++) {
119		struct icn8318_touch *touch = &touch_data.touches[i];
120		bool act = icn8318_touch_active(touch->event);
121
122		input_mt_slot(data->input, touch->slot);
123		input_mt_report_slot_state(data->input, MT_TOOL_FINGER, act);
124		if (!act)
125			continue;
126
127		x = be16_to_cpu(touch->x);
128		y = be16_to_cpu(touch->y);
129
130		if (data->invert_x)
131			x = data->max_x - x;
132
133		if (data->invert_y)
134			y = data->max_y - y;
135
136		if (!data->swap_x_y) {
137			input_event(data->input, EV_ABS, ABS_MT_POSITION_X, x);
138			input_event(data->input, EV_ABS, ABS_MT_POSITION_Y, y);
139		} else {
140			input_event(data->input, EV_ABS, ABS_MT_POSITION_X, y);
141			input_event(data->input, EV_ABS, ABS_MT_POSITION_Y, x);
142		}
143	}
144
145	input_mt_sync_frame(data->input);
146	input_sync(data->input);
147
148	return IRQ_HANDLED;
149}
150
151static int icn8318_start(struct input_dev *dev)
152{
153	struct icn8318_data *data = input_get_drvdata(dev);
154
155	enable_irq(data->client->irq);
156	gpiod_set_value_cansleep(data->wake_gpio, 1);
157
158	return 0;
159}
160
161static void icn8318_stop(struct input_dev *dev)
162{
163	struct icn8318_data *data = input_get_drvdata(dev);
164
165	disable_irq(data->client->irq);
166	i2c_smbus_write_byte_data(data->client, ICN8318_REG_POWER,
167				  ICN8318_POWER_HIBERNATE);
168	gpiod_set_value_cansleep(data->wake_gpio, 0);
169}
170
171#ifdef CONFIG_PM_SLEEP
172static int icn8318_suspend(struct device *dev)
173{
174	struct icn8318_data *data = i2c_get_clientdata(to_i2c_client(dev));
175
176	mutex_lock(&data->input->mutex);
177	if (data->input->users)
178		icn8318_stop(data->input);
179	mutex_unlock(&data->input->mutex);
180
181	return 0;
182}
183
184static int icn8318_resume(struct device *dev)
185{
186	struct icn8318_data *data = i2c_get_clientdata(to_i2c_client(dev));
187
188	mutex_lock(&data->input->mutex);
189	if (data->input->users)
190		icn8318_start(data->input);
191	mutex_unlock(&data->input->mutex);
192
193	return 0;
194}
195#endif
196
197static SIMPLE_DEV_PM_OPS(icn8318_pm_ops, icn8318_suspend, icn8318_resume);
198
199static int icn8318_probe(struct i2c_client *client,
200			 const struct i2c_device_id *id)
201{
202	struct device *dev = &client->dev;
203	struct device_node *np = dev->of_node;
204	struct icn8318_data *data;
205	struct input_dev *input;
206	u32 fuzz_x = 0, fuzz_y = 0;
207	int error;
208
209	if (!client->irq) {
210		dev_err(dev, "Error no irq specified\n");
211		return -EINVAL;
212	}
213
214	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
215	if (!data)
216		return -ENOMEM;
217
218	data->wake_gpio = devm_gpiod_get(dev, "wake", GPIOD_OUT_LOW);
219	if (IS_ERR(data->wake_gpio)) {
220		error = PTR_ERR(data->wake_gpio);
221		if (error != -EPROBE_DEFER)
222			dev_err(dev, "Error getting wake gpio: %d\n", error);
223		return error;
224	}
225
226	if (of_property_read_u32(np, "touchscreen-size-x", &data->max_x) ||
227	    of_property_read_u32(np, "touchscreen-size-y", &data->max_y)) {
228		dev_err(dev, "Error touchscreen-size-x and/or -y missing\n");
229		return -EINVAL;
230	}
231
232	/* Optional */
233	of_property_read_u32(np, "touchscreen-fuzz-x", &fuzz_x);
234	of_property_read_u32(np, "touchscreen-fuzz-y", &fuzz_y);
235	data->invert_x = of_property_read_bool(np, "touchscreen-inverted-x");
236	data->invert_y = of_property_read_bool(np, "touchscreen-inverted-y");
237	data->swap_x_y = of_property_read_bool(np, "touchscreen-swapped-x-y");
238
239	input = devm_input_allocate_device(dev);
240	if (!input)
241		return -ENOMEM;
242
243	input->name = client->name;
244	input->id.bustype = BUS_I2C;
245	input->open = icn8318_start;
246	input->close = icn8318_stop;
247	input->dev.parent = dev;
248
249	if (!data->swap_x_y) {
250		input_set_abs_params(input, ABS_MT_POSITION_X, 0,
251				     data->max_x, fuzz_x, 0);
252		input_set_abs_params(input, ABS_MT_POSITION_Y, 0,
253				     data->max_y, fuzz_y, 0);
254	} else {
255		input_set_abs_params(input, ABS_MT_POSITION_X, 0,
256				     data->max_y, fuzz_y, 0);
257		input_set_abs_params(input, ABS_MT_POSITION_Y, 0,
258				     data->max_x, fuzz_x, 0);
259	}
260
261	error = input_mt_init_slots(input, ICN8318_MAX_TOUCHES,
262				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
263	if (error)
264		return error;
265
266	data->client = client;
267	data->input = input;
268	input_set_drvdata(input, data);
269
270	error = devm_request_threaded_irq(dev, client->irq, NULL, icn8318_irq,
271					  IRQF_ONESHOT, client->name, data);
272	if (error) {
273		dev_err(dev, "Error requesting irq: %d\n", error);
274		return error;
275	}
276
277	/* Stop device till opened */
278	icn8318_stop(data->input);
279
280	error = input_register_device(input);
281	if (error)
282		return error;
283
284	i2c_set_clientdata(client, data);
285
286	return 0;
287}
288
289static const struct of_device_id icn8318_of_match[] = {
290	{ .compatible = "chipone,icn8318" },
291	{ }
292};
293MODULE_DEVICE_TABLE(of, icn8318_of_match);
294
295/* This is useless for OF-enabled devices, but it is needed by I2C subsystem */
296static const struct i2c_device_id icn8318_i2c_id[] = {
297	{ },
298};
299MODULE_DEVICE_TABLE(i2c, icn8318_i2c_id);
300
301static struct i2c_driver icn8318_driver = {
302	.driver = {
303		.name	= "chipone_icn8318",
304		.pm	= &icn8318_pm_ops,
305		.of_match_table = icn8318_of_match,
306	},
307	.probe = icn8318_probe,
308	.id_table = icn8318_i2c_id,
309};
310
311module_i2c_driver(icn8318_driver);
312
313MODULE_DESCRIPTION("ChipOne icn8318 I2C Touchscreen Driver");
314MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
315MODULE_LICENSE("GPL");