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
 29struct 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
 42struct icn8318_touch_data {
 43	__u8 softbutton;
 44	__u8 touch_count;
 45	struct icn8318_touch touches[ICN8318_MAX_TOUCHES];
 46} __packed;
 47
 48struct 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
 55static 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
 76static inline bool icn8318_touch_active(u8 event)
 77{
 78	return (event == ICN8318_EVENT_UPDATE1) ||
 79	       (event == ICN8318_EVENT_UPDATE2);
 80}
 81
 82static 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
131static 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
141static 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#ifdef CONFIG_PM_SLEEP
152static int icn8318_suspend(struct device *dev)
153{
154	struct icn8318_data *data = i2c_get_clientdata(to_i2c_client(dev));
155
156	mutex_lock(&data->input->mutex);
157	if (input_device_enabled(data->input))
158		icn8318_stop(data->input);
159	mutex_unlock(&data->input->mutex);
160
161	return 0;
162}
163
164static int icn8318_resume(struct device *dev)
165{
166	struct icn8318_data *data = i2c_get_clientdata(to_i2c_client(dev));
167
168	mutex_lock(&data->input->mutex);
169	if (input_device_enabled(data->input))
170		icn8318_start(data->input);
171	mutex_unlock(&data->input->mutex);
172
173	return 0;
174}
175#endif
176
177static SIMPLE_DEV_PM_OPS(icn8318_pm_ops, icn8318_suspend, icn8318_resume);
178
179static int icn8318_probe(struct i2c_client *client)
180{
181	struct device *dev = &client->dev;
182	struct icn8318_data *data;
183	struct input_dev *input;
184	int error;
185
186	if (!client->irq) {
187		dev_err(dev, "Error no irq specified\n");
188		return -EINVAL;
189	}
190
191	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
192	if (!data)
193		return -ENOMEM;
194
195	data->wake_gpio = devm_gpiod_get(dev, "wake", GPIOD_OUT_LOW);
196	if (IS_ERR(data->wake_gpio)) {
197		error = PTR_ERR(data->wake_gpio);
198		if (error != -EPROBE_DEFER)
199			dev_err(dev, "Error getting wake gpio: %d\n", error);
200		return error;
201	}
202
203	input = devm_input_allocate_device(dev);
204	if (!input)
205		return -ENOMEM;
206
207	input->name = client->name;
208	input->id.bustype = BUS_I2C;
209	input->open = icn8318_start;
210	input->close = icn8318_stop;
211	input->dev.parent = dev;
212
213	input_set_capability(input, EV_ABS, ABS_MT_POSITION_X);
214	input_set_capability(input, EV_ABS, ABS_MT_POSITION_Y);
215
216	touchscreen_parse_properties(input, true, &data->prop);
217	if (!input_abs_get_max(input, ABS_MT_POSITION_X) ||
218	    !input_abs_get_max(input, ABS_MT_POSITION_Y)) {
219		dev_err(dev, "Error touchscreen-size-x and/or -y missing\n");
220		return -EINVAL;
221	}
222
223	error = input_mt_init_slots(input, ICN8318_MAX_TOUCHES,
224				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
225	if (error)
226		return error;
227
228	data->client = client;
229	data->input = input;
230	input_set_drvdata(input, data);
231
232	error = devm_request_threaded_irq(dev, client->irq, NULL, icn8318_irq,
233					  IRQF_ONESHOT, client->name, data);
234	if (error) {
235		dev_err(dev, "Error requesting irq: %d\n", error);
236		return error;
237	}
238
239	/* Stop device till opened */
240	icn8318_stop(data->input);
241
242	error = input_register_device(input);
243	if (error)
244		return error;
245
246	i2c_set_clientdata(client, data);
247
248	return 0;
249}
250
251static const struct of_device_id icn8318_of_match[] = {
252	{ .compatible = "chipone,icn8318" },
253	{ }
254};
255MODULE_DEVICE_TABLE(of, icn8318_of_match);
256
257/* This is useless for OF-enabled devices, but it is needed by I2C subsystem */
258static const struct i2c_device_id icn8318_i2c_id[] = {
259	{ },
260};
261MODULE_DEVICE_TABLE(i2c, icn8318_i2c_id);
262
263static struct i2c_driver icn8318_driver = {
264	.driver = {
265		.name	= "chipone_icn8318",
266		.pm	= &icn8318_pm_ops,
267		.of_match_table = icn8318_of_match,
268	},
269	.probe_new = icn8318_probe,
270	.id_table = icn8318_i2c_id,
271};
272
273module_i2c_driver(icn8318_driver);
274
275MODULE_DESCRIPTION("ChipOne icn8318 I2C Touchscreen Driver");
276MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
277MODULE_LICENSE("GPL");