1/*
2 * FocalTech FT6236 TouchScreen driver.
3 *
4 * Copyright (c) 2010  Focal tech Ltd.
5 *
6 * This software is licensed under the terms of the GNU General Public
7 * License version 2, as published by the Free Software Foundation, and
8 * may be copied, distributed, and modified under those terms.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 * GNU General Public License for more details.
14 */
15
16#include <linux/delay.h>
17#include <linux/gpio/consumer.h>
18#include <linux/i2c.h>
19#include <linux/input.h>
20#include <linux/input/mt.h>
21#include <linux/interrupt.h>
22#include <linux/module.h>
23#include <linux/property.h>
24
25#define FT6236_MAX_TOUCH_POINTS		2
26
27#define FT6236_REG_TH_GROUP		0x80
28#define FT6236_REG_PERIODACTIVE		0x88
29#define FT6236_REG_LIB_VER_H		0xa1
30#define FT6236_REG_LIB_VER_L		0xa2
31#define FT6236_REG_CIPHER		0xa3
32#define FT6236_REG_FIRMID		0xa6
33#define FT6236_REG_FOCALTECH_ID		0xa8
34#define FT6236_REG_RELEASE_CODE_ID	0xaf
35
36#define FT6236_EVENT_PRESS_DOWN		0
37#define FT6236_EVENT_LIFT_UP		1
38#define FT6236_EVENT_CONTACT		2
39#define FT6236_EVENT_NO_EVENT		3
40
41struct ft6236_data {
42	struct i2c_client *client;
43	struct input_dev *input;
44	struct gpio_desc *reset_gpio;
45	u32 max_x;
46	u32 max_y;
47	bool invert_x;
48	bool invert_y;
49	bool swap_xy;
50};
51
52/*
53 * This struct is a touchpoint as stored in hardware.  Note that the id,
54 * as well as the event, are stored in the upper nybble of the hi byte.
55 */
56struct ft6236_touchpoint {
57	union {
58		u8 xhi;
59		u8 event;
60	};
61	u8 xlo;
62	union {
63		u8 yhi;
64		u8 id;
65	};
66	u8 ylo;
67	u8 weight;
68	u8 misc;
69} __packed;
70
71/* This packet represents the register map as read from offset 0 */
72struct ft6236_packet {
73	u8 dev_mode;
74	u8 gest_id;
75	u8 touches;
76	struct ft6236_touchpoint points[FT6236_MAX_TOUCH_POINTS];
77} __packed;
78
79static int ft6236_read(struct i2c_client *client, u8 reg, u8 len, void *data)
80{
81	int error;
82
83	error = i2c_smbus_read_i2c_block_data(client, reg, len, data);
84	if (error < 0)
85		return error;
86
87	if (error != len)
88		return -EIO;
89
90	return 0;
91}
92
93static irqreturn_t ft6236_interrupt(int irq, void *dev_id)
94{
95	struct ft6236_data *ft6236 = dev_id;
96	struct device *dev = &ft6236->client->dev;
97	struct input_dev *input = ft6236->input;
98	struct ft6236_packet buf;
99	u8 touches;
100	int i, error;
101
102	error = ft6236_read(ft6236->client, 0, sizeof(buf), &buf);
103	if (error) {
104		dev_err(dev, "read touchdata failed %d\n", error);
105		return IRQ_HANDLED;
106	}
107
108	touches = buf.touches & 0xf;
109	if (touches > FT6236_MAX_TOUCH_POINTS) {
110		dev_dbg(dev,
111			"%d touch points reported, only %d are supported\n",
112			touches, FT6236_MAX_TOUCH_POINTS);
113		touches = FT6236_MAX_TOUCH_POINTS;
114	}
115
116	for (i = 0; i < touches; i++) {
117		struct ft6236_touchpoint *point = &buf.points[i];
118		u16 x = ((point->xhi & 0xf) << 8) | buf.points[i].xlo;
119		u16 y = ((point->yhi & 0xf) << 8) | buf.points[i].ylo;
120		u8 event = point->event >> 6;
121		u8 id = point->id >> 4;
122		bool act = (event == FT6236_EVENT_PRESS_DOWN ||
123			    event == FT6236_EVENT_CONTACT);
124
125		input_mt_slot(input, id);
126		input_mt_report_slot_state(input, MT_TOOL_FINGER, act);
127		if (!act)
128			continue;
129
130		if (ft6236->invert_x)
131			x = ft6236->max_x - x;
132
133		if (ft6236->invert_y)
134			y = ft6236->max_y - y;
135
136		if (ft6236->swap_xy) {
137			input_report_abs(input, ABS_MT_POSITION_X, y);
138			input_report_abs(input, ABS_MT_POSITION_Y, x);
139		} else {
140			input_report_abs(input, ABS_MT_POSITION_X, x);
141			input_report_abs(input, ABS_MT_POSITION_Y, y);
142		}
143	}
144
145	input_mt_sync_frame(input);
146	input_sync(input);
147
148	return IRQ_HANDLED;
149}
150
151static u8 ft6236_debug_read_byte(struct ft6236_data *ft6236, u8 reg)
152{
153	struct i2c_client *client = ft6236->client;
154	u8 val = 0;
155	int error;
156
157	error = ft6236_read(client, reg, 1, &val);
158	if (error)
159		dev_dbg(&client->dev,
160			"error reading register 0x%02x: %d\n", reg, error);
161
162	return val;
163}
164
165static void ft6236_debug_info(struct ft6236_data *ft6236)
166{
167	struct device *dev = &ft6236->client->dev;
168
169	dev_dbg(dev, "Touch threshold is %d\n",
170		ft6236_debug_read_byte(ft6236, FT6236_REG_TH_GROUP) * 4);
171	dev_dbg(dev, "Report rate is %dHz\n",
172		ft6236_debug_read_byte(ft6236, FT6236_REG_PERIODACTIVE) * 10);
173	dev_dbg(dev, "Firmware library version 0x%02x%02x\n",
174		ft6236_debug_read_byte(ft6236, FT6236_REG_LIB_VER_H),
175		ft6236_debug_read_byte(ft6236, FT6236_REG_LIB_VER_L));
176	dev_dbg(dev, "Firmware version 0x%02x\n",
177		ft6236_debug_read_byte(ft6236, FT6236_REG_FIRMID));
178	dev_dbg(dev, "Chip vendor ID 0x%02x\n",
179		ft6236_debug_read_byte(ft6236, FT6236_REG_CIPHER));
180	dev_dbg(dev, "CTPM vendor ID 0x%02x\n",
181		ft6236_debug_read_byte(ft6236, FT6236_REG_FOCALTECH_ID));
182	dev_dbg(dev, "Release code version 0x%02x\n",
183		ft6236_debug_read_byte(ft6236, FT6236_REG_RELEASE_CODE_ID));
184}
185
186static void ft6236_reset(struct ft6236_data *ft6236)
187{
188	if (!ft6236->reset_gpio)
189		return;
190
191	gpiod_set_value_cansleep(ft6236->reset_gpio, 1);
192	usleep_range(5000, 20000);
193	gpiod_set_value_cansleep(ft6236->reset_gpio, 0);
194	msleep(300);
195}
196
197static int ft6236_probe(struct i2c_client *client,
198			const struct i2c_device_id *id)
199{
200	struct device *dev = &client->dev;
201	struct ft6236_data *ft6236;
202	struct input_dev *input;
203	u32 fuzz_x = 0, fuzz_y = 0;
204	u8 val;
205	int error;
206
207	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
208		return -ENXIO;
209
210	if (!client->irq) {
211		dev_err(dev, "irq is missing\n");
212		return -EINVAL;
213	}
214
215	ft6236 = devm_kzalloc(dev, sizeof(*ft6236), GFP_KERNEL);
216	if (!ft6236)
217		return -ENOMEM;
218
219	ft6236->client = client;
220	ft6236->reset_gpio = devm_gpiod_get_optional(dev, "reset",
221						     GPIOD_OUT_LOW);
222	if (IS_ERR(ft6236->reset_gpio)) {
223		error = PTR_ERR(ft6236->reset_gpio);
224		if (error != -EPROBE_DEFER)
225			dev_err(dev, "error getting reset gpio: %d\n", error);
226		return error;
227	}
228
229	ft6236_reset(ft6236);
230
231	/* verify that the controller is present */
232	error = ft6236_read(client, 0x00, 1, &val);
233	if (error) {
234		dev_err(dev, "failed to read from controller: %d\n", error);
235		return error;
236	}
237
238	ft6236_debug_info(ft6236);
239
240	input = devm_input_allocate_device(dev);
241	if (!input)
242		return -ENOMEM;
243
244	ft6236->input = input;
245	input->name = client->name;
246	input->id.bustype = BUS_I2C;
247
248	if (device_property_read_u32(dev, "touchscreen-size-x",
249				     &ft6236->max_x) ||
250	    device_property_read_u32(dev, "touchscreen-size-y",
251				     &ft6236->max_y)) {
252		dev_err(dev, "touchscreen-size-x and/or -y missing\n");
253		return -EINVAL;
254	}
255
256	device_property_read_u32(dev, "touchscreen-fuzz-x", &fuzz_x);
257	device_property_read_u32(dev, "touchscreen-fuzz-y", &fuzz_y);
258	ft6236->invert_x = device_property_read_bool(dev,
259						     "touchscreen-inverted-x");
260	ft6236->invert_y = device_property_read_bool(dev,
261						     "touchscreen-inverted-y");
262	ft6236->swap_xy = device_property_read_bool(dev,
263						    "touchscreen-swapped-x-y");
264
265	if (ft6236->swap_xy) {
266		input_set_abs_params(input, ABS_MT_POSITION_X, 0,
267				     ft6236->max_y, fuzz_y, 0);
268		input_set_abs_params(input, ABS_MT_POSITION_Y, 0,
269				     ft6236->max_x, fuzz_x, 0);
270	} else {
271		input_set_abs_params(input, ABS_MT_POSITION_X, 0,
272				     ft6236->max_x, fuzz_x, 0);
273		input_set_abs_params(input, ABS_MT_POSITION_Y, 0,
274				     ft6236->max_y, fuzz_y, 0);
275	}
276
277	error = input_mt_init_slots(input, FT6236_MAX_TOUCH_POINTS,
278				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
279	if (error)
280		return error;
281
282	error = devm_request_threaded_irq(dev, client->irq, NULL,
283					  ft6236_interrupt, IRQF_ONESHOT,
284					  client->name, ft6236);
285	if (error) {
286		dev_err(dev, "request irq %d failed: %d\n", client->irq, error);
287		return error;
288	}
289
290	error = input_register_device(input);
291	if (error) {
292		dev_err(dev, "failed to register input device: %d\n", error);
293		return error;
294	}
295
296	return 0;
297}
298
299#ifdef CONFIG_OF
300static const struct of_device_id ft6236_of_match[] = {
301	{ .compatible = "focaltech,ft6236", },
302	{ }
303};
304MODULE_DEVICE_TABLE(of, ft6236_of_match);
305#endif
306
307static const struct i2c_device_id ft6236_id[] = {
308	{ "ft6236", },
309	{ }
310};
311MODULE_DEVICE_TABLE(i2c, ft6236_id);
312
313static struct i2c_driver ft6236_driver = {
314	.driver = {
315		.name = "ft6236",
316		.of_match_table = of_match_ptr(ft6236_of_match),
317	},
318	.probe = ft6236_probe,
319	.id_table = ft6236_id,
320};
321module_i2c_driver(ft6236_driver);
322
323MODULE_AUTHOR("Sean Cross <xobs@kosagi.com>");
324MODULE_AUTHOR("Noralf Tr��nnes <noralf@tronnes.org>");
325MODULE_DESCRIPTION("FocalTech FT6236 TouchScreen driver");
326MODULE_LICENSE("GPL v2");
327