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
41 struct 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 */
56 struct 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 */
72 struct 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
ft6236_read(struct i2c_client * client,u8 reg,u8 len,void * data)79 static 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
ft6236_interrupt(int irq,void * dev_id)93 static 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
ft6236_debug_read_byte(struct ft6236_data * ft6236,u8 reg)151 static 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
ft6236_debug_info(struct ft6236_data * ft6236)165 static 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
ft6236_reset(struct ft6236_data * ft6236)186 static 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
ft6236_probe(struct i2c_client * client,const struct i2c_device_id * id)197 static 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
300 static const struct of_device_id ft6236_of_match[] = {
301 { .compatible = "focaltech,ft6236", },
302 { }
303 };
304 MODULE_DEVICE_TABLE(of, ft6236_of_match);
305 #endif
306
307 static const struct i2c_device_id ft6236_id[] = {
308 { "ft6236", },
309 { }
310 };
311 MODULE_DEVICE_TABLE(i2c, ft6236_id);
312
313 static 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 };
321 module_i2c_driver(ft6236_driver);
322
323 MODULE_AUTHOR("Sean Cross <xobs@kosagi.com>");
324 MODULE_AUTHOR("Noralf Trønnes <noralf@tronnes.org>");
325 MODULE_DESCRIPTION("FocalTech FT6236 TouchScreen driver");
326 MODULE_LICENSE("GPL v2");
327