1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Touch Screen driver for EETI's I2C connected touch screen panels
4 * Copyright (c) 2009,2018 Daniel Mack <daniel@zonque.org>
5 *
6 * See EETI's software guide for the protocol specification:
7 * http://home.eeti.com.tw/documentation.html
8 *
9 * Based on migor_ts.c
10 * Copyright (c) 2008 Magnus Damm
11 * Copyright (c) 2007 Ujjwal Pande <ujjwal@kenati.com>
12 */
13
14 #include <linux/module.h>
15 #include <linux/kernel.h>
16 #include <linux/input.h>
17 #include <linux/input/touchscreen.h>
18 #include <linux/interrupt.h>
19 #include <linux/i2c.h>
20 #include <linux/timer.h>
21 #include <linux/gpio/consumer.h>
22 #include <linux/of.h>
23 #include <linux/slab.h>
24 #include <linux/unaligned.h>
25
26 struct eeti_ts {
27 struct i2c_client *client;
28 struct input_dev *input;
29 struct gpio_desc *attn_gpio;
30 struct touchscreen_properties props;
31 struct mutex mutex;
32 bool running;
33 };
34
35 #define EETI_TS_BITDEPTH (11)
36 #define EETI_MAXVAL ((1 << (EETI_TS_BITDEPTH + 1)) - 1)
37
38 #define REPORT_BIT_PRESSED BIT(0)
39 #define REPORT_BIT_AD0 BIT(1)
40 #define REPORT_BIT_AD1 BIT(2)
41 #define REPORT_BIT_HAS_PRESSURE BIT(6)
42 #define REPORT_RES_BITS(v) (((v) >> 1) + EETI_TS_BITDEPTH)
43
eeti_ts_report_event(struct eeti_ts * eeti,u8 * buf)44 static void eeti_ts_report_event(struct eeti_ts *eeti, u8 *buf)
45 {
46 unsigned int res;
47 u16 x, y;
48
49 res = REPORT_RES_BITS(buf[0] & (REPORT_BIT_AD0 | REPORT_BIT_AD1));
50
51 x = get_unaligned_be16(&buf[1]);
52 y = get_unaligned_be16(&buf[3]);
53
54 /* fix the range to 11 bits */
55 x >>= res - EETI_TS_BITDEPTH;
56 y >>= res - EETI_TS_BITDEPTH;
57
58 if (buf[0] & REPORT_BIT_HAS_PRESSURE)
59 input_report_abs(eeti->input, ABS_PRESSURE, buf[5]);
60
61 touchscreen_report_pos(eeti->input, &eeti->props, x, y, false);
62 input_report_key(eeti->input, BTN_TOUCH, buf[0] & REPORT_BIT_PRESSED);
63 input_sync(eeti->input);
64 }
65
eeti_ts_read(struct eeti_ts * eeti)66 static int eeti_ts_read(struct eeti_ts *eeti)
67 {
68 int len, error;
69 char buf[6];
70
71 len = i2c_master_recv(eeti->client, buf, sizeof(buf));
72 if (len != sizeof(buf)) {
73 error = len < 0 ? len : -EIO;
74 dev_err(&eeti->client->dev,
75 "failed to read touchscreen data: %d\n",
76 error);
77 return error;
78 }
79
80 /* Motion packet */
81 if (buf[0] & 0x80)
82 eeti_ts_report_event(eeti, buf);
83
84 return 0;
85 }
86
eeti_ts_isr(int irq,void * dev_id)87 static irqreturn_t eeti_ts_isr(int irq, void *dev_id)
88 {
89 struct eeti_ts *eeti = dev_id;
90 int error;
91
92 mutex_lock(&eeti->mutex);
93
94 do {
95 /*
96 * If we have attention GPIO, trust it. Otherwise we'll read
97 * once and exit. We assume that in this case we are using
98 * level triggered interrupt and it will get raised again
99 * if/when there is more data.
100 */
101 if (eeti->attn_gpio &&
102 !gpiod_get_value_cansleep(eeti->attn_gpio)) {
103 break;
104 }
105
106 error = eeti_ts_read(eeti);
107 if (error)
108 break;
109
110 } while (eeti->running && eeti->attn_gpio);
111
112 mutex_unlock(&eeti->mutex);
113 return IRQ_HANDLED;
114 }
115
eeti_ts_start(struct eeti_ts * eeti)116 static void eeti_ts_start(struct eeti_ts *eeti)
117 {
118 mutex_lock(&eeti->mutex);
119
120 eeti->running = true;
121 enable_irq(eeti->client->irq);
122
123 /*
124 * Kick the controller in case we are using edge interrupt and
125 * we missed our edge while interrupt was disabled. We expect
126 * the attention GPIO to be wired in this case.
127 */
128 if (eeti->attn_gpio && gpiod_get_value_cansleep(eeti->attn_gpio))
129 eeti_ts_read(eeti);
130
131 mutex_unlock(&eeti->mutex);
132 }
133
eeti_ts_stop(struct eeti_ts * eeti)134 static void eeti_ts_stop(struct eeti_ts *eeti)
135 {
136 /*
137 * Not locking here, just setting a flag and expect that the
138 * interrupt thread will notice the flag eventually.
139 */
140 eeti->running = false;
141 wmb();
142 disable_irq(eeti->client->irq);
143 }
144
eeti_ts_open(struct input_dev * dev)145 static int eeti_ts_open(struct input_dev *dev)
146 {
147 struct eeti_ts *eeti = input_get_drvdata(dev);
148
149 eeti_ts_start(eeti);
150
151 return 0;
152 }
153
eeti_ts_close(struct input_dev * dev)154 static void eeti_ts_close(struct input_dev *dev)
155 {
156 struct eeti_ts *eeti = input_get_drvdata(dev);
157
158 eeti_ts_stop(eeti);
159 }
160
eeti_ts_probe(struct i2c_client * client)161 static int eeti_ts_probe(struct i2c_client *client)
162 {
163 struct device *dev = &client->dev;
164 struct eeti_ts *eeti;
165 struct input_dev *input;
166 int error;
167
168 /*
169 * In contrast to what's described in the datasheet, there seems
170 * to be no way of probing the presence of that device using I2C
171 * commands. So we need to blindly believe it is there, and wait
172 * for interrupts to occur.
173 */
174
175 eeti = devm_kzalloc(dev, sizeof(*eeti), GFP_KERNEL);
176 if (!eeti) {
177 dev_err(dev, "failed to allocate driver data\n");
178 return -ENOMEM;
179 }
180
181 mutex_init(&eeti->mutex);
182
183 input = devm_input_allocate_device(dev);
184 if (!input) {
185 dev_err(dev, "Failed to allocate input device.\n");
186 return -ENOMEM;
187 }
188
189 input_set_capability(input, EV_KEY, BTN_TOUCH);
190
191 input_set_abs_params(input, ABS_X, 0, EETI_MAXVAL, 0, 0);
192 input_set_abs_params(input, ABS_Y, 0, EETI_MAXVAL, 0, 0);
193 input_set_abs_params(input, ABS_PRESSURE, 0, 0xff, 0, 0);
194
195 touchscreen_parse_properties(input, false, &eeti->props);
196
197 input->name = client->name;
198 input->id.bustype = BUS_I2C;
199 input->open = eeti_ts_open;
200 input->close = eeti_ts_close;
201
202 eeti->client = client;
203 eeti->input = input;
204
205 eeti->attn_gpio = devm_gpiod_get_optional(dev, "attn", GPIOD_IN);
206 if (IS_ERR(eeti->attn_gpio))
207 return PTR_ERR(eeti->attn_gpio);
208
209 i2c_set_clientdata(client, eeti);
210 input_set_drvdata(input, eeti);
211
212 error = devm_request_threaded_irq(dev, client->irq,
213 NULL, eeti_ts_isr,
214 IRQF_ONESHOT,
215 client->name, eeti);
216 if (error) {
217 dev_err(dev, "Unable to request touchscreen IRQ: %d\n",
218 error);
219 return error;
220 }
221
222 /*
223 * Disable the device for now. It will be enabled once the
224 * input device is opened.
225 */
226 eeti_ts_stop(eeti);
227
228 error = input_register_device(input);
229 if (error)
230 return error;
231
232 return 0;
233 }
234
eeti_ts_suspend(struct device * dev)235 static int eeti_ts_suspend(struct device *dev)
236 {
237 struct i2c_client *client = to_i2c_client(dev);
238 struct eeti_ts *eeti = i2c_get_clientdata(client);
239 struct input_dev *input_dev = eeti->input;
240
241 mutex_lock(&input_dev->mutex);
242
243 if (input_device_enabled(input_dev))
244 eeti_ts_stop(eeti);
245
246 mutex_unlock(&input_dev->mutex);
247
248 if (device_may_wakeup(&client->dev))
249 enable_irq_wake(client->irq);
250
251 return 0;
252 }
253
eeti_ts_resume(struct device * dev)254 static int eeti_ts_resume(struct device *dev)
255 {
256 struct i2c_client *client = to_i2c_client(dev);
257 struct eeti_ts *eeti = i2c_get_clientdata(client);
258 struct input_dev *input_dev = eeti->input;
259
260 if (device_may_wakeup(&client->dev))
261 disable_irq_wake(client->irq);
262
263 mutex_lock(&input_dev->mutex);
264
265 if (input_device_enabled(input_dev))
266 eeti_ts_start(eeti);
267
268 mutex_unlock(&input_dev->mutex);
269
270 return 0;
271 }
272
273 static DEFINE_SIMPLE_DEV_PM_OPS(eeti_ts_pm, eeti_ts_suspend, eeti_ts_resume);
274
275 static const struct i2c_device_id eeti_ts_id[] = {
276 { "eeti_ts" },
277 { }
278 };
279 MODULE_DEVICE_TABLE(i2c, eeti_ts_id);
280
281 #ifdef CONFIG_OF
282 static const struct of_device_id of_eeti_ts_match[] = {
283 { .compatible = "eeti,exc3000-i2c", },
284 { }
285 };
286 #endif
287
288 static struct i2c_driver eeti_ts_driver = {
289 .driver = {
290 .name = "eeti_ts",
291 .pm = pm_sleep_ptr(&eeti_ts_pm),
292 .of_match_table = of_match_ptr(of_eeti_ts_match),
293 },
294 .probe = eeti_ts_probe,
295 .id_table = eeti_ts_id,
296 };
297
298 module_i2c_driver(eeti_ts_driver);
299
300 MODULE_DESCRIPTION("EETI Touchscreen driver");
301 MODULE_AUTHOR("Daniel Mack <daniel@zonque.org>");
302 MODULE_LICENSE("GPL");
303