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 <asm/unaligned.h>
25
26struct 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
44static 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(p: &buf[1]);
52 y = get_unaligned_be16(p: &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(dev: eeti->input, ABS_PRESSURE, value: buf[5]);
60
61 touchscreen_report_pos(input: eeti->input, prop: &eeti->props, x, y, multitouch: false);
62 input_report_key(dev: eeti->input, BTN_TOUCH, value: buf[0] & REPORT_BIT_PRESSED);
63 input_sync(dev: eeti->input);
64}
65
66static int eeti_ts_read(struct eeti_ts *eeti)
67{
68 int len, error;
69 char buf[6];
70
71 len = i2c_master_recv(client: eeti->client, buf, count: 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
87static 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(desc: 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(lock: &eeti->mutex);
113 return IRQ_HANDLED;
114}
115
116static void eeti_ts_start(struct eeti_ts *eeti)
117{
118 mutex_lock(&eeti->mutex);
119
120 eeti->running = true;
121 enable_irq(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(desc: eeti->attn_gpio))
129 eeti_ts_read(eeti);
130
131 mutex_unlock(lock: &eeti->mutex);
132}
133
134static 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(irq: eeti->client->irq);
143}
144
145static 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
154static 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
161static 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, size: 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(dev: input, EV_KEY, BTN_TOUCH);
190
191 input_set_abs_params(dev: input, ABS_X, min: 0, EETI_MAXVAL, fuzz: 0, flat: 0);
192 input_set_abs_params(dev: input, ABS_Y, min: 0, EETI_MAXVAL, fuzz: 0, flat: 0);
193 input_set_abs_params(dev: input, ABS_PRESSURE, min: 0, max: 0xff, fuzz: 0, flat: 0);
194
195 touchscreen_parse_properties(input, multitouch: false, prop: &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, con_id: "attn", flags: GPIOD_IN);
206 if (IS_ERR(ptr: eeti->attn_gpio))
207 return PTR_ERR(ptr: eeti->attn_gpio);
208
209 i2c_set_clientdata(client, data: eeti);
210 input_set_drvdata(dev: input, data: eeti);
211
212 error = devm_request_threaded_irq(dev, irq: client->irq,
213 NULL, thread_fn: eeti_ts_isr,
214 IRQF_ONESHOT,
215 devname: client->name, dev_id: 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
235static 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(dev: input_dev))
244 eeti_ts_stop(eeti);
245
246 mutex_unlock(lock: &input_dev->mutex);
247
248 if (device_may_wakeup(dev: &client->dev))
249 enable_irq_wake(irq: client->irq);
250
251 return 0;
252}
253
254static 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(dev: &client->dev))
261 disable_irq_wake(irq: client->irq);
262
263 mutex_lock(&input_dev->mutex);
264
265 if (input_device_enabled(dev: input_dev))
266 eeti_ts_start(eeti);
267
268 mutex_unlock(lock: &input_dev->mutex);
269
270 return 0;
271}
272
273static DEFINE_SIMPLE_DEV_PM_OPS(eeti_ts_pm, eeti_ts_suspend, eeti_ts_resume);
274
275static const struct i2c_device_id eeti_ts_id[] = {
276 { "eeti_ts", 0 },
277 { }
278};
279MODULE_DEVICE_TABLE(i2c, eeti_ts_id);
280
281#ifdef CONFIG_OF
282static const struct of_device_id of_eeti_ts_match[] = {
283 { .compatible = "eeti,exc3000-i2c", },
284 { }
285};
286#endif
287
288static 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
298module_i2c_driver(eeti_ts_driver);
299
300MODULE_DESCRIPTION("EETI Touchscreen driver");
301MODULE_AUTHOR("Daniel Mack <daniel@zonque.org>");
302MODULE_LICENSE("GPL");
303

source code of linux/drivers/input/touchscreen/eeti_ts.c