1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Driver for Cypress CY8CTMA140 (TMA140) touchscreen
4 * (C) 2020 Linus Walleij <linus.walleij@linaro.org>
5 * (C) 2007 Cypress
6 * (C) 2007 Google, Inc.
7 *
8 * Inspired by the tma140_skomer.c driver in the Samsung GT-S7710 code
9 * drop. The GT-S7710 is codenamed "Skomer", the code also indicates
10 * that the same touchscreen was used in a product called "Lucas".
11 *
12 * The code drop for GT-S7710 also contains a firmware downloader and
13 * 15 (!) versions of the firmware drop from Cypress. But here we assume
14 * the firmware got downloaded to the touchscreen flash successfully and
15 * just use it to read the fingers. The shipped vendor driver does the
16 * same.
17 */
18
19 #include <asm/unaligned.h>
20 #include <linux/module.h>
21 #include <linux/kernel.h>
22 #include <linux/input.h>
23 #include <linux/input/touchscreen.h>
24 #include <linux/input/mt.h>
25 #include <linux/slab.h>
26 #include <linux/interrupt.h>
27 #include <linux/io.h>
28 #include <linux/i2c.h>
29 #include <linux/regulator/consumer.h>
30 #include <linux/delay.h>
31
32 #define CY8CTMA140_NAME "cy8ctma140"
33
34 #define CY8CTMA140_MAX_FINGERS 4
35
36 #define CY8CTMA140_GET_FINGERS 0x00
37 #define CY8CTMA140_GET_FW_INFO 0x19
38
39 /* This message also fits some bytes for touchkeys, if used */
40 #define CY8CTMA140_PACKET_SIZE 31
41
42 #define CY8CTMA140_INVALID_BUFFER_BIT 5
43
44 struct cy8ctma140 {
45 struct input_dev *input;
46 struct touchscreen_properties props;
47 struct device *dev;
48 struct i2c_client *client;
49 struct regulator_bulk_data regulators[2];
50 u8 prev_fingers;
51 u8 prev_f1id;
52 u8 prev_f2id;
53 };
54
cy8ctma140_report(struct cy8ctma140 * ts,u8 * data,int n_fingers)55 static void cy8ctma140_report(struct cy8ctma140 *ts, u8 *data, int n_fingers)
56 {
57 static const u8 contact_offsets[] = { 0x03, 0x09, 0x10, 0x16 };
58 u8 *buf;
59 u16 x, y;
60 u8 w;
61 u8 id;
62 int slot;
63 int i;
64
65 for (i = 0; i < n_fingers; i++) {
66 buf = &data[contact_offsets[i]];
67
68 /*
69 * Odd contacts have contact ID in the lower nibble of
70 * the preceding byte, whereas even contacts have it in
71 * the upper nibble of the following byte.
72 */
73 id = i % 2 ? buf[-1] & 0x0f : buf[5] >> 4;
74 slot = input_mt_get_slot_by_key(ts->input, id);
75 if (slot < 0)
76 continue;
77
78 x = get_unaligned_be16(buf);
79 y = get_unaligned_be16(buf + 2);
80 w = buf[4];
81
82 dev_dbg(ts->dev, "finger %d: ID %02x (%d, %d) w: %d\n",
83 slot, id, x, y, w);
84
85 input_mt_slot(ts->input, slot);
86 input_mt_report_slot_state(ts->input, MT_TOOL_FINGER, true);
87 touchscreen_report_pos(ts->input, &ts->props, x, y, true);
88 input_report_abs(ts->input, ABS_MT_TOUCH_MAJOR, w);
89 }
90
91 input_mt_sync_frame(ts->input);
92 input_sync(ts->input);
93 }
94
cy8ctma140_irq_thread(int irq,void * d)95 static irqreturn_t cy8ctma140_irq_thread(int irq, void *d)
96 {
97 struct cy8ctma140 *ts = d;
98 u8 cmdbuf[] = { CY8CTMA140_GET_FINGERS };
99 u8 buf[CY8CTMA140_PACKET_SIZE];
100 struct i2c_msg msg[] = {
101 {
102 .addr = ts->client->addr,
103 .flags = 0,
104 .len = sizeof(cmdbuf),
105 .buf = cmdbuf,
106 }, {
107 .addr = ts->client->addr,
108 .flags = I2C_M_RD,
109 .len = sizeof(buf),
110 .buf = buf,
111 },
112 };
113 u8 n_fingers;
114 int ret;
115
116 ret = i2c_transfer(ts->client->adapter, msg, ARRAY_SIZE(msg));
117 if (ret != ARRAY_SIZE(msg)) {
118 if (ret < 0)
119 dev_err(ts->dev, "error reading message: %d\n", ret);
120 else
121 dev_err(ts->dev, "wrong number of messages\n");
122 goto out;
123 }
124
125 if (buf[1] & BIT(CY8CTMA140_INVALID_BUFFER_BIT)) {
126 dev_dbg(ts->dev, "invalid event\n");
127 goto out;
128 }
129
130 n_fingers = buf[2] & 0x0f;
131 if (n_fingers > CY8CTMA140_MAX_FINGERS) {
132 dev_err(ts->dev, "unexpected number of fingers: %d\n",
133 n_fingers);
134 goto out;
135 }
136
137 cy8ctma140_report(ts, buf, n_fingers);
138
139 out:
140 return IRQ_HANDLED;
141 }
142
cy8ctma140_init(struct cy8ctma140 * ts)143 static int cy8ctma140_init(struct cy8ctma140 *ts)
144 {
145 u8 addr[1];
146 u8 buf[5];
147 int ret;
148
149 addr[0] = CY8CTMA140_GET_FW_INFO;
150 ret = i2c_master_send(ts->client, addr, 1);
151 if (ret < 0) {
152 dev_err(ts->dev, "error sending FW info message\n");
153 return ret;
154 }
155 ret = i2c_master_recv(ts->client, buf, 5);
156 if (ret < 0) {
157 dev_err(ts->dev, "error receiving FW info message\n");
158 return ret;
159 }
160 if (ret != 5) {
161 dev_err(ts->dev, "got only %d bytes\n", ret);
162 return -EIO;
163 }
164
165 dev_dbg(ts->dev, "vendor %c%c, HW ID %.2d, FW ver %.4d\n",
166 buf[0], buf[1], buf[3], buf[4]);
167
168 return 0;
169 }
170
cy8ctma140_power_up(struct cy8ctma140 * ts)171 static int cy8ctma140_power_up(struct cy8ctma140 *ts)
172 {
173 int error;
174
175 error = regulator_bulk_enable(ARRAY_SIZE(ts->regulators),
176 ts->regulators);
177 if (error) {
178 dev_err(ts->dev, "failed to enable regulators\n");
179 return error;
180 }
181
182 msleep(250);
183
184 return 0;
185 }
186
cy8ctma140_power_down(struct cy8ctma140 * ts)187 static void cy8ctma140_power_down(struct cy8ctma140 *ts)
188 {
189 regulator_bulk_disable(ARRAY_SIZE(ts->regulators),
190 ts->regulators);
191 }
192
193 /* Called from the registered devm action */
cy8ctma140_power_off_action(void * d)194 static void cy8ctma140_power_off_action(void *d)
195 {
196 struct cy8ctma140 *ts = d;
197
198 cy8ctma140_power_down(ts);
199 }
200
cy8ctma140_probe(struct i2c_client * client)201 static int cy8ctma140_probe(struct i2c_client *client)
202 {
203 struct cy8ctma140 *ts;
204 struct input_dev *input;
205 struct device *dev = &client->dev;
206 int error;
207
208 ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
209 if (!ts)
210 return -ENOMEM;
211
212 input = devm_input_allocate_device(dev);
213 if (!input)
214 return -ENOMEM;
215
216 ts->dev = dev;
217 ts->client = client;
218 ts->input = input;
219
220 input_set_capability(input, EV_ABS, ABS_MT_POSITION_X);
221 input_set_capability(input, EV_ABS, ABS_MT_POSITION_Y);
222 /* One byte for width 0..255 so this is the limit */
223 input_set_abs_params(input, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);
224 /*
225 * This sets up event max/min capabilities and fuzz.
226 * Some DT properties are compulsory so we do not need
227 * to provide defaults for X/Y max or pressure max.
228 *
229 * We just initialize a very simple MT touchscreen here,
230 * some devices use the capability of this touchscreen to
231 * provide touchkeys, and in that case this needs to be
232 * extended to handle touchkey input.
233 *
234 * The firmware takes care of finger tracking and dropping
235 * invalid ranges.
236 */
237 touchscreen_parse_properties(input, true, &ts->props);
238 input_abs_set_fuzz(input, ABS_MT_POSITION_X, 0);
239 input_abs_set_fuzz(input, ABS_MT_POSITION_Y, 0);
240
241 error = input_mt_init_slots(input, CY8CTMA140_MAX_FINGERS,
242 INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
243 if (error)
244 return error;
245
246 input->name = CY8CTMA140_NAME;
247 input->id.bustype = BUS_I2C;
248 input_set_drvdata(input, ts);
249
250 /*
251 * VCPIN is the analog voltage supply
252 * VDD is the digital voltage supply
253 * since the voltage range of VDD overlaps that of VCPIN,
254 * many designs to just supply both with a single voltage
255 * source of ~3.3 V.
256 */
257 ts->regulators[0].supply = "vcpin";
258 ts->regulators[1].supply = "vdd";
259 error = devm_regulator_bulk_get(dev, ARRAY_SIZE(ts->regulators),
260 ts->regulators);
261 if (error)
262 return dev_err_probe(dev, error, "Failed to get regulators\n");
263
264 error = cy8ctma140_power_up(ts);
265 if (error)
266 return error;
267
268 error = devm_add_action_or_reset(dev, cy8ctma140_power_off_action, ts);
269 if (error) {
270 dev_err(dev, "failed to install power off handler\n");
271 return error;
272 }
273
274 error = devm_request_threaded_irq(dev, client->irq,
275 NULL, cy8ctma140_irq_thread,
276 IRQF_ONESHOT, CY8CTMA140_NAME, ts);
277 if (error) {
278 dev_err(dev, "irq %d busy? error %d\n", client->irq, error);
279 return error;
280 }
281
282 error = cy8ctma140_init(ts);
283 if (error)
284 return error;
285
286 error = input_register_device(input);
287 if (error)
288 return error;
289
290 i2c_set_clientdata(client, ts);
291
292 return 0;
293 }
294
cy8ctma140_suspend(struct device * dev)295 static int cy8ctma140_suspend(struct device *dev)
296 {
297 struct i2c_client *client = to_i2c_client(dev);
298 struct cy8ctma140 *ts = i2c_get_clientdata(client);
299
300 if (!device_may_wakeup(&client->dev))
301 cy8ctma140_power_down(ts);
302
303 return 0;
304 }
305
cy8ctma140_resume(struct device * dev)306 static int cy8ctma140_resume(struct device *dev)
307 {
308 struct i2c_client *client = to_i2c_client(dev);
309 struct cy8ctma140 *ts = i2c_get_clientdata(client);
310 int error;
311
312 if (!device_may_wakeup(&client->dev)) {
313 error = cy8ctma140_power_up(ts);
314 if (error)
315 return error;
316 }
317
318 return 0;
319 }
320
321 static DEFINE_SIMPLE_DEV_PM_OPS(cy8ctma140_pm,
322 cy8ctma140_suspend, cy8ctma140_resume);
323
324 static const struct i2c_device_id cy8ctma140_idtable[] = {
325 { CY8CTMA140_NAME, 0 },
326 { /* sentinel */ }
327 };
328 MODULE_DEVICE_TABLE(i2c, cy8ctma140_idtable);
329
330 static const struct of_device_id cy8ctma140_of_match[] = {
331 { .compatible = "cypress,cy8ctma140", },
332 { /* sentinel */ }
333 };
334 MODULE_DEVICE_TABLE(of, cy8ctma140_of_match);
335
336 static struct i2c_driver cy8ctma140_driver = {
337 .driver = {
338 .name = CY8CTMA140_NAME,
339 .pm = pm_sleep_ptr(&cy8ctma140_pm),
340 .of_match_table = cy8ctma140_of_match,
341 },
342 .id_table = cy8ctma140_idtable,
343 .probe = cy8ctma140_probe,
344 };
345 module_i2c_driver(cy8ctma140_driver);
346
347 MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
348 MODULE_DESCRIPTION("CY8CTMA140 TouchScreen Driver");
349 MODULE_LICENSE("GPL v2");
350