1// SPDX-License-Identifier: GPL-2.0
2//
3// Copyright (C) 2014-2015 Pengutronix, Markus Pargmann <mpa@pengutronix.de>
4// Based on driver from 2011:
5// Juergen Beisert, Pengutronix <kernel@pengutronix.de>
6//
7// This is the driver for the imx25 TCQ (Touchscreen Conversion Queue)
8// connected to the imx25 ADC.
9
10#include <linux/clk.h>
11#include <linux/device.h>
12#include <linux/input.h>
13#include <linux/interrupt.h>
14#include <linux/mfd/imx25-tsadc.h>
15#include <linux/module.h>
16#include <linux/of.h>
17#include <linux/platform_device.h>
18#include <linux/regmap.h>
19
20static const char mx25_tcq_name[] = "mx25-tcq";
21
22enum mx25_tcq_mode {
23 MX25_TS_4WIRE,
24};
25
26struct mx25_tcq_priv {
27 struct regmap *regs;
28 struct regmap *core_regs;
29 struct input_dev *idev;
30 enum mx25_tcq_mode mode;
31 unsigned int pen_threshold;
32 unsigned int sample_count;
33 unsigned int expected_samples;
34 unsigned int pen_debounce;
35 unsigned int settling_time;
36 struct clk *clk;
37 int irq;
38 struct device *dev;
39};
40
41static struct regmap_config mx25_tcq_regconfig = {
42 .fast_io = true,
43 .max_register = 0x5c,
44 .reg_bits = 32,
45 .val_bits = 32,
46 .reg_stride = 4,
47};
48
49static const struct of_device_id mx25_tcq_ids[] = {
50 { .compatible = "fsl,imx25-tcq", },
51 { /* Sentinel */ }
52};
53MODULE_DEVICE_TABLE(of, mx25_tcq_ids);
54
55#define TSC_4WIRE_PRE_INDEX 0
56#define TSC_4WIRE_X_INDEX 1
57#define TSC_4WIRE_Y_INDEX 2
58#define TSC_4WIRE_POST_INDEX 3
59#define TSC_4WIRE_LEAVE 4
60
61#define MX25_TSC_DEF_THRESHOLD 80
62#define TSC_MAX_SAMPLES 16
63
64#define MX25_TSC_REPEAT_WAIT 14
65
66enum mx25_adc_configurations {
67 MX25_CFG_PRECHARGE = 0,
68 MX25_CFG_TOUCH_DETECT,
69 MX25_CFG_X_MEASUREMENT,
70 MX25_CFG_Y_MEASUREMENT,
71};
72
73#define MX25_PRECHARGE_VALUE (\
74 MX25_ADCQ_CFG_YPLL_OFF | \
75 MX25_ADCQ_CFG_XNUR_OFF | \
76 MX25_ADCQ_CFG_XPUL_HIGH | \
77 MX25_ADCQ_CFG_REFP_INT | \
78 MX25_ADCQ_CFG_IN_XP | \
79 MX25_ADCQ_CFG_REFN_NGND2 | \
80 MX25_ADCQ_CFG_IGS)
81
82#define MX25_TOUCH_DETECT_VALUE (\
83 MX25_ADCQ_CFG_YNLR | \
84 MX25_ADCQ_CFG_YPLL_OFF | \
85 MX25_ADCQ_CFG_XNUR_OFF | \
86 MX25_ADCQ_CFG_XPUL_OFF | \
87 MX25_ADCQ_CFG_REFP_INT | \
88 MX25_ADCQ_CFG_IN_XP | \
89 MX25_ADCQ_CFG_REFN_NGND2 | \
90 MX25_ADCQ_CFG_PENIACK)
91
92static void imx25_setup_queue_cfgs(struct mx25_tcq_priv *priv,
93 unsigned int settling_cnt)
94{
95 u32 precharge_cfg =
96 MX25_PRECHARGE_VALUE |
97 MX25_ADCQ_CFG_SETTLING_TIME(settling_cnt);
98 u32 touch_detect_cfg =
99 MX25_TOUCH_DETECT_VALUE |
100 MX25_ADCQ_CFG_NOS(1) |
101 MX25_ADCQ_CFG_SETTLING_TIME(settling_cnt);
102
103 regmap_write(priv->core_regs, MX25_TSC_TICR, precharge_cfg);
104
105 /* PRECHARGE */
106 regmap_write(priv->regs, MX25_ADCQ_CFG(MX25_CFG_PRECHARGE),
107 precharge_cfg);
108
109 /* TOUCH_DETECT */
110 regmap_write(priv->regs, MX25_ADCQ_CFG(MX25_CFG_TOUCH_DETECT),
111 touch_detect_cfg);
112
113 /* X Measurement */
114 regmap_write(priv->regs, MX25_ADCQ_CFG(MX25_CFG_X_MEASUREMENT),
115 MX25_ADCQ_CFG_YPLL_OFF |
116 MX25_ADCQ_CFG_XNUR_LOW |
117 MX25_ADCQ_CFG_XPUL_HIGH |
118 MX25_ADCQ_CFG_REFP_XP |
119 MX25_ADCQ_CFG_IN_YP |
120 MX25_ADCQ_CFG_REFN_XN |
121 MX25_ADCQ_CFG_NOS(priv->sample_count) |
122 MX25_ADCQ_CFG_SETTLING_TIME(settling_cnt));
123
124 /* Y Measurement */
125 regmap_write(priv->regs, MX25_ADCQ_CFG(MX25_CFG_Y_MEASUREMENT),
126 MX25_ADCQ_CFG_YNLR |
127 MX25_ADCQ_CFG_YPLL_HIGH |
128 MX25_ADCQ_CFG_XNUR_OFF |
129 MX25_ADCQ_CFG_XPUL_OFF |
130 MX25_ADCQ_CFG_REFP_YP |
131 MX25_ADCQ_CFG_IN_XP |
132 MX25_ADCQ_CFG_REFN_YN |
133 MX25_ADCQ_CFG_NOS(priv->sample_count) |
134 MX25_ADCQ_CFG_SETTLING_TIME(settling_cnt));
135
136 /* Enable the touch detection right now */
137 regmap_write(priv->core_regs, MX25_TSC_TICR, touch_detect_cfg |
138 MX25_ADCQ_CFG_IGS);
139}
140
141static int imx25_setup_queue_4wire(struct mx25_tcq_priv *priv,
142 unsigned settling_cnt, int *items)
143{
144 imx25_setup_queue_cfgs(priv, settling_cnt);
145
146 /* Setup the conversion queue */
147 regmap_write(priv->regs, MX25_ADCQ_ITEM_7_0,
148 MX25_ADCQ_ITEM(0, MX25_CFG_PRECHARGE) |
149 MX25_ADCQ_ITEM(1, MX25_CFG_TOUCH_DETECT) |
150 MX25_ADCQ_ITEM(2, MX25_CFG_X_MEASUREMENT) |
151 MX25_ADCQ_ITEM(3, MX25_CFG_Y_MEASUREMENT) |
152 MX25_ADCQ_ITEM(4, MX25_CFG_PRECHARGE) |
153 MX25_ADCQ_ITEM(5, MX25_CFG_TOUCH_DETECT));
154
155 /*
156 * We measure X/Y with 'sample_count' number of samples and execute a
157 * touch detection twice, with 1 sample each
158 */
159 priv->expected_samples = priv->sample_count * 2 + 2;
160 *items = 6;
161
162 return 0;
163}
164
165static void mx25_tcq_disable_touch_irq(struct mx25_tcq_priv *priv)
166{
167 regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_PDMSK,
168 MX25_ADCQ_CR_PDMSK);
169}
170
171static void mx25_tcq_enable_touch_irq(struct mx25_tcq_priv *priv)
172{
173 regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_PDMSK, 0);
174}
175
176static void mx25_tcq_disable_fifo_irq(struct mx25_tcq_priv *priv)
177{
178 regmap_update_bits(priv->regs, MX25_ADCQ_MR, MX25_ADCQ_MR_FDRY_IRQ,
179 MX25_ADCQ_MR_FDRY_IRQ);
180}
181
182static void mx25_tcq_enable_fifo_irq(struct mx25_tcq_priv *priv)
183{
184 regmap_update_bits(priv->regs, MX25_ADCQ_MR, MX25_ADCQ_MR_FDRY_IRQ, 0);
185}
186
187static void mx25_tcq_force_queue_start(struct mx25_tcq_priv *priv)
188{
189 regmap_update_bits(priv->regs, MX25_ADCQ_CR,
190 MX25_ADCQ_CR_FQS,
191 MX25_ADCQ_CR_FQS);
192}
193
194static void mx25_tcq_force_queue_stop(struct mx25_tcq_priv *priv)
195{
196 regmap_update_bits(priv->regs, MX25_ADCQ_CR,
197 MX25_ADCQ_CR_FQS, 0);
198}
199
200static void mx25_tcq_fifo_reset(struct mx25_tcq_priv *priv)
201{
202 u32 tcqcr;
203
204 regmap_read(priv->regs, MX25_ADCQ_CR, &tcqcr);
205 regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FRST,
206 MX25_ADCQ_CR_FRST);
207 regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FRST, 0);
208 regmap_write(priv->regs, MX25_ADCQ_CR, tcqcr);
209}
210
211static void mx25_tcq_re_enable_touch_detection(struct mx25_tcq_priv *priv)
212{
213 /* stop the queue from looping */
214 mx25_tcq_force_queue_stop(priv);
215
216 /* for a clean touch detection, preload the X plane */
217 regmap_write(priv->core_regs, MX25_TSC_TICR, MX25_PRECHARGE_VALUE);
218
219 /* waste some time now to pre-load the X plate to high voltage */
220 mx25_tcq_fifo_reset(priv);
221
222 /* re-enable the detection right now */
223 regmap_write(priv->core_regs, MX25_TSC_TICR,
224 MX25_TOUCH_DETECT_VALUE | MX25_ADCQ_CFG_IGS);
225
226 regmap_update_bits(priv->regs, MX25_ADCQ_SR, MX25_ADCQ_SR_PD,
227 MX25_ADCQ_SR_PD);
228
229 /* enable the pen down event to be a source for the interrupt */
230 regmap_update_bits(priv->regs, MX25_ADCQ_MR, MX25_ADCQ_MR_PD_IRQ, 0);
231
232 /* lets fire the next IRQ if someone touches the touchscreen */
233 mx25_tcq_enable_touch_irq(priv);
234}
235
236static void mx25_tcq_create_event_for_4wire(struct mx25_tcq_priv *priv,
237 u32 *sample_buf,
238 unsigned int samples)
239{
240 unsigned int x_pos = 0;
241 unsigned int y_pos = 0;
242 unsigned int touch_pre = 0;
243 unsigned int touch_post = 0;
244 unsigned int i;
245
246 for (i = 0; i < samples; i++) {
247 unsigned int index = MX25_ADCQ_FIFO_ID(sample_buf[i]);
248 unsigned int val = MX25_ADCQ_FIFO_DATA(sample_buf[i]);
249
250 switch (index) {
251 case 1:
252 touch_pre = val;
253 break;
254 case 2:
255 x_pos = val;
256 break;
257 case 3:
258 y_pos = val;
259 break;
260 case 5:
261 touch_post = val;
262 break;
263 default:
264 dev_dbg(priv->dev, "Dropped samples because of invalid index %d\n",
265 index);
266 return;
267 }
268 }
269
270 if (samples != 0) {
271 /*
272 * only if both touch measures are below a threshold,
273 * the position is valid
274 */
275 if (touch_pre < priv->pen_threshold &&
276 touch_post < priv->pen_threshold) {
277 /* valid samples, generate a report */
278 x_pos /= priv->sample_count;
279 y_pos /= priv->sample_count;
280 input_report_abs(priv->idev, ABS_X, x_pos);
281 input_report_abs(priv->idev, ABS_Y, y_pos);
282 input_report_key(priv->idev, BTN_TOUCH, 1);
283 input_sync(priv->idev);
284
285 /* get next sample */
286 mx25_tcq_enable_fifo_irq(priv);
287 } else if (touch_pre >= priv->pen_threshold &&
288 touch_post >= priv->pen_threshold) {
289 /*
290 * if both samples are invalid,
291 * generate a release report
292 */
293 input_report_key(priv->idev, BTN_TOUCH, 0);
294 input_sync(priv->idev);
295 mx25_tcq_re_enable_touch_detection(priv);
296 } else {
297 /*
298 * if only one of both touch measurements are
299 * below the threshold, still some bouncing
300 * happens. Take additional samples in this
301 * case to be sure
302 */
303 mx25_tcq_enable_fifo_irq(priv);
304 }
305 }
306}
307
308static irqreturn_t mx25_tcq_irq_thread(int irq, void *dev_id)
309{
310 struct mx25_tcq_priv *priv = dev_id;
311 u32 sample_buf[TSC_MAX_SAMPLES];
312 unsigned int samples;
313 u32 stats;
314 unsigned int i;
315
316 /*
317 * Check how many samples are available. We always have to read exactly
318 * sample_count samples from the fifo, or a multiple of sample_count.
319 * Otherwise we mixup samples into different touch events.
320 */
321 regmap_read(priv->regs, MX25_ADCQ_SR, &stats);
322 samples = MX25_ADCQ_SR_FDN(stats);
323 samples -= samples % priv->sample_count;
324
325 if (!samples)
326 return IRQ_HANDLED;
327
328 for (i = 0; i != samples; ++i)
329 regmap_read(priv->regs, MX25_ADCQ_FIFO, &sample_buf[i]);
330
331 mx25_tcq_create_event_for_4wire(priv, sample_buf, samples);
332
333 return IRQ_HANDLED;
334}
335
336static irqreturn_t mx25_tcq_irq(int irq, void *dev_id)
337{
338 struct mx25_tcq_priv *priv = dev_id;
339 u32 stat;
340 int ret = IRQ_HANDLED;
341
342 regmap_read(priv->regs, MX25_ADCQ_SR, &stat);
343
344 if (stat & (MX25_ADCQ_SR_FRR | MX25_ADCQ_SR_FUR | MX25_ADCQ_SR_FOR))
345 mx25_tcq_re_enable_touch_detection(priv);
346
347 if (stat & MX25_ADCQ_SR_PD) {
348 mx25_tcq_disable_touch_irq(priv);
349 mx25_tcq_force_queue_start(priv);
350 mx25_tcq_enable_fifo_irq(priv);
351 }
352
353 if (stat & MX25_ADCQ_SR_FDRY) {
354 mx25_tcq_disable_fifo_irq(priv);
355 ret = IRQ_WAKE_THREAD;
356 }
357
358 regmap_update_bits(priv->regs, MX25_ADCQ_SR, MX25_ADCQ_SR_FRR |
359 MX25_ADCQ_SR_FUR | MX25_ADCQ_SR_FOR |
360 MX25_ADCQ_SR_PD,
361 MX25_ADCQ_SR_FRR | MX25_ADCQ_SR_FUR |
362 MX25_ADCQ_SR_FOR | MX25_ADCQ_SR_PD);
363
364 return ret;
365}
366
367/* configure the state machine for a 4-wire touchscreen */
368static int mx25_tcq_init(struct mx25_tcq_priv *priv)
369{
370 u32 tgcr;
371 unsigned int ipg_div;
372 unsigned int adc_period;
373 unsigned int debounce_cnt;
374 unsigned int settling_cnt;
375 int itemct;
376 int error;
377
378 regmap_read(priv->core_regs, MX25_TSC_TGCR, &tgcr);
379 ipg_div = max_t(unsigned int, 4, MX25_TGCR_GET_ADCCLK(tgcr));
380 adc_period = USEC_PER_SEC * ipg_div * 2 + 2;
381 adc_period /= clk_get_rate(priv->clk) / 1000 + 1;
382 debounce_cnt = DIV_ROUND_UP(priv->pen_debounce, adc_period * 8) - 1;
383 settling_cnt = DIV_ROUND_UP(priv->settling_time, adc_period * 8) - 1;
384
385 /* Reset */
386 regmap_write(priv->regs, MX25_ADCQ_CR,
387 MX25_ADCQ_CR_QRST | MX25_ADCQ_CR_FRST);
388 regmap_update_bits(priv->regs, MX25_ADCQ_CR,
389 MX25_ADCQ_CR_QRST | MX25_ADCQ_CR_FRST, 0);
390
391 /* up to 128 * 8 ADC clocks are possible */
392 if (debounce_cnt > 127)
393 debounce_cnt = 127;
394
395 /* up to 255 * 8 ADC clocks are possible */
396 if (settling_cnt > 255)
397 settling_cnt = 255;
398
399 error = imx25_setup_queue_4wire(priv, settling_cnt, &itemct);
400 if (error)
401 return error;
402
403 regmap_update_bits(priv->regs, MX25_ADCQ_CR,
404 MX25_ADCQ_CR_LITEMID_MASK | MX25_ADCQ_CR_WMRK_MASK,
405 MX25_ADCQ_CR_LITEMID(itemct - 1) |
406 MX25_ADCQ_CR_WMRK(priv->expected_samples - 1));
407
408 /* setup debounce count */
409 regmap_update_bits(priv->core_regs, MX25_TSC_TGCR,
410 MX25_TGCR_PDBTIME_MASK,
411 MX25_TGCR_PDBTIME(debounce_cnt));
412
413 /* enable debounce */
414 regmap_update_bits(priv->core_regs, MX25_TSC_TGCR, MX25_TGCR_PDBEN,
415 MX25_TGCR_PDBEN);
416 regmap_update_bits(priv->core_regs, MX25_TSC_TGCR, MX25_TGCR_PDEN,
417 MX25_TGCR_PDEN);
418
419 /* enable the engine on demand */
420 regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_QSM_MASK,
421 MX25_ADCQ_CR_QSM_FQS);
422
423 /* Enable repeat and repeat wait */
424 regmap_update_bits(priv->regs, MX25_ADCQ_CR,
425 MX25_ADCQ_CR_RPT | MX25_ADCQ_CR_RWAIT_MASK,
426 MX25_ADCQ_CR_RPT |
427 MX25_ADCQ_CR_RWAIT(MX25_TSC_REPEAT_WAIT));
428
429 return 0;
430}
431
432static int mx25_tcq_parse_dt(struct platform_device *pdev,
433 struct mx25_tcq_priv *priv)
434{
435 struct device_node *np = pdev->dev.of_node;
436 u32 wires;
437 int error;
438
439 /* Setup defaults */
440 priv->pen_threshold = 500;
441 priv->sample_count = 3;
442 priv->pen_debounce = 1000000;
443 priv->settling_time = 250000;
444
445 error = of_property_read_u32(np, "fsl,wires", &wires);
446 if (error) {
447 dev_err(&pdev->dev, "Failed to find fsl,wires properties\n");
448 return error;
449 }
450
451 if (wires == 4) {
452 priv->mode = MX25_TS_4WIRE;
453 } else {
454 dev_err(&pdev->dev, "%u-wire mode not supported\n", wires);
455 return -EINVAL;
456 }
457
458 /* These are optional, we don't care about the return values */
459 of_property_read_u32(np, "fsl,pen-threshold", &priv->pen_threshold);
460 of_property_read_u32(np, "fsl,settling-time-ns", &priv->settling_time);
461 of_property_read_u32(np, "fsl,pen-debounce-ns", &priv->pen_debounce);
462
463 return 0;
464}
465
466static int mx25_tcq_open(struct input_dev *idev)
467{
468 struct device *dev = &idev->dev;
469 struct mx25_tcq_priv *priv = dev_get_drvdata(dev);
470 int error;
471
472 error = clk_prepare_enable(priv->clk);
473 if (error) {
474 dev_err(dev, "Failed to enable ipg clock\n");
475 return error;
476 }
477
478 error = mx25_tcq_init(priv);
479 if (error) {
480 dev_err(dev, "Failed to init tcq\n");
481 clk_disable_unprepare(priv->clk);
482 return error;
483 }
484
485 mx25_tcq_re_enable_touch_detection(priv);
486
487 return 0;
488}
489
490static void mx25_tcq_close(struct input_dev *idev)
491{
492 struct mx25_tcq_priv *priv = input_get_drvdata(idev);
493
494 mx25_tcq_force_queue_stop(priv);
495 mx25_tcq_disable_touch_irq(priv);
496 mx25_tcq_disable_fifo_irq(priv);
497 clk_disable_unprepare(priv->clk);
498}
499
500static int mx25_tcq_probe(struct platform_device *pdev)
501{
502 struct device *dev = &pdev->dev;
503 struct input_dev *idev;
504 struct mx25_tcq_priv *priv;
505 struct mx25_tsadc *tsadc = dev_get_drvdata(dev->parent);
506 struct resource *res;
507 void __iomem *mem;
508 int error;
509
510 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
511 if (!priv)
512 return -ENOMEM;
513 priv->dev = dev;
514
515 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
516 mem = devm_ioremap_resource(dev, res);
517 if (IS_ERR(mem))
518 return PTR_ERR(mem);
519
520 error = mx25_tcq_parse_dt(pdev, priv);
521 if (error)
522 return error;
523
524 priv->regs = devm_regmap_init_mmio(dev, mem, &mx25_tcq_regconfig);
525 if (IS_ERR(priv->regs)) {
526 dev_err(dev, "Failed to initialize regmap\n");
527 return PTR_ERR(priv->regs);
528 }
529
530 priv->irq = platform_get_irq(pdev, 0);
531 if (priv->irq <= 0) {
532 dev_err(dev, "Failed to get IRQ\n");
533 return priv->irq;
534 }
535
536 idev = devm_input_allocate_device(dev);
537 if (!idev) {
538 dev_err(dev, "Failed to allocate input device\n");
539 return -ENOMEM;
540 }
541
542 idev->name = mx25_tcq_name;
543 input_set_capability(idev, EV_KEY, BTN_TOUCH);
544 input_set_abs_params(idev, ABS_X, 0, 0xfff, 0, 0);
545 input_set_abs_params(idev, ABS_Y, 0, 0xfff, 0, 0);
546
547 idev->id.bustype = BUS_HOST;
548 idev->open = mx25_tcq_open;
549 idev->close = mx25_tcq_close;
550
551 priv->idev = idev;
552 input_set_drvdata(idev, priv);
553
554 priv->core_regs = tsadc->regs;
555 if (!priv->core_regs)
556 return -EINVAL;
557
558 priv->clk = tsadc->clk;
559 if (!priv->clk)
560 return -EINVAL;
561
562 platform_set_drvdata(pdev, priv);
563
564 error = devm_request_threaded_irq(dev, priv->irq, mx25_tcq_irq,
565 mx25_tcq_irq_thread, 0, pdev->name,
566 priv);
567 if (error) {
568 dev_err(dev, "Failed requesting IRQ\n");
569 return error;
570 }
571
572 error = input_register_device(idev);
573 if (error) {
574 dev_err(dev, "Failed to register input device\n");
575 return error;
576 }
577
578 return 0;
579}
580
581static struct platform_driver mx25_tcq_driver = {
582 .driver = {
583 .name = "mx25-tcq",
584 .of_match_table = mx25_tcq_ids,
585 },
586 .probe = mx25_tcq_probe,
587};
588module_platform_driver(mx25_tcq_driver);
589
590MODULE_DESCRIPTION("TS input driver for Freescale mx25");
591MODULE_AUTHOR("Markus Pargmann <mpa@pengutronix.de>");
592MODULE_LICENSE("GPL v2");
593