1 /*
2 * TI Touch Screen driver
3 *
4 * Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation version 2.
9 *
10 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
11 * kind, whether express or implied; without even the implied warranty
12 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 */
15
16
17 #include <linux/kernel.h>
18 #include <linux/err.h>
19 #include <linux/module.h>
20 #include <linux/input.h>
21 #include <linux/slab.h>
22 #include <linux/interrupt.h>
23 #include <linux/clk.h>
24 #include <linux/platform_device.h>
25 #include <linux/io.h>
26 #include <linux/delay.h>
27 #include <linux/of.h>
28 #include <linux/sort.h>
29 #include <linux/pm_wakeirq.h>
30
31 #include <linux/mfd/ti_am335x_tscadc.h>
32
33 #define ADCFSM_STEPID 0x10
34 #define SEQ_SETTLE 275
35 #define MAX_12BIT ((1 << 12) - 1)
36
37 #define TSC_IRQENB_MASK (IRQENB_FIFO0THRES | IRQENB_EOS | IRQENB_HW_PEN)
38
39 static const int config_pins[] = {
40 STEPCONFIG_XPP,
41 STEPCONFIG_XNN,
42 STEPCONFIG_YPP,
43 STEPCONFIG_YNN,
44 };
45
46 struct titsc {
47 struct input_dev *input;
48 struct ti_tscadc_dev *mfd_tscadc;
49 struct device *dev;
50 unsigned int irq;
51 unsigned int wires;
52 unsigned int x_plate_resistance;
53 bool pen_down;
54 int coordinate_readouts;
55 u32 config_inp[4];
56 u32 bit_xp, bit_xn, bit_yp, bit_yn;
57 u32 inp_xp, inp_xn, inp_yp, inp_yn;
58 u32 step_mask;
59 u32 charge_delay;
60 };
61
titsc_readl(struct titsc * ts,unsigned int reg)62 static unsigned int titsc_readl(struct titsc *ts, unsigned int reg)
63 {
64 return readl(ts->mfd_tscadc->tscadc_base + reg);
65 }
66
titsc_writel(struct titsc * tsc,unsigned int reg,unsigned int val)67 static void titsc_writel(struct titsc *tsc, unsigned int reg,
68 unsigned int val)
69 {
70 writel(val, tsc->mfd_tscadc->tscadc_base + reg);
71 }
72
titsc_config_wires(struct titsc * ts_dev)73 static int titsc_config_wires(struct titsc *ts_dev)
74 {
75 u32 analog_line[4];
76 u32 wire_order[4];
77 int i, bit_cfg;
78
79 for (i = 0; i < 4; i++) {
80 /*
81 * Get the order in which TSC wires are attached
82 * w.r.t. each of the analog input lines on the EVM.
83 */
84 analog_line[i] = (ts_dev->config_inp[i] & 0xF0) >> 4;
85 wire_order[i] = ts_dev->config_inp[i] & 0x0F;
86 if (WARN_ON(analog_line[i] > 7))
87 return -EINVAL;
88 if (WARN_ON(wire_order[i] > ARRAY_SIZE(config_pins)))
89 return -EINVAL;
90 }
91
92 for (i = 0; i < 4; i++) {
93 int an_line;
94 int wi_order;
95
96 an_line = analog_line[i];
97 wi_order = wire_order[i];
98 bit_cfg = config_pins[wi_order];
99 if (bit_cfg == 0)
100 return -EINVAL;
101 switch (wi_order) {
102 case 0:
103 ts_dev->bit_xp = bit_cfg;
104 ts_dev->inp_xp = an_line;
105 break;
106
107 case 1:
108 ts_dev->bit_xn = bit_cfg;
109 ts_dev->inp_xn = an_line;
110 break;
111
112 case 2:
113 ts_dev->bit_yp = bit_cfg;
114 ts_dev->inp_yp = an_line;
115 break;
116 case 3:
117 ts_dev->bit_yn = bit_cfg;
118 ts_dev->inp_yn = an_line;
119 break;
120 }
121 }
122 return 0;
123 }
124
titsc_step_config(struct titsc * ts_dev)125 static void titsc_step_config(struct titsc *ts_dev)
126 {
127 unsigned int config;
128 int i, n;
129 int end_step, first_step, tsc_steps;
130 u32 stepenable;
131
132 config = STEPCONFIG_MODE_HWSYNC |
133 STEPCONFIG_AVG_16 | ts_dev->bit_xp |
134 STEPCONFIG_INM_ADCREFM;
135 switch (ts_dev->wires) {
136 case 4:
137 config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn;
138 break;
139 case 5:
140 config |= ts_dev->bit_yn |
141 STEPCONFIG_INP_AN4 | ts_dev->bit_xn |
142 ts_dev->bit_yp;
143 break;
144 case 8:
145 config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn;
146 break;
147 }
148
149 tsc_steps = ts_dev->coordinate_readouts * 2 + 2;
150 first_step = TOTAL_STEPS - tsc_steps;
151 /* Steps 16 to 16-coordinate_readouts is for X */
152 end_step = first_step + tsc_steps;
153 n = 0;
154 for (i = end_step - ts_dev->coordinate_readouts; i < end_step; i++) {
155 titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
156 titsc_writel(ts_dev, REG_STEPDELAY(i),
157 n++ == 0 ? STEPCONFIG_OPENDLY : 0);
158 }
159
160 config = 0;
161 config = STEPCONFIG_MODE_HWSYNC |
162 STEPCONFIG_AVG_16 | ts_dev->bit_yn |
163 STEPCONFIG_INM_ADCREFM;
164 switch (ts_dev->wires) {
165 case 4:
166 config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
167 break;
168 case 5:
169 config |= ts_dev->bit_xp | STEPCONFIG_INP_AN4 |
170 STEPCONFIG_XNP | STEPCONFIG_YPN;
171 break;
172 case 8:
173 config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
174 break;
175 }
176
177 /* 1 ... coordinate_readouts is for Y */
178 end_step = first_step + ts_dev->coordinate_readouts;
179 n = 0;
180 for (i = first_step; i < end_step; i++) {
181 titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
182 titsc_writel(ts_dev, REG_STEPDELAY(i),
183 n++ == 0 ? STEPCONFIG_OPENDLY : 0);
184 }
185
186 /* Make CHARGECONFIG same as IDLECONFIG */
187
188 config = titsc_readl(ts_dev, REG_IDLECONFIG);
189 titsc_writel(ts_dev, REG_CHARGECONFIG, config);
190 titsc_writel(ts_dev, REG_CHARGEDELAY, ts_dev->charge_delay);
191
192 /* coordinate_readouts + 1 ... coordinate_readouts + 2 is for Z */
193 config = STEPCONFIG_MODE_HWSYNC |
194 STEPCONFIG_AVG_16 | ts_dev->bit_yp |
195 ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM |
196 STEPCONFIG_INP(ts_dev->inp_xp);
197 titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
198 titsc_writel(ts_dev, REG_STEPDELAY(end_step),
199 STEPCONFIG_OPENDLY);
200
201 end_step++;
202 config = STEPCONFIG_MODE_HWSYNC |
203 STEPCONFIG_AVG_16 | ts_dev->bit_yp |
204 ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM |
205 STEPCONFIG_INP(ts_dev->inp_yn);
206 titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
207 titsc_writel(ts_dev, REG_STEPDELAY(end_step),
208 STEPCONFIG_OPENDLY);
209
210 /* The steps end ... end - readouts * 2 + 2 and bit 0 for TS_Charge */
211 stepenable = 1;
212 for (i = 0; i < tsc_steps; i++)
213 stepenable |= 1 << (first_step + i + 1);
214
215 ts_dev->step_mask = stepenable;
216 am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask);
217 }
218
titsc_cmp_coord(const void * a,const void * b)219 static int titsc_cmp_coord(const void *a, const void *b)
220 {
221 return *(int *)a - *(int *)b;
222 }
223
titsc_read_coordinates(struct titsc * ts_dev,u32 * x,u32 * y,u32 * z1,u32 * z2)224 static void titsc_read_coordinates(struct titsc *ts_dev,
225 u32 *x, u32 *y, u32 *z1, u32 *z2)
226 {
227 unsigned int yvals[7], xvals[7];
228 unsigned int i, xsum = 0, ysum = 0;
229 unsigned int creads = ts_dev->coordinate_readouts;
230
231 for (i = 0; i < creads; i++) {
232 yvals[i] = titsc_readl(ts_dev, REG_FIFO0);
233 yvals[i] &= 0xfff;
234 }
235
236 *z1 = titsc_readl(ts_dev, REG_FIFO0);
237 *z1 &= 0xfff;
238 *z2 = titsc_readl(ts_dev, REG_FIFO0);
239 *z2 &= 0xfff;
240
241 for (i = 0; i < creads; i++) {
242 xvals[i] = titsc_readl(ts_dev, REG_FIFO0);
243 xvals[i] &= 0xfff;
244 }
245
246 /*
247 * If co-ordinates readouts is less than 4 then
248 * report the average. In case of 4 or more
249 * readouts, sort the co-ordinate samples, drop
250 * min and max values and report the average of
251 * remaining values.
252 */
253 if (creads <= 3) {
254 for (i = 0; i < creads; i++) {
255 ysum += yvals[i];
256 xsum += xvals[i];
257 }
258 ysum /= creads;
259 xsum /= creads;
260 } else {
261 sort(yvals, creads, sizeof(unsigned int),
262 titsc_cmp_coord, NULL);
263 sort(xvals, creads, sizeof(unsigned int),
264 titsc_cmp_coord, NULL);
265 for (i = 1; i < creads - 1; i++) {
266 ysum += yvals[i];
267 xsum += xvals[i];
268 }
269 ysum /= creads - 2;
270 xsum /= creads - 2;
271 }
272 *y = ysum;
273 *x = xsum;
274 }
275
titsc_irq(int irq,void * dev)276 static irqreturn_t titsc_irq(int irq, void *dev)
277 {
278 struct titsc *ts_dev = dev;
279 struct input_dev *input_dev = ts_dev->input;
280 unsigned int fsm, status, irqclr = 0;
281 unsigned int x = 0, y = 0;
282 unsigned int z1, z2, z;
283
284 status = titsc_readl(ts_dev, REG_RAWIRQSTATUS);
285 if (status & IRQENB_HW_PEN) {
286 ts_dev->pen_down = true;
287 irqclr |= IRQENB_HW_PEN;
288 pm_stay_awake(ts_dev->dev);
289 }
290
291 if (status & IRQENB_PENUP) {
292 fsm = titsc_readl(ts_dev, REG_ADCFSM);
293 if (fsm == ADCFSM_STEPID) {
294 ts_dev->pen_down = false;
295 input_report_key(input_dev, BTN_TOUCH, 0);
296 input_report_abs(input_dev, ABS_PRESSURE, 0);
297 input_sync(input_dev);
298 pm_relax(ts_dev->dev);
299 } else {
300 ts_dev->pen_down = true;
301 }
302 irqclr |= IRQENB_PENUP;
303 }
304
305 if (status & IRQENB_EOS)
306 irqclr |= IRQENB_EOS;
307
308 /*
309 * ADC and touchscreen share the IRQ line.
310 * FIFO1 interrupts are used by ADC. Handle FIFO0 IRQs here only
311 */
312 if (status & IRQENB_FIFO0THRES) {
313
314 titsc_read_coordinates(ts_dev, &x, &y, &z1, &z2);
315
316 if (ts_dev->pen_down && z1 != 0 && z2 != 0) {
317 /*
318 * Calculate pressure using formula
319 * Resistance(touch) = x plate resistance *
320 * x position/4096 * ((z2 / z1) - 1)
321 */
322 z = z1 - z2;
323 z *= x;
324 z *= ts_dev->x_plate_resistance;
325 z /= z2;
326 z = (z + 2047) >> 12;
327
328 if (z <= MAX_12BIT) {
329 input_report_abs(input_dev, ABS_X, x);
330 input_report_abs(input_dev, ABS_Y, y);
331 input_report_abs(input_dev, ABS_PRESSURE, z);
332 input_report_key(input_dev, BTN_TOUCH, 1);
333 input_sync(input_dev);
334 }
335 }
336 irqclr |= IRQENB_FIFO0THRES;
337 }
338 if (irqclr) {
339 titsc_writel(ts_dev, REG_IRQSTATUS, irqclr);
340 if (status & IRQENB_EOS)
341 am335x_tsc_se_set_cache(ts_dev->mfd_tscadc,
342 ts_dev->step_mask);
343 return IRQ_HANDLED;
344 }
345 return IRQ_NONE;
346 }
347
titsc_parse_dt(struct platform_device * pdev,struct titsc * ts_dev)348 static int titsc_parse_dt(struct platform_device *pdev,
349 struct titsc *ts_dev)
350 {
351 struct device_node *node = pdev->dev.of_node;
352 int err;
353
354 if (!node)
355 return -EINVAL;
356
357 err = of_property_read_u32(node, "ti,wires", &ts_dev->wires);
358 if (err < 0)
359 return err;
360 switch (ts_dev->wires) {
361 case 4:
362 case 5:
363 case 8:
364 break;
365 default:
366 return -EINVAL;
367 }
368
369 err = of_property_read_u32(node, "ti,x-plate-resistance",
370 &ts_dev->x_plate_resistance);
371 if (err < 0)
372 return err;
373
374 /*
375 * Try with the new binding first. If it fails, try again with
376 * bogus, miss-spelled version.
377 */
378 err = of_property_read_u32(node, "ti,coordinate-readouts",
379 &ts_dev->coordinate_readouts);
380 if (err < 0) {
381 dev_warn(&pdev->dev, "please use 'ti,coordinate-readouts' instead\n");
382 err = of_property_read_u32(node, "ti,coordiante-readouts",
383 &ts_dev->coordinate_readouts);
384 }
385
386 if (err < 0)
387 return err;
388
389 if (ts_dev->coordinate_readouts <= 0) {
390 dev_warn(&pdev->dev,
391 "invalid co-ordinate readouts, resetting it to 5\n");
392 ts_dev->coordinate_readouts = 5;
393 }
394
395 err = of_property_read_u32(node, "ti,charge-delay",
396 &ts_dev->charge_delay);
397 /*
398 * If ti,charge-delay value is not specified, then use
399 * CHARGEDLY_OPENDLY as the default value.
400 */
401 if (err < 0) {
402 ts_dev->charge_delay = CHARGEDLY_OPENDLY;
403 dev_warn(&pdev->dev, "ti,charge-delay not specified\n");
404 }
405
406 return of_property_read_u32_array(node, "ti,wire-config",
407 ts_dev->config_inp, ARRAY_SIZE(ts_dev->config_inp));
408 }
409
410 /*
411 * The functions for inserting/removing driver as a module.
412 */
413
titsc_probe(struct platform_device * pdev)414 static int titsc_probe(struct platform_device *pdev)
415 {
416 struct titsc *ts_dev;
417 struct input_dev *input_dev;
418 struct ti_tscadc_dev *tscadc_dev = ti_tscadc_dev_get(pdev);
419 int err;
420
421 /* Allocate memory for device */
422 ts_dev = kzalloc(sizeof(*ts_dev), GFP_KERNEL);
423 input_dev = input_allocate_device();
424 if (!ts_dev || !input_dev) {
425 dev_err(&pdev->dev, "failed to allocate memory.\n");
426 err = -ENOMEM;
427 goto err_free_mem;
428 }
429
430 tscadc_dev->tsc = ts_dev;
431 ts_dev->mfd_tscadc = tscadc_dev;
432 ts_dev->input = input_dev;
433 ts_dev->irq = tscadc_dev->irq;
434 ts_dev->dev = &pdev->dev;
435
436 err = titsc_parse_dt(pdev, ts_dev);
437 if (err) {
438 dev_err(&pdev->dev, "Could not find valid DT data.\n");
439 goto err_free_mem;
440 }
441
442 err = request_irq(ts_dev->irq, titsc_irq,
443 IRQF_SHARED, pdev->dev.driver->name, ts_dev);
444 if (err) {
445 dev_err(&pdev->dev, "failed to allocate irq.\n");
446 goto err_free_mem;
447 }
448
449 device_init_wakeup(&pdev->dev, true);
450 err = dev_pm_set_wake_irq(&pdev->dev, ts_dev->irq);
451 if (err)
452 dev_err(&pdev->dev, "irq wake enable failed.\n");
453
454 titsc_writel(ts_dev, REG_IRQSTATUS, TSC_IRQENB_MASK);
455 titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES);
456 titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_EOS);
457 err = titsc_config_wires(ts_dev);
458 if (err) {
459 dev_err(&pdev->dev, "wrong i/p wire configuration\n");
460 goto err_free_irq;
461 }
462 titsc_step_config(ts_dev);
463 titsc_writel(ts_dev, REG_FIFO0THR,
464 ts_dev->coordinate_readouts * 2 + 2 - 1);
465
466 input_dev->name = "ti-tsc";
467 input_dev->dev.parent = &pdev->dev;
468
469 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
470 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
471
472 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
473 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
474 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
475
476 /* register to the input system */
477 err = input_register_device(input_dev);
478 if (err)
479 goto err_free_irq;
480
481 platform_set_drvdata(pdev, ts_dev);
482 return 0;
483
484 err_free_irq:
485 dev_pm_clear_wake_irq(&pdev->dev);
486 device_init_wakeup(&pdev->dev, false);
487 free_irq(ts_dev->irq, ts_dev);
488 err_free_mem:
489 input_free_device(input_dev);
490 kfree(ts_dev);
491 return err;
492 }
493
titsc_remove(struct platform_device * pdev)494 static int titsc_remove(struct platform_device *pdev)
495 {
496 struct titsc *ts_dev = platform_get_drvdata(pdev);
497 u32 steps;
498
499 dev_pm_clear_wake_irq(&pdev->dev);
500 device_init_wakeup(&pdev->dev, false);
501 free_irq(ts_dev->irq, ts_dev);
502
503 /* total steps followed by the enable mask */
504 steps = 2 * ts_dev->coordinate_readouts + 2;
505 steps = (1 << steps) - 1;
506 am335x_tsc_se_clr(ts_dev->mfd_tscadc, steps);
507
508 input_unregister_device(ts_dev->input);
509
510 kfree(ts_dev);
511 return 0;
512 }
513
titsc_suspend(struct device * dev)514 static int titsc_suspend(struct device *dev)
515 {
516 struct titsc *ts_dev = dev_get_drvdata(dev);
517 unsigned int idle;
518
519 if (device_may_wakeup(dev)) {
520 titsc_writel(ts_dev, REG_IRQSTATUS, TSC_IRQENB_MASK);
521 idle = titsc_readl(ts_dev, REG_IRQENABLE);
522 titsc_writel(ts_dev, REG_IRQENABLE,
523 (idle | IRQENB_HW_PEN));
524 titsc_writel(ts_dev, REG_IRQWAKEUP, IRQWKUP_ENB);
525 }
526 return 0;
527 }
528
titsc_resume(struct device * dev)529 static int titsc_resume(struct device *dev)
530 {
531 struct titsc *ts_dev = dev_get_drvdata(dev);
532
533 if (device_may_wakeup(dev)) {
534 titsc_writel(ts_dev, REG_IRQWAKEUP,
535 0x00);
536 titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
537 pm_relax(dev);
538 }
539 titsc_step_config(ts_dev);
540 titsc_writel(ts_dev, REG_FIFO0THR,
541 ts_dev->coordinate_readouts * 2 + 2 - 1);
542 return 0;
543 }
544
545 static DEFINE_SIMPLE_DEV_PM_OPS(titsc_pm_ops, titsc_suspend, titsc_resume);
546
547 static const struct of_device_id ti_tsc_dt_ids[] = {
548 { .compatible = "ti,am3359-tsc", },
549 { }
550 };
551 MODULE_DEVICE_TABLE(of, ti_tsc_dt_ids);
552
553 static struct platform_driver ti_tsc_driver = {
554 .probe = titsc_probe,
555 .remove = titsc_remove,
556 .driver = {
557 .name = "TI-am335x-tsc",
558 .pm = pm_sleep_ptr(&titsc_pm_ops),
559 .of_match_table = ti_tsc_dt_ids,
560 },
561 };
562 module_platform_driver(ti_tsc_driver);
563
564 MODULE_DESCRIPTION("TI touchscreen controller driver");
565 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
566 MODULE_LICENSE("GPL");
567