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