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 = 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 n = 0;
179 for (i = first_step; i < end_step; i++) {
180 titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
181 titsc_writel(ts_dev, REG_STEPDELAY(i),
182 n++ == 0 ? STEPCONFIG_OPENDLY : 0);
183 }
184
185 /* Make CHARGECONFIG same as IDLECONFIG */
186
187 config = titsc_readl(ts_dev, REG_IDLECONFIG);
188 titsc_writel(ts_dev, REG_CHARGECONFIG, config);
189 titsc_writel(ts_dev, REG_CHARGEDELAY, ts_dev->charge_delay);
190
191 /* coordinate_readouts + 1 ... coordinate_readouts + 2 is for Z */
192 config = STEPCONFIG_MODE_HWSYNC |
193 STEPCONFIG_AVG_16 | ts_dev->bit_yp |
194 ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM |
195 STEPCONFIG_INP(ts_dev->inp_xp);
196 titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
197 titsc_writel(ts_dev, REG_STEPDELAY(end_step),
198 STEPCONFIG_OPENDLY);
199
200 end_step++;
201 config = STEPCONFIG_MODE_HWSYNC |
202 STEPCONFIG_AVG_16 | ts_dev->bit_yp |
203 ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM |
204 STEPCONFIG_INP(ts_dev->inp_yn);
205 titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
206 titsc_writel(ts_dev, REG_STEPDELAY(end_step),
207 STEPCONFIG_OPENDLY);
208
209 /* The steps end ... end - readouts * 2 + 2 and bit 0 for TS_Charge */
210 stepenable = 1;
211 for (i = 0; i < tsc_steps; i++)
212 stepenable |= 1 << (first_step + i + 1);
213
214 ts_dev->step_mask = stepenable;
215 am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask);
216 }
217
titsc_cmp_coord(const void * a,const void * b)218 static int titsc_cmp_coord(const void *a, const void *b)
219 {
220 return *(int *)a - *(int *)b;
221 }
222
titsc_read_coordinates(struct titsc * ts_dev,u32 * x,u32 * y,u32 * z1,u32 * z2)223 static void titsc_read_coordinates(struct titsc *ts_dev,
224 u32 *x, u32 *y, u32 *z1, u32 *z2)
225 {
226 unsigned int yvals[7], xvals[7];
227 unsigned int i, xsum = 0, ysum = 0;
228 unsigned int creads = ts_dev->coordinate_readouts;
229
230 for (i = 0; i < creads; i++) {
231 yvals[i] = titsc_readl(ts_dev, REG_FIFO0);
232 yvals[i] &= 0xfff;
233 }
234
235 *z1 = titsc_readl(ts_dev, REG_FIFO0);
236 *z1 &= 0xfff;
237 *z2 = titsc_readl(ts_dev, REG_FIFO0);
238 *z2 &= 0xfff;
239
240 for (i = 0; i < creads; i++) {
241 xvals[i] = titsc_readl(ts_dev, REG_FIFO0);
242 xvals[i] &= 0xfff;
243 }
244
245 /*
246 * If co-ordinates readouts is less than 4 then
247 * report the average. In case of 4 or more
248 * readouts, sort the co-ordinate samples, drop
249 * min and max values and report the average of
250 * remaining values.
251 */
252 if (creads <= 3) {
253 for (i = 0; i < creads; i++) {
254 ysum += yvals[i];
255 xsum += xvals[i];
256 }
257 ysum /= creads;
258 xsum /= creads;
259 } else {
260 sort(yvals, creads, sizeof(unsigned int),
261 titsc_cmp_coord, NULL);
262 sort(xvals, creads, sizeof(unsigned int),
263 titsc_cmp_coord, NULL);
264 for (i = 1; i < creads - 1; i++) {
265 ysum += yvals[i];
266 xsum += xvals[i];
267 }
268 ysum /= creads - 2;
269 xsum /= creads - 2;
270 }
271 *y = ysum;
272 *x = xsum;
273 }
274
titsc_irq(int irq,void * dev)275 static irqreturn_t titsc_irq(int irq, void *dev)
276 {
277 struct titsc *ts_dev = dev;
278 struct input_dev *input_dev = ts_dev->input;
279 unsigned int fsm, status, irqclr = 0;
280 unsigned int x = 0, y = 0;
281 unsigned int z1, z2, z;
282
283 status = titsc_readl(ts_dev, REG_RAWIRQSTATUS);
284 if (status & IRQENB_HW_PEN) {
285 ts_dev->pen_down = true;
286 irqclr |= IRQENB_HW_PEN;
287 pm_stay_awake(ts_dev->dev);
288 }
289
290 if (status & IRQENB_PENUP) {
291 fsm = titsc_readl(ts_dev, REG_ADCFSM);
292 if (fsm == ADCFSM_STEPID) {
293 ts_dev->pen_down = false;
294 input_report_key(input_dev, BTN_TOUCH, 0);
295 input_report_abs(input_dev, ABS_PRESSURE, 0);
296 input_sync(input_dev);
297 pm_relax(ts_dev->dev);
298 } else {
299 ts_dev->pen_down = true;
300 }
301 irqclr |= IRQENB_PENUP;
302 }
303
304 if (status & IRQENB_EOS)
305 irqclr |= IRQENB_EOS;
306
307 /*
308 * ADC and touchscreen share the IRQ line.
309 * FIFO1 interrupts are used by ADC. Handle FIFO0 IRQs here only
310 */
311 if (status & IRQENB_FIFO0THRES) {
312
313 titsc_read_coordinates(ts_dev, &x, &y, &z1, &z2);
314
315 if (ts_dev->pen_down && z1 != 0 && z2 != 0) {
316 /*
317 * Calculate pressure using formula
318 * Resistance(touch) = x plate resistance *
319 * x position/4096 * ((z2 / z1) - 1)
320 */
321 z = z1 - z2;
322 z *= x;
323 z *= ts_dev->x_plate_resistance;
324 z /= z2;
325 z = (z + 2047) >> 12;
326
327 if (z <= MAX_12BIT) {
328 input_report_abs(input_dev, ABS_X, x);
329 input_report_abs(input_dev, ABS_Y, y);
330 input_report_abs(input_dev, ABS_PRESSURE, z);
331 input_report_key(input_dev, BTN_TOUCH, 1);
332 input_sync(input_dev);
333 }
334 }
335 irqclr |= IRQENB_FIFO0THRES;
336 }
337 if (irqclr) {
338 titsc_writel(ts_dev, REG_IRQSTATUS, irqclr);
339 if (status & IRQENB_EOS)
340 am335x_tsc_se_set_cache(ts_dev->mfd_tscadc,
341 ts_dev->step_mask);
342 return IRQ_HANDLED;
343 }
344 return IRQ_NONE;
345 }
346
titsc_parse_dt(struct platform_device * pdev,struct titsc * ts_dev)347 static int titsc_parse_dt(struct platform_device *pdev,
348 struct titsc *ts_dev)
349 {
350 struct device_node *node = pdev->dev.of_node;
351 int err;
352
353 if (!node)
354 return -EINVAL;
355
356 err = of_property_read_u32(node, "ti,wires", &ts_dev->wires);
357 if (err < 0)
358 return err;
359 switch (ts_dev->wires) {
360 case 4:
361 case 5:
362 case 8:
363 break;
364 default:
365 return -EINVAL;
366 }
367
368 err = of_property_read_u32(node, "ti,x-plate-resistance",
369 &ts_dev->x_plate_resistance);
370 if (err < 0)
371 return err;
372
373 /*
374 * Try with the new binding first. If it fails, try again with
375 * bogus, miss-spelled version.
376 */
377 err = of_property_read_u32(node, "ti,coordinate-readouts",
378 &ts_dev->coordinate_readouts);
379 if (err < 0) {
380 dev_warn(&pdev->dev, "please use 'ti,coordinate-readouts' instead\n");
381 err = of_property_read_u32(node, "ti,coordiante-readouts",
382 &ts_dev->coordinate_readouts);
383 }
384
385 if (err < 0)
386 return err;
387
388 if (ts_dev->coordinate_readouts <= 0) {
389 dev_warn(&pdev->dev,
390 "invalid co-ordinate readouts, resetting it to 5\n");
391 ts_dev->coordinate_readouts = 5;
392 }
393
394 err = of_property_read_u32(node, "ti,charge-delay",
395 &ts_dev->charge_delay);
396 /*
397 * If ti,charge-delay value is not specified, then use
398 * CHARGEDLY_OPENDLY as the default value.
399 */
400 if (err < 0) {
401 ts_dev->charge_delay = CHARGEDLY_OPENDLY;
402 dev_warn(&pdev->dev, "ti,charge-delay not specified\n");
403 }
404
405 return of_property_read_u32_array(node, "ti,wire-config",
406 ts_dev->config_inp, ARRAY_SIZE(ts_dev->config_inp));
407 }
408
409 /*
410 * The functions for inserting/removing driver as a module.
411 */
412
titsc_probe(struct platform_device * pdev)413 static int titsc_probe(struct platform_device *pdev)
414 {
415 struct titsc *ts_dev;
416 struct input_dev *input_dev;
417 struct ti_tscadc_dev *tscadc_dev = ti_tscadc_dev_get(pdev);
418 int err;
419
420 /* Allocate memory for device */
421 ts_dev = kzalloc(sizeof(*ts_dev), GFP_KERNEL);
422 input_dev = input_allocate_device();
423 if (!ts_dev || !input_dev) {
424 dev_err(&pdev->dev, "failed to allocate memory.\n");
425 err = -ENOMEM;
426 goto err_free_mem;
427 }
428
429 tscadc_dev->tsc = ts_dev;
430 ts_dev->mfd_tscadc = tscadc_dev;
431 ts_dev->input = input_dev;
432 ts_dev->irq = tscadc_dev->irq;
433 ts_dev->dev = &pdev->dev;
434
435 err = titsc_parse_dt(pdev, ts_dev);
436 if (err) {
437 dev_err(&pdev->dev, "Could not find valid DT data.\n");
438 goto err_free_mem;
439 }
440
441 err = request_irq(ts_dev->irq, titsc_irq,
442 IRQF_SHARED, pdev->dev.driver->name, ts_dev);
443 if (err) {
444 dev_err(&pdev->dev, "failed to allocate irq.\n");
445 goto err_free_mem;
446 }
447
448 device_init_wakeup(&pdev->dev, true);
449 err = dev_pm_set_wake_irq(&pdev->dev, ts_dev->irq);
450 if (err)
451 dev_err(&pdev->dev, "irq wake enable failed.\n");
452
453 titsc_writel(ts_dev, REG_IRQSTATUS, TSC_IRQENB_MASK);
454 titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES);
455 titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_EOS);
456 err = titsc_config_wires(ts_dev);
457 if (err) {
458 dev_err(&pdev->dev, "wrong i/p wire configuration\n");
459 goto err_free_irq;
460 }
461 titsc_step_config(ts_dev);
462 titsc_writel(ts_dev, REG_FIFO0THR,
463 ts_dev->coordinate_readouts * 2 + 2 - 1);
464
465 input_dev->name = "ti-tsc";
466 input_dev->dev.parent = &pdev->dev;
467
468 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
469 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
470
471 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
472 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
473 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
474
475 /* register to the input system */
476 err = input_register_device(input_dev);
477 if (err)
478 goto err_free_irq;
479
480 platform_set_drvdata(pdev, ts_dev);
481 return 0;
482
483 err_free_irq:
484 dev_pm_clear_wake_irq(&pdev->dev);
485 device_init_wakeup(&pdev->dev, false);
486 free_irq(ts_dev->irq, ts_dev);
487 err_free_mem:
488 input_free_device(input_dev);
489 kfree(ts_dev);
490 return err;
491 }
492
titsc_remove(struct platform_device * pdev)493 static void titsc_remove(struct platform_device *pdev)
494 {
495 struct titsc *ts_dev = platform_get_drvdata(pdev);
496 u32 steps;
497
498 dev_pm_clear_wake_irq(&pdev->dev);
499 device_init_wakeup(&pdev->dev, false);
500 free_irq(ts_dev->irq, ts_dev);
501
502 /* total steps followed by the enable mask */
503 steps = 2 * ts_dev->coordinate_readouts + 2;
504 steps = (1 << steps) - 1;
505 am335x_tsc_se_clr(ts_dev->mfd_tscadc, steps);
506
507 input_unregister_device(ts_dev->input);
508
509 kfree(ts_dev);
510 }
511
titsc_suspend(struct device * dev)512 static int titsc_suspend(struct device *dev)
513 {
514 struct titsc *ts_dev = dev_get_drvdata(dev);
515 unsigned int idle;
516
517 if (device_may_wakeup(dev)) {
518 titsc_writel(ts_dev, REG_IRQSTATUS, TSC_IRQENB_MASK);
519 idle = titsc_readl(ts_dev, REG_IRQENABLE);
520 titsc_writel(ts_dev, REG_IRQENABLE,
521 (idle | IRQENB_HW_PEN));
522 titsc_writel(ts_dev, REG_IRQWAKEUP, IRQWKUP_ENB);
523 }
524 return 0;
525 }
526
titsc_resume(struct device * dev)527 static int titsc_resume(struct device *dev)
528 {
529 struct titsc *ts_dev = dev_get_drvdata(dev);
530
531 if (device_may_wakeup(dev)) {
532 titsc_writel(ts_dev, REG_IRQWAKEUP,
533 0x00);
534 titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
535 pm_relax(dev);
536 }
537 titsc_step_config(ts_dev);
538 titsc_writel(ts_dev, REG_FIFO0THR,
539 ts_dev->coordinate_readouts * 2 + 2 - 1);
540 return 0;
541 }
542
543 static DEFINE_SIMPLE_DEV_PM_OPS(titsc_pm_ops, titsc_suspend, titsc_resume);
544
545 static const struct of_device_id ti_tsc_dt_ids[] = {
546 { .compatible = "ti,am3359-tsc", },
547 { }
548 };
549 MODULE_DEVICE_TABLE(of, ti_tsc_dt_ids);
550
551 static struct platform_driver ti_tsc_driver = {
552 .probe = titsc_probe,
553 .remove_new = titsc_remove,
554 .driver = {
555 .name = "TI-am335x-tsc",
556 .pm = pm_sleep_ptr(&titsc_pm_ops),
557 .of_match_table = ti_tsc_dt_ids,
558 },
559 };
560 module_platform_driver(ti_tsc_driver);
561
562 MODULE_DESCRIPTION("TI touchscreen controller driver");
563 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
564 MODULE_LICENSE("GPL");
565