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 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 for (i = end_step - ts_dev->coordinate_readouts; i < end_step; i++) {
154 titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
155 titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
156 }
157
158 config = 0;
159 config = STEPCONFIG_MODE_HWSYNC |
160 STEPCONFIG_AVG_16 | ts_dev->bit_yn |
161 STEPCONFIG_INM_ADCREFM;
162 switch (ts_dev->wires) {
163 case 4:
164 config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
165 break;
166 case 5:
167 config |= ts_dev->bit_xp | STEPCONFIG_INP_AN4 |
168 STEPCONFIG_XNP | STEPCONFIG_YPN;
169 break;
170 case 8:
171 config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
172 break;
173 }
174
175 /* 1 ... coordinate_readouts is for Y */
176 end_step = first_step + ts_dev->coordinate_readouts;
177 for (i = first_step; i < end_step; i++) {
178 titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
179 titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
180 }
181
182 /* Make CHARGECONFIG same as IDLECONFIG */
183
184 config = titsc_readl(ts_dev, REG_IDLECONFIG);
185 titsc_writel(ts_dev, REG_CHARGECONFIG, config);
186 titsc_writel(ts_dev, REG_CHARGEDELAY, ts_dev->charge_delay);
187
188 /* coordinate_readouts + 1 ... coordinate_readouts + 2 is for Z */
189 config = STEPCONFIG_MODE_HWSYNC |
190 STEPCONFIG_AVG_16 | ts_dev->bit_yp |
191 ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM |
192 STEPCONFIG_INP(ts_dev->inp_xp);
193 titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
194 titsc_writel(ts_dev, REG_STEPDELAY(end_step),
195 STEPCONFIG_OPENDLY);
196
197 end_step++;
198 config |= STEPCONFIG_INP(ts_dev->inp_yn);
199 titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
200 titsc_writel(ts_dev, REG_STEPDELAY(end_step),
201 STEPCONFIG_OPENDLY);
202
203 /* The steps end ... end - readouts * 2 + 2 and bit 0 for TS_Charge */
204 stepenable = 1;
205 for (i = 0; i < tsc_steps; i++)
206 stepenable |= 1 << (first_step + i + 1);
207
208 ts_dev->step_mask = stepenable;
209 am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask);
210 }
211
titsc_cmp_coord(const void * a,const void * b)212 static int titsc_cmp_coord(const void *a, const void *b)
213 {
214 return *(int *)a - *(int *)b;
215 }
216
titsc_read_coordinates(struct titsc * ts_dev,u32 * x,u32 * y,u32 * z1,u32 * z2)217 static void titsc_read_coordinates(struct titsc *ts_dev,
218 u32 *x, u32 *y, u32 *z1, u32 *z2)
219 {
220 unsigned int yvals[7], xvals[7];
221 unsigned int i, xsum = 0, ysum = 0;
222 unsigned int creads = ts_dev->coordinate_readouts;
223
224 for (i = 0; i < creads; i++) {
225 yvals[i] = titsc_readl(ts_dev, REG_FIFO0);
226 yvals[i] &= 0xfff;
227 }
228
229 *z1 = titsc_readl(ts_dev, REG_FIFO0);
230 *z1 &= 0xfff;
231 *z2 = titsc_readl(ts_dev, REG_FIFO0);
232 *z2 &= 0xfff;
233
234 for (i = 0; i < creads; i++) {
235 xvals[i] = titsc_readl(ts_dev, REG_FIFO0);
236 xvals[i] &= 0xfff;
237 }
238
239 /*
240 * If co-ordinates readouts is less than 4 then
241 * report the average. In case of 4 or more
242 * readouts, sort the co-ordinate samples, drop
243 * min and max values and report the average of
244 * remaining values.
245 */
246 if (creads <= 3) {
247 for (i = 0; i < creads; i++) {
248 ysum += yvals[i];
249 xsum += xvals[i];
250 }
251 ysum /= creads;
252 xsum /= creads;
253 } else {
254 sort(yvals, creads, sizeof(unsigned int),
255 titsc_cmp_coord, NULL);
256 sort(xvals, creads, sizeof(unsigned int),
257 titsc_cmp_coord, NULL);
258 for (i = 1; i < creads - 1; i++) {
259 ysum += yvals[i];
260 xsum += xvals[i];
261 }
262 ysum /= creads - 2;
263 xsum /= creads - 2;
264 }
265 *y = ysum;
266 *x = xsum;
267 }
268
titsc_irq(int irq,void * dev)269 static irqreturn_t titsc_irq(int irq, void *dev)
270 {
271 struct titsc *ts_dev = dev;
272 struct input_dev *input_dev = ts_dev->input;
273 unsigned int fsm, status, irqclr = 0;
274 unsigned int x = 0, y = 0;
275 unsigned int z1, z2, z;
276
277 status = titsc_readl(ts_dev, REG_RAWIRQSTATUS);
278 if (status & IRQENB_HW_PEN) {
279 ts_dev->pen_down = true;
280 irqclr |= IRQENB_HW_PEN;
281 pm_stay_awake(ts_dev->dev);
282 }
283
284 if (status & IRQENB_PENUP) {
285 fsm = titsc_readl(ts_dev, REG_ADCFSM);
286 if (fsm == ADCFSM_STEPID) {
287 ts_dev->pen_down = false;
288 input_report_key(input_dev, BTN_TOUCH, 0);
289 input_report_abs(input_dev, ABS_PRESSURE, 0);
290 input_sync(input_dev);
291 pm_relax(ts_dev->dev);
292 } else {
293 ts_dev->pen_down = true;
294 }
295 irqclr |= IRQENB_PENUP;
296 }
297
298 if (status & IRQENB_EOS)
299 irqclr |= IRQENB_EOS;
300
301 /*
302 * ADC and touchscreen share the IRQ line.
303 * FIFO1 interrupts are used by ADC. Handle FIFO0 IRQs here only
304 */
305 if (status & IRQENB_FIFO0THRES) {
306
307 titsc_read_coordinates(ts_dev, &x, &y, &z1, &z2);
308
309 if (ts_dev->pen_down && z1 != 0 && z2 != 0) {
310 /*
311 * Calculate pressure using formula
312 * Resistance(touch) = x plate resistance *
313 * x postion/4096 * ((z2 / z1) - 1)
314 */
315 z = z1 - z2;
316 z *= x;
317 z *= ts_dev->x_plate_resistance;
318 z /= z2;
319 z = (z + 2047) >> 12;
320
321 if (z <= MAX_12BIT) {
322 input_report_abs(input_dev, ABS_X, x);
323 input_report_abs(input_dev, ABS_Y, y);
324 input_report_abs(input_dev, ABS_PRESSURE, z);
325 input_report_key(input_dev, BTN_TOUCH, 1);
326 input_sync(input_dev);
327 }
328 }
329 irqclr |= IRQENB_FIFO0THRES;
330 }
331 if (irqclr) {
332 titsc_writel(ts_dev, REG_IRQSTATUS, irqclr);
333 if (status & IRQENB_EOS)
334 am335x_tsc_se_set_cache(ts_dev->mfd_tscadc,
335 ts_dev->step_mask);
336 return IRQ_HANDLED;
337 }
338 return IRQ_NONE;
339 }
340
titsc_parse_dt(struct platform_device * pdev,struct titsc * ts_dev)341 static int titsc_parse_dt(struct platform_device *pdev,
342 struct titsc *ts_dev)
343 {
344 struct device_node *node = pdev->dev.of_node;
345 int err;
346
347 if (!node)
348 return -EINVAL;
349
350 err = of_property_read_u32(node, "ti,wires", &ts_dev->wires);
351 if (err < 0)
352 return err;
353 switch (ts_dev->wires) {
354 case 4:
355 case 5:
356 case 8:
357 break;
358 default:
359 return -EINVAL;
360 }
361
362 err = of_property_read_u32(node, "ti,x-plate-resistance",
363 &ts_dev->x_plate_resistance);
364 if (err < 0)
365 return err;
366
367 /*
368 * Try with the new binding first. If it fails, try again with
369 * bogus, miss-spelled version.
370 */
371 err = of_property_read_u32(node, "ti,coordinate-readouts",
372 &ts_dev->coordinate_readouts);
373 if (err < 0) {
374 dev_warn(&pdev->dev, "please use 'ti,coordinate-readouts' instead\n");
375 err = of_property_read_u32(node, "ti,coordiante-readouts",
376 &ts_dev->coordinate_readouts);
377 }
378
379 if (err < 0)
380 return err;
381
382 if (ts_dev->coordinate_readouts <= 0) {
383 dev_warn(&pdev->dev,
384 "invalid co-ordinate readouts, resetting it to 5\n");
385 ts_dev->coordinate_readouts = 5;
386 }
387
388 err = of_property_read_u32(node, "ti,charge-delay",
389 &ts_dev->charge_delay);
390 /*
391 * If ti,charge-delay value is not specified, then use
392 * CHARGEDLY_OPENDLY as the default value.
393 */
394 if (err < 0) {
395 ts_dev->charge_delay = CHARGEDLY_OPENDLY;
396 dev_warn(&pdev->dev, "ti,charge-delay not specified\n");
397 }
398
399 return of_property_read_u32_array(node, "ti,wire-config",
400 ts_dev->config_inp, ARRAY_SIZE(ts_dev->config_inp));
401 }
402
403 /*
404 * The functions for inserting/removing driver as a module.
405 */
406
titsc_probe(struct platform_device * pdev)407 static int titsc_probe(struct platform_device *pdev)
408 {
409 struct titsc *ts_dev;
410 struct input_dev *input_dev;
411 struct ti_tscadc_dev *tscadc_dev = ti_tscadc_dev_get(pdev);
412 int err;
413
414 /* Allocate memory for device */
415 ts_dev = kzalloc(sizeof(*ts_dev), GFP_KERNEL);
416 input_dev = input_allocate_device();
417 if (!ts_dev || !input_dev) {
418 dev_err(&pdev->dev, "failed to allocate memory.\n");
419 err = -ENOMEM;
420 goto err_free_mem;
421 }
422
423 tscadc_dev->tsc = ts_dev;
424 ts_dev->mfd_tscadc = tscadc_dev;
425 ts_dev->input = input_dev;
426 ts_dev->irq = tscadc_dev->irq;
427 ts_dev->dev = &pdev->dev;
428
429 err = titsc_parse_dt(pdev, ts_dev);
430 if (err) {
431 dev_err(&pdev->dev, "Could not find valid DT data.\n");
432 goto err_free_mem;
433 }
434
435 err = request_irq(ts_dev->irq, titsc_irq,
436 IRQF_SHARED, pdev->dev.driver->name, ts_dev);
437 if (err) {
438 dev_err(&pdev->dev, "failed to allocate irq.\n");
439 goto err_free_mem;
440 }
441
442 device_init_wakeup(&pdev->dev, true);
443 err = dev_pm_set_wake_irq(&pdev->dev, ts_dev->irq);
444 if (err)
445 dev_err(&pdev->dev, "irq wake enable failed.\n");
446
447 titsc_writel(ts_dev, REG_IRQSTATUS, TSC_IRQENB_MASK);
448 titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES);
449 titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_EOS);
450 err = titsc_config_wires(ts_dev);
451 if (err) {
452 dev_err(&pdev->dev, "wrong i/p wire configuration\n");
453 goto err_free_irq;
454 }
455 titsc_step_config(ts_dev);
456 titsc_writel(ts_dev, REG_FIFO0THR,
457 ts_dev->coordinate_readouts * 2 + 2 - 1);
458
459 input_dev->name = "ti-tsc";
460 input_dev->dev.parent = &pdev->dev;
461
462 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
463 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
464
465 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
466 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
467 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
468
469 /* register to the input system */
470 err = input_register_device(input_dev);
471 if (err)
472 goto err_free_irq;
473
474 platform_set_drvdata(pdev, ts_dev);
475 return 0;
476
477 err_free_irq:
478 dev_pm_clear_wake_irq(&pdev->dev);
479 device_init_wakeup(&pdev->dev, false);
480 free_irq(ts_dev->irq, ts_dev);
481 err_free_mem:
482 input_free_device(input_dev);
483 kfree(ts_dev);
484 return err;
485 }
486
titsc_remove(struct platform_device * pdev)487 static int titsc_remove(struct platform_device *pdev)
488 {
489 struct titsc *ts_dev = platform_get_drvdata(pdev);
490 u32 steps;
491
492 dev_pm_clear_wake_irq(&pdev->dev);
493 device_init_wakeup(&pdev->dev, false);
494 free_irq(ts_dev->irq, ts_dev);
495
496 /* total steps followed by the enable mask */
497 steps = 2 * ts_dev->coordinate_readouts + 2;
498 steps = (1 << steps) - 1;
499 am335x_tsc_se_clr(ts_dev->mfd_tscadc, steps);
500
501 input_unregister_device(ts_dev->input);
502
503 kfree(ts_dev);
504 return 0;
505 }
506
titsc_suspend(struct device * dev)507 static int __maybe_unused titsc_suspend(struct device *dev)
508 {
509 struct titsc *ts_dev = dev_get_drvdata(dev);
510 unsigned int idle;
511
512 if (device_may_wakeup(dev)) {
513 titsc_writel(ts_dev, REG_IRQSTATUS, TSC_IRQENB_MASK);
514 idle = titsc_readl(ts_dev, REG_IRQENABLE);
515 titsc_writel(ts_dev, REG_IRQENABLE,
516 (idle | IRQENB_HW_PEN));
517 titsc_writel(ts_dev, REG_IRQWAKEUP, IRQWKUP_ENB);
518 }
519 return 0;
520 }
521
titsc_resume(struct device * dev)522 static int __maybe_unused titsc_resume(struct device *dev)
523 {
524 struct titsc *ts_dev = dev_get_drvdata(dev);
525
526 if (device_may_wakeup(dev)) {
527 titsc_writel(ts_dev, REG_IRQWAKEUP,
528 0x00);
529 titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
530 pm_relax(dev);
531 }
532 titsc_step_config(ts_dev);
533 titsc_writel(ts_dev, REG_FIFO0THR,
534 ts_dev->coordinate_readouts * 2 + 2 - 1);
535 return 0;
536 }
537
538 static SIMPLE_DEV_PM_OPS(titsc_pm_ops, titsc_suspend, titsc_resume);
539
540 static const struct of_device_id ti_tsc_dt_ids[] = {
541 { .compatible = "ti,am3359-tsc", },
542 { }
543 };
544 MODULE_DEVICE_TABLE(of, ti_tsc_dt_ids);
545
546 static struct platform_driver ti_tsc_driver = {
547 .probe = titsc_probe,
548 .remove = titsc_remove,
549 .driver = {
550 .name = "TI-am335x-tsc",
551 .pm = &titsc_pm_ops,
552 .of_match_table = ti_tsc_dt_ids,
553 },
554 };
555 module_platform_driver(ti_tsc_driver);
556
557 MODULE_DESCRIPTION("TI touchscreen controller driver");
558 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
559 MODULE_LICENSE("GPL");
560