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
39static const int config_pins[] = {
40 STEPCONFIG_XPP,
41 STEPCONFIG_XNN,
42 STEPCONFIG_YPP,
43 STEPCONFIG_YNN,
44};
45
46struct 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
62static unsigned int titsc_readl(struct titsc *ts, unsigned int reg)
63{
64 return readl(addr: ts->mfd_tscadc->tscadc_base + reg);
65}
66
67static void titsc_writel(struct titsc *tsc, unsigned int reg,
68 unsigned int val)
69{
70 writel(val, addr: tsc->mfd_tscadc->tscadc_base + reg);
71}
72
73static 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
125static 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(tsc: ts_dev, REG_STEPCONFIG(i), val: config);
156 titsc_writel(tsc: ts_dev, REG_STEPDELAY(i),
157 val: 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(tsc: ts_dev, REG_STEPCONFIG(i), val: config);
182 titsc_writel(tsc: ts_dev, REG_STEPDELAY(i),
183 val: n++ == 0 ? STEPCONFIG_OPENDLY : 0);
184 }
185
186 /* Make CHARGECONFIG same as IDLECONFIG */
187
188 config = titsc_readl(ts: ts_dev, REG_IDLECONFIG);
189 titsc_writel(tsc: ts_dev, REG_CHARGECONFIG, val: config);
190 titsc_writel(tsc: ts_dev, REG_CHARGEDELAY, val: 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(tsc: ts_dev, REG_STEPCONFIG(end_step), val: config);
198 titsc_writel(tsc: 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(tsc: ts_dev, REG_STEPCONFIG(end_step), val: config);
207 titsc_writel(tsc: 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(tsadc: ts_dev->mfd_tscadc, val: ts_dev->step_mask);
217}
218
219static int titsc_cmp_coord(const void *a, const void *b)
220{
221 return *(int *)a - *(int *)b;
222}
223
224static 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: ts_dev, REG_FIFO0);
233 yvals[i] &= 0xfff;
234 }
235
236 *z1 = titsc_readl(ts: ts_dev, REG_FIFO0);
237 *z1 &= 0xfff;
238 *z2 = titsc_readl(ts: ts_dev, REG_FIFO0);
239 *z2 &= 0xfff;
240
241 for (i = 0; i < creads; i++) {
242 xvals[i] = titsc_readl(ts: 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(base: yvals, num: creads, size: sizeof(unsigned int),
262 cmp_func: titsc_cmp_coord, NULL);
263 sort(base: xvals, num: creads, size: sizeof(unsigned int),
264 cmp_func: 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
276static 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: 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(dev: ts_dev->dev);
289 }
290
291 if (status & IRQENB_PENUP) {
292 fsm = titsc_readl(ts: ts_dev, REG_ADCFSM);
293 if (fsm == ADCFSM_STEPID) {
294 ts_dev->pen_down = false;
295 input_report_key(dev: input_dev, BTN_TOUCH, value: 0);
296 input_report_abs(dev: input_dev, ABS_PRESSURE, value: 0);
297 input_sync(dev: input_dev);
298 pm_relax(dev: 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: &x, y: &y, z1: &z1, z2: &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(dev: input_dev, ABS_X, value: x);
330 input_report_abs(dev: input_dev, ABS_Y, value: y);
331 input_report_abs(dev: input_dev, ABS_PRESSURE, value: z);
332 input_report_key(dev: input_dev, BTN_TOUCH, value: 1);
333 input_sync(dev: input_dev);
334 }
335 }
336 irqclr |= IRQENB_FIFO0THRES;
337 }
338 if (irqclr) {
339 titsc_writel(tsc: ts_dev, REG_IRQSTATUS, val: irqclr);
340 if (status & IRQENB_EOS)
341 am335x_tsc_se_set_cache(tsadc: ts_dev->mfd_tscadc,
342 val: ts_dev->step_mask);
343 return IRQ_HANDLED;
344 }
345 return IRQ_NONE;
346}
347
348static 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(np: node, propname: "ti,wires", out_value: &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(np: node, propname: "ti,x-plate-resistance",
370 out_value: &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(np: node, propname: "ti,coordinate-readouts",
379 out_value: &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(np: node, propname: "ti,coordiante-readouts",
383 out_value: &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(np: node, propname: "ti,charge-delay",
396 out_value: &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(np: node, propname: "ti,wire-config",
407 out_values: 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
414static 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(p: pdev);
419 int err;
420
421 /* Allocate memory for device */
422 ts_dev = kzalloc(size: 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(irq: ts_dev->irq, handler: titsc_irq,
443 IRQF_SHARED, name: pdev->dev.driver->name, dev: 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(dev: &pdev->dev, enable: true);
450 err = dev_pm_set_wake_irq(dev: &pdev->dev, irq: ts_dev->irq);
451 if (err)
452 dev_err(&pdev->dev, "irq wake enable failed.\n");
453
454 titsc_writel(tsc: ts_dev, REG_IRQSTATUS, TSC_IRQENB_MASK);
455 titsc_writel(tsc: ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES);
456 titsc_writel(tsc: 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(tsc: ts_dev, REG_FIFO0THR,
464 val: 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(dev: input_dev, ABS_X, min: 0, MAX_12BIT, fuzz: 0, flat: 0);
473 input_set_abs_params(dev: input_dev, ABS_Y, min: 0, MAX_12BIT, fuzz: 0, flat: 0);
474 input_set_abs_params(dev: input_dev, ABS_PRESSURE, min: 0, MAX_12BIT, fuzz: 0, flat: 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, data: ts_dev);
482 return 0;
483
484err_free_irq:
485 dev_pm_clear_wake_irq(dev: &pdev->dev);
486 device_init_wakeup(dev: &pdev->dev, enable: false);
487 free_irq(ts_dev->irq, ts_dev);
488err_free_mem:
489 input_free_device(dev: input_dev);
490 kfree(objp: ts_dev);
491 return err;
492}
493
494static 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(dev: &pdev->dev);
500 device_init_wakeup(dev: &pdev->dev, enable: 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(tsadc: ts_dev->mfd_tscadc, val: steps);
507
508 input_unregister_device(ts_dev->input);
509
510 kfree(objp: ts_dev);
511 return 0;
512}
513
514static 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(tsc: ts_dev, REG_IRQSTATUS, TSC_IRQENB_MASK);
521 idle = titsc_readl(ts: ts_dev, REG_IRQENABLE);
522 titsc_writel(tsc: ts_dev, REG_IRQENABLE,
523 val: (idle | IRQENB_HW_PEN));
524 titsc_writel(tsc: ts_dev, REG_IRQWAKEUP, IRQWKUP_ENB);
525 }
526 return 0;
527}
528
529static 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(tsc: ts_dev, REG_IRQWAKEUP,
535 val: 0x00);
536 titsc_writel(tsc: ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
537 pm_relax(dev);
538 }
539 titsc_step_config(ts_dev);
540 titsc_writel(tsc: ts_dev, REG_FIFO0THR,
541 val: ts_dev->coordinate_readouts * 2 + 2 - 1);
542 return 0;
543}
544
545static DEFINE_SIMPLE_DEV_PM_OPS(titsc_pm_ops, titsc_suspend, titsc_resume);
546
547static const struct of_device_id ti_tsc_dt_ids[] = {
548 { .compatible = "ti,am3359-tsc", },
549 { }
550};
551MODULE_DEVICE_TABLE(of, ti_tsc_dt_ids);
552
553static 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};
562module_platform_driver(ti_tsc_driver);
563
564MODULE_DESCRIPTION("TI touchscreen controller driver");
565MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
566MODULE_LICENSE("GPL");
567

source code of linux/drivers/input/touchscreen/ti_am335x_tsc.c