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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
30#include <linux/mfd/ti_am335x_tscadc.h>
31
32#define ADCFSM_STEPID 0x10
33#define SEQ_SETTLE 275
34#define MAX_12BIT ((1 << 12) - 1)
35
36static const int config_pins[] = {
37 STEPCONFIG_XPP,
38 STEPCONFIG_XNN,
39 STEPCONFIG_YPP,
40 STEPCONFIG_YNN,
41};
42
43struct titsc {
44 struct input_dev *input;
45 struct ti_tscadc_dev *mfd_tscadc;
46 unsigned int irq;
47 unsigned int wires;
48 unsigned int x_plate_resistance;
49 bool pen_down;
50 int coordinate_readouts;
51 u32 config_inp[4];
52 u32 bit_xp, bit_xn, bit_yp, bit_yn;
53 u32 inp_xp, inp_xn, inp_yp, inp_yn;
54 u32 step_mask;
55};
56
57static unsigned int titsc_readl(struct titsc *ts, unsigned int reg)
58{
59 return readl(ts->mfd_tscadc->tscadc_base + reg);
60}
61
62static void titsc_writel(struct titsc *tsc, unsigned int reg,
63 unsigned int val)
64{
65 writel(val, tsc->mfd_tscadc->tscadc_base + reg);
66}
67
68static int titsc_config_wires(struct titsc *ts_dev)
69{
70 u32 analog_line[4];
71 u32 wire_order[4];
72 int i, bit_cfg;
73
74 for (i = 0; i < 4; i++) {
75 /*
76 * Get the order in which TSC wires are attached
77 * w.r.t. each of the analog input lines on the EVM.
78 */
79 analog_line[i] = (ts_dev->config_inp[i] & 0xF0) >> 4;
80 wire_order[i] = ts_dev->config_inp[i] & 0x0F;
81 if (WARN_ON(analog_line[i] > 7))
82 return -EINVAL;
83 if (WARN_ON(wire_order[i] > ARRAY_SIZE(config_pins)))
84 return -EINVAL;
85 }
86
87 for (i = 0; i < 4; i++) {
88 int an_line;
89 int wi_order;
90
91 an_line = analog_line[i];
92 wi_order = wire_order[i];
93 bit_cfg = config_pins[wi_order];
94 if (bit_cfg == 0)
95 return -EINVAL;
96 switch (wi_order) {
97 case 0:
98 ts_dev->bit_xp = bit_cfg;
99 ts_dev->inp_xp = an_line;
100 break;
101
102 case 1:
103 ts_dev->bit_xn = bit_cfg;
104 ts_dev->inp_xn = an_line;
105 break;
106
107 case 2:
108 ts_dev->bit_yp = bit_cfg;
109 ts_dev->inp_yp = an_line;
110 break;
111 case 3:
112 ts_dev->bit_yn = bit_cfg;
113 ts_dev->inp_yn = an_line;
114 break;
115 }
116 }
117 return 0;
118}
119
120static void titsc_step_config(struct titsc *ts_dev)
121{
122 unsigned int config;
123 int i;
124 int end_step;
125 u32 stepenable;
126
127 config = STEPCONFIG_MODE_HWSYNC |
128 STEPCONFIG_AVG_16 | ts_dev->bit_xp;
129 switch (ts_dev->wires) {
130 case 4:
131 config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn;
132 break;
133 case 5:
134 config |= ts_dev->bit_yn |
135 STEPCONFIG_INP_AN4 | ts_dev->bit_xn |
136 ts_dev->bit_yp;
137 break;
138 case 8:
139 config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn;
140 break;
141 }
142
143 /* 1 … coordinate_readouts is for X */
144 end_step = ts_dev->coordinate_readouts;
145 for (i = 0; i < end_step; i++) {
146 titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
147 titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
148 }
149
150 config = 0;
151 config = STEPCONFIG_MODE_HWSYNC |
152 STEPCONFIG_AVG_16 | ts_dev->bit_yn |
153 STEPCONFIG_INM_ADCREFM;
154 switch (ts_dev->wires) {
155 case 4:
156 config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
157 break;
158 case 5:
159 config |= ts_dev->bit_xp | STEPCONFIG_INP_AN4 |
160 ts_dev->bit_xn | ts_dev->bit_yp;
161 break;
162 case 8:
163 config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
164 break;
165 }
166
167 /* coordinate_readouts … coordinate_readouts * 2 is for Y */
168 end_step = ts_dev->coordinate_readouts * 2;
169 for (i = ts_dev->coordinate_readouts; i < end_step; i++) {
170 titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
171 titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
172 }
173
174 /* Charge step configuration */
175 config = ts_dev->bit_xp | ts_dev->bit_yn |
176 STEPCHARGE_RFP_XPUL | STEPCHARGE_RFM_XNUR |
177 STEPCHARGE_INM_AN1 | STEPCHARGE_INP(ts_dev->inp_yp);
178
179 titsc_writel(ts_dev, REG_CHARGECONFIG, config);
180 titsc_writel(ts_dev, REG_CHARGEDELAY, CHARGEDLY_OPENDLY);
181
182 /* coordinate_readouts * 2 … coordinate_readouts * 2 + 2 is for Z */
183 config = STEPCONFIG_MODE_HWSYNC |
184 STEPCONFIG_AVG_16 | ts_dev->bit_yp |
185 ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM |
186 STEPCONFIG_INP(ts_dev->inp_xp);
187 titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
188 titsc_writel(ts_dev, REG_STEPDELAY(end_step),
189 STEPCONFIG_OPENDLY);
190
191 end_step++;
192 config |= STEPCONFIG_INP(ts_dev->inp_yn);
193 titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
194 titsc_writel(ts_dev, REG_STEPDELAY(end_step),
195 STEPCONFIG_OPENDLY);
196
197 /* The steps1 … end and bit 0 for TS_Charge */
198 stepenable = (1 << (end_step + 2)) - 1;
199 ts_dev->step_mask = stepenable;
200 am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask);
201}
202
203static void titsc_read_coordinates(struct titsc *ts_dev,
204 u32 *x, u32 *y, u32 *z1, u32 *z2)
205{
206 unsigned int fifocount = titsc_readl(ts_dev, REG_FIFO0CNT);
207 unsigned int prev_val_x = ~0, prev_val_y = ~0;
208 unsigned int prev_diff_x = ~0, prev_diff_y = ~0;
209 unsigned int read, diff;
210 unsigned int i, channel;
211 unsigned int creads = ts_dev->coordinate_readouts;
212
213 *z1 = *z2 = 0;
214 if (fifocount % (creads * 2 + 2))
215 fifocount -= fifocount % (creads * 2 + 2);
216 /*
217 * Delta filter is used to remove large variations in sampled
218 * values from ADC. The filter tries to predict where the next
219 * coordinate could be. This is done by taking a previous
220 * coordinate and subtracting it form current one. Further the
221 * algorithm compares the difference with that of a present value,
222 * if true the value is reported to the sub system.
223 */
224 for (i = 0; i < fifocount; i++) {
225 read = titsc_readl(ts_dev, REG_FIFO0);
226
227 channel = (read & 0xf0000) >> 16;
228 read &= 0xfff;
229 if (channel < creads) {
230 diff = abs(read - prev_val_x);
231 if (diff < prev_diff_x) {
232 prev_diff_x = diff;
233 *x = read;
234 }
235 prev_val_x = read;
236
237 } else if (channel < creads * 2) {
238 diff = abs(read - prev_val_y);
239 if (diff < prev_diff_y) {
240 prev_diff_y = diff;
241 *y = read;
242 }
243 prev_val_y = read;
244
245 } else if (channel < creads * 2 + 1) {
246 *z1 = read;
247
248 } else if (channel < creads * 2 + 2) {
249 *z2 = read;
250 }
251 }
252}
253
254static irqreturn_t titsc_irq(int irq, void *dev)
255{
256 struct titsc *ts_dev = dev;
257 struct input_dev *input_dev = ts_dev->input;
258 unsigned int status, irqclr = 0;
259 unsigned int x = 0, y = 0;
260 unsigned int z1, z2, z;
261 unsigned int fsm;
262
263 status = titsc_readl(ts_dev, REG_IRQSTATUS);
264 /*
265 * ADC and touchscreen share the IRQ line.
266 * FIFO1 interrupts are used by ADC. Handle FIFO0 IRQs here only
267 */
268 if (status & IRQENB_FIFO0THRES) {
269
270 titsc_read_coordinates(ts_dev, &x, &y, &z1, &z2);
271
272 if (ts_dev->pen_down && z1 != 0 && z2 != 0) {
273 /*
274 * Calculate pressure using formula
275 * Resistance(touch) = x plate resistance *
276 * x postion/4096 * ((z2 / z1) - 1)
277 */
278 z = z1 - z2;
279 z *= x;
280 z *= ts_dev->x_plate_resistance;
281 z /= z2;
282 z = (z + 2047) >> 12;
283
284 if (z <= MAX_12BIT) {
285 input_report_abs(input_dev, ABS_X, x);
286 input_report_abs(input_dev, ABS_Y, y);
287 input_report_abs(input_dev, ABS_PRESSURE, z);
288 input_report_key(input_dev, BTN_TOUCH, 1);
289 input_sync(input_dev);
290 }
291 }
292 irqclr |= IRQENB_FIFO0THRES;
293 }
294
295 /*
296 * Time for sequencer to settle, to read
297 * correct state of the sequencer.
298 */
299 udelay(SEQ_SETTLE);
300
301 status = titsc_readl(ts_dev, REG_RAWIRQSTATUS);
302 if (status & IRQENB_PENUP) {
303 /* Pen up event */
304 fsm = titsc_readl(ts_dev, REG_ADCFSM);
305 if (fsm == ADCFSM_STEPID) {
306 ts_dev->pen_down = false;
307 input_report_key(input_dev, BTN_TOUCH, 0);
308 input_report_abs(input_dev, ABS_PRESSURE, 0);
309 input_sync(input_dev);
310 } else {
311 ts_dev->pen_down = true;
312 }
313 irqclr |= IRQENB_PENUP;
314 }
315
316 if (status & IRQENB_HW_PEN) {
317
318 titsc_writel(ts_dev, REG_IRQWAKEUP, 0x00);
319 titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
320 }
321
322 if (irqclr) {
323 titsc_writel(ts_dev, REG_IRQSTATUS, irqclr);
324 am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask);
325 return IRQ_HANDLED;
326 }
327 return IRQ_NONE;
328}
329
330static int titsc_parse_dt(struct platform_device *pdev,
331 struct titsc *ts_dev)
332{
333 struct device_node *node = pdev->dev.of_node;
334 int err;
335
336 if (!node)
337 return -EINVAL;
338
339 err = of_property_read_u32(node, "ti,wires", &ts_dev->wires);
340 if (err < 0)
341 return err;
342 switch (ts_dev->wires) {
343 case 4:
344 case 5:
345 case 8:
346 break;
347 default:
348 return -EINVAL;
349 }
350
351 err = of_property_read_u32(node, "ti,x-plate-resistance",
352 &ts_dev->x_plate_resistance);
353 if (err < 0)
354 return err;
355
356 /*
357 * Try with the new binding first. If it fails, try again with
358 * bogus, miss-spelled version.
359 */
360 err = of_property_read_u32(node, "ti,coordinate-readouts",
361 &ts_dev->coordinate_readouts);
362 if (err < 0)
363 err = of_property_read_u32(node, "ti,coordiante-readouts",
364 &ts_dev->coordinate_readouts);
365 if (err < 0)
366 return err;
367
368 return of_property_read_u32_array(node, "ti,wire-config",
369 ts_dev->config_inp, ARRAY_SIZE(ts_dev->config_inp));
370}
371
372/*
373 * The functions for inserting/removing driver as a module.
374 */
375
376static int titsc_probe(struct platform_device *pdev)
377{
378 struct titsc *ts_dev;
379 struct input_dev *input_dev;
380 struct ti_tscadc_dev *tscadc_dev = ti_tscadc_dev_get(pdev);
381 int err;
382
383 /* Allocate memory for device */
384 ts_dev = kzalloc(sizeof(struct titsc), GFP_KERNEL);
385 input_dev = input_allocate_device();
386 if (!ts_dev || !input_dev) {
387 dev_err(&pdev->dev, "failed to allocate memory.\n");
388 err = -ENOMEM;
389 goto err_free_mem;
390 }
391
392 tscadc_dev->tsc = ts_dev;
393 ts_dev->mfd_tscadc = tscadc_dev;
394 ts_dev->input = input_dev;
395 ts_dev->irq = tscadc_dev->irq;
396
397 err = titsc_parse_dt(pdev, ts_dev);
398 if (err) {
399 dev_err(&pdev->dev, "Could not find valid DT data.\n");
400 goto err_free_mem;
401 }
402
403 err = request_irq(ts_dev->irq, titsc_irq,
404 IRQF_SHARED, pdev->dev.driver->name, ts_dev);
405 if (err) {
406 dev_err(&pdev->dev, "failed to allocate irq.\n");
407 goto err_free_mem;
408 }
409
410 titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES);
411 err = titsc_config_wires(ts_dev);
412 if (err) {
413 dev_err(&pdev->dev, "wrong i/p wire configuration\n");
414 goto err_free_irq;
415 }
416 titsc_step_config(ts_dev);
417 titsc_writel(ts_dev, REG_FIFO0THR,
418 ts_dev->coordinate_readouts * 2 + 2 - 1);
419
420 input_dev->name = "ti-tsc";
421 input_dev->dev.parent = &pdev->dev;
422
423 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
424 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
425
426 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
427 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
428 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
429
430 /* register to the input system */
431 err = input_register_device(input_dev);
432 if (err)
433 goto err_free_irq;
434
435 platform_set_drvdata(pdev, ts_dev);
436 return 0;
437
438err_free_irq:
439 free_irq(ts_dev->irq, ts_dev);
440err_free_mem:
441 input_free_device(input_dev);
442 kfree(ts_dev);
443 return err;
444}
445
446static int titsc_remove(struct platform_device *pdev)
447{
448 struct titsc *ts_dev = platform_get_drvdata(pdev);
449 u32 steps;
450
451 free_irq(ts_dev->irq, ts_dev);
452
453 /* total steps followed by the enable mask */
454 steps = 2 * ts_dev->coordinate_readouts + 2;
455 steps = (1 << steps) - 1;
456 am335x_tsc_se_clr(ts_dev->mfd_tscadc, steps);
457
458 input_unregister_device(ts_dev->input);
459
460 kfree(ts_dev);
461 return 0;
462}
463
464#ifdef CONFIG_PM
465static int titsc_suspend(struct device *dev)
466{
467 struct titsc *ts_dev = dev_get_drvdata(dev);
468 struct ti_tscadc_dev *tscadc_dev;
469 unsigned int idle;
470
471 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
472 if (device_may_wakeup(tscadc_dev->dev)) {
473 idle = titsc_readl(ts_dev, REG_IRQENABLE);
474 titsc_writel(ts_dev, REG_IRQENABLE,
475 (idle | IRQENB_HW_PEN));
476 titsc_writel(ts_dev, REG_IRQWAKEUP, IRQWKUP_ENB);
477 }
478 return 0;
479}
480
481static int titsc_resume(struct device *dev)
482{
483 struct titsc *ts_dev = dev_get_drvdata(dev);
484 struct ti_tscadc_dev *tscadc_dev;
485
486 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
487 if (device_may_wakeup(tscadc_dev->dev)) {
488 titsc_writel(ts_dev, REG_IRQWAKEUP,
489 0x00);
490 titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
491 }
492 titsc_step_config(ts_dev);
493 titsc_writel(ts_dev, REG_FIFO0THR,
494 ts_dev->coordinate_readouts * 2 + 2 - 1);
495 return 0;
496}
497
498static const struct dev_pm_ops titsc_pm_ops = {
499 .suspend = titsc_suspend,
500 .resume = titsc_resume,
501};
502#define TITSC_PM_OPS (&titsc_pm_ops)
503#else
504#define TITSC_PM_OPS NULL
505#endif
506
507static const struct of_device_id ti_tsc_dt_ids[] = {
508 { .compatible = "ti,am3359-tsc", },
509 { }
510};
511MODULE_DEVICE_TABLE(of, ti_tsc_dt_ids);
512
513static struct platform_driver ti_tsc_driver = {
514 .probe = titsc_probe,
515 .remove = titsc_remove,
516 .driver = {
517 .name = "TI-am335x-tsc",
518 .owner = THIS_MODULE,
519 .pm = TITSC_PM_OPS,
520 .of_match_table = ti_tsc_dt_ids,
521 },
522};
523module_platform_driver(ti_tsc_driver);
524
525MODULE_DESCRIPTION("TI touchscreen controller driver");
526MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
527MODULE_LICENSE("GPL");