summaryrefslogtreecommitdiff
path: root/drivers/input/touchscreen/ti_am335x_tsc.c
blob: e1c5300cacfc2044f83175dccffd864a8bd01fbc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
/*
 * TI Touch Screen driver
 *
 * Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation version 2.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */


#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/input.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/of.h>
#include <linux/of_device.h>

#include <linux/mfd/ti_am335x_tscadc.h>

#define ADCFSM_STEPID		0x10
#define SEQ_SETTLE		275
#define MAX_12BIT		((1 << 12) - 1)

static const int config_pins[] = {
	STEPCONFIG_XPP,
	STEPCONFIG_XNN,
	STEPCONFIG_YPP,
	STEPCONFIG_YNN,
};

struct titsc {
	struct input_dev	*input;
	struct ti_tscadc_dev	*mfd_tscadc;
	unsigned int		irq;
	unsigned int		wires;
	unsigned int		x_plate_resistance;
	bool			pen_down;
	int			coordinate_readouts;
	u32			config_inp[4];
	u32			bit_xp, bit_xn, bit_yp, bit_yn;
	u32			inp_xp, inp_xn, inp_yp, inp_yn;
};

static unsigned int titsc_readl(struct titsc *ts, unsigned int reg)
{
	return readl(ts->mfd_tscadc->tscadc_base + reg);
}

static void titsc_writel(struct titsc *tsc, unsigned int reg,
					unsigned int val)
{
	writel(val, tsc->mfd_tscadc->tscadc_base + reg);
}

static int titsc_config_wires(struct titsc *ts_dev)
{
	u32 analog_line[4];
	u32 wire_order[4];
	int i, bit_cfg;

	for (i = 0; i < 4; i++) {
		/*
		 * Get the order in which TSC wires are attached
		 * w.r.t. each of the analog input lines on the EVM.
		 */
		analog_line[i] = (ts_dev->config_inp[i] & 0xF0) >> 4;
		wire_order[i] = ts_dev->config_inp[i] & 0x0F;
		if (WARN_ON(analog_line[i] > 7))
			return -EINVAL;
		if (WARN_ON(wire_order[i] > ARRAY_SIZE(config_pins)))
			return -EINVAL;
	}

	for (i = 0; i < 4; i++) {
		int an_line;
		int wi_order;

		an_line = analog_line[i];
		wi_order = wire_order[i];
		bit_cfg = config_pins[wi_order];
		if (bit_cfg == 0)
			return -EINVAL;
		switch (wi_order) {
		case 0:
			ts_dev->bit_xp = bit_cfg;
			ts_dev->inp_xp = an_line;
			break;

		case 1:
			ts_dev->bit_xn = bit_cfg;
			ts_dev->inp_xn = an_line;
			break;

		case 2:
			ts_dev->bit_yp = bit_cfg;
			ts_dev->inp_yp = an_line;
			break;
		case 3:
			ts_dev->bit_yn = bit_cfg;
			ts_dev->inp_yn = an_line;
			break;
		}
	}
	return 0;
}

static void titsc_step_config(struct titsc *ts_dev)
{
	unsigned int	config;
	int i;
	int end_step;
	u32 stepenable;

	config = STEPCONFIG_MODE_HWSYNC |
			STEPCONFIG_AVG_16 | ts_dev->bit_xp;
	switch (ts_dev->wires) {
	case 4:
		config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn;
		break;
	case 5:
		config |= ts_dev->bit_yn |
				STEPCONFIG_INP_AN4 | ts_dev->bit_xn |
				ts_dev->bit_yp;
		break;
	case 8:
		config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn;
		break;
	}

	/* 1 … coordinate_readouts is for X */
	end_step = ts_dev->coordinate_readouts;
	for (i = 0; i < end_step; i++) {
		titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
		titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
	}

	config = 0;
	config = STEPCONFIG_MODE_HWSYNC |
			STEPCONFIG_AVG_16 | ts_dev->bit_yn |
			STEPCONFIG_INM_ADCREFM;
	switch (ts_dev->wires) {
	case 4:
		config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
		break;
	case 5:
		config |= ts_dev->bit_xp | STEPCONFIG_INP_AN4 |
				ts_dev->bit_xn | ts_dev->bit_yp;
		break;
	case 8:
		config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
		break;
	}

	/* coordinate_readouts … coordinate_readouts * 2 is for Y */
	end_step = ts_dev->coordinate_readouts * 2;
	for (i = ts_dev->coordinate_readouts; i < end_step; i++) {
		titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
		titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
	}

	/* Charge step configuration */
	config = ts_dev->bit_xp | ts_dev->bit_yn |
			STEPCHARGE_RFP_XPUL | STEPCHARGE_RFM_XNUR |
			STEPCHARGE_INM_AN1 | STEPCHARGE_INP(ts_dev->inp_yp);

	titsc_writel(ts_dev, REG_CHARGECONFIG, config);
	titsc_writel(ts_dev, REG_CHARGEDELAY, CHARGEDLY_OPENDLY);

	/* coordinate_readouts * 2 … coordinate_readouts * 2 + 2 is for Z */
	config = STEPCONFIG_MODE_HWSYNC |
			STEPCONFIG_AVG_16 | ts_dev->bit_yp |
			ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM |
			STEPCONFIG_INP(ts_dev->inp_xp);
	titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
	titsc_writel(ts_dev, REG_STEPDELAY(end_step),
			STEPCONFIG_OPENDLY);

	end_step++;
	config |= STEPCONFIG_INP(ts_dev->inp_yn);
	titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
	titsc_writel(ts_dev, REG_STEPDELAY(end_step),
			STEPCONFIG_OPENDLY);

	/* The steps1 … end and bit 0 for TS_Charge */
	stepenable = (1 << (end_step + 2)) - 1;
	am335x_tsc_se_set(ts_dev->mfd_tscadc, stepenable);
}

static void titsc_read_coordinates(struct titsc *ts_dev,
		u32 *x, u32 *y, u32 *z1, u32 *z2)
{
	unsigned int fifocount = titsc_readl(ts_dev, REG_FIFO0CNT);
	unsigned int prev_val_x = ~0, prev_val_y = ~0;
	unsigned int prev_diff_x = ~0, prev_diff_y = ~0;
	unsigned int read, diff;
	unsigned int i, channel;
	unsigned int creads = ts_dev->coordinate_readouts;

	*z1 = *z2 = 0;
	if (fifocount % (creads * 2 + 2))
		fifocount -= fifocount % (creads * 2 + 2);
	/*
	 * Delta filter is used to remove large variations in sampled
	 * values from ADC. The filter tries to predict where the next
	 * coordinate could be. This is done by taking a previous
	 * coordinate and subtracting it form current one. Further the
	 * algorithm compares the difference with that of a present value,
	 * if true the value is reported to the sub system.
	 */
	for (i = 0; i < fifocount; i++) {
		read = titsc_readl(ts_dev, REG_FIFO0);

		channel = (read & 0xf0000) >> 16;
		read &= 0xfff;
		if (channel < creads) {
			diff = abs(read - prev_val_x);
			if (diff < prev_diff_x) {
				prev_diff_x = diff;
				*x = read;
			}
			prev_val_x = read;

		} else if (channel < creads * 2) {
			diff = abs(read - prev_val_y);
			if (diff < prev_diff_y) {
				prev_diff_y = diff;
				*y = read;
			}
			prev_val_y = read;

		} else if (channel < creads * 2 + 1) {
			*z1 = read;

		} else if (channel < creads * 2 + 2) {
			*z2 = read;
		}
	}
}

static irqreturn_t titsc_irq(int irq, void *dev)
{
	struct titsc *ts_dev = dev;
	struct input_dev *input_dev = ts_dev->input;
	unsigned int status, irqclr = 0;
	unsigned int x = 0, y = 0;
	unsigned int z1, z2, z;
	unsigned int fsm;

	status = titsc_readl(ts_dev, REG_IRQSTATUS);
	if (status & IRQENB_FIFO0THRES) {

		titsc_read_coordinates(ts_dev, &x, &y, &z1, &z2);

		if (ts_dev->pen_down && z1 != 0 && z2 != 0) {
			/*
			 * Calculate pressure using formula
			 * Resistance(touch) = x plate resistance *
			 * x postion/4096 * ((z2 / z1) - 1)
			 */
			z = z1 - z2;
			z *= x;
			z *= ts_dev->x_plate_resistance;
			z /= z2;
			z = (z + 2047) >> 12;

			if (z <= MAX_12BIT) {
				input_report_abs(input_dev, ABS_X, x);
				input_report_abs(input_dev, ABS_Y, y);
				input_report_abs(input_dev, ABS_PRESSURE, z);
				input_report_key(input_dev, BTN_TOUCH, 1);
				input_sync(input_dev);
			}
		}
		irqclr |= IRQENB_FIFO0THRES;
	}

	/*
	 * Time for sequencer to settle, to read
	 * correct state of the sequencer.
	 */
	udelay(SEQ_SETTLE);

	status = titsc_readl(ts_dev, REG_RAWIRQSTATUS);
	if (status & IRQENB_PENUP) {
		/* Pen up event */
		fsm = titsc_readl(ts_dev, REG_ADCFSM);
		if (fsm == ADCFSM_STEPID) {
			ts_dev->pen_down = false;
			input_report_key(input_dev, BTN_TOUCH, 0);
			input_report_abs(input_dev, ABS_PRESSURE, 0);
			input_sync(input_dev);
		} else {
			ts_dev->pen_down = true;
		}
		irqclr |= IRQENB_PENUP;
	}

	if (status & IRQENB_HW_PEN) {

		titsc_writel(ts_dev, REG_IRQWAKEUP, 0x00);
		titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
	}

	if (irqclr) {
		titsc_writel(ts_dev, REG_IRQSTATUS, irqclr);
		am335x_tsc_se_update(ts_dev->mfd_tscadc);
		return IRQ_HANDLED;
	}
	return IRQ_NONE;
}

static int titsc_parse_dt(struct platform_device *pdev,
					struct titsc *ts_dev)
{
	struct device_node *node = pdev->dev.of_node;
	int err;

	if (!node)
		return -EINVAL;

	err = of_property_read_u32(node, "ti,wires", &ts_dev->wires);
	if (err < 0)
		return err;
	switch (ts_dev->wires) {
	case 4:
	case 5:
	case 8:
		break;
	default:
		return -EINVAL;
	}

	err = of_property_read_u32(node, "ti,x-plate-resistance",
			&ts_dev->x_plate_resistance);
	if (err < 0)
		return err;

	err = of_property_read_u32(node, "ti,coordiante-readouts",
			&ts_dev->coordinate_readouts);
	if (err < 0)
		return err;

	return of_property_read_u32_array(node, "ti,wire-config",
			ts_dev->config_inp, ARRAY_SIZE(ts_dev->config_inp));
}

/*
 * The functions for inserting/removing driver as a module.
 */

static int titsc_probe(struct platform_device *pdev)
{
	struct titsc *ts_dev;
	struct input_dev *input_dev;
	struct ti_tscadc_dev *tscadc_dev = ti_tscadc_dev_get(pdev);
	int err;

	/* Allocate memory for device */
	ts_dev = kzalloc(sizeof(struct titsc), GFP_KERNEL);
	input_dev = input_allocate_device();
	if (!ts_dev || !input_dev) {
		dev_err(&pdev->dev, "failed to allocate memory.\n");
		err = -ENOMEM;
		goto err_free_mem;
	}

	tscadc_dev->tsc = ts_dev;
	ts_dev->mfd_tscadc = tscadc_dev;
	ts_dev->input = input_dev;
	ts_dev->irq = tscadc_dev->irq;

	err = titsc_parse_dt(pdev, ts_dev);
	if (err) {
		dev_err(&pdev->dev, "Could not find valid DT data.\n");
		goto err_free_mem;
	}

	err = request_irq(ts_dev->irq, titsc_irq,
			  0, pdev->dev.driver->name, ts_dev);
	if (err) {
		dev_err(&pdev->dev, "failed to allocate irq.\n");
		goto err_free_mem;
	}

	titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES);
	err = titsc_config_wires(ts_dev);
	if (err) {
		dev_err(&pdev->dev, "wrong i/p wire configuration\n");
		goto err_free_irq;
	}
	titsc_step_config(ts_dev);
	titsc_writel(ts_dev, REG_FIFO0THR,
			ts_dev->coordinate_readouts * 2 + 2 - 1);

	input_dev->name = "ti-tsc";
	input_dev->dev.parent = &pdev->dev;

	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);

	input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
	input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
	input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);

	/* register to the input system */
	err = input_register_device(input_dev);
	if (err)
		goto err_free_irq;

	platform_set_drvdata(pdev, ts_dev);
	return 0;

err_free_irq:
	free_irq(ts_dev->irq, ts_dev);
err_free_mem:
	input_free_device(input_dev);
	kfree(ts_dev);
	return err;
}

static int titsc_remove(struct platform_device *pdev)
{
	struct titsc *ts_dev = platform_get_drvdata(pdev);
	u32 steps;

	free_irq(ts_dev->irq, ts_dev);

	/* total steps followed by the enable mask */
	steps = 2 * ts_dev->coordinate_readouts + 2;
	steps = (1 << steps) - 1;
	am335x_tsc_se_clr(ts_dev->mfd_tscadc, steps);

	input_unregister_device(ts_dev->input);

	kfree(ts_dev);
	return 0;
}

#ifdef CONFIG_PM
static int titsc_suspend(struct device *dev)
{
	struct titsc *ts_dev = dev_get_drvdata(dev);
	struct ti_tscadc_dev *tscadc_dev;
	unsigned int idle;

	tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
	if (device_may_wakeup(tscadc_dev->dev)) {
		idle = titsc_readl(ts_dev, REG_IRQENABLE);
		titsc_writel(ts_dev, REG_IRQENABLE,
				(idle | IRQENB_HW_PEN));
		titsc_writel(ts_dev, REG_IRQWAKEUP, IRQWKUP_ENB);
	}
	return 0;
}

static int titsc_resume(struct device *dev)
{
	struct titsc *ts_dev = dev_get_drvdata(dev);
	struct ti_tscadc_dev *tscadc_dev;

	tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
	if (device_may_wakeup(tscadc_dev->dev)) {
		titsc_writel(ts_dev, REG_IRQWAKEUP,
				0x00);
		titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
	}
	titsc_step_config(ts_dev);
	titsc_writel(ts_dev, REG_FIFO0THR,
			ts_dev->coordinate_readouts * 2 + 2 - 1);
	return 0;
}

static const struct dev_pm_ops titsc_pm_ops = {
	.suspend = titsc_suspend,
	.resume  = titsc_resume,
};
#define TITSC_PM_OPS (&titsc_pm_ops)
#else
#define TITSC_PM_OPS NULL
#endif

static const struct of_device_id ti_tsc_dt_ids[] = {
	{ .compatible = "ti,am3359-tsc", },
	{ }
};
MODULE_DEVICE_TABLE(of, ti_tsc_dt_ids);

static struct platform_driver ti_tsc_driver = {
	.probe	= titsc_probe,
	.remove	= titsc_remove,
	.driver	= {
		.name   = "TI-am335x-tsc",
		.owner	= THIS_MODULE,
		.pm	= TITSC_PM_OPS,
		.of_match_table = of_match_ptr(ti_tsc_dt_ids),
	},
};
module_platform_driver(ti_tsc_driver);

MODULE_DESCRIPTION("TI touchscreen controller driver");
MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
MODULE_LICENSE("GPL");