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 = 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(ts_dev, REG_STEPCONFIG(i), config);
182 		titsc_writel(ts_dev, REG_STEPDELAY(i),
183 			     n++ == 0 ? STEPCONFIG_OPENDLY : 0);
184 	}
185 
186 	/* Make CHARGECONFIG same as IDLECONFIG */
187 
188 	config = titsc_readl(ts_dev, REG_IDLECONFIG);
189 	titsc_writel(ts_dev, REG_CHARGECONFIG, config);
190 	titsc_writel(ts_dev, REG_CHARGEDELAY, 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(ts_dev, REG_STEPCONFIG(end_step), config);
198 	titsc_writel(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(ts_dev, REG_STEPCONFIG(end_step), config);
207 	titsc_writel(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(ts_dev->mfd_tscadc, ts_dev->step_mask);
217 }
218 
titsc_cmp_coord(const void * a,const void * b)219 static int titsc_cmp_coord(const void *a, const void *b)
220 {
221 	return *(int *)a - *(int *)b;
222 }
223 
titsc_read_coordinates(struct titsc * ts_dev,u32 * x,u32 * y,u32 * z1,u32 * z2)224 static 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_dev, REG_FIFO0);
233 		yvals[i] &= 0xfff;
234 	}
235 
236 	*z1 = titsc_readl(ts_dev, REG_FIFO0);
237 	*z1 &= 0xfff;
238 	*z2 = titsc_readl(ts_dev, REG_FIFO0);
239 	*z2 &= 0xfff;
240 
241 	for (i = 0; i < creads; i++) {
242 		xvals[i] = titsc_readl(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(yvals, creads, sizeof(unsigned int),
262 		     titsc_cmp_coord, NULL);
263 		sort(xvals, creads, sizeof(unsigned int),
264 		     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 
titsc_irq(int irq,void * dev)276 static 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_dev, REG_RAWIRQSTATUS);
285 	if (status & IRQENB_HW_PEN) {
286 		ts_dev->pen_down = true;
287 		irqclr |= IRQENB_HW_PEN;
288 		pm_stay_awake(ts_dev->dev);
289 	}
290 
291 	if (status & IRQENB_PENUP) {
292 		fsm = titsc_readl(ts_dev, REG_ADCFSM);
293 		if (fsm == ADCFSM_STEPID) {
294 			ts_dev->pen_down = false;
295 			input_report_key(input_dev, BTN_TOUCH, 0);
296 			input_report_abs(input_dev, ABS_PRESSURE, 0);
297 			input_sync(input_dev);
298 			pm_relax(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, &y, &z1, &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(input_dev, ABS_X, x);
330 				input_report_abs(input_dev, ABS_Y, y);
331 				input_report_abs(input_dev, ABS_PRESSURE, z);
332 				input_report_key(input_dev, BTN_TOUCH, 1);
333 				input_sync(input_dev);
334 			}
335 		}
336 		irqclr |= IRQENB_FIFO0THRES;
337 	}
338 	if (irqclr) {
339 		titsc_writel(ts_dev, REG_IRQSTATUS, irqclr);
340 		if (status & IRQENB_EOS)
341 			am335x_tsc_se_set_cache(ts_dev->mfd_tscadc,
342 						ts_dev->step_mask);
343 		return IRQ_HANDLED;
344 	}
345 	return IRQ_NONE;
346 }
347 
titsc_parse_dt(struct platform_device * pdev,struct titsc * ts_dev)348 static 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(node, "ti,wires", &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(node, "ti,x-plate-resistance",
370 			&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(node, "ti,coordinate-readouts",
379 			&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(node, "ti,coordiante-readouts",
383 				&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(node, "ti,charge-delay",
396 				   &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(node, "ti,wire-config",
407 			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 
titsc_probe(struct platform_device * pdev)414 static 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(pdev);
419 	int err;
420 
421 	/* Allocate memory for device */
422 	ts_dev = kzalloc(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(ts_dev->irq, titsc_irq,
443 			  IRQF_SHARED, pdev->dev.driver->name, 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(&pdev->dev, true);
450 	err = dev_pm_set_wake_irq(&pdev->dev, ts_dev->irq);
451 	if (err)
452 		dev_err(&pdev->dev, "irq wake enable failed.\n");
453 
454 	titsc_writel(ts_dev, REG_IRQSTATUS, TSC_IRQENB_MASK);
455 	titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES);
456 	titsc_writel(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(ts_dev, REG_FIFO0THR,
464 			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(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
473 	input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
474 	input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 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, ts_dev);
482 	return 0;
483 
484 err_free_irq:
485 	dev_pm_clear_wake_irq(&pdev->dev);
486 	device_init_wakeup(&pdev->dev, false);
487 	free_irq(ts_dev->irq, ts_dev);
488 err_free_mem:
489 	input_free_device(input_dev);
490 	kfree(ts_dev);
491 	return err;
492 }
493 
titsc_remove(struct platform_device * pdev)494 static 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(&pdev->dev);
500 	device_init_wakeup(&pdev->dev, 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(ts_dev->mfd_tscadc, steps);
507 
508 	input_unregister_device(ts_dev->input);
509 
510 	kfree(ts_dev);
511 	return 0;
512 }
513 
titsc_suspend(struct device * dev)514 static 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(ts_dev, REG_IRQSTATUS, TSC_IRQENB_MASK);
521 		idle = titsc_readl(ts_dev, REG_IRQENABLE);
522 		titsc_writel(ts_dev, REG_IRQENABLE,
523 				(idle | IRQENB_HW_PEN));
524 		titsc_writel(ts_dev, REG_IRQWAKEUP, IRQWKUP_ENB);
525 	}
526 	return 0;
527 }
528 
titsc_resume(struct device * dev)529 static 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(ts_dev, REG_IRQWAKEUP,
535 				0x00);
536 		titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
537 		pm_relax(dev);
538 	}
539 	titsc_step_config(ts_dev);
540 	titsc_writel(ts_dev, REG_FIFO0THR,
541 			ts_dev->coordinate_readouts * 2 + 2 - 1);
542 	return 0;
543 }
544 
545 static DEFINE_SIMPLE_DEV_PM_OPS(titsc_pm_ops, titsc_suspend, titsc_resume);
546 
547 static const struct of_device_id ti_tsc_dt_ids[] = {
548 	{ .compatible = "ti,am3359-tsc", },
549 	{ }
550 };
551 MODULE_DEVICE_TABLE(of, ti_tsc_dt_ids);
552 
553 static 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 };
562 module_platform_driver(ti_tsc_driver);
563 
564 MODULE_DESCRIPTION("TI touchscreen controller driver");
565 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
566 MODULE_LICENSE("GPL");
567