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 
63 static unsigned int titsc_readl(struct titsc *ts, unsigned int reg)
64 {
65 	return readl(ts->mfd_tscadc->tscadc_base + reg);
66 }
67 
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 
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 
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 
212 static int titsc_cmp_coord(const void *a, const void *b)
213 {
214 	return *(int *)a - *(int *)b;
215 }
216 
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 
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 
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 
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 
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 
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 
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