ti_am335x_tsc.c

  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(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, 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(ts_dev, REG_STEPCONFIG(i), config);
156		titsc_writel(ts_dev, REG_STEPDELAY(i),
157			     n++ == 0 ? STEPCONFIG_OPENDLY : 0);
158	}
159
160	config = STEPCONFIG_MODE_HWSYNC |
161			STEPCONFIG_AVG_16 | ts_dev->bit_yn |
162			STEPCONFIG_INM_ADCREFM;
163	switch (ts_dev->wires) {
164	case 4:
165		config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
166		break;
167	case 5:
168		config |= ts_dev->bit_xp | STEPCONFIG_INP_AN4 |
169				STEPCONFIG_XNP | STEPCONFIG_YPN;
170		break;
171	case 8:
172		config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
173		break;
174	}
175
176	/* 1 ... coordinate_readouts is for Y */
177	end_step = first_step + ts_dev->coordinate_readouts;
178	n = 0;
179	for (i = first_step; i < end_step; i++) {
180		titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
181		titsc_writel(ts_dev, REG_STEPDELAY(i),
182			     n++ == 0 ? STEPCONFIG_OPENDLY : 0);
183	}
184
185	/* Make CHARGECONFIG same as IDLECONFIG */
186
187	config = titsc_readl(ts_dev, REG_IDLECONFIG);
188	titsc_writel(ts_dev, REG_CHARGECONFIG, config);
189	titsc_writel(ts_dev, REG_CHARGEDELAY, ts_dev->charge_delay);
190
191	/* coordinate_readouts + 1 ... coordinate_readouts + 2 is for Z */
192	config = STEPCONFIG_MODE_HWSYNC |
193			STEPCONFIG_AVG_16 | ts_dev->bit_yp |
194			ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM |
195			STEPCONFIG_INP(ts_dev->inp_xp);
196	titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
197	titsc_writel(ts_dev, REG_STEPDELAY(end_step),
198			STEPCONFIG_OPENDLY);
199
200	end_step++;
201	config = STEPCONFIG_MODE_HWSYNC |
202			STEPCONFIG_AVG_16 | ts_dev->bit_yp |
203			ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM |
204			STEPCONFIG_INP(ts_dev->inp_yn);
205	titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
206	titsc_writel(ts_dev, REG_STEPDELAY(end_step),
207			STEPCONFIG_OPENDLY);
208
209	/* The steps end ... end - readouts * 2 + 2 and bit 0 for TS_Charge */
210	stepenable = 1;
211	for (i = 0; i < tsc_steps; i++)
212		stepenable |= 1 << (first_step + i + 1);
213
214	ts_dev->step_mask = stepenable;
215	am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask);
216}
217
218static int titsc_cmp_coord(const void *a, const void *b)
219{
220	return *(int *)a - *(int *)b;
221}
222
223static void titsc_read_coordinates(struct titsc *ts_dev,
224		u32 *x, u32 *y, u32 *z1, u32 *z2)
225{
226	unsigned int yvals[7], xvals[7];
227	unsigned int i, xsum = 0, ysum = 0;
228	unsigned int creads = ts_dev->coordinate_readouts;
229
230	for (i = 0; i < creads; i++) {
231		yvals[i] = titsc_readl(ts_dev, REG_FIFO0);
232		yvals[i] &= 0xfff;
233	}
234
235	*z1 = titsc_readl(ts_dev, REG_FIFO0);
236	*z1 &= 0xfff;
237	*z2 = titsc_readl(ts_dev, REG_FIFO0);
238	*z2 &= 0xfff;
239
240	for (i = 0; i < creads; i++) {
241		xvals[i] = titsc_readl(ts_dev, REG_FIFO0);
242		xvals[i] &= 0xfff;
243	}
244
245	/*
246	 * If co-ordinates readouts is less than 4 then
247	 * report the average. In case of 4 or more
248	 * readouts, sort the co-ordinate samples, drop
249	 * min and max values and report the average of
250	 * remaining values.
251	 */
252	if (creads <=  3) {
253		for (i = 0; i < creads; i++) {
254			ysum += yvals[i];
255			xsum += xvals[i];
256		}
257		ysum /= creads;
258		xsum /= creads;
259	} else {
260		sort(yvals, creads, sizeof(unsigned int),
261		     titsc_cmp_coord, NULL);
262		sort(xvals, creads, sizeof(unsigned int),
263		     titsc_cmp_coord, NULL);
264		for (i = 1; i < creads - 1; i++) {
265			ysum += yvals[i];
266			xsum += xvals[i];
267		}
268		ysum /= creads - 2;
269		xsum /= creads - 2;
270	}
271	*y = ysum;
272	*x = xsum;
273}
274
275static irqreturn_t titsc_irq(int irq, void *dev)
276{
277	struct titsc *ts_dev = dev;
278	struct input_dev *input_dev = ts_dev->input;
279	unsigned int fsm, status, irqclr = 0;
280	unsigned int x = 0, y = 0;
281	unsigned int z1, z2, z;
282
283	status = titsc_readl(ts_dev, REG_RAWIRQSTATUS);
284	if (status & IRQENB_HW_PEN) {
285		ts_dev->pen_down = true;
286		irqclr |= IRQENB_HW_PEN;
287		pm_stay_awake(ts_dev->dev);
288	}
289
290	if (status & IRQENB_PENUP) {
291		fsm = titsc_readl(ts_dev, REG_ADCFSM);
292		if (fsm == ADCFSM_STEPID) {
293			ts_dev->pen_down = false;
294			input_report_key(input_dev, BTN_TOUCH, 0);
295			input_report_abs(input_dev, ABS_PRESSURE, 0);
296			input_sync(input_dev);
297			pm_relax(ts_dev->dev);
298		} else {
299			ts_dev->pen_down = true;
300		}
301		irqclr |= IRQENB_PENUP;
302	}
303
304	if (status & IRQENB_EOS)
305		irqclr |= IRQENB_EOS;
306
307	/*
308	 * ADC and touchscreen share the IRQ line.
309	 * FIFO1 interrupts are used by ADC. Handle FIFO0 IRQs here only
310	 */
311	if (status & IRQENB_FIFO0THRES) {
312
313		titsc_read_coordinates(ts_dev, &x, &y, &z1, &z2);
314
315		if (ts_dev->pen_down && z1 != 0 && z2 != 0) {
316			/*
317			 * Calculate pressure using formula
318			 * Resistance(touch) = x plate resistance *
319			 * x position/4096 * ((z2 / z1) - 1)
320			 */
321			z = z1 - z2;
322			z *= x;
323			z *= ts_dev->x_plate_resistance;
324			z /= z2;
325			z = (z + 2047) >> 12;
326
327			if (z <= MAX_12BIT) {
328				input_report_abs(input_dev, ABS_X, x);
329				input_report_abs(input_dev, ABS_Y, y);
330				input_report_abs(input_dev, ABS_PRESSURE, z);
331				input_report_key(input_dev, BTN_TOUCH, 1);
332				input_sync(input_dev);
333			}
334		}
335		irqclr |= IRQENB_FIFO0THRES;
336	}
337	if (irqclr) {
338		titsc_writel(ts_dev, REG_IRQSTATUS, irqclr);
339		if (status & IRQENB_EOS)
340			am335x_tsc_se_set_cache(ts_dev->mfd_tscadc,
341						ts_dev->step_mask);
342		return IRQ_HANDLED;
343	}
344	return IRQ_NONE;
345}
346
347static int titsc_parse_dt(struct platform_device *pdev,
348					struct titsc *ts_dev)
349{
350	struct device_node *node = pdev->dev.of_node;
351	int err;
352
353	if (!node)
354		return -EINVAL;
355
356	err = of_property_read_u32(node, "ti,wires", &ts_dev->wires);
357	if (err < 0)
358		return err;
359	switch (ts_dev->wires) {
360	case 4:
361	case 5:
362	case 8:
363		break;
364	default:
365		return -EINVAL;
366	}
367
368	err = of_property_read_u32(node, "ti,x-plate-resistance",
369			&ts_dev->x_plate_resistance);
370	if (err < 0)
371		return err;
372
373	/*
374	 * Try with the new binding first. If it fails, try again with
375	 * bogus, miss-spelled version.
376	 */
377	err = of_property_read_u32(node, "ti,coordinate-readouts",
378			&ts_dev->coordinate_readouts);
379	if (err < 0) {
380		dev_warn(&pdev->dev, "please use 'ti,coordinate-readouts' instead\n");
381		err = of_property_read_u32(node, "ti,coordiante-readouts",
382				&ts_dev->coordinate_readouts);
383	}
384
385	if (err < 0)
386		return err;
387
388	if (ts_dev->coordinate_readouts <= 0) {
389		dev_warn(&pdev->dev,
390			 "invalid co-ordinate readouts, resetting it to 5\n");
391		ts_dev->coordinate_readouts = 5;
392	} else if (ts_dev->coordinate_readouts > 6) {
393		dev_warn(&pdev->dev,
394			 "co-ordinate readouts too large, limiting to 6\n");
395		ts_dev->coordinate_readouts = 6;
396	}
397
398	err = of_property_read_u32(node, "ti,charge-delay",
399				   &ts_dev->charge_delay);
400	/*
401	 * If ti,charge-delay value is not specified, then use
402	 * CHARGEDLY_OPENDLY as the default value.
403	 */
404	if (err < 0) {
405		ts_dev->charge_delay = CHARGEDLY_OPENDLY;
406		dev_warn(&pdev->dev, "ti,charge-delay not specified\n");
407	}
408
409	return of_property_read_u32_array(node, "ti,wire-config",
410			ts_dev->config_inp, ARRAY_SIZE(ts_dev->config_inp));
411}
412
413/*
414 * The functions for inserting/removing driver as a module.
415 */
416
417static int titsc_probe(struct platform_device *pdev)
418{
419	struct titsc *ts_dev;
420	struct input_dev *input_dev;
421	struct ti_tscadc_dev *tscadc_dev = ti_tscadc_dev_get(pdev);
422	int err;
423
424	/* Allocate memory for device */
425	ts_dev = kzalloc(sizeof(*ts_dev), GFP_KERNEL);
426	input_dev = input_allocate_device();
427	if (!ts_dev || !input_dev) {
428		dev_err(&pdev->dev, "failed to allocate memory.\n");
429		err = -ENOMEM;
430		goto err_free_mem;
431	}
432
433	tscadc_dev->tsc = ts_dev;
434	ts_dev->mfd_tscadc = tscadc_dev;
435	ts_dev->input = input_dev;
436	ts_dev->irq = tscadc_dev->irq;
437	ts_dev->dev = &pdev->dev;
438
439	err = titsc_parse_dt(pdev, ts_dev);
440	if (err) {
441		dev_err(&pdev->dev, "Could not find valid DT data.\n");
442		goto err_free_mem;
443	}
444
445	err = request_irq(ts_dev->irq, titsc_irq,
446			  IRQF_SHARED, pdev->dev.driver->name, ts_dev);
447	if (err) {
448		dev_err(&pdev->dev, "failed to allocate irq.\n");
449		goto err_free_mem;
450	}
451
452	device_init_wakeup(&pdev->dev, true);
453	err = dev_pm_set_wake_irq(&pdev->dev, ts_dev->irq);
454	if (err)
455		dev_err(&pdev->dev, "irq wake enable failed.\n");
456
457	titsc_writel(ts_dev, REG_IRQSTATUS, TSC_IRQENB_MASK);
458	titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES);
459	titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_EOS);
460	err = titsc_config_wires(ts_dev);
461	if (err) {
462		dev_err(&pdev->dev, "wrong i/p wire configuration\n");
463		goto err_free_irq;
464	}
465	titsc_step_config(ts_dev);
466	titsc_writel(ts_dev, REG_FIFO0THR,
467			ts_dev->coordinate_readouts * 2 + 2 - 1);
468
469	input_dev->name = "ti-tsc";
470	input_dev->dev.parent = &pdev->dev;
471
472	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
473	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
474
475	input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
476	input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
477	input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
478
479	/* register to the input system */
480	err = input_register_device(input_dev);
481	if (err)
482		goto err_free_irq;
483
484	platform_set_drvdata(pdev, ts_dev);
485	return 0;
486
487err_free_irq:
488	dev_pm_clear_wake_irq(&pdev->dev);
489	device_init_wakeup(&pdev->dev, false);
490	free_irq(ts_dev->irq, ts_dev);
491err_free_mem:
492	input_free_device(input_dev);
493	kfree(ts_dev);
494	return err;
495}
496
497static void titsc_remove(struct platform_device *pdev)
498{
499	struct titsc *ts_dev = platform_get_drvdata(pdev);
500	u32 steps;
501
502	dev_pm_clear_wake_irq(&pdev->dev);
503	device_init_wakeup(&pdev->dev, false);
504	free_irq(ts_dev->irq, ts_dev);
505
506	/* total steps followed by the enable mask */
507	steps = 2 * ts_dev->coordinate_readouts + 2;
508	steps = (1 << steps) - 1;
509	am335x_tsc_se_clr(ts_dev->mfd_tscadc, steps);
510
511	input_unregister_device(ts_dev->input);
512
513	kfree(ts_dev);
514}
515
516static int titsc_suspend(struct device *dev)
517{
518	struct titsc *ts_dev = dev_get_drvdata(dev);
519	unsigned int idle;
520
521	if (device_may_wakeup(dev)) {
522		titsc_writel(ts_dev, REG_IRQSTATUS, TSC_IRQENB_MASK);
523		idle = titsc_readl(ts_dev, REG_IRQENABLE);
524		titsc_writel(ts_dev, REG_IRQENABLE,
525				(idle | IRQENB_HW_PEN));
526		titsc_writel(ts_dev, REG_IRQWAKEUP, IRQWKUP_ENB);
527	}
528	return 0;
529}
530
531static int titsc_resume(struct device *dev)
532{
533	struct titsc *ts_dev = dev_get_drvdata(dev);
534
535	if (device_may_wakeup(dev)) {
536		titsc_writel(ts_dev, REG_IRQWAKEUP,
537				0x00);
538		titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
539		pm_relax(dev);
540	}
541	titsc_step_config(ts_dev);
542	titsc_writel(ts_dev, REG_FIFO0THR,
543			ts_dev->coordinate_readouts * 2 + 2 - 1);
544	return 0;
545}
546
547static DEFINE_SIMPLE_DEV_PM_OPS(titsc_pm_ops, titsc_suspend, titsc_resume);
548
549static const struct of_device_id ti_tsc_dt_ids[] = {
550	{ .compatible = "ti,am3359-tsc", },
551	{ }
552};
553MODULE_DEVICE_TABLE(of, ti_tsc_dt_ids);
554
555static struct platform_driver ti_tsc_driver = {
556	.probe	= titsc_probe,
557	.remove	= titsc_remove,
558	.driver	= {
559		.name	= "TI-am335x-tsc",
560		.pm	= pm_sleep_ptr(&titsc_pm_ops),
561		.of_match_table = ti_tsc_dt_ids,
562	},
563};
564module_platform_driver(ti_tsc_driver);
565
566MODULE_DESCRIPTION("TI touchscreen controller driver");
567MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
568MODULE_LICENSE("GPL");