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
 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
 37static const int config_pins[] = {
 38	STEPCONFIG_XPP,
 39	STEPCONFIG_XNN,
 40	STEPCONFIG_YPP,
 41	STEPCONFIG_YNN,
 42};
 43
 44struct titsc {
 45	struct input_dev	*input;
 46	struct ti_tscadc_dev	*mfd_tscadc;
 47	unsigned int		irq;
 48	unsigned int		wires;
 49	unsigned int		x_plate_resistance;
 50	bool			pen_down;
 51	int			coordinate_readouts;
 52	u32			config_inp[4];
 53	u32			bit_xp, bit_xn, bit_yp, bit_yn;
 54	u32			inp_xp, inp_xn, inp_yp, inp_yn;
 55	u32			step_mask;
 56	u32			charge_delay;
 57};
 58
 59static unsigned int titsc_readl(struct titsc *ts, unsigned int reg)
 60{
 61	return readl(ts->mfd_tscadc->tscadc_base + reg);
 62}
 63
 64static void titsc_writel(struct titsc *tsc, unsigned int reg,
 65					unsigned int val)
 66{
 67	writel(val, tsc->mfd_tscadc->tscadc_base + reg);
 68}
 69
 70static int titsc_config_wires(struct titsc *ts_dev)
 71{
 72	u32 analog_line[4];
 73	u32 wire_order[4];
 74	int i, bit_cfg;
 75
 76	for (i = 0; i < 4; i++) {
 77		/*
 78		 * Get the order in which TSC wires are attached
 79		 * w.r.t. each of the analog input lines on the EVM.
 80		 */
 81		analog_line[i] = (ts_dev->config_inp[i] & 0xF0) >> 4;
 82		wire_order[i] = ts_dev->config_inp[i] & 0x0F;
 83		if (WARN_ON(analog_line[i] > 7))
 84			return -EINVAL;
 85		if (WARN_ON(wire_order[i] > ARRAY_SIZE(config_pins)))
 86			return -EINVAL;
 87	}
 88
 89	for (i = 0; i < 4; i++) {
 90		int an_line;
 91		int wi_order;
 92
 93		an_line = analog_line[i];
 94		wi_order = wire_order[i];
 95		bit_cfg = config_pins[wi_order];
 96		if (bit_cfg == 0)
 97			return -EINVAL;
 98		switch (wi_order) {
 99		case 0:
100			ts_dev->bit_xp = bit_cfg;
101			ts_dev->inp_xp = an_line;
102			break;
103
104		case 1:
105			ts_dev->bit_xn = bit_cfg;
106			ts_dev->inp_xn = an_line;
107			break;
108
109		case 2:
110			ts_dev->bit_yp = bit_cfg;
111			ts_dev->inp_yp = an_line;
112			break;
113		case 3:
114			ts_dev->bit_yn = bit_cfg;
115			ts_dev->inp_yn = an_line;
116			break;
117		}
118	}
119	return 0;
120}
121
122static void titsc_step_config(struct titsc *ts_dev)
123{
124	unsigned int	config;
125	int i;
126	int end_step, first_step, tsc_steps;
127	u32 stepenable;
128
129	config = STEPCONFIG_MODE_HWSYNC |
130			STEPCONFIG_AVG_16 | ts_dev->bit_xp;
131	switch (ts_dev->wires) {
132	case 4:
133		config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn;
134		break;
135	case 5:
136		config |= ts_dev->bit_yn |
137				STEPCONFIG_INP_AN4 | ts_dev->bit_xn |
138				ts_dev->bit_yp;
139		break;
140	case 8:
141		config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn;
142		break;
143	}
144
145	tsc_steps = ts_dev->coordinate_readouts * 2 + 2;
146	first_step = TOTAL_STEPS - tsc_steps;
147	/* Steps 16 to 16-coordinate_readouts is for X */
148	end_step = first_step + tsc_steps;
149	for (i = end_step - ts_dev->coordinate_readouts; i < end_step; i++) {
150		titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
151		titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
152	}
153
154	config = 0;
155	config = STEPCONFIG_MODE_HWSYNC |
156			STEPCONFIG_AVG_16 | ts_dev->bit_yn |
157			STEPCONFIG_INM_ADCREFM;
158	switch (ts_dev->wires) {
159	case 4:
160		config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
161		break;
162	case 5:
163		config |= ts_dev->bit_xp | STEPCONFIG_INP_AN4 |
164				ts_dev->bit_xn | ts_dev->bit_yp;
165		break;
166	case 8:
167		config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
168		break;
169	}
170
171	/* 1 ... coordinate_readouts is for Y */
172	end_step = first_step + ts_dev->coordinate_readouts;
173	for (i = first_step; i < end_step; i++) {
174		titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
175		titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
176	}
177
178	/* Make CHARGECONFIG same as IDLECONFIG */
179
180	config = titsc_readl(ts_dev, REG_IDLECONFIG);
181	titsc_writel(ts_dev, REG_CHARGECONFIG, config);
182	titsc_writel(ts_dev, REG_CHARGEDELAY, ts_dev->charge_delay);
183
184	/* coordinate_readouts + 1 ... coordinate_readouts + 2 is for Z */
185	config = STEPCONFIG_MODE_HWSYNC |
186			STEPCONFIG_AVG_16 | ts_dev->bit_yp |
187			ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM |
188			STEPCONFIG_INP(ts_dev->inp_xp);
189	titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
190	titsc_writel(ts_dev, REG_STEPDELAY(end_step),
191			STEPCONFIG_OPENDLY);
192
193	end_step++;
194	config |= STEPCONFIG_INP(ts_dev->inp_yn);
195	titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
196	titsc_writel(ts_dev, REG_STEPDELAY(end_step),
197			STEPCONFIG_OPENDLY);
198
199	/* The steps end ... end - readouts * 2 + 2 and bit 0 for TS_Charge */
200	stepenable = 1;
201	for (i = 0; i < tsc_steps; i++)
202		stepenable |= 1 << (first_step + i + 1);
203
204	ts_dev->step_mask = stepenable;
205	am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask);
206}
207
208static int titsc_cmp_coord(const void *a, const void *b)
209{
210	return *(int *)a - *(int *)b;
211}
212
213static void titsc_read_coordinates(struct titsc *ts_dev,
214		u32 *x, u32 *y, u32 *z1, u32 *z2)
215{
216	unsigned int yvals[7], xvals[7];
217	unsigned int i, xsum = 0, ysum = 0;
218	unsigned int creads = ts_dev->coordinate_readouts;
219
220	for (i = 0; i < creads; i++) {
221		yvals[i] = titsc_readl(ts_dev, REG_FIFO0);
222		yvals[i] &= 0xfff;
223	}
224
225	*z1 = titsc_readl(ts_dev, REG_FIFO0);
226	*z1 &= 0xfff;
227	*z2 = titsc_readl(ts_dev, REG_FIFO0);
228	*z2 &= 0xfff;
229
230	for (i = 0; i < creads; i++) {
231		xvals[i] = titsc_readl(ts_dev, REG_FIFO0);
232		xvals[i] &= 0xfff;
233	}
234
235	/*
236	 * If co-ordinates readouts is less than 4 then
237	 * report the average. In case of 4 or more
238	 * readouts, sort the co-ordinate samples, drop
239	 * min and max values and report the average of
240	 * remaining values.
241	 */
242	if (creads <=  3) {
243		for (i = 0; i < creads; i++) {
244			ysum += yvals[i];
245			xsum += xvals[i];
246		}
247		ysum /= creads;
248		xsum /= creads;
249	} else {
250		sort(yvals, creads, sizeof(unsigned int),
251		     titsc_cmp_coord, NULL);
252		sort(xvals, creads, sizeof(unsigned int),
253		     titsc_cmp_coord, NULL);
254		for (i = 1; i < creads - 1; i++) {
255			ysum += yvals[i];
256			xsum += xvals[i];
257		}
258		ysum /= creads - 2;
259		xsum /= creads - 2;
260	}
261	*y = ysum;
262	*x = xsum;
263}
264
265static irqreturn_t titsc_irq(int irq, void *dev)
266{
267	struct titsc *ts_dev = dev;
268	struct input_dev *input_dev = ts_dev->input;
269	unsigned int fsm, status, irqclr = 0;
270	unsigned int x = 0, y = 0;
271	unsigned int z1, z2, z;
272
273	status = titsc_readl(ts_dev, REG_RAWIRQSTATUS);
274	if (status & IRQENB_HW_PEN) {
275		ts_dev->pen_down = true;
276		irqclr |= IRQENB_HW_PEN;
277	}
278
279	if (status & IRQENB_PENUP) {
280		fsm = titsc_readl(ts_dev, REG_ADCFSM);
281		if (fsm == ADCFSM_STEPID) {
282			ts_dev->pen_down = false;
283			input_report_key(input_dev, BTN_TOUCH, 0);
284			input_report_abs(input_dev, ABS_PRESSURE, 0);
285			input_sync(input_dev);
286		} else {
287			ts_dev->pen_down = true;
288		}
289		irqclr |= IRQENB_PENUP;
290	}
291
292	if (status & IRQENB_EOS)
293		irqclr |= IRQENB_EOS;
294
295	/*
296	 * ADC and touchscreen share the IRQ line.
297	 * FIFO1 interrupts are used by ADC. Handle FIFO0 IRQs here only
298	 */
299	if (status & IRQENB_FIFO0THRES) {
300
301		titsc_read_coordinates(ts_dev, &x, &y, &z1, &z2);
302
303		if (ts_dev->pen_down && z1 != 0 && z2 != 0) {
304			/*
305			 * Calculate pressure using formula
306			 * Resistance(touch) = x plate resistance *
307			 * x postion/4096 * ((z2 / z1) - 1)
308			 */
309			z = z1 - z2;
310			z *= x;
311			z *= ts_dev->x_plate_resistance;
312			z /= z2;
313			z = (z + 2047) >> 12;
314
315			if (z <= MAX_12BIT) {
316				input_report_abs(input_dev, ABS_X, x);
317				input_report_abs(input_dev, ABS_Y, y);
318				input_report_abs(input_dev, ABS_PRESSURE, z);
319				input_report_key(input_dev, BTN_TOUCH, 1);
320				input_sync(input_dev);
321			}
322		}
323		irqclr |= IRQENB_FIFO0THRES;
324	}
325	if (irqclr) {
326		titsc_writel(ts_dev, REG_IRQSTATUS, irqclr);
327		if (status & IRQENB_EOS)
328			am335x_tsc_se_set_cache(ts_dev->mfd_tscadc,
329						ts_dev->step_mask);
330		return IRQ_HANDLED;
331	}
332	return IRQ_NONE;
333}
334
335static int titsc_parse_dt(struct platform_device *pdev,
336					struct titsc *ts_dev)
337{
338	struct device_node *node = pdev->dev.of_node;
339	int err;
340
341	if (!node)
342		return -EINVAL;
343
344	err = of_property_read_u32(node, "ti,wires", &ts_dev->wires);
345	if (err < 0)
346		return err;
347	switch (ts_dev->wires) {
348	case 4:
349	case 5:
350	case 8:
351		break;
352	default:
353		return -EINVAL;
354	}
355
356	err = of_property_read_u32(node, "ti,x-plate-resistance",
357			&ts_dev->x_plate_resistance);
358	if (err < 0)
359		return err;
360
361	/*
362	 * Try with the new binding first. If it fails, try again with
363	 * bogus, miss-spelled version.
364	 */
365	err = of_property_read_u32(node, "ti,coordinate-readouts",
366			&ts_dev->coordinate_readouts);
367	if (err < 0) {
368		dev_warn(&pdev->dev, "please use 'ti,coordinate-readouts' instead\n");
369		err = of_property_read_u32(node, "ti,coordiante-readouts",
370				&ts_dev->coordinate_readouts);
371	}
372
373	if (err < 0)
374		return err;
375
376	if (ts_dev->coordinate_readouts <= 0) {
377		dev_warn(&pdev->dev,
378			 "invalid co-ordinate readouts, resetting it to 5\n");
379		ts_dev->coordinate_readouts = 5;
380	}
381
382	err = of_property_read_u32(node, "ti,charge-delay",
383				   &ts_dev->charge_delay);
384	/*
385	 * If ti,charge-delay value is not specified, then use
386	 * CHARGEDLY_OPENDLY as the default value.
387	 */
388	if (err < 0) {
389		ts_dev->charge_delay = CHARGEDLY_OPENDLY;
390		dev_warn(&pdev->dev, "ti,charge-delay not specified\n");
391	}
392
393	return of_property_read_u32_array(node, "ti,wire-config",
394			ts_dev->config_inp, ARRAY_SIZE(ts_dev->config_inp));
395}
396
397/*
398 * The functions for inserting/removing driver as a module.
399 */
400
401static int titsc_probe(struct platform_device *pdev)
402{
403	struct titsc *ts_dev;
404	struct input_dev *input_dev;
405	struct ti_tscadc_dev *tscadc_dev = ti_tscadc_dev_get(pdev);
406	int err;
407
408	/* Allocate memory for device */
409	ts_dev = kzalloc(sizeof(struct titsc), GFP_KERNEL);
410	input_dev = input_allocate_device();
411	if (!ts_dev || !input_dev) {
412		dev_err(&pdev->dev, "failed to allocate memory.\n");
413		err = -ENOMEM;
414		goto err_free_mem;
415	}
416
417	tscadc_dev->tsc = ts_dev;
418	ts_dev->mfd_tscadc = tscadc_dev;
419	ts_dev->input = input_dev;
420	ts_dev->irq = tscadc_dev->irq;
421
422	err = titsc_parse_dt(pdev, ts_dev);
423	if (err) {
424		dev_err(&pdev->dev, "Could not find valid DT data.\n");
425		goto err_free_mem;
426	}
427
428	err = request_irq(ts_dev->irq, titsc_irq,
429			  IRQF_SHARED, pdev->dev.driver->name, ts_dev);
430	if (err) {
431		dev_err(&pdev->dev, "failed to allocate irq.\n");
432		goto err_free_mem;
433	}
434
435	titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES);
436	titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_EOS);
437	err = titsc_config_wires(ts_dev);
438	if (err) {
439		dev_err(&pdev->dev, "wrong i/p wire configuration\n");
440		goto err_free_irq;
441	}
442	titsc_step_config(ts_dev);
443	titsc_writel(ts_dev, REG_FIFO0THR,
444			ts_dev->coordinate_readouts * 2 + 2 - 1);
445
446	input_dev->name = "ti-tsc";
447	input_dev->dev.parent = &pdev->dev;
448
449	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
450	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
451
452	input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
453	input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
454	input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
455
456	/* register to the input system */
457	err = input_register_device(input_dev);
458	if (err)
459		goto err_free_irq;
460
461	platform_set_drvdata(pdev, ts_dev);
462	return 0;
463
464err_free_irq:
465	free_irq(ts_dev->irq, ts_dev);
466err_free_mem:
467	input_free_device(input_dev);
468	kfree(ts_dev);
469	return err;
470}
471
472static int titsc_remove(struct platform_device *pdev)
473{
474	struct titsc *ts_dev = platform_get_drvdata(pdev);
475	u32 steps;
476
477	free_irq(ts_dev->irq, ts_dev);
478
479	/* total steps followed by the enable mask */
480	steps = 2 * ts_dev->coordinate_readouts + 2;
481	steps = (1 << steps) - 1;
482	am335x_tsc_se_clr(ts_dev->mfd_tscadc, steps);
483
484	input_unregister_device(ts_dev->input);
485
486	kfree(ts_dev);
487	return 0;
488}
489
490#ifdef CONFIG_PM
491static int titsc_suspend(struct device *dev)
492{
493	struct titsc *ts_dev = dev_get_drvdata(dev);
494	struct ti_tscadc_dev *tscadc_dev;
495	unsigned int idle;
496
497	tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
498	if (device_may_wakeup(tscadc_dev->dev)) {
499		idle = titsc_readl(ts_dev, REG_IRQENABLE);
500		titsc_writel(ts_dev, REG_IRQENABLE,
501				(idle | IRQENB_HW_PEN));
502		titsc_writel(ts_dev, REG_IRQWAKEUP, IRQWKUP_ENB);
503	}
504	return 0;
505}
506
507static int titsc_resume(struct device *dev)
508{
509	struct titsc *ts_dev = dev_get_drvdata(dev);
510	struct ti_tscadc_dev *tscadc_dev;
511
512	tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
513	if (device_may_wakeup(tscadc_dev->dev)) {
514		titsc_writel(ts_dev, REG_IRQWAKEUP,
515				0x00);
516		titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
517	}
518	titsc_step_config(ts_dev);
519	titsc_writel(ts_dev, REG_FIFO0THR,
520			ts_dev->coordinate_readouts * 2 + 2 - 1);
521	return 0;
522}
523
524static const struct dev_pm_ops titsc_pm_ops = {
525	.suspend = titsc_suspend,
526	.resume  = titsc_resume,
527};
528#define TITSC_PM_OPS (&titsc_pm_ops)
529#else
530#define TITSC_PM_OPS NULL
531#endif
532
533static const struct of_device_id ti_tsc_dt_ids[] = {
534	{ .compatible = "ti,am3359-tsc", },
535	{ }
536};
537MODULE_DEVICE_TABLE(of, ti_tsc_dt_ids);
538
539static struct platform_driver ti_tsc_driver = {
540	.probe	= titsc_probe,
541	.remove	= titsc_remove,
542	.driver	= {
543		.name   = "TI-am335x-tsc",
544		.pm	= TITSC_PM_OPS,
545		.of_match_table = ti_tsc_dt_ids,
546	},
547};
548module_platform_driver(ti_tsc_driver);
549
550MODULE_DESCRIPTION("TI touchscreen controller driver");
551MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
552MODULE_LICENSE("GPL");