Free Electrons

Embedded Linux Experts

  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
/*
 *  Philips UCB1400 touchscreen driver
 *
 *  Author:	Nicolas Pitre
 *  Created:	September 25, 2006
 *  Copyright:	MontaVista Software, Inc.
 *
 * Spliting done by: Marek Vasut <marek.vasut@gmail.com>
 * If something doesn't work and it worked before spliting, e-mail me,
 * dont bother Nicolas please ;-)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This code is heavily based on ucb1x00-*.c copyrighted by Russell King
 * covering the UCB1100, UCB1200 and UCB1300..  Support for the UCB1400 has
 * been made separate from ucb1x00-core/ucb1x00-ts on Russell's request.
 */

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/input.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/ucb1400.h>

#define UCB1400_TS_POLL_PERIOD	10 /* ms */

static bool adcsync;
static int ts_delay = 55; /* us */
static int ts_delay_pressure;	/* us */

/* Switch to interrupt mode. */
static void ucb1400_ts_mode_int(struct ucb1400_ts *ucb)
{
	ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
			UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
			UCB_TS_CR_MODE_INT);
}

/*
 * Switch to pressure mode, and read pressure.  We don't need to wait
 * here, since both plates are being driven.
 */
static unsigned int ucb1400_ts_read_pressure(struct ucb1400_ts *ucb)
{
	ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
			UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);

	udelay(ts_delay_pressure);

	return ucb1400_adc_read(ucb->ac97, UCB_ADC_INP_TSPY, adcsync);
}

/*
 * Switch to X position mode and measure Y plate.  We switch the plate
 * configuration in pressure mode, then switch to position mode.  This
 * gives a faster response time.  Even so, we need to wait about 55us
 * for things to stabilise.
 */
static unsigned int ucb1400_ts_read_xpos(struct ucb1400_ts *ucb)
{
	ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
			UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
	ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
			UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
	ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
			UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
			UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);

	udelay(ts_delay);

	return ucb1400_adc_read(ucb->ac97, UCB_ADC_INP_TSPY, adcsync);
}

/*
 * Switch to Y position mode and measure X plate.  We switch the plate
 * configuration in pressure mode, then switch to position mode.  This
 * gives a faster response time.  Even so, we need to wait about 55us
 * for things to stabilise.
 */
static int ucb1400_ts_read_ypos(struct ucb1400_ts *ucb)
{
	ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
	ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
	ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
			UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);

	udelay(ts_delay);

	return ucb1400_adc_read(ucb->ac97, UCB_ADC_INP_TSPX, adcsync);
}

/*
 * Switch to X plate resistance mode.  Set MX to ground, PX to
 * supply.  Measure current.
 */
static unsigned int ucb1400_ts_read_xres(struct ucb1400_ts *ucb)
{
	ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
			UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
	return ucb1400_adc_read(ucb->ac97, 0, adcsync);
}

/*
 * Switch to Y plate resistance mode.  Set MY to ground, PY to
 * supply.  Measure current.
 */
static unsigned int ucb1400_ts_read_yres(struct ucb1400_ts *ucb)
{
	ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
	return ucb1400_adc_read(ucb->ac97, 0, adcsync);
}

static int ucb1400_ts_pen_up(struct ucb1400_ts *ucb)
{
	unsigned short val = ucb1400_reg_read(ucb->ac97, UCB_TS_CR);

	return val & (UCB_TS_CR_TSPX_LOW | UCB_TS_CR_TSMX_LOW);
}

static void ucb1400_ts_irq_enable(struct ucb1400_ts *ucb)
{
	ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, UCB_IE_TSPX);
	ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0);
	ucb1400_reg_write(ucb->ac97, UCB_IE_FAL, UCB_IE_TSPX);
}

static void ucb1400_ts_irq_disable(struct ucb1400_ts *ucb)
{
	ucb1400_reg_write(ucb->ac97, UCB_IE_FAL, 0);
}

static void ucb1400_ts_report_event(struct input_dev *idev, u16 pressure, u16 x, u16 y)
{
	input_report_abs(idev, ABS_X, x);
	input_report_abs(idev, ABS_Y, y);
	input_report_abs(idev, ABS_PRESSURE, pressure);
	input_report_key(idev, BTN_TOUCH, 1);
	input_sync(idev);
}

static void ucb1400_ts_event_release(struct input_dev *idev)
{
	input_report_abs(idev, ABS_PRESSURE, 0);
	input_report_key(idev, BTN_TOUCH, 0);
	input_sync(idev);
}

static void ucb1400_clear_pending_irq(struct ucb1400_ts *ucb)
{
	unsigned int isr;

	isr = ucb1400_reg_read(ucb->ac97, UCB_IE_STATUS);
	ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, isr);
	ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0);

	if (isr & UCB_IE_TSPX)
		ucb1400_ts_irq_disable(ucb);
	else
		dev_dbg(&ucb->ts_idev->dev,
			"ucb1400: unexpected IE_STATUS = %#x\n", isr);
}

/*
 * A restriction with interrupts exists when using the ucb1400, as
 * the codec read/write routines may sleep while waiting for codec
 * access completion and uses semaphores for access control to the
 * AC97 bus. Therefore the driver is forced to use threaded interrupt
 * handler.
 */
static irqreturn_t ucb1400_irq(int irqnr, void *devid)
{
	struct ucb1400_ts *ucb = devid;
	unsigned int x, y, p;
	bool penup;

	if (unlikely(irqnr != ucb->irq))
		return IRQ_NONE;

	ucb1400_clear_pending_irq(ucb);

	/* Start with a small delay before checking pendown state */
	msleep(UCB1400_TS_POLL_PERIOD);

	while (!ucb->stopped && !(penup = ucb1400_ts_pen_up(ucb))) {

		ucb1400_adc_enable(ucb->ac97);
		x = ucb1400_ts_read_xpos(ucb);
		y = ucb1400_ts_read_ypos(ucb);
		p = ucb1400_ts_read_pressure(ucb);
		ucb1400_adc_disable(ucb->ac97);

		ucb1400_ts_report_event(ucb->ts_idev, p, x, y);

		wait_event_timeout(ucb->ts_wait, ucb->stopped,
				   msecs_to_jiffies(UCB1400_TS_POLL_PERIOD));
	}

	ucb1400_ts_event_release(ucb->ts_idev);

	if (!ucb->stopped) {
		/* Switch back to interrupt mode. */
		ucb1400_ts_mode_int(ucb);
		ucb1400_ts_irq_enable(ucb);
	}

	return IRQ_HANDLED;
}

static void ucb1400_ts_stop(struct ucb1400_ts *ucb)
{
	/* Signal IRQ thread to stop polling and disable the handler. */
	ucb->stopped = true;
	mb();
	wake_up(&ucb->ts_wait);
	disable_irq(ucb->irq);

	ucb1400_ts_irq_disable(ucb);
	ucb1400_reg_write(ucb->ac97, UCB_TS_CR, 0);
}

/* Must be called with ts->lock held */
static void ucb1400_ts_start(struct ucb1400_ts *ucb)
{
	/* Tell IRQ thread that it may poll the device. */
	ucb->stopped = false;
	mb();

	ucb1400_ts_mode_int(ucb);
	ucb1400_ts_irq_enable(ucb);

	enable_irq(ucb->irq);
}

static int ucb1400_ts_open(struct input_dev *idev)
{
	struct ucb1400_ts *ucb = input_get_drvdata(idev);

	ucb1400_ts_start(ucb);

	return 0;
}

static void ucb1400_ts_close(struct input_dev *idev)
{
	struct ucb1400_ts *ucb = input_get_drvdata(idev);

	ucb1400_ts_stop(ucb);
}

#ifndef NO_IRQ
#define NO_IRQ	0
#endif

/*
 * Try to probe our interrupt, rather than relying on lots of
 * hard-coded machine dependencies.
 */
static int ucb1400_ts_detect_irq(struct ucb1400_ts *ucb,
					   struct platform_device *pdev)
{
	unsigned long mask, timeout;

	mask = probe_irq_on();

	/* Enable the ADC interrupt. */
	ucb1400_reg_write(ucb->ac97, UCB_IE_RIS, UCB_IE_ADC);
	ucb1400_reg_write(ucb->ac97, UCB_IE_FAL, UCB_IE_ADC);
	ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0xffff);
	ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0);

	/* Cause an ADC interrupt. */
	ucb1400_reg_write(ucb->ac97, UCB_ADC_CR, UCB_ADC_ENA);
	ucb1400_reg_write(ucb->ac97, UCB_ADC_CR, UCB_ADC_ENA | UCB_ADC_START);

	/* Wait for the conversion to complete. */
	timeout = jiffies + HZ/2;
	while (!(ucb1400_reg_read(ucb->ac97, UCB_ADC_DATA) &
						UCB_ADC_DAT_VALID)) {
		cpu_relax();
		if (time_after(jiffies, timeout)) {
			dev_err(&pdev->dev, "timed out in IRQ probe\n");
			probe_irq_off(mask);
			return -ENODEV;
		}
	}
	ucb1400_reg_write(ucb->ac97, UCB_ADC_CR, 0);

	/* Disable and clear interrupt. */
	ucb1400_reg_write(ucb->ac97, UCB_IE_RIS, 0);
	ucb1400_reg_write(ucb->ac97, UCB_IE_FAL, 0);
	ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0xffff);
	ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0);

	/* Read triggered interrupt. */
	ucb->irq = probe_irq_off(mask);
	if (ucb->irq < 0 || ucb->irq == NO_IRQ)
		return -ENODEV;

	return 0;
}

static int ucb1400_ts_probe(struct platform_device *pdev)
{
	struct ucb1400_ts *ucb = dev_get_platdata(&pdev->dev);
	int error, x_res, y_res;
	u16 fcsr;

	ucb->ts_idev = input_allocate_device();
	if (!ucb->ts_idev) {
		error = -ENOMEM;
		goto err;
	}

	/* Only in case the IRQ line wasn't supplied, try detecting it */
	if (ucb->irq < 0) {
		error = ucb1400_ts_detect_irq(ucb, pdev);
		if (error) {
			dev_err(&pdev->dev, "IRQ probe failed\n");
			goto err_free_devs;
		}
	}
	dev_dbg(&pdev->dev, "found IRQ %d\n", ucb->irq);

	init_waitqueue_head(&ucb->ts_wait);

	input_set_drvdata(ucb->ts_idev, ucb);

	ucb->ts_idev->dev.parent	= &pdev->dev;
	ucb->ts_idev->name		= "UCB1400 touchscreen interface";
	ucb->ts_idev->id.vendor		= ucb1400_reg_read(ucb->ac97,
						AC97_VENDOR_ID1);
	ucb->ts_idev->id.product	= ucb->id;
	ucb->ts_idev->open		= ucb1400_ts_open;
	ucb->ts_idev->close		= ucb1400_ts_close;
	ucb->ts_idev->evbit[0]		= BIT_MASK(EV_ABS) | BIT_MASK(EV_KEY);
	ucb->ts_idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);

	/*
	 * Enable ADC filter to prevent horrible jitter on Colibri.
	 * This also further reduces jitter on boards where ADCSYNC
	 * pin is connected.
	 */
	fcsr = ucb1400_reg_read(ucb->ac97, UCB_FCSR);
	ucb1400_reg_write(ucb->ac97, UCB_FCSR, fcsr | UCB_FCSR_AVE);

	ucb1400_adc_enable(ucb->ac97);
	x_res = ucb1400_ts_read_xres(ucb);
	y_res = ucb1400_ts_read_yres(ucb);
	ucb1400_adc_disable(ucb->ac97);
	dev_dbg(&pdev->dev, "x/y = %d/%d\n", x_res, y_res);

	input_set_abs_params(ucb->ts_idev, ABS_X, 0, x_res, 0, 0);
	input_set_abs_params(ucb->ts_idev, ABS_Y, 0, y_res, 0, 0);
	input_set_abs_params(ucb->ts_idev, ABS_PRESSURE, 0, 0, 0, 0);

	ucb1400_ts_stop(ucb);

	error = request_threaded_irq(ucb->irq, NULL, ucb1400_irq,
				     IRQF_TRIGGER_RISING | IRQF_ONESHOT,
				     "UCB1400", ucb);
	if (error) {
		dev_err(&pdev->dev,
			"unable to grab irq%d: %d\n", ucb->irq, error);
		goto err_free_devs;
	}

	error = input_register_device(ucb->ts_idev);
	if (error)
		goto err_free_irq;

	return 0;

err_free_irq:
	free_irq(ucb->irq, ucb);
err_free_devs:
	input_free_device(ucb->ts_idev);
err:
	return error;
}

static int ucb1400_ts_remove(struct platform_device *pdev)
{
	struct ucb1400_ts *ucb = dev_get_platdata(&pdev->dev);

	free_irq(ucb->irq, ucb);
	input_unregister_device(ucb->ts_idev);

	return 0;
}

static int __maybe_unused ucb1400_ts_suspend(struct device *dev)
{
	struct ucb1400_ts *ucb = dev_get_platdata(dev);
	struct input_dev *idev = ucb->ts_idev;

	mutex_lock(&idev->mutex);

	if (idev->users)
		ucb1400_ts_stop(ucb);

	mutex_unlock(&idev->mutex);
	return 0;
}

static int __maybe_unused ucb1400_ts_resume(struct device *dev)
{
	struct ucb1400_ts *ucb = dev_get_platdata(dev);
	struct input_dev *idev = ucb->ts_idev;

	mutex_lock(&idev->mutex);

	if (idev->users)
		ucb1400_ts_start(ucb);

	mutex_unlock(&idev->mutex);
	return 0;
}

static SIMPLE_DEV_PM_OPS(ucb1400_ts_pm_ops,
			 ucb1400_ts_suspend, ucb1400_ts_resume);

static struct platform_driver ucb1400_ts_driver = {
	.probe	= ucb1400_ts_probe,
	.remove	= ucb1400_ts_remove,
	.driver	= {
		.name	= "ucb1400_ts",
		.pm	= &ucb1400_ts_pm_ops,
	},
};
module_platform_driver(ucb1400_ts_driver);

module_param(adcsync, bool, 0444);
MODULE_PARM_DESC(adcsync, "Synchronize touch readings with ADCSYNC pin.");

module_param(ts_delay, int, 0444);
MODULE_PARM_DESC(ts_delay, "Delay between panel setup and"
			    " position read. Default = 55us.");

module_param(ts_delay_pressure, int, 0444);
MODULE_PARM_DESC(ts_delay_pressure,
		"delay between panel setup and pressure read."
		"  Default = 0us.");

MODULE_DESCRIPTION("Philips UCB1400 touchscreen driver");
MODULE_LICENSE("GPL");