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Linux/drivers/input/touchscreen/intel-mid-touch.c

  1 /*
  2  * Intel MID Resistive Touch Screen Driver
  3  *
  4  * Copyright (C) 2008 Intel Corp
  5  *
  6  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  7  *
  8  * This program is free software; you can redistribute it and/or modify
  9  * it under the terms of the GNU General Public License as published by
 10  * the Free Software Foundation; version 2 of the License.
 11  *
 12  * This program is distributed in the hope that it will be useful, but
 13  * WITHOUT ANY WARRANTY; without even the implied warranty of
 14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 15  * General Public License for more details.
 16  *
 17  * You should have received a copy of the GNU General Public License along
 18  * with this program; if not, write to the Free Software Foundation, Inc.,
 19  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 20  *
 21  * Questions/Comments/Bug fixes to Sreedhara (sreedhara.ds@intel.com)
 22  *                          Ramesh Agarwal (ramesh.agarwal@intel.com)
 23  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 24  *
 25  * TODO:
 26  *      review conversion of r/m/w sequences
 27  */
 28 
 29 #include <linux/module.h>
 30 #include <linux/input.h>
 31 #include <linux/interrupt.h>
 32 #include <linux/err.h>
 33 #include <linux/param.h>
 34 #include <linux/slab.h>
 35 #include <linux/platform_device.h>
 36 #include <linux/irq.h>
 37 #include <linux/delay.h>
 38 #include <asm/intel_scu_ipc.h>
 39 
 40 /* PMIC Interrupt registers */
 41 #define PMIC_REG_ID1            0x00 /* PMIC ID1 register */
 42 
 43 /* PMIC Interrupt registers */
 44 #define PMIC_REG_INT            0x04 /* PMIC interrupt register */
 45 #define PMIC_REG_MINT           0x05 /* PMIC interrupt mask register */
 46 
 47 /* ADC Interrupt registers */
 48 #define PMIC_REG_ADCINT         0x5F /* ADC interrupt register */
 49 #define PMIC_REG_MADCINT        0x60 /* ADC interrupt mask register */
 50 
 51 /* ADC Control registers */
 52 #define PMIC_REG_ADCCNTL1       0x61 /* ADC control register */
 53 
 54 /* ADC Channel Selection registers */
 55 #define PMICADDR0               0xA4
 56 #define END_OF_CHANNEL          0x1F
 57 
 58 /* ADC Result register */
 59 #define PMIC_REG_ADCSNS0H       0x64
 60 
 61 /* ADC channels for touch screen */
 62 #define MRST_TS_CHAN10          0xA /* Touch screen X+ connection */
 63 #define MRST_TS_CHAN11          0xB /* Touch screen X- connection */
 64 #define MRST_TS_CHAN12          0xC /* Touch screen Y+ connection */
 65 #define MRST_TS_CHAN13          0xD /* Touch screen Y- connection */
 66 
 67 /* Touch screen channel BIAS constants */
 68 #define MRST_XBIAS              0x20
 69 #define MRST_YBIAS              0x40
 70 #define MRST_ZBIAS              0x80
 71 
 72 /* Touch screen coordinates */
 73 #define MRST_X_MIN              10
 74 #define MRST_X_MAX              1024
 75 #define MRST_X_FUZZ             5
 76 #define MRST_Y_MIN              10
 77 #define MRST_Y_MAX              1024
 78 #define MRST_Y_FUZZ             5
 79 #define MRST_PRESSURE_MIN       0
 80 #define MRST_PRESSURE_NOMINAL   50
 81 #define MRST_PRESSURE_MAX       100
 82 
 83 #define WAIT_ADC_COMPLETION     10 /* msec */
 84 
 85 /* PMIC ADC round robin delays */
 86 #define ADC_LOOP_DELAY0         0x0 /* Continuous loop */
 87 #define ADC_LOOP_DELAY1         0x1 /* 4.5  ms approximate */
 88 
 89 /* PMIC Vendor Identifiers */
 90 #define PMIC_VENDOR_FS          0 /* PMIC vendor FreeScale */
 91 #define PMIC_VENDOR_MAXIM       1 /* PMIC vendor MAXIM */
 92 #define PMIC_VENDOR_NEC         2 /* PMIC vendor NEC */
 93 #define MRSTOUCH_MAX_CHANNELS   32 /* Maximum ADC channels */
 94 
 95 /* Touch screen device structure */
 96 struct mrstouch_dev {
 97         struct device *dev; /* device associated with touch screen */
 98         struct input_dev *input;
 99         char phys[32];
100         u16 asr;                /* Address selection register */
101         int irq;
102         unsigned int vendor;    /* PMIC vendor */
103         unsigned int rev;       /* PMIC revision */
104 
105         int (*read_prepare)(struct mrstouch_dev *tsdev);
106         int (*read)(struct mrstouch_dev *tsdev, u16 *x, u16 *y, u16 *z);
107         int (*read_finish)(struct mrstouch_dev *tsdev);
108 };
109 
110 
111 /*************************** NEC and Maxim Interface ************************/
112 
113 static int mrstouch_nec_adc_read_prepare(struct mrstouch_dev *tsdev)
114 {
115         return intel_scu_ipc_update_register(PMIC_REG_MADCINT, 0, 0x20);
116 }
117 
118 /*
119  * Enables PENDET interrupt.
120  */
121 static int mrstouch_nec_adc_read_finish(struct mrstouch_dev *tsdev)
122 {
123         int err;
124 
125         err = intel_scu_ipc_update_register(PMIC_REG_MADCINT, 0x20, 0x20);
126         if (!err)
127                 err = intel_scu_ipc_update_register(PMIC_REG_ADCCNTL1, 0, 0x05);
128 
129         return err;
130 }
131 
132 /*
133  * Reads PMIC ADC touch screen result
134  * Reads ADC storage registers for higher 7 and lower 3 bits and
135  * converts the two readings into a single value and turns off gain bit
136  */
137 static int mrstouch_ts_chan_read(u16 offset, u16 chan, u16 *vp, u16 *vm)
138 {
139         int err;
140         u16 result;
141         u32 res;
142 
143         result = PMIC_REG_ADCSNS0H + offset;
144 
145         if (chan == MRST_TS_CHAN12)
146                 result += 4;
147 
148         err = intel_scu_ipc_ioread32(result, &res);
149         if (err)
150                 return err;
151 
152         /* Mash the bits up */
153 
154         *vp = (res & 0xFF) << 3;        /* Highest 7 bits */
155         *vp |= (res >> 8) & 0x07;       /* Lower 3 bits */
156         *vp &= 0x3FF;
157 
158         res >>= 16;
159 
160         *vm = (res & 0xFF) << 3;        /* Highest 7 bits */
161         *vm |= (res >> 8) & 0x07;       /* Lower 3 bits */
162         *vm &= 0x3FF;
163 
164         return 0;
165 }
166 
167 /*
168  * Enables X, Y and Z bias values
169  * Enables YPYM for X channels and XPXM for Y channels
170  */
171 static int mrstouch_ts_bias_set(uint offset, uint bias)
172 {
173         int count;
174         u16 chan, start;
175         u16 reg[4];
176         u8 data[4];
177 
178         chan = PMICADDR0 + offset;
179         start = MRST_TS_CHAN10;
180 
181         for (count = 0; count <= 3; count++) {
182                 reg[count] = chan++;
183                 data[count] = bias | (start + count);
184         }
185 
186         return intel_scu_ipc_writev(reg, data, 4);
187 }
188 
189 /* To read touch screen channel values */
190 static int mrstouch_nec_adc_read(struct mrstouch_dev *tsdev,
191                                  u16 *x, u16 *y, u16 *z)
192 {
193         int err;
194         u16 xm, ym, zm;
195 
196         /* configure Y bias for X channels */
197         err = mrstouch_ts_bias_set(tsdev->asr, MRST_YBIAS);
198         if (err)
199                 goto ipc_error;
200 
201         msleep(WAIT_ADC_COMPLETION);
202 
203         /* read x+ and x- channels */
204         err = mrstouch_ts_chan_read(tsdev->asr, MRST_TS_CHAN10, x, &xm);
205         if (err)
206                 goto ipc_error;
207 
208         /* configure x bias for y channels */
209         err = mrstouch_ts_bias_set(tsdev->asr, MRST_XBIAS);
210         if (err)
211                 goto ipc_error;
212 
213         msleep(WAIT_ADC_COMPLETION);
214 
215         /* read y+ and y- channels */
216         err = mrstouch_ts_chan_read(tsdev->asr, MRST_TS_CHAN12, y, &ym);
217         if (err)
218                 goto ipc_error;
219 
220         /* configure z bias for x and y channels */
221         err = mrstouch_ts_bias_set(tsdev->asr, MRST_ZBIAS);
222         if (err)
223                 goto ipc_error;
224 
225         msleep(WAIT_ADC_COMPLETION);
226 
227         /* read z+ and z- channels */
228         err = mrstouch_ts_chan_read(tsdev->asr, MRST_TS_CHAN10, z, &zm);
229         if (err)
230                 goto ipc_error;
231 
232         return 0;
233 
234 ipc_error:
235         dev_err(tsdev->dev, "ipc error during adc read\n");
236         return err;
237 }
238 
239 
240 /*************************** Freescale Interface ************************/
241 
242 static int mrstouch_fs_adc_read_prepare(struct mrstouch_dev *tsdev)
243 {
244         int err, count;
245         u16 chan;
246         u16 reg[5];
247         u8 data[5];
248 
249         /* Stop the ADC */
250         err = intel_scu_ipc_update_register(PMIC_REG_MADCINT, 0x00, 0x02);
251         if (err)
252                 goto ipc_error;
253 
254         chan = PMICADDR0 + tsdev->asr;
255 
256         /* Set X BIAS */
257         for (count = 0; count <= 3; count++) {
258                 reg[count] = chan++;
259                 data[count] = 0x2A;
260         }
261         reg[count] =  chan++; /* Dummy */
262         data[count] = 0;
263 
264         err = intel_scu_ipc_writev(reg, data, 5);
265         if (err)
266                 goto ipc_error;
267 
268         msleep(WAIT_ADC_COMPLETION);
269 
270         /* Set Y BIAS */
271         for (count = 0; count <= 3; count++) {
272                 reg[count] = chan++;
273                 data[count] = 0x4A;
274         }
275         reg[count] = chan++; /* Dummy */
276         data[count] = 0;
277 
278         err = intel_scu_ipc_writev(reg, data, 5);
279         if (err)
280                 goto ipc_error;
281 
282         msleep(WAIT_ADC_COMPLETION);
283 
284         /* Set Z BIAS */
285         err = intel_scu_ipc_iowrite32(chan + 2, 0x8A8A8A8A);
286         if (err)
287                 goto ipc_error;
288 
289         msleep(WAIT_ADC_COMPLETION);
290 
291         return 0;
292 
293 ipc_error:
294         dev_err(tsdev->dev, "ipc error during %s\n", __func__);
295         return err;
296 }
297 
298 static int mrstouch_fs_adc_read(struct mrstouch_dev *tsdev,
299                                 u16 *x, u16 *y, u16 *z)
300 {
301         int err;
302         u16 result;
303         u16 reg[4];
304         u8 data[4];
305 
306         result = PMIC_REG_ADCSNS0H + tsdev->asr;
307 
308         reg[0] = result + 4;
309         reg[1] = result + 5;
310         reg[2] = result + 16;
311         reg[3] = result + 17;
312 
313         err = intel_scu_ipc_readv(reg, data, 4);
314         if (err)
315                 goto ipc_error;
316 
317         *x = data[0] << 3; /* Higher 7 bits */
318         *x |= data[1] & 0x7; /* Lower 3 bits */
319         *x &= 0x3FF;
320 
321         *y = data[2] << 3; /* Higher 7 bits */
322         *y |= data[3] & 0x7; /* Lower 3 bits */
323         *y &= 0x3FF;
324 
325         /* Read Z value */
326         reg[0] = result + 28;
327         reg[1] = result + 29;
328 
329         err = intel_scu_ipc_readv(reg, data, 4);
330         if (err)
331                 goto ipc_error;
332 
333         *z = data[0] << 3; /* Higher 7 bits */
334         *z |= data[1] & 0x7; /* Lower 3 bits */
335         *z &= 0x3FF;
336 
337         return 0;
338 
339 ipc_error:
340         dev_err(tsdev->dev, "ipc error during %s\n", __func__);
341         return err;
342 }
343 
344 static int mrstouch_fs_adc_read_finish(struct mrstouch_dev *tsdev)
345 {
346         int err, count;
347         u16 chan;
348         u16 reg[5];
349         u8 data[5];
350 
351         /* Clear all TS channels */
352         chan = PMICADDR0 + tsdev->asr;
353         for (count = 0; count <= 4; count++) {
354                 reg[count] = chan++;
355                 data[count] = 0;
356         }
357         err = intel_scu_ipc_writev(reg, data, 5);
358         if (err)
359                 goto ipc_error;
360 
361         for (count = 0; count <= 4; count++) {
362                 reg[count] = chan++;
363                 data[count] = 0;
364         }
365         err = intel_scu_ipc_writev(reg, data, 5);
366         if (err)
367                 goto ipc_error;
368 
369         err = intel_scu_ipc_iowrite32(chan + 2, 0x00000000);
370         if (err)
371                 goto ipc_error;
372 
373         /* Start ADC */
374         err = intel_scu_ipc_update_register(PMIC_REG_MADCINT, 0x02, 0x02);
375         if (err)
376                 goto ipc_error;
377 
378         return 0;
379 
380 ipc_error:
381         dev_err(tsdev->dev, "ipc error during %s\n", __func__);
382         return err;
383 }
384 
385 static void mrstouch_report_event(struct input_dev *input,
386                         unsigned int x, unsigned int y, unsigned int z)
387 {
388         if (z > MRST_PRESSURE_NOMINAL) {
389                 /* Pen touched, report button touch and coordinates */
390                 input_report_key(input, BTN_TOUCH, 1);
391                 input_report_abs(input, ABS_X, x);
392                 input_report_abs(input, ABS_Y, y);
393         } else {
394                 input_report_key(input, BTN_TOUCH, 0);
395         }
396 
397         input_report_abs(input, ABS_PRESSURE, z);
398         input_sync(input);
399 }
400 
401 /* PENDET interrupt handler */
402 static irqreturn_t mrstouch_pendet_irq(int irq, void *dev_id)
403 {
404         struct mrstouch_dev *tsdev = dev_id;
405         u16 x, y, z;
406 
407         /*
408          * Should we lower thread priority? Probably not, since we are
409          * not spinning but sleeping...
410          */
411 
412         if (tsdev->read_prepare(tsdev))
413                 goto out;
414 
415         do {
416                 if (tsdev->read(tsdev, &x, &y, &z))
417                         break;
418 
419                 mrstouch_report_event(tsdev->input, x, y, z);
420         } while (z > MRST_PRESSURE_NOMINAL);
421 
422         tsdev->read_finish(tsdev);
423 
424 out:
425         return IRQ_HANDLED;
426 }
427 
428 /* Utility to read PMIC ID */
429 static int mrstouch_read_pmic_id(uint *vendor, uint *rev)
430 {
431         int err;
432         u8 r;
433 
434         err = intel_scu_ipc_ioread8(PMIC_REG_ID1, &r);
435         if (err)
436                 return err;
437 
438         *vendor = r & 0x7;
439         *rev = (r >> 3) & 0x7;
440 
441         return 0;
442 }
443 
444 /*
445  * Parse ADC channels to find end of the channel configured by other ADC user
446  * NEC and MAXIM requires 4 channels and FreeScale needs 18 channels
447  */
448 static int mrstouch_chan_parse(struct mrstouch_dev *tsdev)
449 {
450         int found = 0;
451         int err, i;
452         u8 r8;
453 
454         for (i = 0; i < MRSTOUCH_MAX_CHANNELS; i++) {
455                 err = intel_scu_ipc_ioread8(PMICADDR0 + i, &r8);
456                 if (err)
457                         return err;
458 
459                 if (r8 == END_OF_CHANNEL) {
460                         found = i;
461                         break;
462                 }
463         }
464 
465         if (tsdev->vendor == PMIC_VENDOR_FS) {
466                 if (found > MRSTOUCH_MAX_CHANNELS - 18)
467                         return -ENOSPC;
468         } else {
469                 if (found > MRSTOUCH_MAX_CHANNELS - 4)
470                         return -ENOSPC;
471         }
472 
473         return found;
474 }
475 
476 
477 /*
478  * Writes touch screen channels to ADC address selection registers
479  */
480 static int mrstouch_ts_chan_set(uint offset)
481 {
482         u16 chan;
483 
484         int ret, count;
485 
486         chan = PMICADDR0 + offset;
487         for (count = 0; count <= 3; count++) {
488                 ret = intel_scu_ipc_iowrite8(chan++, MRST_TS_CHAN10 + count);
489                 if (ret)
490                         return ret;
491         }
492         return intel_scu_ipc_iowrite8(chan++, END_OF_CHANNEL);
493 }
494 
495 /* Initialize ADC */
496 static int mrstouch_adc_init(struct mrstouch_dev *tsdev)
497 {
498         int err, start;
499         u8 ra, rm;
500 
501         err = mrstouch_read_pmic_id(&tsdev->vendor, &tsdev->rev);
502         if (err) {
503                 dev_err(tsdev->dev, "Unable to read PMIC id\n");
504                 return err;
505         }
506 
507         switch (tsdev->vendor) {
508         case PMIC_VENDOR_NEC:
509         case PMIC_VENDOR_MAXIM:
510                 tsdev->read_prepare = mrstouch_nec_adc_read_prepare;
511                 tsdev->read = mrstouch_nec_adc_read;
512                 tsdev->read_finish = mrstouch_nec_adc_read_finish;
513                 break;
514 
515         case PMIC_VENDOR_FS:
516                 tsdev->read_prepare = mrstouch_fs_adc_read_prepare;
517                 tsdev->read = mrstouch_fs_adc_read;
518                 tsdev->read_finish = mrstouch_fs_adc_read_finish;
519                 break;
520 
521         default:
522                 dev_err(tsdev->dev,
523                         "Unsupported touchscreen: %d\n", tsdev->vendor);
524                 return -ENXIO;
525         }
526 
527         start = mrstouch_chan_parse(tsdev);
528         if (start < 0) {
529                 dev_err(tsdev->dev, "Unable to parse channels\n");
530                 return start;
531         }
532 
533         tsdev->asr = start;
534 
535         /*
536          * ADC power on, start, enable PENDET and set loop delay
537          * ADC loop delay is set to 4.5 ms approximately
538          * Loop delay more than this results in jitter in adc readings
539          * Setting loop delay to 0 (continuous loop) in MAXIM stops PENDET
540          * interrupt generation sometimes.
541          */
542 
543         if (tsdev->vendor == PMIC_VENDOR_FS) {
544                 ra = 0xE0 | ADC_LOOP_DELAY0;
545                 rm = 0x5;
546         } else {
547                 /* NEC and MAXIm not consistent with loop delay 0 */
548                 ra = 0xE0 | ADC_LOOP_DELAY1;
549                 rm = 0x0;
550 
551                 /* configure touch screen channels */
552                 err = mrstouch_ts_chan_set(tsdev->asr);
553                 if (err)
554                         return err;
555         }
556 
557         err = intel_scu_ipc_update_register(PMIC_REG_ADCCNTL1, ra, 0xE7);
558         if (err)
559                 return err;
560 
561         err = intel_scu_ipc_update_register(PMIC_REG_MADCINT, rm, 0x03);
562         if (err)
563                 return err;
564 
565         return 0;
566 }
567 
568 
569 /* Probe function for touch screen driver */
570 static int mrstouch_probe(struct platform_device *pdev)
571 {
572         struct mrstouch_dev *tsdev;
573         struct input_dev *input;
574         int err;
575         int irq;
576 
577         irq = platform_get_irq(pdev, 0);
578         if (irq < 0) {
579                 dev_err(&pdev->dev, "no interrupt assigned\n");
580                 return -EINVAL;
581         }
582 
583         tsdev = kzalloc(sizeof(struct mrstouch_dev), GFP_KERNEL);
584         input = input_allocate_device();
585         if (!tsdev || !input) {
586                 dev_err(&pdev->dev, "unable to allocate memory\n");
587                 err = -ENOMEM;
588                 goto err_free_mem;
589         }
590 
591         tsdev->dev = &pdev->dev;
592         tsdev->input = input;
593         tsdev->irq = irq;
594 
595         snprintf(tsdev->phys, sizeof(tsdev->phys),
596                  "%s/input0", dev_name(tsdev->dev));
597 
598         err = mrstouch_adc_init(tsdev);
599         if (err) {
600                 dev_err(&pdev->dev, "ADC initialization failed\n");
601                 goto err_free_mem;
602         }
603 
604         input->name = "mrst_touchscreen";
605         input->phys = tsdev->phys;
606         input->dev.parent = tsdev->dev;
607 
608         input->id.vendor = tsdev->vendor;
609         input->id.version = tsdev->rev;
610 
611         input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
612         input->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
613 
614         input_set_abs_params(tsdev->input, ABS_X,
615                              MRST_X_MIN, MRST_X_MAX, MRST_X_FUZZ, 0);
616         input_set_abs_params(tsdev->input, ABS_Y,
617                              MRST_Y_MIN, MRST_Y_MAX, MRST_Y_FUZZ, 0);
618         input_set_abs_params(tsdev->input, ABS_PRESSURE,
619                              MRST_PRESSURE_MIN, MRST_PRESSURE_MAX, 0, 0);
620 
621         err = request_threaded_irq(tsdev->irq, NULL, mrstouch_pendet_irq,
622                                    IRQF_ONESHOT, "mrstouch", tsdev);
623         if (err) {
624                 dev_err(tsdev->dev, "unable to allocate irq\n");
625                 goto err_free_mem;
626         }
627 
628         err = input_register_device(tsdev->input);
629         if (err) {
630                 dev_err(tsdev->dev, "unable to register input device\n");
631                 goto err_free_irq;
632         }
633 
634         platform_set_drvdata(pdev, tsdev);
635         return 0;
636 
637 err_free_irq:
638         free_irq(tsdev->irq, tsdev);
639 err_free_mem:
640         input_free_device(input);
641         kfree(tsdev);
642         return err;
643 }
644 
645 static int mrstouch_remove(struct platform_device *pdev)
646 {
647         struct mrstouch_dev *tsdev = platform_get_drvdata(pdev);
648 
649         free_irq(tsdev->irq, tsdev);
650         input_unregister_device(tsdev->input);
651         kfree(tsdev);
652 
653         return 0;
654 }
655 
656 static struct platform_driver mrstouch_driver = {
657         .driver = {
658                 .name   = "pmic_touch",
659                 .owner  = THIS_MODULE,
660         },
661         .probe          = mrstouch_probe,
662         .remove         = mrstouch_remove,
663 };
664 module_platform_driver(mrstouch_driver);
665 
666 MODULE_AUTHOR("Sreedhara Murthy. D.S, sreedhara.ds@intel.com");
667 MODULE_DESCRIPTION("Intel Moorestown Resistive Touch Screen Driver");
668 MODULE_LICENSE("GPL");
669 

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