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Linux/drivers/input/touchscreen/ads7846.c

  1 /*
  2  * ADS7846 based touchscreen and sensor driver
  3  *
  4  * Copyright (c) 2005 David Brownell
  5  * Copyright (c) 2006 Nokia Corporation
  6  * Various changes: Imre Deak <imre.deak@nokia.com>
  7  *
  8  * Using code from:
  9  *  - corgi_ts.c
 10  *      Copyright (C) 2004-2005 Richard Purdie
 11  *  - omap_ts.[hc], ads7846.h, ts_osk.c
 12  *      Copyright (C) 2002 MontaVista Software
 13  *      Copyright (C) 2004 Texas Instruments
 14  *      Copyright (C) 2005 Dirk Behme
 15  *
 16  *  This program is free software; you can redistribute it and/or modify
 17  *  it under the terms of the GNU General Public License version 2 as
 18  *  published by the Free Software Foundation.
 19  */
 20 #include <linux/types.h>
 21 #include <linux/hwmon.h>
 22 #include <linux/err.h>
 23 #include <linux/sched.h>
 24 #include <linux/delay.h>
 25 #include <linux/input.h>
 26 #include <linux/interrupt.h>
 27 #include <linux/slab.h>
 28 #include <linux/pm.h>
 29 #include <linux/of.h>
 30 #include <linux/of_gpio.h>
 31 #include <linux/of_device.h>
 32 #include <linux/gpio.h>
 33 #include <linux/spi/spi.h>
 34 #include <linux/spi/ads7846.h>
 35 #include <linux/regulator/consumer.h>
 36 #include <linux/module.h>
 37 #include <asm/irq.h>
 38 
 39 /*
 40  * This code has been heavily tested on a Nokia 770, and lightly
 41  * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
 42  * TSC2046 is just newer ads7846 silicon.
 43  * Support for ads7843 tested on Atmel at91sam926x-EK.
 44  * Support for ads7845 has only been stubbed in.
 45  * Support for Analog Devices AD7873 and AD7843 tested.
 46  *
 47  * IRQ handling needs a workaround because of a shortcoming in handling
 48  * edge triggered IRQs on some platforms like the OMAP1/2. These
 49  * platforms don't handle the ARM lazy IRQ disabling properly, thus we
 50  * have to maintain our own SW IRQ disabled status. This should be
 51  * removed as soon as the affected platform's IRQ handling is fixed.
 52  *
 53  * App note sbaa036 talks in more detail about accurate sampling...
 54  * that ought to help in situations like LCDs inducing noise (which
 55  * can also be helped by using synch signals) and more generally.
 56  * This driver tries to utilize the measures described in the app
 57  * note. The strength of filtering can be set in the board-* specific
 58  * files.
 59  */
 60 
 61 #define TS_POLL_DELAY   1       /* ms delay before the first sample */
 62 #define TS_POLL_PERIOD  5       /* ms delay between samples */
 63 
 64 /* this driver doesn't aim at the peak continuous sample rate */
 65 #define SAMPLE_BITS     (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
 66 
 67 struct ts_event {
 68         /*
 69          * For portability, we can't read 12 bit values using SPI (which
 70          * would make the controller deliver them as native byte order u16
 71          * with msbs zeroed).  Instead, we read them as two 8-bit values,
 72          * *** WHICH NEED BYTESWAPPING *** and range adjustment.
 73          */
 74         u16     x;
 75         u16     y;
 76         u16     z1, z2;
 77         bool    ignore;
 78         u8      x_buf[3];
 79         u8      y_buf[3];
 80 };
 81 
 82 /*
 83  * We allocate this separately to avoid cache line sharing issues when
 84  * driver is used with DMA-based SPI controllers (like atmel_spi) on
 85  * systems where main memory is not DMA-coherent (most non-x86 boards).
 86  */
 87 struct ads7846_packet {
 88         u8                      read_x, read_y, read_z1, read_z2, pwrdown;
 89         u16                     dummy;          /* for the pwrdown read */
 90         struct ts_event         tc;
 91         /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
 92         u8                      read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3];
 93 };
 94 
 95 struct ads7846 {
 96         struct input_dev        *input;
 97         char                    phys[32];
 98         char                    name[32];
 99 
100         struct spi_device       *spi;
101         struct regulator        *reg;
102 
103 #if IS_ENABLED(CONFIG_HWMON)
104         struct device           *hwmon;
105 #endif
106 
107         u16                     model;
108         u16                     vref_mv;
109         u16                     vref_delay_usecs;
110         u16                     x_plate_ohms;
111         u16                     pressure_max;
112 
113         bool                    swap_xy;
114         bool                    use_internal;
115 
116         struct ads7846_packet   *packet;
117 
118         struct spi_transfer     xfer[18];
119         struct spi_message      msg[5];
120         int                     msg_count;
121         wait_queue_head_t       wait;
122 
123         bool                    pendown;
124 
125         int                     read_cnt;
126         int                     read_rep;
127         int                     last_read;
128 
129         u16                     debounce_max;
130         u16                     debounce_tol;
131         u16                     debounce_rep;
132 
133         u16                     penirq_recheck_delay_usecs;
134 
135         struct mutex            lock;
136         bool                    stopped;        /* P: lock */
137         bool                    disabled;       /* P: lock */
138         bool                    suspended;      /* P: lock */
139 
140         int                     (*filter)(void *data, int data_idx, int *val);
141         void                    *filter_data;
142         void                    (*filter_cleanup)(void *data);
143         int                     (*get_pendown_state)(void);
144         int                     gpio_pendown;
145 
146         void                    (*wait_for_sync)(void);
147 };
148 
149 /* leave chip selected when we're done, for quicker re-select? */
150 #if     0
151 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
152 #else
153 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
154 #endif
155 
156 /*--------------------------------------------------------------------------*/
157 
158 /* The ADS7846 has touchscreen and other sensors.
159  * Earlier ads784x chips are somewhat compatible.
160  */
161 #define ADS_START               (1 << 7)
162 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
163 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
164 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
165 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
166 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
167 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
168 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
169 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
170 #define ADS_8_BIT               (1 << 3)
171 #define ADS_12_BIT              (0 << 3)
172 #define ADS_SER                 (1 << 2)        /* non-differential */
173 #define ADS_DFR                 (0 << 2)        /* differential */
174 #define ADS_PD10_PDOWN          (0 << 0)        /* low power mode + penirq */
175 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
176 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
177 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
178 
179 #define MAX_12BIT       ((1<<12)-1)
180 
181 /* leave ADC powered up (disables penirq) between differential samples */
182 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
183         | ADS_12_BIT | ADS_DFR | \
184         (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
185 
186 #define READ_Y(vref)    (READ_12BIT_DFR(y,  1, vref))
187 #define READ_Z1(vref)   (READ_12BIT_DFR(z1, 1, vref))
188 #define READ_Z2(vref)   (READ_12BIT_DFR(z2, 1, vref))
189 
190 #define READ_X(vref)    (READ_12BIT_DFR(x,  1, vref))
191 #define PWRDOWN         (READ_12BIT_DFR(y,  0, 0))      /* LAST */
192 
193 /* single-ended samples need to first power up reference voltage;
194  * we leave both ADC and VREF powered
195  */
196 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
197         | ADS_12_BIT | ADS_SER)
198 
199 #define REF_ON  (READ_12BIT_DFR(x, 1, 1))
200 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
201 
202 /* Must be called with ts->lock held */
203 static void ads7846_stop(struct ads7846 *ts)
204 {
205         if (!ts->disabled && !ts->suspended) {
206                 /* Signal IRQ thread to stop polling and disable the handler. */
207                 ts->stopped = true;
208                 mb();
209                 wake_up(&ts->wait);
210                 disable_irq(ts->spi->irq);
211         }
212 }
213 
214 /* Must be called with ts->lock held */
215 static void ads7846_restart(struct ads7846 *ts)
216 {
217         if (!ts->disabled && !ts->suspended) {
218                 /* Tell IRQ thread that it may poll the device. */
219                 ts->stopped = false;
220                 mb();
221                 enable_irq(ts->spi->irq);
222         }
223 }
224 
225 /* Must be called with ts->lock held */
226 static void __ads7846_disable(struct ads7846 *ts)
227 {
228         ads7846_stop(ts);
229         regulator_disable(ts->reg);
230 
231         /*
232          * We know the chip's in low power mode since we always
233          * leave it that way after every request
234          */
235 }
236 
237 /* Must be called with ts->lock held */
238 static void __ads7846_enable(struct ads7846 *ts)
239 {
240         int error;
241 
242         error = regulator_enable(ts->reg);
243         if (error != 0)
244                 dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error);
245 
246         ads7846_restart(ts);
247 }
248 
249 static void ads7846_disable(struct ads7846 *ts)
250 {
251         mutex_lock(&ts->lock);
252 
253         if (!ts->disabled) {
254 
255                 if  (!ts->suspended)
256                         __ads7846_disable(ts);
257 
258                 ts->disabled = true;
259         }
260 
261         mutex_unlock(&ts->lock);
262 }
263 
264 static void ads7846_enable(struct ads7846 *ts)
265 {
266         mutex_lock(&ts->lock);
267 
268         if (ts->disabled) {
269 
270                 ts->disabled = false;
271 
272                 if (!ts->suspended)
273                         __ads7846_enable(ts);
274         }
275 
276         mutex_unlock(&ts->lock);
277 }
278 
279 /*--------------------------------------------------------------------------*/
280 
281 /*
282  * Non-touchscreen sensors only use single-ended conversions.
283  * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
284  * ads7846 lets that pin be unconnected, to use internal vREF.
285  */
286 
287 struct ser_req {
288         u8                      ref_on;
289         u8                      command;
290         u8                      ref_off;
291         u16                     scratch;
292         struct spi_message      msg;
293         struct spi_transfer     xfer[6];
294         /*
295          * DMA (thus cache coherency maintenance) requires the
296          * transfer buffers to live in their own cache lines.
297          */
298         __be16 sample ____cacheline_aligned;
299 };
300 
301 struct ads7845_ser_req {
302         u8                      command[3];
303         struct spi_message      msg;
304         struct spi_transfer     xfer[2];
305         /*
306          * DMA (thus cache coherency maintenance) requires the
307          * transfer buffers to live in their own cache lines.
308          */
309         u8 sample[3] ____cacheline_aligned;
310 };
311 
312 static int ads7846_read12_ser(struct device *dev, unsigned command)
313 {
314         struct spi_device *spi = to_spi_device(dev);
315         struct ads7846 *ts = dev_get_drvdata(dev);
316         struct ser_req *req;
317         int status;
318 
319         req = kzalloc(sizeof *req, GFP_KERNEL);
320         if (!req)
321                 return -ENOMEM;
322 
323         spi_message_init(&req->msg);
324 
325         /* maybe turn on internal vREF, and let it settle */
326         if (ts->use_internal) {
327                 req->ref_on = REF_ON;
328                 req->xfer[0].tx_buf = &req->ref_on;
329                 req->xfer[0].len = 1;
330                 spi_message_add_tail(&req->xfer[0], &req->msg);
331 
332                 req->xfer[1].rx_buf = &req->scratch;
333                 req->xfer[1].len = 2;
334 
335                 /* for 1uF, settle for 800 usec; no cap, 100 usec.  */
336                 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
337                 spi_message_add_tail(&req->xfer[1], &req->msg);
338 
339                 /* Enable reference voltage */
340                 command |= ADS_PD10_REF_ON;
341         }
342 
343         /* Enable ADC in every case */
344         command |= ADS_PD10_ADC_ON;
345 
346         /* take sample */
347         req->command = (u8) command;
348         req->xfer[2].tx_buf = &req->command;
349         req->xfer[2].len = 1;
350         spi_message_add_tail(&req->xfer[2], &req->msg);
351 
352         req->xfer[3].rx_buf = &req->sample;
353         req->xfer[3].len = 2;
354         spi_message_add_tail(&req->xfer[3], &req->msg);
355 
356         /* REVISIT:  take a few more samples, and compare ... */
357 
358         /* converter in low power mode & enable PENIRQ */
359         req->ref_off = PWRDOWN;
360         req->xfer[4].tx_buf = &req->ref_off;
361         req->xfer[4].len = 1;
362         spi_message_add_tail(&req->xfer[4], &req->msg);
363 
364         req->xfer[5].rx_buf = &req->scratch;
365         req->xfer[5].len = 2;
366         CS_CHANGE(req->xfer[5]);
367         spi_message_add_tail(&req->xfer[5], &req->msg);
368 
369         mutex_lock(&ts->lock);
370         ads7846_stop(ts);
371         status = spi_sync(spi, &req->msg);
372         ads7846_restart(ts);
373         mutex_unlock(&ts->lock);
374 
375         if (status == 0) {
376                 /* on-wire is a must-ignore bit, a BE12 value, then padding */
377                 status = be16_to_cpu(req->sample);
378                 status = status >> 3;
379                 status &= 0x0fff;
380         }
381 
382         kfree(req);
383         return status;
384 }
385 
386 static int ads7845_read12_ser(struct device *dev, unsigned command)
387 {
388         struct spi_device *spi = to_spi_device(dev);
389         struct ads7846 *ts = dev_get_drvdata(dev);
390         struct ads7845_ser_req *req;
391         int status;
392 
393         req = kzalloc(sizeof *req, GFP_KERNEL);
394         if (!req)
395                 return -ENOMEM;
396 
397         spi_message_init(&req->msg);
398 
399         req->command[0] = (u8) command;
400         req->xfer[0].tx_buf = req->command;
401         req->xfer[0].rx_buf = req->sample;
402         req->xfer[0].len = 3;
403         spi_message_add_tail(&req->xfer[0], &req->msg);
404 
405         mutex_lock(&ts->lock);
406         ads7846_stop(ts);
407         status = spi_sync(spi, &req->msg);
408         ads7846_restart(ts);
409         mutex_unlock(&ts->lock);
410 
411         if (status == 0) {
412                 /* BE12 value, then padding */
413                 status = be16_to_cpu(*((u16 *)&req->sample[1]));
414                 status = status >> 3;
415                 status &= 0x0fff;
416         }
417 
418         kfree(req);
419         return status;
420 }
421 
422 #if IS_ENABLED(CONFIG_HWMON)
423 
424 #define SHOW(name, var, adjust) static ssize_t \
425 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
426 { \
427         struct ads7846 *ts = dev_get_drvdata(dev); \
428         ssize_t v = ads7846_read12_ser(&ts->spi->dev, \
429                         READ_12BIT_SER(var)); \
430         if (v < 0) \
431                 return v; \
432         return sprintf(buf, "%u\n", adjust(ts, v)); \
433 } \
434 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
435 
436 
437 /* Sysfs conventions report temperatures in millidegrees Celsius.
438  * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
439  * accuracy scheme without calibration data.  For now we won't try either;
440  * userspace sees raw sensor values, and must scale/calibrate appropriately.
441  */
442 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
443 {
444         return v;
445 }
446 
447 SHOW(temp0, temp0, null_adjust)         /* temp1_input */
448 SHOW(temp1, temp1, null_adjust)         /* temp2_input */
449 
450 
451 /* sysfs conventions report voltages in millivolts.  We can convert voltages
452  * if we know vREF.  userspace may need to scale vAUX to match the board's
453  * external resistors; we assume that vBATT only uses the internal ones.
454  */
455 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
456 {
457         unsigned retval = v;
458 
459         /* external resistors may scale vAUX into 0..vREF */
460         retval *= ts->vref_mv;
461         retval = retval >> 12;
462 
463         return retval;
464 }
465 
466 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
467 {
468         unsigned retval = vaux_adjust(ts, v);
469 
470         /* ads7846 has a resistor ladder to scale this signal down */
471         if (ts->model == 7846)
472                 retval *= 4;
473 
474         return retval;
475 }
476 
477 SHOW(in0_input, vaux, vaux_adjust)
478 SHOW(in1_input, vbatt, vbatt_adjust)
479 
480 static umode_t ads7846_is_visible(struct kobject *kobj, struct attribute *attr,
481                                   int index)
482 {
483         struct device *dev = container_of(kobj, struct device, kobj);
484         struct ads7846 *ts = dev_get_drvdata(dev);
485 
486         if (ts->model == 7843 && index < 2)     /* in0, in1 */
487                 return 0;
488         if (ts->model == 7845 && index != 2)    /* in0 */
489                 return 0;
490 
491         return attr->mode;
492 }
493 
494 static struct attribute *ads7846_attributes[] = {
495         &dev_attr_temp0.attr,           /* 0 */
496         &dev_attr_temp1.attr,           /* 1 */
497         &dev_attr_in0_input.attr,       /* 2 */
498         &dev_attr_in1_input.attr,       /* 3 */
499         NULL,
500 };
501 
502 static struct attribute_group ads7846_attr_group = {
503         .attrs = ads7846_attributes,
504         .is_visible = ads7846_is_visible,
505 };
506 __ATTRIBUTE_GROUPS(ads7846_attr);
507 
508 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
509 {
510         /* hwmon sensors need a reference voltage */
511         switch (ts->model) {
512         case 7846:
513                 if (!ts->vref_mv) {
514                         dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
515                         ts->vref_mv = 2500;
516                         ts->use_internal = true;
517                 }
518                 break;
519         case 7845:
520         case 7843:
521                 if (!ts->vref_mv) {
522                         dev_warn(&spi->dev,
523                                 "external vREF for ADS%d not specified\n",
524                                 ts->model);
525                         return 0;
526                 }
527                 break;
528         }
529 
530         ts->hwmon = hwmon_device_register_with_groups(&spi->dev, spi->modalias,
531                                                       ts, ads7846_attr_groups);
532 
533         return PTR_ERR_OR_ZERO(ts->hwmon);
534 }
535 
536 static void ads784x_hwmon_unregister(struct spi_device *spi,
537                                      struct ads7846 *ts)
538 {
539         if (ts->hwmon)
540                 hwmon_device_unregister(ts->hwmon);
541 }
542 
543 #else
544 static inline int ads784x_hwmon_register(struct spi_device *spi,
545                                          struct ads7846 *ts)
546 {
547         return 0;
548 }
549 
550 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
551                                             struct ads7846 *ts)
552 {
553 }
554 #endif
555 
556 static ssize_t ads7846_pen_down_show(struct device *dev,
557                                      struct device_attribute *attr, char *buf)
558 {
559         struct ads7846 *ts = dev_get_drvdata(dev);
560 
561         return sprintf(buf, "%u\n", ts->pendown);
562 }
563 
564 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
565 
566 static ssize_t ads7846_disable_show(struct device *dev,
567                                      struct device_attribute *attr, char *buf)
568 {
569         struct ads7846 *ts = dev_get_drvdata(dev);
570 
571         return sprintf(buf, "%u\n", ts->disabled);
572 }
573 
574 static ssize_t ads7846_disable_store(struct device *dev,
575                                      struct device_attribute *attr,
576                                      const char *buf, size_t count)
577 {
578         struct ads7846 *ts = dev_get_drvdata(dev);
579         unsigned int i;
580         int err;
581 
582         err = kstrtouint(buf, 10, &i);
583         if (err)
584                 return err;
585 
586         if (i)
587                 ads7846_disable(ts);
588         else
589                 ads7846_enable(ts);
590 
591         return count;
592 }
593 
594 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
595 
596 static struct attribute *ads784x_attributes[] = {
597         &dev_attr_pen_down.attr,
598         &dev_attr_disable.attr,
599         NULL,
600 };
601 
602 static struct attribute_group ads784x_attr_group = {
603         .attrs = ads784x_attributes,
604 };
605 
606 /*--------------------------------------------------------------------------*/
607 
608 static int get_pendown_state(struct ads7846 *ts)
609 {
610         if (ts->get_pendown_state)
611                 return ts->get_pendown_state();
612 
613         return !gpio_get_value(ts->gpio_pendown);
614 }
615 
616 static void null_wait_for_sync(void)
617 {
618 }
619 
620 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
621 {
622         struct ads7846 *ts = ads;
623 
624         if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
625                 /* Start over collecting consistent readings. */
626                 ts->read_rep = 0;
627                 /*
628                  * Repeat it, if this was the first read or the read
629                  * wasn't consistent enough.
630                  */
631                 if (ts->read_cnt < ts->debounce_max) {
632                         ts->last_read = *val;
633                         ts->read_cnt++;
634                         return ADS7846_FILTER_REPEAT;
635                 } else {
636                         /*
637                          * Maximum number of debouncing reached and still
638                          * not enough number of consistent readings. Abort
639                          * the whole sample, repeat it in the next sampling
640                          * period.
641                          */
642                         ts->read_cnt = 0;
643                         return ADS7846_FILTER_IGNORE;
644                 }
645         } else {
646                 if (++ts->read_rep > ts->debounce_rep) {
647                         /*
648                          * Got a good reading for this coordinate,
649                          * go for the next one.
650                          */
651                         ts->read_cnt = 0;
652                         ts->read_rep = 0;
653                         return ADS7846_FILTER_OK;
654                 } else {
655                         /* Read more values that are consistent. */
656                         ts->read_cnt++;
657                         return ADS7846_FILTER_REPEAT;
658                 }
659         }
660 }
661 
662 static int ads7846_no_filter(void *ads, int data_idx, int *val)
663 {
664         return ADS7846_FILTER_OK;
665 }
666 
667 static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
668 {
669         int value;
670         struct spi_transfer *t =
671                 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
672 
673         if (ts->model == 7845) {
674                 value = be16_to_cpup((__be16 *)&(((char *)t->rx_buf)[1]));
675         } else {
676                 /*
677                  * adjust:  on-wire is a must-ignore bit, a BE12 value, then
678                  * padding; built from two 8 bit values written msb-first.
679                  */
680                 value = be16_to_cpup((__be16 *)t->rx_buf);
681         }
682 
683         /* enforce ADC output is 12 bits width */
684         return (value >> 3) & 0xfff;
685 }
686 
687 static void ads7846_update_value(struct spi_message *m, int val)
688 {
689         struct spi_transfer *t =
690                 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
691 
692         *(u16 *)t->rx_buf = val;
693 }
694 
695 static void ads7846_read_state(struct ads7846 *ts)
696 {
697         struct ads7846_packet *packet = ts->packet;
698         struct spi_message *m;
699         int msg_idx = 0;
700         int val;
701         int action;
702         int error;
703 
704         while (msg_idx < ts->msg_count) {
705 
706                 ts->wait_for_sync();
707 
708                 m = &ts->msg[msg_idx];
709                 error = spi_sync(ts->spi, m);
710                 if (error) {
711                         dev_err(&ts->spi->dev, "spi_sync --> %d\n", error);
712                         packet->tc.ignore = true;
713                         return;
714                 }
715 
716                 /*
717                  * Last message is power down request, no need to convert
718                  * or filter the value.
719                  */
720                 if (msg_idx < ts->msg_count - 1) {
721 
722                         val = ads7846_get_value(ts, m);
723 
724                         action = ts->filter(ts->filter_data, msg_idx, &val);
725                         switch (action) {
726                         case ADS7846_FILTER_REPEAT:
727                                 continue;
728 
729                         case ADS7846_FILTER_IGNORE:
730                                 packet->tc.ignore = true;
731                                 msg_idx = ts->msg_count - 1;
732                                 continue;
733 
734                         case ADS7846_FILTER_OK:
735                                 ads7846_update_value(m, val);
736                                 packet->tc.ignore = false;
737                                 msg_idx++;
738                                 break;
739 
740                         default:
741                                 BUG();
742                         }
743                 } else {
744                         msg_idx++;
745                 }
746         }
747 }
748 
749 static void ads7846_report_state(struct ads7846 *ts)
750 {
751         struct ads7846_packet *packet = ts->packet;
752         unsigned int Rt;
753         u16 x, y, z1, z2;
754 
755         /*
756          * ads7846_get_value() does in-place conversion (including byte swap)
757          * from on-the-wire format as part of debouncing to get stable
758          * readings.
759          */
760         if (ts->model == 7845) {
761                 x = *(u16 *)packet->tc.x_buf;
762                 y = *(u16 *)packet->tc.y_buf;
763                 z1 = 0;
764                 z2 = 0;
765         } else {
766                 x = packet->tc.x;
767                 y = packet->tc.y;
768                 z1 = packet->tc.z1;
769                 z2 = packet->tc.z2;
770         }
771 
772         /* range filtering */
773         if (x == MAX_12BIT)
774                 x = 0;
775 
776         if (ts->model == 7843) {
777                 Rt = ts->pressure_max / 2;
778         } else if (ts->model == 7845) {
779                 if (get_pendown_state(ts))
780                         Rt = ts->pressure_max / 2;
781                 else
782                         Rt = 0;
783                 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
784         } else if (likely(x && z1)) {
785                 /* compute touch pressure resistance using equation #2 */
786                 Rt = z2;
787                 Rt -= z1;
788                 Rt *= x;
789                 Rt *= ts->x_plate_ohms;
790                 Rt /= z1;
791                 Rt = (Rt + 2047) >> 12;
792         } else {
793                 Rt = 0;
794         }
795 
796         /*
797          * Sample found inconsistent by debouncing or pressure is beyond
798          * the maximum. Don't report it to user space, repeat at least
799          * once more the measurement
800          */
801         if (packet->tc.ignore || Rt > ts->pressure_max) {
802                 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
803                          packet->tc.ignore, Rt);
804                 return;
805         }
806 
807         /*
808          * Maybe check the pendown state before reporting. This discards
809          * false readings when the pen is lifted.
810          */
811         if (ts->penirq_recheck_delay_usecs) {
812                 udelay(ts->penirq_recheck_delay_usecs);
813                 if (!get_pendown_state(ts))
814                         Rt = 0;
815         }
816 
817         /*
818          * NOTE: We can't rely on the pressure to determine the pen down
819          * state, even this controller has a pressure sensor. The pressure
820          * value can fluctuate for quite a while after lifting the pen and
821          * in some cases may not even settle at the expected value.
822          *
823          * The only safe way to check for the pen up condition is in the
824          * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
825          */
826         if (Rt) {
827                 struct input_dev *input = ts->input;
828 
829                 if (ts->swap_xy)
830                         swap(x, y);
831 
832                 if (!ts->pendown) {
833                         input_report_key(input, BTN_TOUCH, 1);
834                         ts->pendown = true;
835                         dev_vdbg(&ts->spi->dev, "DOWN\n");
836                 }
837 
838                 input_report_abs(input, ABS_X, x);
839                 input_report_abs(input, ABS_Y, y);
840                 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
841 
842                 input_sync(input);
843                 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
844         }
845 }
846 
847 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
848 {
849         struct ads7846 *ts = handle;
850 
851         return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
852 }
853 
854 
855 static irqreturn_t ads7846_irq(int irq, void *handle)
856 {
857         struct ads7846 *ts = handle;
858 
859         /* Start with a small delay before checking pendown state */
860         msleep(TS_POLL_DELAY);
861 
862         while (!ts->stopped && get_pendown_state(ts)) {
863 
864                 /* pen is down, continue with the measurement */
865                 ads7846_read_state(ts);
866 
867                 if (!ts->stopped)
868                         ads7846_report_state(ts);
869 
870                 wait_event_timeout(ts->wait, ts->stopped,
871                                    msecs_to_jiffies(TS_POLL_PERIOD));
872         }
873 
874         if (ts->pendown) {
875                 struct input_dev *input = ts->input;
876 
877                 input_report_key(input, BTN_TOUCH, 0);
878                 input_report_abs(input, ABS_PRESSURE, 0);
879                 input_sync(input);
880 
881                 ts->pendown = false;
882                 dev_vdbg(&ts->spi->dev, "UP\n");
883         }
884 
885         return IRQ_HANDLED;
886 }
887 
888 static int __maybe_unused ads7846_suspend(struct device *dev)
889 {
890         struct ads7846 *ts = dev_get_drvdata(dev);
891 
892         mutex_lock(&ts->lock);
893 
894         if (!ts->suspended) {
895 
896                 if (!ts->disabled)
897                         __ads7846_disable(ts);
898 
899                 if (device_may_wakeup(&ts->spi->dev))
900                         enable_irq_wake(ts->spi->irq);
901 
902                 ts->suspended = true;
903         }
904 
905         mutex_unlock(&ts->lock);
906 
907         return 0;
908 }
909 
910 static int __maybe_unused ads7846_resume(struct device *dev)
911 {
912         struct ads7846 *ts = dev_get_drvdata(dev);
913 
914         mutex_lock(&ts->lock);
915 
916         if (ts->suspended) {
917 
918                 ts->suspended = false;
919 
920                 if (device_may_wakeup(&ts->spi->dev))
921                         disable_irq_wake(ts->spi->irq);
922 
923                 if (!ts->disabled)
924                         __ads7846_enable(ts);
925         }
926 
927         mutex_unlock(&ts->lock);
928 
929         return 0;
930 }
931 
932 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
933 
934 static int ads7846_setup_pendown(struct spi_device *spi,
935                                  struct ads7846 *ts,
936                                  const struct ads7846_platform_data *pdata)
937 {
938         int err;
939 
940         /*
941          * REVISIT when the irq can be triggered active-low, or if for some
942          * reason the touchscreen isn't hooked up, we don't need to access
943          * the pendown state.
944          */
945 
946         if (pdata->get_pendown_state) {
947                 ts->get_pendown_state = pdata->get_pendown_state;
948         } else if (gpio_is_valid(pdata->gpio_pendown)) {
949 
950                 err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN,
951                                        "ads7846_pendown");
952                 if (err) {
953                         dev_err(&spi->dev,
954                                 "failed to request/setup pendown GPIO%d: %d\n",
955                                 pdata->gpio_pendown, err);
956                         return err;
957                 }
958 
959                 ts->gpio_pendown = pdata->gpio_pendown;
960 
961                 if (pdata->gpio_pendown_debounce)
962                         gpio_set_debounce(pdata->gpio_pendown,
963                                           pdata->gpio_pendown_debounce);
964         } else {
965                 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
966                 return -EINVAL;
967         }
968 
969         return 0;
970 }
971 
972 /*
973  * Set up the transfers to read touchscreen state; this assumes we
974  * use formula #2 for pressure, not #3.
975  */
976 static void ads7846_setup_spi_msg(struct ads7846 *ts,
977                                   const struct ads7846_platform_data *pdata)
978 {
979         struct spi_message *m = &ts->msg[0];
980         struct spi_transfer *x = ts->xfer;
981         struct ads7846_packet *packet = ts->packet;
982         int vref = pdata->keep_vref_on;
983 
984         if (ts->model == 7873) {
985                 /*
986                  * The AD7873 is almost identical to the ADS7846
987                  * keep VREF off during differential/ratiometric
988                  * conversion modes.
989                  */
990                 ts->model = 7846;
991                 vref = 0;
992         }
993 
994         ts->msg_count = 1;
995         spi_message_init(m);
996         m->context = ts;
997 
998         if (ts->model == 7845) {
999                 packet->read_y_cmd[0] = READ_Y(vref);
1000                 packet->read_y_cmd[1] = 0;
1001                 packet->read_y_cmd[2] = 0;
1002                 x->tx_buf = &packet->read_y_cmd[0];
1003                 x->rx_buf = &packet->tc.y_buf[0];
1004                 x->len = 3;
1005                 spi_message_add_tail(x, m);
1006         } else {
1007                 /* y- still on; turn on only y+ (and ADC) */
1008                 packet->read_y = READ_Y(vref);
1009                 x->tx_buf = &packet->read_y;
1010                 x->len = 1;
1011                 spi_message_add_tail(x, m);
1012 
1013                 x++;
1014                 x->rx_buf = &packet->tc.y;
1015                 x->len = 2;
1016                 spi_message_add_tail(x, m);
1017         }
1018 
1019         /*
1020          * The first sample after switching drivers can be low quality;
1021          * optionally discard it, using a second one after the signals
1022          * have had enough time to stabilize.
1023          */
1024         if (pdata->settle_delay_usecs) {
1025                 x->delay_usecs = pdata->settle_delay_usecs;
1026 
1027                 x++;
1028                 x->tx_buf = &packet->read_y;
1029                 x->len = 1;
1030                 spi_message_add_tail(x, m);
1031 
1032                 x++;
1033                 x->rx_buf = &packet->tc.y;
1034                 x->len = 2;
1035                 spi_message_add_tail(x, m);
1036         }
1037 
1038         ts->msg_count++;
1039         m++;
1040         spi_message_init(m);
1041         m->context = ts;
1042 
1043         if (ts->model == 7845) {
1044                 x++;
1045                 packet->read_x_cmd[0] = READ_X(vref);
1046                 packet->read_x_cmd[1] = 0;
1047                 packet->read_x_cmd[2] = 0;
1048                 x->tx_buf = &packet->read_x_cmd[0];
1049                 x->rx_buf = &packet->tc.x_buf[0];
1050                 x->len = 3;
1051                 spi_message_add_tail(x, m);
1052         } else {
1053                 /* turn y- off, x+ on, then leave in lowpower */
1054                 x++;
1055                 packet->read_x = READ_X(vref);
1056                 x->tx_buf = &packet->read_x;
1057                 x->len = 1;
1058                 spi_message_add_tail(x, m);
1059 
1060                 x++;
1061                 x->rx_buf = &packet->tc.x;
1062                 x->len = 2;
1063                 spi_message_add_tail(x, m);
1064         }
1065 
1066         /* ... maybe discard first sample ... */
1067         if (pdata->settle_delay_usecs) {
1068                 x->delay_usecs = pdata->settle_delay_usecs;
1069 
1070                 x++;
1071                 x->tx_buf = &packet->read_x;
1072                 x->len = 1;
1073                 spi_message_add_tail(x, m);
1074 
1075                 x++;
1076                 x->rx_buf = &packet->tc.x;
1077                 x->len = 2;
1078                 spi_message_add_tail(x, m);
1079         }
1080 
1081         /* turn y+ off, x- on; we'll use formula #2 */
1082         if (ts->model == 7846) {
1083                 ts->msg_count++;
1084                 m++;
1085                 spi_message_init(m);
1086                 m->context = ts;
1087 
1088                 x++;
1089                 packet->read_z1 = READ_Z1(vref);
1090                 x->tx_buf = &packet->read_z1;
1091                 x->len = 1;
1092                 spi_message_add_tail(x, m);
1093 
1094                 x++;
1095                 x->rx_buf = &packet->tc.z1;
1096                 x->len = 2;
1097                 spi_message_add_tail(x, m);
1098 
1099                 /* ... maybe discard first sample ... */
1100                 if (pdata->settle_delay_usecs) {
1101                         x->delay_usecs = pdata->settle_delay_usecs;
1102 
1103                         x++;
1104                         x->tx_buf = &packet->read_z1;
1105                         x->len = 1;
1106                         spi_message_add_tail(x, m);
1107 
1108                         x++;
1109                         x->rx_buf = &packet->tc.z1;
1110                         x->len = 2;
1111                         spi_message_add_tail(x, m);
1112                 }
1113 
1114                 ts->msg_count++;
1115                 m++;
1116                 spi_message_init(m);
1117                 m->context = ts;
1118 
1119                 x++;
1120                 packet->read_z2 = READ_Z2(vref);
1121                 x->tx_buf = &packet->read_z2;
1122                 x->len = 1;
1123                 spi_message_add_tail(x, m);
1124 
1125                 x++;
1126                 x->rx_buf = &packet->tc.z2;
1127                 x->len = 2;
1128                 spi_message_add_tail(x, m);
1129 
1130                 /* ... maybe discard first sample ... */
1131                 if (pdata->settle_delay_usecs) {
1132                         x->delay_usecs = pdata->settle_delay_usecs;
1133 
1134                         x++;
1135                         x->tx_buf = &packet->read_z2;
1136                         x->len = 1;
1137                         spi_message_add_tail(x, m);
1138 
1139                         x++;
1140                         x->rx_buf = &packet->tc.z2;
1141                         x->len = 2;
1142                         spi_message_add_tail(x, m);
1143                 }
1144         }
1145 
1146         /* power down */
1147         ts->msg_count++;
1148         m++;
1149         spi_message_init(m);
1150         m->context = ts;
1151 
1152         if (ts->model == 7845) {
1153                 x++;
1154                 packet->pwrdown_cmd[0] = PWRDOWN;
1155                 packet->pwrdown_cmd[1] = 0;
1156                 packet->pwrdown_cmd[2] = 0;
1157                 x->tx_buf = &packet->pwrdown_cmd[0];
1158                 x->len = 3;
1159         } else {
1160                 x++;
1161                 packet->pwrdown = PWRDOWN;
1162                 x->tx_buf = &packet->pwrdown;
1163                 x->len = 1;
1164                 spi_message_add_tail(x, m);
1165 
1166                 x++;
1167                 x->rx_buf = &packet->dummy;
1168                 x->len = 2;
1169         }
1170 
1171         CS_CHANGE(*x);
1172         spi_message_add_tail(x, m);
1173 }
1174 
1175 #ifdef CONFIG_OF
1176 static const struct of_device_id ads7846_dt_ids[] = {
1177         { .compatible = "ti,tsc2046",   .data = (void *) 7846 },
1178         { .compatible = "ti,ads7843",   .data = (void *) 7843 },
1179         { .compatible = "ti,ads7845",   .data = (void *) 7845 },
1180         { .compatible = "ti,ads7846",   .data = (void *) 7846 },
1181         { .compatible = "ti,ads7873",   .data = (void *) 7873 },
1182         { }
1183 };
1184 MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1185 
1186 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1187 {
1188         struct ads7846_platform_data *pdata;
1189         struct device_node *node = dev->of_node;
1190         const struct of_device_id *match;
1191 
1192         if (!node) {
1193                 dev_err(dev, "Device does not have associated DT data\n");
1194                 return ERR_PTR(-EINVAL);
1195         }
1196 
1197         match = of_match_device(ads7846_dt_ids, dev);
1198         if (!match) {
1199                 dev_err(dev, "Unknown device model\n");
1200                 return ERR_PTR(-EINVAL);
1201         }
1202 
1203         pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1204         if (!pdata)
1205                 return ERR_PTR(-ENOMEM);
1206 
1207         pdata->model = (unsigned long)match->data;
1208 
1209         of_property_read_u16(node, "ti,vref-delay-usecs",
1210                              &pdata->vref_delay_usecs);
1211         of_property_read_u16(node, "ti,vref-mv", &pdata->vref_mv);
1212         pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
1213 
1214         pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy");
1215 
1216         of_property_read_u16(node, "ti,settle-delay-usec",
1217                              &pdata->settle_delay_usecs);
1218         of_property_read_u16(node, "ti,penirq-recheck-delay-usecs",
1219                              &pdata->penirq_recheck_delay_usecs);
1220 
1221         of_property_read_u16(node, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1222         of_property_read_u16(node, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1223 
1224         of_property_read_u16(node, "ti,x-min", &pdata->x_min);
1225         of_property_read_u16(node, "ti,y-min", &pdata->y_min);
1226         of_property_read_u16(node, "ti,x-max", &pdata->x_max);
1227         of_property_read_u16(node, "ti,y-max", &pdata->y_max);
1228 
1229         of_property_read_u16(node, "ti,pressure-min", &pdata->pressure_min);
1230         of_property_read_u16(node, "ti,pressure-max", &pdata->pressure_max);
1231 
1232         of_property_read_u16(node, "ti,debounce-max", &pdata->debounce_max);
1233         of_property_read_u16(node, "ti,debounce-tol", &pdata->debounce_tol);
1234         of_property_read_u16(node, "ti,debounce-rep", &pdata->debounce_rep);
1235 
1236         of_property_read_u32(node, "ti,pendown-gpio-debounce",
1237                              &pdata->gpio_pendown_debounce);
1238 
1239         pdata->wakeup = of_property_read_bool(node, "wakeup-source") ||
1240                         of_property_read_bool(node, "linux,wakeup");
1241 
1242         pdata->gpio_pendown = of_get_named_gpio(dev->of_node, "pendown-gpio", 0);
1243 
1244         return pdata;
1245 }
1246 #else
1247 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1248 {
1249         dev_err(dev, "no platform data defined\n");
1250         return ERR_PTR(-EINVAL);
1251 }
1252 #endif
1253 
1254 static int ads7846_probe(struct spi_device *spi)
1255 {
1256         const struct ads7846_platform_data *pdata;
1257         struct ads7846 *ts;
1258         struct ads7846_packet *packet;
1259         struct input_dev *input_dev;
1260         unsigned long irq_flags;
1261         int err;
1262 
1263         if (!spi->irq) {
1264                 dev_dbg(&spi->dev, "no IRQ?\n");
1265                 return -EINVAL;
1266         }
1267 
1268         /* don't exceed max specified sample rate */
1269         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1270                 dev_err(&spi->dev, "f(sample) %d KHz?\n",
1271                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1272                 return -EINVAL;
1273         }
1274 
1275         /*
1276          * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1277          * that even if the hardware can do that, the SPI controller driver
1278          * may not.  So we stick to very-portable 8 bit words, both RX and TX.
1279          */
1280         spi->bits_per_word = 8;
1281         spi->mode = SPI_MODE_0;
1282         err = spi_setup(spi);
1283         if (err < 0)
1284                 return err;
1285 
1286         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1287         packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1288         input_dev = input_allocate_device();
1289         if (!ts || !packet || !input_dev) {
1290                 err = -ENOMEM;
1291                 goto err_free_mem;
1292         }
1293 
1294         spi_set_drvdata(spi, ts);
1295 
1296         ts->packet = packet;
1297         ts->spi = spi;
1298         ts->input = input_dev;
1299 
1300         mutex_init(&ts->lock);
1301         init_waitqueue_head(&ts->wait);
1302 
1303         pdata = dev_get_platdata(&spi->dev);
1304         if (!pdata) {
1305                 pdata = ads7846_probe_dt(&spi->dev);
1306                 if (IS_ERR(pdata)) {
1307                         err = PTR_ERR(pdata);
1308                         goto err_free_mem;
1309                 }
1310         }
1311 
1312         ts->model = pdata->model ? : 7846;
1313         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1314         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1315         ts->pressure_max = pdata->pressure_max ? : ~0;
1316 
1317         ts->vref_mv = pdata->vref_mv;
1318         ts->swap_xy = pdata->swap_xy;
1319 
1320         if (pdata->filter != NULL) {
1321                 if (pdata->filter_init != NULL) {
1322                         err = pdata->filter_init(pdata, &ts->filter_data);
1323                         if (err < 0)
1324                                 goto err_free_mem;
1325                 }
1326                 ts->filter = pdata->filter;
1327                 ts->filter_cleanup = pdata->filter_cleanup;
1328         } else if (pdata->debounce_max) {
1329                 ts->debounce_max = pdata->debounce_max;
1330                 if (ts->debounce_max < 2)
1331                         ts->debounce_max = 2;
1332                 ts->debounce_tol = pdata->debounce_tol;
1333                 ts->debounce_rep = pdata->debounce_rep;
1334                 ts->filter = ads7846_debounce_filter;
1335                 ts->filter_data = ts;
1336         } else {
1337                 ts->filter = ads7846_no_filter;
1338         }
1339 
1340         err = ads7846_setup_pendown(spi, ts, pdata);
1341         if (err)
1342                 goto err_cleanup_filter;
1343 
1344         if (pdata->penirq_recheck_delay_usecs)
1345                 ts->penirq_recheck_delay_usecs =
1346                                 pdata->penirq_recheck_delay_usecs;
1347 
1348         ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1349 
1350         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1351         snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1352 
1353         input_dev->name = ts->name;
1354         input_dev->phys = ts->phys;
1355         input_dev->dev.parent = &spi->dev;
1356 
1357         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1358         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1359         input_set_abs_params(input_dev, ABS_X,
1360                         pdata->x_min ? : 0,
1361                         pdata->x_max ? : MAX_12BIT,
1362                         0, 0);
1363         input_set_abs_params(input_dev, ABS_Y,
1364                         pdata->y_min ? : 0,
1365                         pdata->y_max ? : MAX_12BIT,
1366                         0, 0);
1367         input_set_abs_params(input_dev, ABS_PRESSURE,
1368                         pdata->pressure_min, pdata->pressure_max, 0, 0);
1369 
1370         ads7846_setup_spi_msg(ts, pdata);
1371 
1372         ts->reg = regulator_get(&spi->dev, "vcc");
1373         if (IS_ERR(ts->reg)) {
1374                 err = PTR_ERR(ts->reg);
1375                 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1376                 goto err_free_gpio;
1377         }
1378 
1379         err = regulator_enable(ts->reg);
1380         if (err) {
1381                 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1382                 goto err_put_regulator;
1383         }
1384 
1385         irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1386         irq_flags |= IRQF_ONESHOT;
1387 
1388         err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1389                                    irq_flags, spi->dev.driver->name, ts);
1390         if (err && !pdata->irq_flags) {
1391                 dev_info(&spi->dev,
1392                         "trying pin change workaround on irq %d\n", spi->irq);
1393                 irq_flags |= IRQF_TRIGGER_RISING;
1394                 err = request_threaded_irq(spi->irq,
1395                                   ads7846_hard_irq, ads7846_irq,
1396                                   irq_flags, spi->dev.driver->name, ts);
1397         }
1398 
1399         if (err) {
1400                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1401                 goto err_disable_regulator;
1402         }
1403 
1404         err = ads784x_hwmon_register(spi, ts);
1405         if (err)
1406                 goto err_free_irq;
1407 
1408         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1409 
1410         /*
1411          * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1412          * the touchscreen, in case it's not connected.
1413          */
1414         if (ts->model == 7845)
1415                 ads7845_read12_ser(&spi->dev, PWRDOWN);
1416         else
1417                 (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1418 
1419         err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1420         if (err)
1421                 goto err_remove_hwmon;
1422 
1423         err = input_register_device(input_dev);
1424         if (err)
1425                 goto err_remove_attr_group;
1426 
1427         device_init_wakeup(&spi->dev, pdata->wakeup);
1428 
1429         /*
1430          * If device does not carry platform data we must have allocated it
1431          * when parsing DT data.
1432          */
1433         if (!dev_get_platdata(&spi->dev))
1434                 devm_kfree(&spi->dev, (void *)pdata);
1435 
1436         return 0;
1437 
1438  err_remove_attr_group:
1439         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1440  err_remove_hwmon:
1441         ads784x_hwmon_unregister(spi, ts);
1442  err_free_irq:
1443         free_irq(spi->irq, ts);
1444  err_disable_regulator:
1445         regulator_disable(ts->reg);
1446  err_put_regulator:
1447         regulator_put(ts->reg);
1448  err_free_gpio:
1449         if (!ts->get_pendown_state)
1450                 gpio_free(ts->gpio_pendown);
1451  err_cleanup_filter:
1452         if (ts->filter_cleanup)
1453                 ts->filter_cleanup(ts->filter_data);
1454  err_free_mem:
1455         input_free_device(input_dev);
1456         kfree(packet);
1457         kfree(ts);
1458         return err;
1459 }
1460 
1461 static int ads7846_remove(struct spi_device *spi)
1462 {
1463         struct ads7846 *ts = spi_get_drvdata(spi);
1464 
1465         device_init_wakeup(&spi->dev, false);
1466 
1467         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1468 
1469         ads7846_disable(ts);
1470         free_irq(ts->spi->irq, ts);
1471 
1472         input_unregister_device(ts->input);
1473 
1474         ads784x_hwmon_unregister(spi, ts);
1475 
1476         regulator_disable(ts->reg);
1477         regulator_put(ts->reg);
1478 
1479         if (!ts->get_pendown_state) {
1480                 /*
1481                  * If we are not using specialized pendown method we must
1482                  * have been relying on gpio we set up ourselves.
1483                  */
1484                 gpio_free(ts->gpio_pendown);
1485         }
1486 
1487         if (ts->filter_cleanup)
1488                 ts->filter_cleanup(ts->filter_data);
1489 
1490         kfree(ts->packet);
1491         kfree(ts);
1492 
1493         dev_dbg(&spi->dev, "unregistered touchscreen\n");
1494 
1495         return 0;
1496 }
1497 
1498 static struct spi_driver ads7846_driver = {
1499         .driver = {
1500                 .name   = "ads7846",
1501                 .pm     = &ads7846_pm,
1502                 .of_match_table = of_match_ptr(ads7846_dt_ids),
1503         },
1504         .probe          = ads7846_probe,
1505         .remove         = ads7846_remove,
1506 };
1507 
1508 module_spi_driver(ads7846_driver);
1509 
1510 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1511 MODULE_LICENSE("GPL");
1512 MODULE_ALIAS("spi:ads7846");
1513 

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