Version:  2.0.40 2.2.26 2.4.37 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8

Linux/drivers/iio/adc/ti_am335x_adc.c

  1 /*
  2  * TI ADC MFD driver
  3  *
  4  * Copyright (C) 2012 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 #include <linux/kernel.h>
 17 #include <linux/err.h>
 18 #include <linux/module.h>
 19 #include <linux/slab.h>
 20 #include <linux/interrupt.h>
 21 #include <linux/platform_device.h>
 22 #include <linux/io.h>
 23 #include <linux/iio/iio.h>
 24 #include <linux/of.h>
 25 #include <linux/of_device.h>
 26 #include <linux/iio/machine.h>
 27 #include <linux/iio/driver.h>
 28 
 29 #include <linux/mfd/ti_am335x_tscadc.h>
 30 #include <linux/iio/buffer.h>
 31 #include <linux/iio/kfifo_buf.h>
 32 
 33 struct tiadc_device {
 34         struct ti_tscadc_dev *mfd_tscadc;
 35         struct mutex fifo1_lock; /* to protect fifo access */
 36         int channels;
 37         u8 channel_line[8];
 38         u8 channel_step[8];
 39         int buffer_en_ch_steps;
 40         u16 data[8];
 41         u32 open_delay[8], sample_delay[8], step_avg[8];
 42 };
 43 
 44 static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
 45 {
 46         return readl(adc->mfd_tscadc->tscadc_base + reg);
 47 }
 48 
 49 static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
 50                                         unsigned int val)
 51 {
 52         writel(val, adc->mfd_tscadc->tscadc_base + reg);
 53 }
 54 
 55 static u32 get_adc_step_mask(struct tiadc_device *adc_dev)
 56 {
 57         u32 step_en;
 58 
 59         step_en = ((1 << adc_dev->channels) - 1);
 60         step_en <<= TOTAL_STEPS - adc_dev->channels + 1;
 61         return step_en;
 62 }
 63 
 64 static u32 get_adc_chan_step_mask(struct tiadc_device *adc_dev,
 65                 struct iio_chan_spec const *chan)
 66 {
 67         int i;
 68 
 69         for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
 70                 if (chan->channel == adc_dev->channel_line[i]) {
 71                         u32 step;
 72 
 73                         step = adc_dev->channel_step[i];
 74                         /* +1 for the charger */
 75                         return 1 << (step + 1);
 76                 }
 77         }
 78         WARN_ON(1);
 79         return 0;
 80 }
 81 
 82 static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan)
 83 {
 84         return 1 << adc_dev->channel_step[chan];
 85 }
 86 
 87 static void tiadc_step_config(struct iio_dev *indio_dev)
 88 {
 89         struct tiadc_device *adc_dev = iio_priv(indio_dev);
 90         struct device *dev = adc_dev->mfd_tscadc->dev;
 91         unsigned int stepconfig;
 92         int i, steps = 0;
 93 
 94         /*
 95          * There are 16 configurable steps and 8 analog input
 96          * lines available which are shared between Touchscreen and ADC.
 97          *
 98          * Steps forwards i.e. from 0 towards 16 are used by ADC
 99          * depending on number of input lines needed.
100          * Channel would represent which analog input
101          * needs to be given to ADC to digitalize data.
102          */
103 
104 
105         for (i = 0; i < adc_dev->channels; i++) {
106                 int chan;
107 
108                 chan = adc_dev->channel_line[i];
109 
110                 if (adc_dev->step_avg[i] > STEPCONFIG_AVG_16) {
111                         dev_warn(dev, "chan %d step_avg truncating to %d\n",
112                                  chan, STEPCONFIG_AVG_16);
113                         adc_dev->step_avg[i] = STEPCONFIG_AVG_16;
114                 }
115 
116                 if (adc_dev->step_avg[i])
117                         stepconfig =
118                         STEPCONFIG_AVG(ffs(adc_dev->step_avg[i]) - 1) |
119                         STEPCONFIG_FIFO1;
120                 else
121                         stepconfig = STEPCONFIG_FIFO1;
122 
123                 if (iio_buffer_enabled(indio_dev))
124                         stepconfig |= STEPCONFIG_MODE_SWCNT;
125 
126                 tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
127                                 stepconfig | STEPCONFIG_INP(chan));
128 
129                 if (adc_dev->open_delay[i] > STEPDELAY_OPEN_MASK) {
130                         dev_warn(dev, "chan %d open delay truncating to 0x3FFFF\n",
131                                  chan);
132                         adc_dev->open_delay[i] = STEPDELAY_OPEN_MASK;
133                 }
134 
135                 if (adc_dev->sample_delay[i] > 0xFF) {
136                         dev_warn(dev, "chan %d sample delay truncating to 0xFF\n",
137                                  chan);
138                         adc_dev->sample_delay[i] = 0xFF;
139                 }
140 
141                 tiadc_writel(adc_dev, REG_STEPDELAY(steps),
142                                 STEPDELAY_OPEN(adc_dev->open_delay[i]) |
143                                 STEPDELAY_SAMPLE(adc_dev->sample_delay[i]));
144 
145                 adc_dev->channel_step[i] = steps;
146                 steps++;
147         }
148 }
149 
150 static irqreturn_t tiadc_irq_h(int irq, void *private)
151 {
152         struct iio_dev *indio_dev = private;
153         struct tiadc_device *adc_dev = iio_priv(indio_dev);
154         unsigned int status, config;
155         status = tiadc_readl(adc_dev, REG_IRQSTATUS);
156 
157         /*
158          * ADC and touchscreen share the IRQ line.
159          * FIFO0 interrupts are used by TSC. Handle FIFO1 IRQs here only
160          */
161         if (status & IRQENB_FIFO1OVRRUN) {
162                 /* FIFO Overrun. Clear flag. Disable/Enable ADC to recover */
163                 config = tiadc_readl(adc_dev, REG_CTRL);
164                 config &= ~(CNTRLREG_TSCSSENB);
165                 tiadc_writel(adc_dev, REG_CTRL, config);
166                 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1OVRRUN
167                                 | IRQENB_FIFO1UNDRFLW | IRQENB_FIFO1THRES);
168                 tiadc_writel(adc_dev, REG_CTRL, (config | CNTRLREG_TSCSSENB));
169                 return IRQ_HANDLED;
170         } else if (status & IRQENB_FIFO1THRES) {
171                 /* Disable irq and wake worker thread */
172                 tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_FIFO1THRES);
173                 return IRQ_WAKE_THREAD;
174         }
175 
176         return IRQ_NONE;
177 }
178 
179 static irqreturn_t tiadc_worker_h(int irq, void *private)
180 {
181         struct iio_dev *indio_dev = private;
182         struct tiadc_device *adc_dev = iio_priv(indio_dev);
183         int i, k, fifo1count, read;
184         u16 *data = adc_dev->data;
185 
186         fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
187         for (k = 0; k < fifo1count; k = k + i) {
188                 for (i = 0; i < (indio_dev->scan_bytes)/2; i++) {
189                         read = tiadc_readl(adc_dev, REG_FIFO1);
190                         data[i] = read & FIFOREAD_DATA_MASK;
191                 }
192                 iio_push_to_buffers(indio_dev, (u8 *) data);
193         }
194 
195         tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES);
196         tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES);
197 
198         return IRQ_HANDLED;
199 }
200 
201 static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
202 {
203         struct tiadc_device *adc_dev = iio_priv(indio_dev);
204         int i, fifo1count, read;
205 
206         tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
207                                 IRQENB_FIFO1OVRRUN |
208                                 IRQENB_FIFO1UNDRFLW));
209 
210         /* Flush FIFO. Needed in corner cases in simultaneous tsc/adc use */
211         fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
212         for (i = 0; i < fifo1count; i++)
213                 read = tiadc_readl(adc_dev, REG_FIFO1);
214 
215         return 0;
216 }
217 
218 static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
219 {
220         struct tiadc_device *adc_dev = iio_priv(indio_dev);
221         unsigned int enb = 0;
222         u8 bit;
223 
224         tiadc_step_config(indio_dev);
225         for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels)
226                 enb |= (get_adc_step_bit(adc_dev, bit) << 1);
227         adc_dev->buffer_en_ch_steps = enb;
228 
229         am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, enb);
230 
231         tiadc_writel(adc_dev,  REG_IRQSTATUS, IRQENB_FIFO1THRES
232                                 | IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW);
233         tiadc_writel(adc_dev,  REG_IRQENABLE, IRQENB_FIFO1THRES
234                                 | IRQENB_FIFO1OVRRUN);
235 
236         return 0;
237 }
238 
239 static int tiadc_buffer_predisable(struct iio_dev *indio_dev)
240 {
241         struct tiadc_device *adc_dev = iio_priv(indio_dev);
242         int fifo1count, i, read;
243 
244         tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
245                                 IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW));
246         am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps);
247         adc_dev->buffer_en_ch_steps = 0;
248 
249         /* Flush FIFO of leftover data in the time it takes to disable adc */
250         fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
251         for (i = 0; i < fifo1count; i++)
252                 read = tiadc_readl(adc_dev, REG_FIFO1);
253 
254         return 0;
255 }
256 
257 static int tiadc_buffer_postdisable(struct iio_dev *indio_dev)
258 {
259         tiadc_step_config(indio_dev);
260 
261         return 0;
262 }
263 
264 static const struct iio_buffer_setup_ops tiadc_buffer_setup_ops = {
265         .preenable = &tiadc_buffer_preenable,
266         .postenable = &tiadc_buffer_postenable,
267         .predisable = &tiadc_buffer_predisable,
268         .postdisable = &tiadc_buffer_postdisable,
269 };
270 
271 static int tiadc_iio_buffered_hardware_setup(struct iio_dev *indio_dev,
272         irqreturn_t (*pollfunc_bh)(int irq, void *p),
273         irqreturn_t (*pollfunc_th)(int irq, void *p),
274         int irq,
275         unsigned long flags,
276         const struct iio_buffer_setup_ops *setup_ops)
277 {
278         struct iio_buffer *buffer;
279         int ret;
280 
281         buffer = iio_kfifo_allocate();
282         if (!buffer)
283                 return -ENOMEM;
284 
285         iio_device_attach_buffer(indio_dev, buffer);
286 
287         ret = request_threaded_irq(irq, pollfunc_th, pollfunc_bh,
288                                 flags, indio_dev->name, indio_dev);
289         if (ret)
290                 goto error_kfifo_free;
291 
292         indio_dev->setup_ops = setup_ops;
293         indio_dev->modes |= INDIO_BUFFER_SOFTWARE;
294 
295         return 0;
296 
297 error_kfifo_free:
298         iio_kfifo_free(indio_dev->buffer);
299         return ret;
300 }
301 
302 static void tiadc_iio_buffered_hardware_remove(struct iio_dev *indio_dev)
303 {
304         struct tiadc_device *adc_dev = iio_priv(indio_dev);
305 
306         free_irq(adc_dev->mfd_tscadc->irq, indio_dev);
307         iio_kfifo_free(indio_dev->buffer);
308 }
309 
310 
311 static const char * const chan_name_ain[] = {
312         "AIN0",
313         "AIN1",
314         "AIN2",
315         "AIN3",
316         "AIN4",
317         "AIN5",
318         "AIN6",
319         "AIN7",
320 };
321 
322 static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
323 {
324         struct tiadc_device *adc_dev = iio_priv(indio_dev);
325         struct iio_chan_spec *chan_array;
326         struct iio_chan_spec *chan;
327         int i;
328 
329         indio_dev->num_channels = channels;
330         chan_array = kcalloc(channels, sizeof(*chan_array), GFP_KERNEL);
331         if (chan_array == NULL)
332                 return -ENOMEM;
333 
334         chan = chan_array;
335         for (i = 0; i < channels; i++, chan++) {
336 
337                 chan->type = IIO_VOLTAGE;
338                 chan->indexed = 1;
339                 chan->channel = adc_dev->channel_line[i];
340                 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
341                 chan->datasheet_name = chan_name_ain[chan->channel];
342                 chan->scan_index = i;
343                 chan->scan_type.sign = 'u';
344                 chan->scan_type.realbits = 12;
345                 chan->scan_type.storagebits = 16;
346         }
347 
348         indio_dev->channels = chan_array;
349 
350         return 0;
351 }
352 
353 static void tiadc_channels_remove(struct iio_dev *indio_dev)
354 {
355         kfree(indio_dev->channels);
356 }
357 
358 static int tiadc_read_raw(struct iio_dev *indio_dev,
359                 struct iio_chan_spec const *chan,
360                 int *val, int *val2, long mask)
361 {
362         struct tiadc_device *adc_dev = iio_priv(indio_dev);
363         int ret = IIO_VAL_INT;
364         int i, map_val;
365         unsigned int fifo1count, read, stepid;
366         bool found = false;
367         u32 step_en;
368         unsigned long timeout;
369 
370         if (iio_buffer_enabled(indio_dev))
371                 return -EBUSY;
372 
373         step_en = get_adc_chan_step_mask(adc_dev, chan);
374         if (!step_en)
375                 return -EINVAL;
376 
377         mutex_lock(&adc_dev->fifo1_lock);
378         fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
379         while (fifo1count--)
380                 tiadc_readl(adc_dev, REG_FIFO1);
381 
382         am335x_tsc_se_set_once(adc_dev->mfd_tscadc, step_en);
383 
384         timeout = jiffies + msecs_to_jiffies
385                                 (IDLE_TIMEOUT * adc_dev->channels);
386         /* Wait for Fifo threshold interrupt */
387         while (1) {
388                 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
389                 if (fifo1count)
390                         break;
391 
392                 if (time_after(jiffies, timeout)) {
393                         am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
394                         ret = -EAGAIN;
395                         goto err_unlock;
396                 }
397         }
398         map_val = adc_dev->channel_step[chan->scan_index];
399 
400         /*
401          * We check the complete FIFO. We programmed just one entry but in case
402          * something went wrong we left empty handed (-EAGAIN previously) and
403          * then the value apeared somehow in the FIFO we would have two entries.
404          * Therefore we read every item and keep only the latest version of the
405          * requested channel.
406          */
407         for (i = 0; i < fifo1count; i++) {
408                 read = tiadc_readl(adc_dev, REG_FIFO1);
409                 stepid = read & FIFOREAD_CHNLID_MASK;
410                 stepid = stepid >> 0x10;
411 
412                 if (stepid == map_val) {
413                         read = read & FIFOREAD_DATA_MASK;
414                         found = true;
415                         *val = (u16) read;
416                 }
417         }
418         am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
419 
420         if (found == false)
421                 ret =  -EBUSY;
422 
423 err_unlock:
424         mutex_unlock(&adc_dev->fifo1_lock);
425         return ret;
426 }
427 
428 static const struct iio_info tiadc_info = {
429         .read_raw = &tiadc_read_raw,
430         .driver_module = THIS_MODULE,
431 };
432 
433 static int tiadc_parse_dt(struct platform_device *pdev,
434                           struct tiadc_device *adc_dev)
435 {
436         struct device_node *node = pdev->dev.of_node;
437         struct property *prop;
438         const __be32 *cur;
439         int channels = 0;
440         u32 val;
441 
442         of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
443                 adc_dev->channel_line[channels] = val;
444 
445                 /* Set Default values for optional DT parameters */
446                 adc_dev->open_delay[channels] = STEPCONFIG_OPENDLY;
447                 adc_dev->sample_delay[channels] = STEPCONFIG_SAMPLEDLY;
448                 adc_dev->step_avg[channels] = 16;
449 
450                 channels++;
451         }
452 
453         of_property_read_u32_array(node, "ti,chan-step-avg",
454                                    adc_dev->step_avg, channels);
455         of_property_read_u32_array(node, "ti,chan-step-opendelay",
456                                    adc_dev->open_delay, channels);
457         of_property_read_u32_array(node, "ti,chan-step-sampledelay",
458                                    adc_dev->sample_delay, channels);
459 
460         adc_dev->channels = channels;
461         return 0;
462 }
463 
464 static int tiadc_probe(struct platform_device *pdev)
465 {
466         struct iio_dev          *indio_dev;
467         struct tiadc_device     *adc_dev;
468         struct device_node      *node = pdev->dev.of_node;
469         int                     err;
470 
471         if (!node) {
472                 dev_err(&pdev->dev, "Could not find valid DT data.\n");
473                 return -EINVAL;
474         }
475 
476         indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*indio_dev));
477         if (indio_dev == NULL) {
478                 dev_err(&pdev->dev, "failed to allocate iio device\n");
479                 return -ENOMEM;
480         }
481         adc_dev = iio_priv(indio_dev);
482 
483         adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
484         tiadc_parse_dt(pdev, adc_dev);
485 
486         indio_dev->dev.parent = &pdev->dev;
487         indio_dev->name = dev_name(&pdev->dev);
488         indio_dev->modes = INDIO_DIRECT_MODE;
489         indio_dev->info = &tiadc_info;
490 
491         tiadc_step_config(indio_dev);
492         tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD);
493         mutex_init(&adc_dev->fifo1_lock);
494 
495         err = tiadc_channel_init(indio_dev, adc_dev->channels);
496         if (err < 0)
497                 return err;
498 
499         err = tiadc_iio_buffered_hardware_setup(indio_dev,
500                 &tiadc_worker_h,
501                 &tiadc_irq_h,
502                 adc_dev->mfd_tscadc->irq,
503                 IRQF_SHARED,
504                 &tiadc_buffer_setup_ops);
505 
506         if (err)
507                 goto err_free_channels;
508 
509         err = iio_device_register(indio_dev);
510         if (err)
511                 goto err_buffer_unregister;
512 
513         platform_set_drvdata(pdev, indio_dev);
514 
515         return 0;
516 
517 err_buffer_unregister:
518         tiadc_iio_buffered_hardware_remove(indio_dev);
519 err_free_channels:
520         tiadc_channels_remove(indio_dev);
521         return err;
522 }
523 
524 static int tiadc_remove(struct platform_device *pdev)
525 {
526         struct iio_dev *indio_dev = platform_get_drvdata(pdev);
527         struct tiadc_device *adc_dev = iio_priv(indio_dev);
528         u32 step_en;
529 
530         iio_device_unregister(indio_dev);
531         tiadc_iio_buffered_hardware_remove(indio_dev);
532         tiadc_channels_remove(indio_dev);
533 
534         step_en = get_adc_step_mask(adc_dev);
535         am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);
536 
537         return 0;
538 }
539 
540 static int __maybe_unused tiadc_suspend(struct device *dev)
541 {
542         struct iio_dev *indio_dev = dev_get_drvdata(dev);
543         struct tiadc_device *adc_dev = iio_priv(indio_dev);
544         struct ti_tscadc_dev *tscadc_dev;
545         unsigned int idle;
546 
547         tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
548         if (!device_may_wakeup(tscadc_dev->dev)) {
549                 idle = tiadc_readl(adc_dev, REG_CTRL);
550                 idle &= ~(CNTRLREG_TSCSSENB);
551                 tiadc_writel(adc_dev, REG_CTRL, (idle |
552                                 CNTRLREG_POWERDOWN));
553         }
554 
555         return 0;
556 }
557 
558 static int __maybe_unused tiadc_resume(struct device *dev)
559 {
560         struct iio_dev *indio_dev = dev_get_drvdata(dev);
561         struct tiadc_device *adc_dev = iio_priv(indio_dev);
562         unsigned int restore;
563 
564         /* Make sure ADC is powered up */
565         restore = tiadc_readl(adc_dev, REG_CTRL);
566         restore &= ~(CNTRLREG_POWERDOWN);
567         tiadc_writel(adc_dev, REG_CTRL, restore);
568 
569         tiadc_step_config(indio_dev);
570         am335x_tsc_se_set_cache(adc_dev->mfd_tscadc,
571                         adc_dev->buffer_en_ch_steps);
572         return 0;
573 }
574 
575 static SIMPLE_DEV_PM_OPS(tiadc_pm_ops, tiadc_suspend, tiadc_resume);
576 
577 static const struct of_device_id ti_adc_dt_ids[] = {
578         { .compatible = "ti,am3359-adc", },
579         { }
580 };
581 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
582 
583 static struct platform_driver tiadc_driver = {
584         .driver = {
585                 .name   = "TI-am335x-adc",
586                 .pm     = &tiadc_pm_ops,
587                 .of_match_table = ti_adc_dt_ids,
588         },
589         .probe  = tiadc_probe,
590         .remove = tiadc_remove,
591 };
592 module_platform_driver(tiadc_driver);
593 
594 MODULE_DESCRIPTION("TI ADC controller driver");
595 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
596 MODULE_LICENSE("GPL");
597 

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