Version:  2.0.40 2.2.26 2.4.37 3.8 3.9 3.10 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

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         int channels;
 36         u8 channel_line[8];
 37         u8 channel_step[8];
 38         int buffer_en_ch_steps;
 39         u16 data[8];
 40         u32 open_delay[8], sample_delay[8], step_avg[8];
 41 };
 42 
 43 static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
 44 {
 45         return readl(adc->mfd_tscadc->tscadc_base + reg);
 46 }
 47 
 48 static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
 49                                         unsigned int val)
 50 {
 51         writel(val, adc->mfd_tscadc->tscadc_base + reg);
 52 }
 53 
 54 static u32 get_adc_step_mask(struct tiadc_device *adc_dev)
 55 {
 56         u32 step_en;
 57 
 58         step_en = ((1 << adc_dev->channels) - 1);
 59         step_en <<= TOTAL_STEPS - adc_dev->channels + 1;
 60         return step_en;
 61 }
 62 
 63 static u32 get_adc_chan_step_mask(struct tiadc_device *adc_dev,
 64                 struct iio_chan_spec const *chan)
 65 {
 66         int i;
 67 
 68         for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
 69                 if (chan->channel == adc_dev->channel_line[i]) {
 70                         u32 step;
 71 
 72                         step = adc_dev->channel_step[i];
 73                         /* +1 for the charger */
 74                         return 1 << (step + 1);
 75                 }
 76         }
 77         WARN_ON(1);
 78         return 0;
 79 }
 80 
 81 static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan)
 82 {
 83         return 1 << adc_dev->channel_step[chan];
 84 }
 85 
 86 static void tiadc_step_config(struct iio_dev *indio_dev)
 87 {
 88         struct tiadc_device *adc_dev = iio_priv(indio_dev);
 89         struct device *dev = adc_dev->mfd_tscadc->dev;
 90         unsigned int stepconfig;
 91         int i, steps = 0;
 92 
 93         /*
 94          * There are 16 configurable steps and 8 analog input
 95          * lines available which are shared between Touchscreen and ADC.
 96          *
 97          * Steps forwards i.e. from 0 towards 16 are used by ADC
 98          * depending on number of input lines needed.
 99          * Channel would represent which analog input
100          * needs to be given to ADC to digitalize data.
101          */
102 
103 
104         for (i = 0; i < adc_dev->channels; i++) {
105                 int chan;
106 
107                 chan = adc_dev->channel_line[i];
108 
109                 if (adc_dev->step_avg[i] > STEPCONFIG_AVG_16) {
110                         dev_warn(dev, "chan %d step_avg truncating to %d\n",
111                                  chan, STEPCONFIG_AVG_16);
112                         adc_dev->step_avg[i] = STEPCONFIG_AVG_16;
113                 }
114 
115                 if (adc_dev->step_avg[i])
116                         stepconfig =
117                         STEPCONFIG_AVG(ffs(adc_dev->step_avg[i]) - 1) |
118                         STEPCONFIG_FIFO1;
119                 else
120                         stepconfig = STEPCONFIG_FIFO1;
121 
122                 if (iio_buffer_enabled(indio_dev))
123                         stepconfig |= STEPCONFIG_MODE_SWCNT;
124 
125                 tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
126                                 stepconfig | STEPCONFIG_INP(chan));
127 
128                 if (adc_dev->open_delay[i] > STEPDELAY_OPEN_MASK) {
129                         dev_warn(dev, "chan %d open delay truncating to 0x3FFFF\n",
130                                  chan);
131                         adc_dev->open_delay[i] = STEPDELAY_OPEN_MASK;
132                 }
133 
134                 if (adc_dev->sample_delay[i] > 0xFF) {
135                         dev_warn(dev, "chan %d sample delay truncating to 0xFF\n",
136                                  chan);
137                         adc_dev->sample_delay[i] = 0xFF;
138                 }
139 
140                 tiadc_writel(adc_dev, REG_STEPDELAY(steps),
141                                 STEPDELAY_OPEN(adc_dev->open_delay[i]) |
142                                 STEPDELAY_SAMPLE(adc_dev->sample_delay[i]));
143 
144                 adc_dev->channel_step[i] = steps;
145                 steps++;
146         }
147 }
148 
149 static irqreturn_t tiadc_irq_h(int irq, void *private)
150 {
151         struct iio_dev *indio_dev = private;
152         struct tiadc_device *adc_dev = iio_priv(indio_dev);
153         unsigned int status, config;
154         status = tiadc_readl(adc_dev, REG_IRQSTATUS);
155 
156         /*
157          * ADC and touchscreen share the IRQ line.
158          * FIFO0 interrupts are used by TSC. Handle FIFO1 IRQs here only
159          */
160         if (status & IRQENB_FIFO1OVRRUN) {
161                 /* FIFO Overrun. Clear flag. Disable/Enable ADC to recover */
162                 config = tiadc_readl(adc_dev, REG_CTRL);
163                 config &= ~(CNTRLREG_TSCSSENB);
164                 tiadc_writel(adc_dev, REG_CTRL, config);
165                 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1OVRRUN
166                                 | IRQENB_FIFO1UNDRFLW | IRQENB_FIFO1THRES);
167                 tiadc_writel(adc_dev, REG_CTRL, (config | CNTRLREG_TSCSSENB));
168                 return IRQ_HANDLED;
169         } else if (status & IRQENB_FIFO1THRES) {
170                 /* Disable irq and wake worker thread */
171                 tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_FIFO1THRES);
172                 return IRQ_WAKE_THREAD;
173         }
174 
175         return IRQ_NONE;
176 }
177 
178 static irqreturn_t tiadc_worker_h(int irq, void *private)
179 {
180         struct iio_dev *indio_dev = private;
181         struct tiadc_device *adc_dev = iio_priv(indio_dev);
182         int i, k, fifo1count, read;
183         u16 *data = adc_dev->data;
184 
185         fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
186         for (k = 0; k < fifo1count; k = k + i) {
187                 for (i = 0; i < (indio_dev->scan_bytes)/2; i++) {
188                         read = tiadc_readl(adc_dev, REG_FIFO1);
189                         data[i] = read & FIFOREAD_DATA_MASK;
190                 }
191                 iio_push_to_buffers(indio_dev, (u8 *) data);
192         }
193 
194         tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES);
195         tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES);
196 
197         return IRQ_HANDLED;
198 }
199 
200 static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
201 {
202         struct tiadc_device *adc_dev = iio_priv(indio_dev);
203         int i, fifo1count, read;
204 
205         tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
206                                 IRQENB_FIFO1OVRRUN |
207                                 IRQENB_FIFO1UNDRFLW));
208 
209         /* Flush FIFO. Needed in corner cases in simultaneous tsc/adc use */
210         fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
211         for (i = 0; i < fifo1count; i++)
212                 read = tiadc_readl(adc_dev, REG_FIFO1);
213 
214         return 0;
215 }
216 
217 static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
218 {
219         struct tiadc_device *adc_dev = iio_priv(indio_dev);
220         unsigned int enb = 0;
221         u8 bit;
222 
223         tiadc_step_config(indio_dev);
224         for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels)
225                 enb |= (get_adc_step_bit(adc_dev, bit) << 1);
226         adc_dev->buffer_en_ch_steps = enb;
227 
228         am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, enb);
229 
230         tiadc_writel(adc_dev,  REG_IRQSTATUS, IRQENB_FIFO1THRES
231                                 | IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW);
232         tiadc_writel(adc_dev,  REG_IRQENABLE, IRQENB_FIFO1THRES
233                                 | IRQENB_FIFO1OVRRUN);
234 
235         return 0;
236 }
237 
238 static int tiadc_buffer_predisable(struct iio_dev *indio_dev)
239 {
240         struct tiadc_device *adc_dev = iio_priv(indio_dev);
241         int fifo1count, i, read;
242 
243         tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
244                                 IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW));
245         am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps);
246         adc_dev->buffer_en_ch_steps = 0;
247 
248         /* Flush FIFO of leftover data in the time it takes to disable adc */
249         fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
250         for (i = 0; i < fifo1count; i++)
251                 read = tiadc_readl(adc_dev, REG_FIFO1);
252 
253         return 0;
254 }
255 
256 static int tiadc_buffer_postdisable(struct iio_dev *indio_dev)
257 {
258         tiadc_step_config(indio_dev);
259 
260         return 0;
261 }
262 
263 static const struct iio_buffer_setup_ops tiadc_buffer_setup_ops = {
264         .preenable = &tiadc_buffer_preenable,
265         .postenable = &tiadc_buffer_postenable,
266         .predisable = &tiadc_buffer_predisable,
267         .postdisable = &tiadc_buffer_postdisable,
268 };
269 
270 static int tiadc_iio_buffered_hardware_setup(struct iio_dev *indio_dev,
271         irqreturn_t (*pollfunc_bh)(int irq, void *p),
272         irqreturn_t (*pollfunc_th)(int irq, void *p),
273         int irq,
274         unsigned long flags,
275         const struct iio_buffer_setup_ops *setup_ops)
276 {
277         struct iio_buffer *buffer;
278         int ret;
279 
280         buffer = iio_kfifo_allocate();
281         if (!buffer)
282                 return -ENOMEM;
283 
284         iio_device_attach_buffer(indio_dev, buffer);
285 
286         ret = request_threaded_irq(irq, pollfunc_th, pollfunc_bh,
287                                 flags, indio_dev->name, indio_dev);
288         if (ret)
289                 goto error_kfifo_free;
290 
291         indio_dev->setup_ops = setup_ops;
292         indio_dev->modes |= INDIO_BUFFER_SOFTWARE;
293 
294         return 0;
295 
296 error_kfifo_free:
297         iio_kfifo_free(indio_dev->buffer);
298         return ret;
299 }
300 
301 static void tiadc_iio_buffered_hardware_remove(struct iio_dev *indio_dev)
302 {
303         struct tiadc_device *adc_dev = iio_priv(indio_dev);
304 
305         free_irq(adc_dev->mfd_tscadc->irq, indio_dev);
306         iio_kfifo_free(indio_dev->buffer);
307 }
308 
309 
310 static const char * const chan_name_ain[] = {
311         "AIN0",
312         "AIN1",
313         "AIN2",
314         "AIN3",
315         "AIN4",
316         "AIN5",
317         "AIN6",
318         "AIN7",
319 };
320 
321 static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
322 {
323         struct tiadc_device *adc_dev = iio_priv(indio_dev);
324         struct iio_chan_spec *chan_array;
325         struct iio_chan_spec *chan;
326         int i;
327 
328         indio_dev->num_channels = channels;
329         chan_array = kcalloc(channels,
330                         sizeof(struct iio_chan_spec), 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 i, map_val;
364         unsigned int fifo1count, read, stepid;
365         bool found = false;
366         u32 step_en;
367         unsigned long timeout;
368 
369         if (iio_buffer_enabled(indio_dev))
370                 return -EBUSY;
371 
372         step_en = get_adc_chan_step_mask(adc_dev, chan);
373         if (!step_en)
374                 return -EINVAL;
375 
376         fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
377         while (fifo1count--)
378                 tiadc_readl(adc_dev, REG_FIFO1);
379 
380         am335x_tsc_se_set_once(adc_dev->mfd_tscadc, step_en);
381 
382         timeout = jiffies + usecs_to_jiffies
383                                 (IDLE_TIMEOUT * adc_dev->channels);
384         /* Wait for Fifo threshold interrupt */
385         while (1) {
386                 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
387                 if (fifo1count)
388                         break;
389 
390                 if (time_after(jiffies, timeout)) {
391                         am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
392                         return -EAGAIN;
393                 }
394         }
395         map_val = adc_dev->channel_step[chan->scan_index];
396 
397         /*
398          * We check the complete FIFO. We programmed just one entry but in case
399          * something went wrong we left empty handed (-EAGAIN previously) and
400          * then the value apeared somehow in the FIFO we would have two entries.
401          * Therefore we read every item and keep only the latest version of the
402          * requested channel.
403          */
404         for (i = 0; i < fifo1count; i++) {
405                 read = tiadc_readl(adc_dev, REG_FIFO1);
406                 stepid = read & FIFOREAD_CHNLID_MASK;
407                 stepid = stepid >> 0x10;
408 
409                 if (stepid == map_val) {
410                         read = read & FIFOREAD_DATA_MASK;
411                         found = true;
412                         *val = (u16) read;
413                 }
414         }
415         am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
416 
417         if (found == false)
418                 return -EBUSY;
419         return IIO_VAL_INT;
420 }
421 
422 static const struct iio_info tiadc_info = {
423         .read_raw = &tiadc_read_raw,
424         .driver_module = THIS_MODULE,
425 };
426 
427 static int tiadc_parse_dt(struct platform_device *pdev,
428                           struct tiadc_device *adc_dev)
429 {
430         struct device_node *node = pdev->dev.of_node;
431         struct property *prop;
432         const __be32 *cur;
433         int channels = 0;
434         u32 val;
435 
436         of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
437                 adc_dev->channel_line[channels] = val;
438 
439                 /* Set Default values for optional DT parameters */
440                 adc_dev->open_delay[channels] = STEPCONFIG_OPENDLY;
441                 adc_dev->sample_delay[channels] = STEPCONFIG_SAMPLEDLY;
442                 adc_dev->step_avg[channels] = 16;
443 
444                 channels++;
445         }
446 
447         of_property_read_u32_array(node, "ti,chan-step-avg",
448                                    adc_dev->step_avg, channels);
449         of_property_read_u32_array(node, "ti,chan-step-opendelay",
450                                    adc_dev->open_delay, channels);
451         of_property_read_u32_array(node, "ti,chan-step-sampledelay",
452                                    adc_dev->sample_delay, channels);
453 
454         adc_dev->channels = channels;
455         return 0;
456 }
457 
458 static int tiadc_probe(struct platform_device *pdev)
459 {
460         struct iio_dev          *indio_dev;
461         struct tiadc_device     *adc_dev;
462         struct device_node      *node = pdev->dev.of_node;
463         int                     err;
464 
465         if (!node) {
466                 dev_err(&pdev->dev, "Could not find valid DT data.\n");
467                 return -EINVAL;
468         }
469 
470         indio_dev = devm_iio_device_alloc(&pdev->dev,
471                                           sizeof(struct tiadc_device));
472         if (indio_dev == NULL) {
473                 dev_err(&pdev->dev, "failed to allocate iio device\n");
474                 return -ENOMEM;
475         }
476         adc_dev = iio_priv(indio_dev);
477 
478         adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
479         tiadc_parse_dt(pdev, adc_dev);
480 
481         indio_dev->dev.parent = &pdev->dev;
482         indio_dev->name = dev_name(&pdev->dev);
483         indio_dev->modes = INDIO_DIRECT_MODE;
484         indio_dev->info = &tiadc_info;
485 
486         tiadc_step_config(indio_dev);
487         tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD);
488 
489         err = tiadc_channel_init(indio_dev, adc_dev->channels);
490         if (err < 0)
491                 return err;
492 
493         err = tiadc_iio_buffered_hardware_setup(indio_dev,
494                 &tiadc_worker_h,
495                 &tiadc_irq_h,
496                 adc_dev->mfd_tscadc->irq,
497                 IRQF_SHARED,
498                 &tiadc_buffer_setup_ops);
499 
500         if (err)
501                 goto err_free_channels;
502 
503         err = iio_device_register(indio_dev);
504         if (err)
505                 goto err_buffer_unregister;
506 
507         platform_set_drvdata(pdev, indio_dev);
508 
509         return 0;
510 
511 err_buffer_unregister:
512         tiadc_iio_buffered_hardware_remove(indio_dev);
513 err_free_channels:
514         tiadc_channels_remove(indio_dev);
515         return err;
516 }
517 
518 static int tiadc_remove(struct platform_device *pdev)
519 {
520         struct iio_dev *indio_dev = platform_get_drvdata(pdev);
521         struct tiadc_device *adc_dev = iio_priv(indio_dev);
522         u32 step_en;
523 
524         iio_device_unregister(indio_dev);
525         tiadc_iio_buffered_hardware_remove(indio_dev);
526         tiadc_channels_remove(indio_dev);
527 
528         step_en = get_adc_step_mask(adc_dev);
529         am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);
530 
531         return 0;
532 }
533 
534 #ifdef CONFIG_PM
535 static int tiadc_suspend(struct device *dev)
536 {
537         struct iio_dev *indio_dev = dev_get_drvdata(dev);
538         struct tiadc_device *adc_dev = iio_priv(indio_dev);
539         struct ti_tscadc_dev *tscadc_dev;
540         unsigned int idle;
541 
542         tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
543         if (!device_may_wakeup(tscadc_dev->dev)) {
544                 idle = tiadc_readl(adc_dev, REG_CTRL);
545                 idle &= ~(CNTRLREG_TSCSSENB);
546                 tiadc_writel(adc_dev, REG_CTRL, (idle |
547                                 CNTRLREG_POWERDOWN));
548         }
549 
550         return 0;
551 }
552 
553 static int tiadc_resume(struct device *dev)
554 {
555         struct iio_dev *indio_dev = dev_get_drvdata(dev);
556         struct tiadc_device *adc_dev = iio_priv(indio_dev);
557         unsigned int restore;
558 
559         /* Make sure ADC is powered up */
560         restore = tiadc_readl(adc_dev, REG_CTRL);
561         restore &= ~(CNTRLREG_POWERDOWN);
562         tiadc_writel(adc_dev, REG_CTRL, restore);
563 
564         tiadc_step_config(indio_dev);
565         am335x_tsc_se_set_cache(adc_dev->mfd_tscadc,
566                         adc_dev->buffer_en_ch_steps);
567         return 0;
568 }
569 
570 static const struct dev_pm_ops tiadc_pm_ops = {
571         .suspend = tiadc_suspend,
572         .resume = tiadc_resume,
573 };
574 #define TIADC_PM_OPS (&tiadc_pm_ops)
575 #else
576 #define TIADC_PM_OPS NULL
577 #endif
578 
579 static const struct of_device_id ti_adc_dt_ids[] = {
580         { .compatible = "ti,am3359-adc", },
581         { }
582 };
583 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
584 
585 static struct platform_driver tiadc_driver = {
586         .driver = {
587                 .name   = "TI-am335x-adc",
588                 .pm     = TIADC_PM_OPS,
589                 .of_match_table = ti_adc_dt_ids,
590         },
591         .probe  = tiadc_probe,
592         .remove = tiadc_remove,
593 };
594 module_platform_driver(tiadc_driver);
595 
596 MODULE_DESCRIPTION("TI ADC controller driver");
597 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
598 MODULE_LICENSE("GPL");
599 

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