Version:  2.0.40 2.2.26 2.4.37 3.5 3.6 3.7 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

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

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