Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 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

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;
 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 backwards i.e. from 16 towards 0 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         steps = TOTAL_STEPS - adc_dev->channels;
102         if (iio_buffer_enabled(indio_dev))
103                 stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1
104                                         | STEPCONFIG_MODE_SWCNT;
105         else
106                 stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
107 
108         for (i = 0; i < adc_dev->channels; i++) {
109                 int chan;
110 
111                 chan = adc_dev->channel_line[i];
112                 tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
113                                 stepconfig | STEPCONFIG_INP(chan));
114                 tiadc_writel(adc_dev, REG_STEPDELAY(steps),
115                                 STEPCONFIG_OPENDLY);
116                 adc_dev->channel_step[i] = steps;
117                 steps++;
118         }
119 }
120 
121 static irqreturn_t tiadc_irq_h(int irq, void *private)
122 {
123         struct iio_dev *indio_dev = private;
124         struct tiadc_device *adc_dev = iio_priv(indio_dev);
125         unsigned int status, config;
126         status = tiadc_readl(adc_dev, REG_IRQSTATUS);
127 
128         /*
129          * ADC and touchscreen share the IRQ line.
130          * FIFO0 interrupts are used by TSC. Handle FIFO1 IRQs here only
131          */
132         if (status & IRQENB_FIFO1OVRRUN) {
133                 /* FIFO Overrun. Clear flag. Disable/Enable ADC to recover */
134                 config = tiadc_readl(adc_dev, REG_CTRL);
135                 config &= ~(CNTRLREG_TSCSSENB);
136                 tiadc_writel(adc_dev, REG_CTRL, config);
137                 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1OVRRUN
138                                 | IRQENB_FIFO1UNDRFLW | IRQENB_FIFO1THRES);
139                 tiadc_writel(adc_dev, REG_CTRL, (config | CNTRLREG_TSCSSENB));
140                 return IRQ_HANDLED;
141         } else if (status & IRQENB_FIFO1THRES) {
142                 /* Disable irq and wake worker thread */
143                 tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_FIFO1THRES);
144                 return IRQ_WAKE_THREAD;
145         }
146 
147         return IRQ_NONE;
148 }
149 
150 static irqreturn_t tiadc_worker_h(int irq, void *private)
151 {
152         struct iio_dev *indio_dev = private;
153         struct tiadc_device *adc_dev = iio_priv(indio_dev);
154         int i, k, fifo1count, read;
155         u16 *data = adc_dev->data;
156 
157         fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
158         for (k = 0; k < fifo1count; k = k + i) {
159                 for (i = 0; i < (indio_dev->scan_bytes)/2; i++) {
160                         read = tiadc_readl(adc_dev, REG_FIFO1);
161                         data[i] = read & FIFOREAD_DATA_MASK;
162                 }
163                 iio_push_to_buffers(indio_dev, (u8 *) data);
164         }
165 
166         tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES);
167         tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES);
168 
169         return IRQ_HANDLED;
170 }
171 
172 static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
173 {
174         struct tiadc_device *adc_dev = iio_priv(indio_dev);
175         int i, fifo1count, read;
176 
177         tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
178                                 IRQENB_FIFO1OVRRUN |
179                                 IRQENB_FIFO1UNDRFLW));
180 
181         /* Flush FIFO. Needed in corner cases in simultaneous tsc/adc use */
182         fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
183         for (i = 0; i < fifo1count; i++)
184                 read = tiadc_readl(adc_dev, REG_FIFO1);
185 
186         return 0;
187 }
188 
189 static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
190 {
191         struct tiadc_device *adc_dev = iio_priv(indio_dev);
192         struct iio_buffer *buffer = indio_dev->buffer;
193         unsigned int enb = 0;
194         u8 bit;
195 
196         tiadc_step_config(indio_dev);
197         for_each_set_bit(bit, buffer->scan_mask, adc_dev->channels)
198                 enb |= (get_adc_step_bit(adc_dev, bit) << 1);
199         adc_dev->buffer_en_ch_steps = enb;
200 
201         am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, enb);
202 
203         tiadc_writel(adc_dev,  REG_IRQSTATUS, IRQENB_FIFO1THRES
204                                 | IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW);
205         tiadc_writel(adc_dev,  REG_IRQENABLE, IRQENB_FIFO1THRES
206                                 | IRQENB_FIFO1OVRRUN);
207 
208         return 0;
209 }
210 
211 static int tiadc_buffer_predisable(struct iio_dev *indio_dev)
212 {
213         struct tiadc_device *adc_dev = iio_priv(indio_dev);
214         int fifo1count, i, read;
215 
216         tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
217                                 IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW));
218         am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps);
219         adc_dev->buffer_en_ch_steps = 0;
220 
221         /* Flush FIFO of leftover data in the time it takes to disable adc */
222         fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
223         for (i = 0; i < fifo1count; i++)
224                 read = tiadc_readl(adc_dev, REG_FIFO1);
225 
226         return 0;
227 }
228 
229 static int tiadc_buffer_postdisable(struct iio_dev *indio_dev)
230 {
231         tiadc_step_config(indio_dev);
232 
233         return 0;
234 }
235 
236 static const struct iio_buffer_setup_ops tiadc_buffer_setup_ops = {
237         .preenable = &tiadc_buffer_preenable,
238         .postenable = &tiadc_buffer_postenable,
239         .predisable = &tiadc_buffer_predisable,
240         .postdisable = &tiadc_buffer_postdisable,
241 };
242 
243 static int tiadc_iio_buffered_hardware_setup(struct iio_dev *indio_dev,
244         irqreturn_t (*pollfunc_bh)(int irq, void *p),
245         irqreturn_t (*pollfunc_th)(int irq, void *p),
246         int irq,
247         unsigned long flags,
248         const struct iio_buffer_setup_ops *setup_ops)
249 {
250         struct iio_buffer *buffer;
251         int ret;
252 
253         buffer = iio_kfifo_allocate(indio_dev);
254         if (!buffer)
255                 return -ENOMEM;
256 
257         iio_device_attach_buffer(indio_dev, buffer);
258 
259         ret = request_threaded_irq(irq, pollfunc_th, pollfunc_bh,
260                                 flags, indio_dev->name, indio_dev);
261         if (ret)
262                 goto error_kfifo_free;
263 
264         indio_dev->setup_ops = setup_ops;
265         indio_dev->modes |= INDIO_BUFFER_HARDWARE;
266 
267         ret = iio_buffer_register(indio_dev,
268                                   indio_dev->channels,
269                                   indio_dev->num_channels);
270         if (ret)
271                 goto error_free_irq;
272 
273         return 0;
274 
275 error_free_irq:
276         free_irq(irq, indio_dev);
277 error_kfifo_free:
278         iio_kfifo_free(indio_dev->buffer);
279         return ret;
280 }
281 
282 static void tiadc_iio_buffered_hardware_remove(struct iio_dev *indio_dev)
283 {
284         struct tiadc_device *adc_dev = iio_priv(indio_dev);
285 
286         free_irq(adc_dev->mfd_tscadc->irq, indio_dev);
287         iio_kfifo_free(indio_dev->buffer);
288         iio_buffer_unregister(indio_dev);
289 }
290 
291 
292 static const char * const chan_name_ain[] = {
293         "AIN0",
294         "AIN1",
295         "AIN2",
296         "AIN3",
297         "AIN4",
298         "AIN5",
299         "AIN6",
300         "AIN7",
301 };
302 
303 static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
304 {
305         struct tiadc_device *adc_dev = iio_priv(indio_dev);
306         struct iio_chan_spec *chan_array;
307         struct iio_chan_spec *chan;
308         int i;
309 
310         indio_dev->num_channels = channels;
311         chan_array = kcalloc(channels,
312                         sizeof(struct iio_chan_spec), GFP_KERNEL);
313         if (chan_array == NULL)
314                 return -ENOMEM;
315 
316         chan = chan_array;
317         for (i = 0; i < channels; i++, chan++) {
318 
319                 chan->type = IIO_VOLTAGE;
320                 chan->indexed = 1;
321                 chan->channel = adc_dev->channel_line[i];
322                 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
323                 chan->datasheet_name = chan_name_ain[chan->channel];
324                 chan->scan_index = i;
325                 chan->scan_type.sign = 'u';
326                 chan->scan_type.realbits = 12;
327                 chan->scan_type.storagebits = 16;
328         }
329 
330         indio_dev->channels = chan_array;
331 
332         return 0;
333 }
334 
335 static void tiadc_channels_remove(struct iio_dev *indio_dev)
336 {
337         kfree(indio_dev->channels);
338 }
339 
340 static int tiadc_read_raw(struct iio_dev *indio_dev,
341                 struct iio_chan_spec const *chan,
342                 int *val, int *val2, long mask)
343 {
344         struct tiadc_device *adc_dev = iio_priv(indio_dev);
345         int i, map_val;
346         unsigned int fifo1count, read, stepid;
347         bool found = false;
348         u32 step_en;
349         unsigned long timeout;
350 
351         if (iio_buffer_enabled(indio_dev))
352                 return -EBUSY;
353 
354         step_en = get_adc_chan_step_mask(adc_dev, chan);
355         if (!step_en)
356                 return -EINVAL;
357 
358         fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
359         while (fifo1count--)
360                 tiadc_readl(adc_dev, REG_FIFO1);
361 
362         am335x_tsc_se_set_once(adc_dev->mfd_tscadc, step_en);
363 
364         timeout = jiffies + usecs_to_jiffies
365                                 (IDLE_TIMEOUT * adc_dev->channels);
366         /* Wait for Fifo threshold interrupt */
367         while (1) {
368                 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
369                 if (fifo1count)
370                         break;
371 
372                 if (time_after(jiffies, timeout)) {
373                         am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
374                         return -EAGAIN;
375                 }
376         }
377         map_val = adc_dev->channel_step[chan->scan_index];
378 
379         /*
380          * We check the complete FIFO. We programmed just one entry but in case
381          * something went wrong we left empty handed (-EAGAIN previously) and
382          * then the value apeared somehow in the FIFO we would have two entries.
383          * Therefore we read every item and keep only the latest version of the
384          * requested channel.
385          */
386         for (i = 0; i < fifo1count; i++) {
387                 read = tiadc_readl(adc_dev, REG_FIFO1);
388                 stepid = read & FIFOREAD_CHNLID_MASK;
389                 stepid = stepid >> 0x10;
390 
391                 if (stepid == map_val) {
392                         read = read & FIFOREAD_DATA_MASK;
393                         found = true;
394                         *val = (u16) read;
395                 }
396         }
397         am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
398 
399         if (found == false)
400                 return -EBUSY;
401         return IIO_VAL_INT;
402 }
403 
404 static const struct iio_info tiadc_info = {
405         .read_raw = &tiadc_read_raw,
406         .driver_module = THIS_MODULE,
407 };
408 
409 static int tiadc_probe(struct platform_device *pdev)
410 {
411         struct iio_dev          *indio_dev;
412         struct tiadc_device     *adc_dev;
413         struct device_node      *node = pdev->dev.of_node;
414         struct property         *prop;
415         const __be32            *cur;
416         int                     err;
417         u32                     val;
418         int                     channels = 0;
419 
420         if (!node) {
421                 dev_err(&pdev->dev, "Could not find valid DT data.\n");
422                 return -EINVAL;
423         }
424 
425         indio_dev = devm_iio_device_alloc(&pdev->dev,
426                                           sizeof(struct tiadc_device));
427         if (indio_dev == NULL) {
428                 dev_err(&pdev->dev, "failed to allocate iio device\n");
429                 return -ENOMEM;
430         }
431         adc_dev = iio_priv(indio_dev);
432 
433         adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
434 
435         of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
436                 adc_dev->channel_line[channels] = val;
437                 channels++;
438         }
439         adc_dev->channels = channels;
440 
441         indio_dev->dev.parent = &pdev->dev;
442         indio_dev->name = dev_name(&pdev->dev);
443         indio_dev->modes = INDIO_DIRECT_MODE;
444         indio_dev->info = &tiadc_info;
445 
446         tiadc_step_config(indio_dev);
447         tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD);
448 
449         err = tiadc_channel_init(indio_dev, adc_dev->channels);
450         if (err < 0)
451                 return err;
452 
453         err = tiadc_iio_buffered_hardware_setup(indio_dev,
454                 &tiadc_worker_h,
455                 &tiadc_irq_h,
456                 adc_dev->mfd_tscadc->irq,
457                 IRQF_SHARED,
458                 &tiadc_buffer_setup_ops);
459 
460         if (err)
461                 goto err_free_channels;
462 
463         err = iio_device_register(indio_dev);
464         if (err)
465                 goto err_buffer_unregister;
466 
467         platform_set_drvdata(pdev, indio_dev);
468 
469         return 0;
470 
471 err_buffer_unregister:
472         tiadc_iio_buffered_hardware_remove(indio_dev);
473 err_free_channels:
474         tiadc_channels_remove(indio_dev);
475         return err;
476 }
477 
478 static int tiadc_remove(struct platform_device *pdev)
479 {
480         struct iio_dev *indio_dev = platform_get_drvdata(pdev);
481         struct tiadc_device *adc_dev = iio_priv(indio_dev);
482         u32 step_en;
483 
484         iio_device_unregister(indio_dev);
485         tiadc_iio_buffered_hardware_remove(indio_dev);
486         tiadc_channels_remove(indio_dev);
487 
488         step_en = get_adc_step_mask(adc_dev);
489         am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);
490 
491         return 0;
492 }
493 
494 #ifdef CONFIG_PM
495 static int tiadc_suspend(struct device *dev)
496 {
497         struct iio_dev *indio_dev = dev_get_drvdata(dev);
498         struct tiadc_device *adc_dev = iio_priv(indio_dev);
499         struct ti_tscadc_dev *tscadc_dev;
500         unsigned int idle;
501 
502         tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
503         if (!device_may_wakeup(tscadc_dev->dev)) {
504                 idle = tiadc_readl(adc_dev, REG_CTRL);
505                 idle &= ~(CNTRLREG_TSCSSENB);
506                 tiadc_writel(adc_dev, REG_CTRL, (idle |
507                                 CNTRLREG_POWERDOWN));
508         }
509 
510         return 0;
511 }
512 
513 static int tiadc_resume(struct device *dev)
514 {
515         struct iio_dev *indio_dev = dev_get_drvdata(dev);
516         struct tiadc_device *adc_dev = iio_priv(indio_dev);
517         unsigned int restore;
518 
519         /* Make sure ADC is powered up */
520         restore = tiadc_readl(adc_dev, REG_CTRL);
521         restore &= ~(CNTRLREG_POWERDOWN);
522         tiadc_writel(adc_dev, REG_CTRL, restore);
523 
524         tiadc_step_config(indio_dev);
525         am335x_tsc_se_set_cache(adc_dev->mfd_tscadc,
526                         adc_dev->buffer_en_ch_steps);
527         return 0;
528 }
529 
530 static const struct dev_pm_ops tiadc_pm_ops = {
531         .suspend = tiadc_suspend,
532         .resume = tiadc_resume,
533 };
534 #define TIADC_PM_OPS (&tiadc_pm_ops)
535 #else
536 #define TIADC_PM_OPS NULL
537 #endif
538 
539 static const struct of_device_id ti_adc_dt_ids[] = {
540         { .compatible = "ti,am3359-adc", },
541         { }
542 };
543 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
544 
545 static struct platform_driver tiadc_driver = {
546         .driver = {
547                 .name   = "TI-am335x-adc",
548                 .pm     = TIADC_PM_OPS,
549                 .of_match_table = ti_adc_dt_ids,
550         },
551         .probe  = tiadc_probe,
552         .remove = tiadc_remove,
553 };
554 module_platform_driver(tiadc_driver);
555 
556 MODULE_DESCRIPTION("TI ADC controller driver");
557 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
558 MODULE_LICENSE("GPL");
559 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us