Version:  2.6.34 2.6.35 2.6.36 2.6.37 2.6.38 2.6.39 3.0 3.1 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

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

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