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mm: Initialize error in shmem_file_aio_read()
[linux/fpc-iii.git] / drivers / iio / adc / ti_am335x_adc.c
bloba4db3026bec6f443417b2a13daf27a9f8ad75561
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 = chan->channel + TOTAL_CHANNELS;
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 .owner = THIS_MODULE,
549 .pm = TIADC_PM_OPS,
550 .of_match_table = ti_adc_dt_ids,
551 },
552 .probe = tiadc_probe,
553 .remove = tiadc_remove,
554 };
555 module_platform_driver(tiadc_driver);
556
557 MODULE_DESCRIPTION("TI ADC controller driver");
558 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
559 MODULE_LICENSE("GPL");
Linux with added FPC-III support