aboutsummaryrefslogtreecommitdiff
path: root/drivers/iio/adc/ti_am335x_adc.c
blob: 728411ec764203c371270c390ac77176d788ffd9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
/*
 * TI ADC MFD driver
 *
 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation version 2.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/iio/iio.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/iio/machine.h>
#include <linux/iio/driver.h>

#include <linux/mfd/ti_am335x_tscadc.h>
#include <linux/iio/buffer.h>
#include <linux/iio/kfifo_buf.h>

struct tiadc_device {
	struct ti_tscadc_dev *mfd_tscadc;
	int channels;
	u8 channel_line[8];
	u8 channel_step[8];
	int buffer_en_ch_steps;
	u16 data[8];
};

static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
{
	return readl(adc->mfd_tscadc->tscadc_base + reg);
}

static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
					unsigned int val)
{
	writel(val, adc->mfd_tscadc->tscadc_base + reg);
}

static u32 get_adc_step_mask(struct tiadc_device *adc_dev)
{
	u32 step_en;

	step_en = ((1 << adc_dev->channels) - 1);
	step_en <<= TOTAL_STEPS - adc_dev->channels + 1;
	return step_en;
}

static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan)
{
	return 1 << adc_dev->channel_step[chan];
}

static void tiadc_step_config(struct iio_dev *indio_dev)
{
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	unsigned int stepconfig;
	int i, steps;

	/*
	 * There are 16 configurable steps and 8 analog input
	 * lines available which are shared between Touchscreen and ADC.
	 *
	 * Steps backwards i.e. from 16 towards 0 are used by ADC
	 * depending on number of input lines needed.
	 * Channel would represent which analog input
	 * needs to be given to ADC to digitalize data.
	 */

	steps = TOTAL_STEPS - adc_dev->channels;
	if (iio_buffer_enabled(indio_dev))
		stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1
					| STEPCONFIG_MODE_SWCNT;
	else
		stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;

	for (i = 0; i < adc_dev->channels; i++) {
		int chan;

		chan = adc_dev->channel_line[i];
		tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
				stepconfig | STEPCONFIG_INP(chan));
		tiadc_writel(adc_dev, REG_STEPDELAY(steps),
				STEPCONFIG_OPENDLY);
		adc_dev->channel_step[i] = steps;
		steps++;
	}
}

static irqreturn_t tiadc_irq_h(int irq, void *private)
{
	struct iio_dev *indio_dev = private;
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	unsigned int status, config;
	status = tiadc_readl(adc_dev, REG_IRQSTATUS);

	/*
	 * ADC and touchscreen share the IRQ line.
	 * FIFO0 interrupts are used by TSC. Handle FIFO1 IRQs here only
	 */
	if (status & IRQENB_FIFO1OVRRUN) {
		/* FIFO Overrun. Clear flag. Disable/Enable ADC to recover */
		config = tiadc_readl(adc_dev, REG_CTRL);
		config &= ~(CNTRLREG_TSCSSENB);
		tiadc_writel(adc_dev, REG_CTRL, config);
		tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1OVRRUN
				| IRQENB_FIFO1UNDRFLW | IRQENB_FIFO1THRES);
		tiadc_writel(adc_dev, REG_CTRL, (config | CNTRLREG_TSCSSENB));
		return IRQ_HANDLED;
	} else if (status & IRQENB_FIFO1THRES) {
		/* Disable irq and wake worker thread */
		tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_FIFO1THRES);
		return IRQ_WAKE_THREAD;
	}

	return IRQ_NONE;
}

static irqreturn_t tiadc_worker_h(int irq, void *private)
{
	struct iio_dev *indio_dev = private;
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	int i, k, fifo1count, read;
	u16 *data = adc_dev->data;

	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
	for (k = 0; k < fifo1count; k = k + i) {
		for (i = 0; i < (indio_dev->scan_bytes)/2; i++) {
			read = tiadc_readl(adc_dev, REG_FIFO1);
			data[i] = read & FIFOREAD_DATA_MASK;
		}
		iio_push_to_buffers(indio_dev, (u8 *) data);
	}

	tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES);
	tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES);

	return IRQ_HANDLED;
}

static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
{
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	int i, fifo1count, read;

	tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
				IRQENB_FIFO1OVRRUN |
				IRQENB_FIFO1UNDRFLW));

	/* Flush FIFO. Needed in corner cases in simultaneous tsc/adc use */
	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
	for (i = 0; i < fifo1count; i++)
		read = tiadc_readl(adc_dev, REG_FIFO1);

	return 0;
}

static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
{
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	struct iio_buffer *buffer = indio_dev->buffer;
	unsigned int enb = 0;
	u8 bit;

	tiadc_step_config(indio_dev);
	for_each_set_bit(bit, buffer->scan_mask, adc_dev->channels)
		enb |= (get_adc_step_bit(adc_dev, bit) << 1);
	adc_dev->buffer_en_ch_steps = enb;

	am335x_tsc_se_set(adc_dev->mfd_tscadc, enb);

	tiadc_writel(adc_dev,  REG_IRQSTATUS, IRQENB_FIFO1THRES
				| IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW);
	tiadc_writel(adc_dev,  REG_IRQENABLE, IRQENB_FIFO1THRES
				| IRQENB_FIFO1OVRRUN);

	return 0;
}

static int tiadc_buffer_predisable(struct iio_dev *indio_dev)
{
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	int fifo1count, i, read;

	tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
				IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW));
	am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps);

	/* Flush FIFO of leftover data in the time it takes to disable adc */
	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
	for (i = 0; i < fifo1count; i++)
		read = tiadc_readl(adc_dev, REG_FIFO1);

	return 0;
}

static int tiadc_buffer_postdisable(struct iio_dev *indio_dev)
{
	tiadc_step_config(indio_dev);

	return 0;
}

static const struct iio_buffer_setup_ops tiadc_buffer_setup_ops = {
	.preenable = &tiadc_buffer_preenable,
	.postenable = &tiadc_buffer_postenable,
	.predisable = &tiadc_buffer_predisable,
	.postdisable = &tiadc_buffer_postdisable,
};

static int tiadc_iio_buffered_hardware_setup(struct iio_dev *indio_dev,
	irqreturn_t (*pollfunc_bh)(int irq, void *p),
	irqreturn_t (*pollfunc_th)(int irq, void *p),
	int irq,
	unsigned long flags,
	const struct iio_buffer_setup_ops *setup_ops)
{
	int ret;

	indio_dev->buffer = iio_kfifo_allocate(indio_dev);
	if (!indio_dev->buffer)
		return -ENOMEM;

	ret = request_threaded_irq(irq,	pollfunc_th, pollfunc_bh,
				flags, indio_dev->name, indio_dev);
	if (ret)
		goto error_kfifo_free;

	indio_dev->setup_ops = setup_ops;
	indio_dev->modes |= INDIO_BUFFER_HARDWARE;

	ret = iio_buffer_register(indio_dev,
				  indio_dev->channels,
				  indio_dev->num_channels);
	if (ret)
		goto error_free_irq;

	return 0;

error_free_irq:
	free_irq(irq, indio_dev);
error_kfifo_free:
	iio_kfifo_free(indio_dev->buffer);
	return ret;
}

static void tiadc_iio_buffered_hardware_remove(struct iio_dev *indio_dev)
{
	struct tiadc_device *adc_dev = iio_priv(indio_dev);

	free_irq(adc_dev->mfd_tscadc->irq, indio_dev);
	iio_kfifo_free(indio_dev->buffer);
	iio_buffer_unregister(indio_dev);
}


static const char * const chan_name_ain[] = {
	"AIN0",
	"AIN1",
	"AIN2",
	"AIN3",
	"AIN4",
	"AIN5",
	"AIN6",
	"AIN7",
};

static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
{
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	struct iio_chan_spec *chan_array;
	struct iio_chan_spec *chan;
	int i;

	indio_dev->num_channels = channels;
	chan_array = kcalloc(channels,
			sizeof(struct iio_chan_spec), GFP_KERNEL);
	if (chan_array == NULL)
		return -ENOMEM;

	chan = chan_array;
	for (i = 0; i < channels; i++, chan++) {

		chan->type = IIO_VOLTAGE;
		chan->indexed = 1;
		chan->channel = adc_dev->channel_line[i];
		chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
		chan->datasheet_name = chan_name_ain[chan->channel];
		chan->scan_index = i;
		chan->scan_type.sign = 'u';
		chan->scan_type.realbits = 12;
		chan->scan_type.storagebits = 16;
	}

	indio_dev->channels = chan_array;

	return 0;
}

static void tiadc_channels_remove(struct iio_dev *indio_dev)
{
	kfree(indio_dev->channels);
}

static int tiadc_read_raw(struct iio_dev *indio_dev,
		struct iio_chan_spec const *chan,
		int *val, int *val2, long mask)
{
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	int i, map_val;
	unsigned int fifo1count, read, stepid;
	bool found = false;
	u32 step_en;
	unsigned long timeout = jiffies + usecs_to_jiffies
				(IDLE_TIMEOUT * adc_dev->channels);

	if (iio_buffer_enabled(indio_dev))
		return -EBUSY;

	step_en = get_adc_step_mask(adc_dev);
	am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en);

	/* Wait for ADC sequencer to complete sampling */
	while (tiadc_readl(adc_dev, REG_ADCFSM) & SEQ_STATUS) {
		if (time_after(jiffies, timeout))
			return -EAGAIN;
		}
	map_val = chan->channel + TOTAL_CHANNELS;

	/*
	 * When the sub-system is first enabled,
	 * the sequencer will always start with the
	 * lowest step (1) and continue until step (16).
	 * For ex: If we have enabled 4 ADC channels and
	 * currently use only 1 out of them, the
	 * sequencer still configures all the 4 steps,
	 * leading to 3 unwanted data.
	 * Hence we need to flush out this data.
	 */

	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
	for (i = 0; i < fifo1count; i++) {
		read = tiadc_readl(adc_dev, REG_FIFO1);
		stepid = read & FIFOREAD_CHNLID_MASK;
		stepid = stepid >> 0x10;

		if (stepid == map_val) {
			read = read & FIFOREAD_DATA_MASK;
			found = true;
			*val = (u16) read;
		}
	}

	if (found == false)
		return -EBUSY;
	return IIO_VAL_INT;
}

static const struct iio_info tiadc_info = {
	.read_raw = &tiadc_read_raw,
	.driver_module = THIS_MODULE,
};

static int tiadc_probe(struct platform_device *pdev)
{
	struct iio_dev		*indio_dev;
	struct tiadc_device	*adc_dev;
	struct device_node	*node = pdev->dev.of_node;
	struct property		*prop;
	const __be32		*cur;
	int			err;
	u32			val;
	int			channels = 0;

	if (!node) {
		dev_err(&pdev->dev, "Could not find valid DT data.\n");
		return -EINVAL;
	}

	indio_dev = devm_iio_device_alloc(&pdev->dev,
					  sizeof(struct tiadc_device));
	if (indio_dev == NULL) {
		dev_err(&pdev->dev, "failed to allocate iio device\n");
		return -ENOMEM;
	}
	adc_dev = iio_priv(indio_dev);

	adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);

	of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
		adc_dev->channel_line[channels] = val;
		channels++;
	}
	adc_dev->channels = channels;

	indio_dev->dev.parent = &pdev->dev;
	indio_dev->name = dev_name(&pdev->dev);
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->info = &tiadc_info;

	tiadc_step_config(indio_dev);
	tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD);

	err = tiadc_channel_init(indio_dev, adc_dev->channels);
	if (err < 0)
		return err;

	err = tiadc_iio_buffered_hardware_setup(indio_dev,
		&tiadc_worker_h,
		&tiadc_irq_h,
		adc_dev->mfd_tscadc->irq,
		IRQF_SHARED,
		&tiadc_buffer_setup_ops);

	if (err)
		goto err_free_channels;

	err = iio_device_register(indio_dev);
	if (err)
		goto err_buffer_unregister;

	platform_set_drvdata(pdev, indio_dev);

	return 0;

err_buffer_unregister:
	tiadc_iio_buffered_hardware_remove(indio_dev);
err_free_channels:
	tiadc_channels_remove(indio_dev);
	return err;
}

static int tiadc_remove(struct platform_device *pdev)
{
	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	u32 step_en;

	iio_device_unregister(indio_dev);
	tiadc_iio_buffered_hardware_remove(indio_dev);
	tiadc_channels_remove(indio_dev);

	step_en = get_adc_step_mask(adc_dev);
	am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);

	return 0;
}

#ifdef CONFIG_PM
static int tiadc_suspend(struct device *dev)
{
	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	struct ti_tscadc_dev *tscadc_dev;
	unsigned int idle;

	tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
	if (!device_may_wakeup(tscadc_dev->dev)) {
		idle = tiadc_readl(adc_dev, REG_CTRL);
		idle &= ~(CNTRLREG_TSCSSENB);
		tiadc_writel(adc_dev, REG_CTRL, (idle |
				CNTRLREG_POWERDOWN));
	}

	return 0;
}

static int tiadc_resume(struct device *dev)
{
	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	unsigned int restore;

	/* Make sure ADC is powered up */
	restore = tiadc_readl(adc_dev, REG_CTRL);
	restore &= ~(CNTRLREG_POWERDOWN);
	tiadc_writel(adc_dev, REG_CTRL, restore);

	tiadc_step_config(indio_dev);

	return 0;
}

static const struct dev_pm_ops tiadc_pm_ops = {
	.suspend = tiadc_suspend,
	.resume = tiadc_resume,
};
#define TIADC_PM_OPS (&tiadc_pm_ops)
#else
#define TIADC_PM_OPS NULL
#endif

static const struct of_device_id ti_adc_dt_ids[] = {
	{ .compatible = "ti,am3359-adc", },
	{ }
};
MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);

static struct platform_driver tiadc_driver = {
	.driver = {
		.name   = "TI-am335x-adc",
		.owner	= THIS_MODULE,
		.pm	= TIADC_PM_OPS,
		.of_match_table = ti_adc_dt_ids,
	},
	.probe	= tiadc_probe,
	.remove	= tiadc_remove,
};
module_platform_driver(tiadc_driver);

MODULE_DESCRIPTION("TI ADC controller driver");
MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
MODULE_LICENSE("GPL");