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
33struct 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
42static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
43{
44	return readl(adc->mfd_tscadc->tscadc_base + reg);
45}
46
47static 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
53static 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
62static 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
80static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan)
81{
82	return 1 << adc_dev->channel_step[chan];
83}
84
85static 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
120static 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
149static 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
171static 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
188static 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
209static 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
227static int tiadc_buffer_postdisable(struct iio_dev *indio_dev)
228{
229	tiadc_step_config(indio_dev);
230
231	return 0;
232}
233
234static 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
241static 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
267error_kfifo_free:
268	iio_kfifo_free(indio_dev->buffer);
269	return ret;
270}
271
272static 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
281static const char * const chan_name_ain[] = {
282	"AIN0",
283	"AIN1",
284	"AIN2",
285	"AIN3",
286	"AIN4",
287	"AIN5",
288	"AIN6",
289	"AIN7",
290};
291
292static 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
324static void tiadc_channels_remove(struct iio_dev *indio_dev)
325{
326	kfree(indio_dev->channels);
327}
328
329static 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
393static const struct iio_info tiadc_info = {
394	.read_raw = &tiadc_read_raw,
395	.driver_module = THIS_MODULE,
396};
397
398static 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
460err_buffer_unregister:
461	tiadc_iio_buffered_hardware_remove(indio_dev);
462err_free_channels:
463	tiadc_channels_remove(indio_dev);
464	return err;
465}
466
467static 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
484static 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
502static 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
519static 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
528static const struct of_device_id ti_adc_dt_ids[] = {
529	{ .compatible = "ti,am3359-adc", },
530	{ }
531};
532MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
533
534static 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};
543module_platform_driver(tiadc_driver);
544
545MODULE_DESCRIPTION("TI ADC controller driver");
546MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
547MODULE_LICENSE("GPL");
548