summaryrefslogtreecommitdiff
path: root/drivers/iio/dac/stm32-dac.c
blob: 5a722f307e7e305fe4b0fd959af45fa663d3a948 (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
// SPDX-License-Identifier: GPL-2.0
/*
 * This file is part of STM32 DAC driver
 *
 * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
 * Authors: Amelie Delaunay <amelie.delaunay@st.com>
 *	    Fabrice Gasnier <fabrice.gasnier@st.com>
 */

#include <linux/bitfield.h>
#include <linux/delay.h>
#include <linux/iio/iio.h>
#include <linux/kernel.h>
#include <linux/kstrtox.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/string_choices.h>

#include "stm32-dac-core.h"

#define STM32_DAC_CHANNEL_1		1
#define STM32_DAC_CHANNEL_2		2
#define STM32_DAC_IS_CHAN_1(ch)		((ch) & STM32_DAC_CHANNEL_1)

#define STM32_DAC_AUTO_SUSPEND_DELAY_MS	2000

/**
 * struct stm32_dac - private data of DAC driver
 * @common:		reference to DAC common data
 * @lock:		lock to protect against potential races when reading
 *			and update CR, to keep it in sync with pm_runtime
 */
struct stm32_dac {
	struct stm32_dac_common *common;
	struct mutex		lock;
};

static int stm32_dac_is_enabled(struct iio_dev *indio_dev, int channel)
{
	struct stm32_dac *dac = iio_priv(indio_dev);
	u32 en, val;
	int ret;

	ret = regmap_read(dac->common->regmap, STM32_DAC_CR, &val);
	if (ret < 0)
		return ret;
	if (STM32_DAC_IS_CHAN_1(channel))
		en = FIELD_GET(STM32_DAC_CR_EN1, val);
	else
		en = FIELD_GET(STM32_DAC_CR_EN2, val);

	return !!en;
}

static int stm32_dac_set_enable_state(struct iio_dev *indio_dev, int ch,
				      bool enable)
{
	struct stm32_dac *dac = iio_priv(indio_dev);
	struct device *dev = indio_dev->dev.parent;
	u32 msk = STM32_DAC_IS_CHAN_1(ch) ? STM32_DAC_CR_EN1 : STM32_DAC_CR_EN2;
	u32 en = enable ? msk : 0;
	int ret;

	/* already enabled / disabled ? */
	mutex_lock(&dac->lock);
	ret = stm32_dac_is_enabled(indio_dev, ch);
	if (ret < 0 || enable == !!ret) {
		mutex_unlock(&dac->lock);
		return ret < 0 ? ret : 0;
	}

	if (enable) {
		ret = pm_runtime_resume_and_get(dev);
		if (ret < 0) {
			mutex_unlock(&dac->lock);
			return ret;
		}
	}

	ret = regmap_update_bits(dac->common->regmap, STM32_DAC_CR, msk, en);
	mutex_unlock(&dac->lock);
	if (ret < 0) {
		dev_err(&indio_dev->dev, "%s failed\n", str_enable_disable(en));
		goto err_put_pm;
	}

	/*
	 * When HFSEL is set, it is not allowed to write the DHRx register
	 * during 8 clock cycles after the ENx bit is set. It is not allowed
	 * to make software/hardware trigger during this period either.
	 */
	if (en && dac->common->hfsel)
		udelay(1);

	if (!enable) {
		pm_runtime_mark_last_busy(dev);
		pm_runtime_put_autosuspend(dev);
	}

	return 0;

err_put_pm:
	if (enable) {
		pm_runtime_mark_last_busy(dev);
		pm_runtime_put_autosuspend(dev);
	}

	return ret;
}

static int stm32_dac_get_value(struct stm32_dac *dac, int channel, int *val)
{
	int ret;

	if (STM32_DAC_IS_CHAN_1(channel))
		ret = regmap_read(dac->common->regmap, STM32_DAC_DOR1, val);
	else
		ret = regmap_read(dac->common->regmap, STM32_DAC_DOR2, val);

	return ret ? ret : IIO_VAL_INT;
}

static int stm32_dac_set_value(struct stm32_dac *dac, int channel, int val)
{
	int ret;

	if (STM32_DAC_IS_CHAN_1(channel))
		ret = regmap_write(dac->common->regmap, STM32_DAC_DHR12R1, val);
	else
		ret = regmap_write(dac->common->regmap, STM32_DAC_DHR12R2, val);

	return ret;
}

static int stm32_dac_read_raw(struct iio_dev *indio_dev,
			      struct iio_chan_spec const *chan,
			      int *val, int *val2, long mask)
{
	struct stm32_dac *dac = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		return stm32_dac_get_value(dac, chan->channel, val);
	case IIO_CHAN_INFO_SCALE:
		*val = dac->common->vref_mv;
		*val2 = chan->scan_type.realbits;
		return IIO_VAL_FRACTIONAL_LOG2;
	default:
		return -EINVAL;
	}
}

static int stm32_dac_write_raw(struct iio_dev *indio_dev,
			       struct iio_chan_spec const *chan,
			       int val, int val2, long mask)
{
	struct stm32_dac *dac = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		return stm32_dac_set_value(dac, chan->channel, val);
	default:
		return -EINVAL;
	}
}

static int stm32_dac_debugfs_reg_access(struct iio_dev *indio_dev,
					unsigned reg, unsigned writeval,
					unsigned *readval)
{
	struct stm32_dac *dac = iio_priv(indio_dev);

	if (!readval)
		return regmap_write(dac->common->regmap, reg, writeval);
	else
		return regmap_read(dac->common->regmap, reg, readval);
}

static const struct iio_info stm32_dac_iio_info = {
	.read_raw = stm32_dac_read_raw,
	.write_raw = stm32_dac_write_raw,
	.debugfs_reg_access = stm32_dac_debugfs_reg_access,
};

static const char * const stm32_dac_powerdown_modes[] = {
	"three_state",
};

static int stm32_dac_get_powerdown_mode(struct iio_dev *indio_dev,
					const struct iio_chan_spec *chan)
{
	return 0;
}

static int stm32_dac_set_powerdown_mode(struct iio_dev *indio_dev,
					const struct iio_chan_spec *chan,
					unsigned int type)
{
	return 0;
}

static ssize_t stm32_dac_read_powerdown(struct iio_dev *indio_dev,
					uintptr_t private,
					const struct iio_chan_spec *chan,
					char *buf)
{
	int ret = stm32_dac_is_enabled(indio_dev, chan->channel);

	if (ret < 0)
		return ret;

	return sysfs_emit(buf, "%d\n", ret ? 0 : 1);
}

static ssize_t stm32_dac_write_powerdown(struct iio_dev *indio_dev,
					 uintptr_t private,
					 const struct iio_chan_spec *chan,
					 const char *buf, size_t len)
{
	bool powerdown;
	int ret;

	ret = kstrtobool(buf, &powerdown);
	if (ret)
		return ret;

	ret = stm32_dac_set_enable_state(indio_dev, chan->channel, !powerdown);
	if (ret)
		return ret;

	return len;
}

static const struct iio_enum stm32_dac_powerdown_mode_en = {
	.items = stm32_dac_powerdown_modes,
	.num_items = ARRAY_SIZE(stm32_dac_powerdown_modes),
	.get = stm32_dac_get_powerdown_mode,
	.set = stm32_dac_set_powerdown_mode,
};

static const struct iio_chan_spec_ext_info stm32_dac_ext_info[] = {
	{
		.name = "powerdown",
		.read = stm32_dac_read_powerdown,
		.write = stm32_dac_write_powerdown,
		.shared = IIO_SEPARATE,
	},
	IIO_ENUM("powerdown_mode", IIO_SEPARATE, &stm32_dac_powerdown_mode_en),
	IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE, &stm32_dac_powerdown_mode_en),
	{},
};

#define STM32_DAC_CHANNEL(chan, name) {			\
	.type = IIO_VOLTAGE,				\
	.indexed = 1,					\
	.output = 1,					\
	.channel = chan,				\
	.info_mask_separate =				\
		BIT(IIO_CHAN_INFO_RAW) |		\
		BIT(IIO_CHAN_INFO_SCALE),		\
	/* scan_index is always 0 as num_channels is 1 */ \
	.scan_type = {					\
		.sign = 'u',				\
		.realbits = 12,				\
		.storagebits = 16,			\
	},						\
	.datasheet_name = name,				\
	.ext_info = stm32_dac_ext_info			\
}

static const struct iio_chan_spec stm32_dac_channels[] = {
	STM32_DAC_CHANNEL(STM32_DAC_CHANNEL_1, "out1"),
	STM32_DAC_CHANNEL(STM32_DAC_CHANNEL_2, "out2"),
};

static int stm32_dac_chan_of_init(struct iio_dev *indio_dev)
{
	struct device_node *np = indio_dev->dev.of_node;
	unsigned int i;
	u32 channel;
	int ret;

	ret = of_property_read_u32(np, "reg", &channel);
	if (ret) {
		dev_err(&indio_dev->dev, "Failed to read reg property\n");
		return ret;
	}

	for (i = 0; i < ARRAY_SIZE(stm32_dac_channels); i++) {
		if (stm32_dac_channels[i].channel == channel)
			break;
	}
	if (i >= ARRAY_SIZE(stm32_dac_channels)) {
		dev_err(&indio_dev->dev, "Invalid reg property\n");
		return -EINVAL;
	}

	indio_dev->channels = &stm32_dac_channels[i];
	/*
	 * Expose only one channel here, as they can be used independently,
	 * with separate trigger. Then separate IIO devices are instantiated
	 * to manage this.
	 */
	indio_dev->num_channels = 1;

	return 0;
};

static int stm32_dac_probe(struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	struct device *dev = &pdev->dev;
	struct iio_dev *indio_dev;
	struct stm32_dac *dac;
	int ret;

	if (!np)
		return -ENODEV;

	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*dac));
	if (!indio_dev)
		return -ENOMEM;
	platform_set_drvdata(pdev, indio_dev);

	dac = iio_priv(indio_dev);
	dac->common = dev_get_drvdata(pdev->dev.parent);
	indio_dev->name = dev_name(&pdev->dev);
	indio_dev->dev.of_node = pdev->dev.of_node;
	indio_dev->info = &stm32_dac_iio_info;
	indio_dev->modes = INDIO_DIRECT_MODE;

	mutex_init(&dac->lock);

	ret = stm32_dac_chan_of_init(indio_dev);
	if (ret < 0)
		return ret;

	/* Get stm32-dac-core PM online */
	pm_runtime_get_noresume(dev);
	pm_runtime_set_active(dev);
	pm_runtime_set_autosuspend_delay(dev, STM32_DAC_AUTO_SUSPEND_DELAY_MS);
	pm_runtime_use_autosuspend(dev);
	pm_runtime_enable(dev);

	ret = iio_device_register(indio_dev);
	if (ret)
		goto err_pm_put;

	pm_runtime_mark_last_busy(dev);
	pm_runtime_put_autosuspend(dev);

	return 0;

err_pm_put:
	pm_runtime_disable(dev);
	pm_runtime_set_suspended(dev);
	pm_runtime_put_noidle(dev);

	return ret;
}

static void stm32_dac_remove(struct platform_device *pdev)
{
	struct iio_dev *indio_dev = platform_get_drvdata(pdev);

	pm_runtime_get_sync(&pdev->dev);
	iio_device_unregister(indio_dev);
	pm_runtime_disable(&pdev->dev);
	pm_runtime_set_suspended(&pdev->dev);
	pm_runtime_put_noidle(&pdev->dev);
}

static int stm32_dac_suspend(struct device *dev)
{
	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	int channel = indio_dev->channels[0].channel;
	int ret;

	/* Ensure DAC is disabled before suspend */
	ret = stm32_dac_is_enabled(indio_dev, channel);
	if (ret)
		return ret < 0 ? ret : -EBUSY;

	return pm_runtime_force_suspend(dev);
}

static DEFINE_SIMPLE_DEV_PM_OPS(stm32_dac_pm_ops, stm32_dac_suspend,
				pm_runtime_force_resume);

static const struct of_device_id stm32_dac_of_match[] = {
	{ .compatible = "st,stm32-dac", },
	{},
};
MODULE_DEVICE_TABLE(of, stm32_dac_of_match);

static struct platform_driver stm32_dac_driver = {
	.probe = stm32_dac_probe,
	.remove_new = stm32_dac_remove,
	.driver = {
		.name = "stm32-dac",
		.of_match_table = stm32_dac_of_match,
		.pm = pm_sleep_ptr(&stm32_dac_pm_ops),
	},
};
module_platform_driver(stm32_dac_driver);

MODULE_ALIAS("platform:stm32-dac");
MODULE_AUTHOR("Amelie Delaunay <amelie.delaunay@st.com>");
MODULE_DESCRIPTION("STMicroelectronics STM32 DAC driver");
MODULE_LICENSE("GPL v2");