xref: /linux/drivers/iio/dac/ad5449.c (revision b889fcf63cb62e7fdb7816565e28f44dbe4a76a5)
1 /*
2  * AD5415, AD5426, AD5429, AD5432, AD5439, AD5443, AD5449 Digital to Analog
3  * Converter driver.
4  *
5  * Copyright 2012 Analog Devices Inc.
6  *  Author: Lars-Peter Clausen <lars@metafoo.de>
7  *
8  * Licensed under the GPL-2.
9  */
10 
11 #include <linux/device.h>
12 #include <linux/err.h>
13 #include <linux/module.h>
14 #include <linux/kernel.h>
15 #include <linux/spi/spi.h>
16 #include <linux/slab.h>
17 #include <linux/sysfs.h>
18 #include <linux/regulator/consumer.h>
19 #include <asm/unaligned.h>
20 
21 #include <linux/iio/iio.h>
22 #include <linux/iio/sysfs.h>
23 
24 #include <linux/platform_data/ad5449.h>
25 
26 #define AD5449_MAX_CHANNELS		2
27 #define AD5449_MAX_VREFS		2
28 
29 #define AD5449_CMD_NOOP			0x0
30 #define AD5449_CMD_LOAD_AND_UPDATE(x)	(0x1 + (x) * 3)
31 #define AD5449_CMD_READ(x)		(0x2 + (x) * 3)
32 #define AD5449_CMD_LOAD(x)		(0x3 + (x) * 3)
33 #define AD5449_CMD_CTRL			13
34 
35 #define AD5449_CTRL_SDO_OFFSET		10
36 #define AD5449_CTRL_DAISY_CHAIN		BIT(9)
37 #define AD5449_CTRL_HCLR_TO_MIDSCALE	BIT(8)
38 #define AD5449_CTRL_SAMPLE_RISING	BIT(7)
39 
40 /**
41  * struct ad5449_chip_info - chip specific information
42  * @channels:		Channel specification
43  * @num_channels:	Number of channels
44  * @has_ctrl:		Chip has a control register
45  */
46 struct ad5449_chip_info {
47 	const struct iio_chan_spec *channels;
48 	unsigned int num_channels;
49 	bool has_ctrl;
50 };
51 
52 /**
53  * struct ad5449 - driver instance specific data
54  * @spi:		the SPI device for this driver instance
55  * @chip_info:		chip model specific constants, available modes etc
56  * @vref_reg:		vref supply regulators
57  * @has_sdo:		whether the SDO line is connected
58  * @dac_cache:		Cache for the DAC values
59  * @data:		spi transfer buffers
60  */
61 struct ad5449 {
62 	struct spi_device		*spi;
63 	const struct ad5449_chip_info	*chip_info;
64 	struct regulator_bulk_data	vref_reg[AD5449_MAX_VREFS];
65 
66 	bool has_sdo;
67 	uint16_t dac_cache[AD5449_MAX_CHANNELS];
68 
69 	/*
70 	 * DMA (thus cache coherency maintenance) requires the
71 	 * transfer buffers to live in their own cache lines.
72 	 */
73 	__be16 data[2] ____cacheline_aligned;
74 };
75 
76 enum ad5449_type {
77 	ID_AD5426,
78 	ID_AD5429,
79 	ID_AD5432,
80 	ID_AD5439,
81 	ID_AD5443,
82 	ID_AD5449,
83 };
84 
85 static int ad5449_write(struct iio_dev *indio_dev, unsigned int addr,
86 	unsigned int val)
87 {
88 	struct ad5449 *st = iio_priv(indio_dev);
89 	int ret;
90 
91 	mutex_lock(&indio_dev->mlock);
92 	st->data[0] = cpu_to_be16((addr << 12) | val);
93 	ret = spi_write(st->spi, st->data, 2);
94 	mutex_unlock(&indio_dev->mlock);
95 
96 	return ret;
97 }
98 
99 static int ad5449_read(struct iio_dev *indio_dev, unsigned int addr,
100 	unsigned int *val)
101 {
102 	struct ad5449 *st = iio_priv(indio_dev);
103 	int ret;
104 	struct spi_message msg;
105 	struct spi_transfer t[] = {
106 		{
107 			.tx_buf = &st->data[0],
108 			.len = 2,
109 			.cs_change = 1,
110 		}, {
111 			.tx_buf = &st->data[1],
112 			.rx_buf = &st->data[1],
113 			.len = 2,
114 		},
115 	};
116 
117 	spi_message_init(&msg);
118 	spi_message_add_tail(&t[0], &msg);
119 	spi_message_add_tail(&t[1], &msg);
120 
121 	mutex_lock(&indio_dev->mlock);
122 	st->data[0] = cpu_to_be16(addr << 12);
123 	st->data[1] = cpu_to_be16(AD5449_CMD_NOOP);
124 
125 	ret = spi_sync(st->spi, &msg);
126 	if (ret < 0)
127 		goto out_unlock;
128 
129 	*val = be16_to_cpu(st->data[1]);
130 
131 out_unlock:
132 	mutex_unlock(&indio_dev->mlock);
133 	return ret;
134 }
135 
136 static int ad5449_read_raw(struct iio_dev *indio_dev,
137 	struct iio_chan_spec const *chan, int *val, int *val2, long info)
138 {
139 	struct ad5449 *st = iio_priv(indio_dev);
140 	struct regulator_bulk_data *reg;
141 	int scale_uv;
142 	int ret;
143 
144 	switch (info) {
145 	case IIO_CHAN_INFO_RAW:
146 		if (st->has_sdo) {
147 			ret = ad5449_read(indio_dev,
148 				AD5449_CMD_READ(chan->address), val);
149 			if (ret)
150 				return ret;
151 			*val &= 0xfff;
152 		} else {
153 			*val = st->dac_cache[chan->address];
154 		}
155 
156 		return IIO_VAL_INT;
157 	case IIO_CHAN_INFO_SCALE:
158 		reg = &st->vref_reg[chan->channel];
159 		scale_uv = regulator_get_voltage(reg->consumer);
160 		if (scale_uv < 0)
161 			return scale_uv;
162 
163 		*val = scale_uv / 1000;
164 		*val2 = chan->scan_type.realbits;
165 
166 		return IIO_VAL_FRACTIONAL_LOG2;
167 	default:
168 		break;
169 	}
170 
171 	return -EINVAL;
172 }
173 
174 static int ad5449_write_raw(struct iio_dev *indio_dev,
175 	struct iio_chan_spec const *chan, int val, int val2, long info)
176 {
177 	struct ad5449 *st = iio_priv(indio_dev);
178 	int ret;
179 
180 	switch (info) {
181 	case IIO_CHAN_INFO_RAW:
182 		if (val < 0 || val >= (1 << chan->scan_type.realbits))
183 			return -EINVAL;
184 
185 		ret = ad5449_write(indio_dev,
186 			AD5449_CMD_LOAD_AND_UPDATE(chan->address),
187 			val << chan->scan_type.shift);
188 		if (ret == 0)
189 			st->dac_cache[chan->address] = val;
190 		break;
191 	default:
192 		ret = -EINVAL;
193 	}
194 
195 	return ret;
196 }
197 
198 static const struct iio_info ad5449_info = {
199 	.read_raw = ad5449_read_raw,
200 	.write_raw = ad5449_write_raw,
201 	.driver_module = THIS_MODULE,
202 };
203 
204 #define AD5449_CHANNEL(chan, bits) {				\
205 	.type = IIO_VOLTAGE,					\
206 	.indexed = 1,						\
207 	.output = 1,						\
208 	.channel = (chan),					\
209 	.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |		\
210 		IIO_CHAN_INFO_SCALE_SEPARATE_BIT,		\
211 	.address = (chan),					\
212 	.scan_type = IIO_ST('u', (bits), 16, 12 - (bits)),	\
213 }
214 
215 #define DECLARE_AD5449_CHANNELS(name, bits) \
216 const struct iio_chan_spec name[] = { \
217 	AD5449_CHANNEL(0, bits), \
218 	AD5449_CHANNEL(1, bits), \
219 }
220 
221 static DECLARE_AD5449_CHANNELS(ad5429_channels, 8);
222 static DECLARE_AD5449_CHANNELS(ad5439_channels, 10);
223 static DECLARE_AD5449_CHANNELS(ad5449_channels, 12);
224 
225 static const struct ad5449_chip_info ad5449_chip_info[] = {
226 	[ID_AD5426] = {
227 		.channels = ad5429_channels,
228 		.num_channels = 1,
229 		.has_ctrl = false,
230 	},
231 	[ID_AD5429] = {
232 		.channels = ad5429_channels,
233 		.num_channels = 2,
234 		.has_ctrl = true,
235 	},
236 	[ID_AD5432] = {
237 		.channels = ad5439_channels,
238 		.num_channels = 1,
239 		.has_ctrl = false,
240 	},
241 	[ID_AD5439] = {
242 		.channels = ad5439_channels,
243 		.num_channels = 2,
244 		.has_ctrl = true,
245 	},
246 	[ID_AD5443] = {
247 		.channels = ad5449_channels,
248 		.num_channels = 1,
249 		.has_ctrl = false,
250 	},
251 	[ID_AD5449] = {
252 		.channels = ad5449_channels,
253 		.num_channels = 2,
254 		.has_ctrl = true,
255 	},
256 };
257 
258 static const char *ad5449_vref_name(struct ad5449 *st, int n)
259 {
260 	if (st->chip_info->num_channels == 1)
261 		return "VREF";
262 
263 	if (n == 0)
264 		return "VREFA";
265 	else
266 		return "VREFB";
267 }
268 
269 static int __devinit ad5449_spi_probe(struct spi_device *spi)
270 {
271 	struct ad5449_platform_data *pdata = spi->dev.platform_data;
272 	const struct spi_device_id *id = spi_get_device_id(spi);
273 	struct iio_dev *indio_dev;
274 	struct ad5449 *st;
275 	unsigned int i;
276 	int ret;
277 
278 	indio_dev = iio_device_alloc(sizeof(*st));
279 	if (indio_dev == NULL)
280 		return -ENOMEM;
281 
282 	st = iio_priv(indio_dev);
283 	spi_set_drvdata(spi, indio_dev);
284 
285 	st->chip_info = &ad5449_chip_info[id->driver_data];
286 	st->spi = spi;
287 
288 	for (i = 0; i < st->chip_info->num_channels; ++i)
289 		st->vref_reg[i].supply = ad5449_vref_name(st, i);
290 
291 	ret = regulator_bulk_get(&spi->dev, st->chip_info->num_channels,
292 				st->vref_reg);
293 	if (ret)
294 		goto error_free;
295 
296 	ret = regulator_bulk_enable(st->chip_info->num_channels, st->vref_reg);
297 	if (ret)
298 		goto error_free_reg;
299 
300 	indio_dev->dev.parent = &spi->dev;
301 	indio_dev->name = id->name;
302 	indio_dev->info = &ad5449_info;
303 	indio_dev->modes = INDIO_DIRECT_MODE;
304 	indio_dev->channels = st->chip_info->channels;
305 	indio_dev->num_channels = st->chip_info->num_channels;
306 
307 	if (st->chip_info->has_ctrl) {
308 		unsigned int ctrl = 0x00;
309 		if (pdata) {
310 			if (pdata->hardware_clear_to_midscale)
311 				ctrl |= AD5449_CTRL_HCLR_TO_MIDSCALE;
312 			ctrl |= pdata->sdo_mode << AD5449_CTRL_SDO_OFFSET;
313 			st->has_sdo = pdata->sdo_mode != AD5449_SDO_DISABLED;
314 		} else {
315 			st->has_sdo = true;
316 		}
317 		ad5449_write(indio_dev, AD5449_CMD_CTRL, ctrl);
318 	}
319 
320 	ret = iio_device_register(indio_dev);
321 	if (ret)
322 		goto error_disable_reg;
323 
324 	return 0;
325 
326 error_disable_reg:
327 	regulator_bulk_disable(st->chip_info->num_channels, st->vref_reg);
328 error_free_reg:
329 	regulator_bulk_free(st->chip_info->num_channels, st->vref_reg);
330 error_free:
331 	iio_device_free(indio_dev);
332 
333 	return ret;
334 }
335 
336 static int __devexit ad5449_spi_remove(struct spi_device *spi)
337 {
338 	struct iio_dev *indio_dev = spi_get_drvdata(spi);
339 	struct ad5449 *st = iio_priv(indio_dev);
340 
341 	iio_device_unregister(indio_dev);
342 
343 	regulator_bulk_disable(st->chip_info->num_channels, st->vref_reg);
344 	regulator_bulk_free(st->chip_info->num_channels, st->vref_reg);
345 
346 	iio_device_free(indio_dev);
347 
348 	return 0;
349 }
350 
351 static const struct spi_device_id ad5449_spi_ids[] = {
352 	{ "ad5415", ID_AD5449 },
353 	{ "ad5426", ID_AD5426 },
354 	{ "ad5429", ID_AD5429 },
355 	{ "ad5432", ID_AD5432 },
356 	{ "ad5439", ID_AD5439 },
357 	{ "ad5443", ID_AD5443 },
358 	{ "ad5449", ID_AD5449 },
359 	{}
360 };
361 MODULE_DEVICE_TABLE(spi, ad5449_spi_ids);
362 
363 static struct spi_driver ad5449_spi_driver = {
364 	.driver = {
365 		.name = "ad5449",
366 		.owner = THIS_MODULE,
367 	},
368 	.probe = ad5449_spi_probe,
369 	.remove = __devexit_p(ad5449_spi_remove),
370 	.id_table = ad5449_spi_ids,
371 };
372 module_spi_driver(ad5449_spi_driver);
373 
374 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
375 MODULE_DESCRIPTION("Analog Devices AD5449 and similar DACs");
376 MODULE_LICENSE("GPL v2");
377