xref: /openbmc/linux/drivers/iio/dac/ad5791.c (revision b2d5e9de)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * AD5760, AD5780, AD5781, AD5790, AD5791 Voltage Output Digital to Analog
4  * Converter
5  *
6  * Copyright 2011 Analog Devices Inc.
7  */
8 
9 #include <linux/interrupt.h>
10 #include <linux/fs.h>
11 #include <linux/device.h>
12 #include <linux/kernel.h>
13 #include <linux/spi/spi.h>
14 #include <linux/slab.h>
15 #include <linux/sysfs.h>
16 #include <linux/regulator/consumer.h>
17 #include <linux/module.h>
18 #include <linux/bitops.h>
19 
20 #include <linux/iio/iio.h>
21 #include <linux/iio/sysfs.h>
22 #include <linux/iio/dac/ad5791.h>
23 
24 #define AD5791_DAC_MASK			GENMASK(19, 0)
25 
26 #define AD5791_CMD_READ			BIT(23)
27 #define AD5791_CMD_WRITE		0
28 #define AD5791_ADDR(addr)		((addr) << 20)
29 
30 /* Registers */
31 #define AD5791_ADDR_NOOP		0
32 #define AD5791_ADDR_DAC0		1
33 #define AD5791_ADDR_CTRL		2
34 #define AD5791_ADDR_CLRCODE		3
35 #define AD5791_ADDR_SW_CTRL		4
36 
37 /* Control Register */
38 #define AD5791_CTRL_RBUF		BIT(1)
39 #define AD5791_CTRL_OPGND		BIT(2)
40 #define AD5791_CTRL_DACTRI		BIT(3)
41 #define AD5791_CTRL_BIN2SC		BIT(4)
42 #define AD5791_CTRL_SDODIS		BIT(5)
43 #define AD5761_CTRL_LINCOMP(x)		((x) << 6)
44 
45 #define AD5791_LINCOMP_0_10		0
46 #define AD5791_LINCOMP_10_12		1
47 #define AD5791_LINCOMP_12_16		2
48 #define AD5791_LINCOMP_16_19		3
49 #define AD5791_LINCOMP_19_20		12
50 
51 #define AD5780_LINCOMP_0_10		0
52 #define AD5780_LINCOMP_10_20		12
53 
54 /* Software Control Register */
55 #define AD5791_SWCTRL_LDAC		BIT(0)
56 #define AD5791_SWCTRL_CLR		BIT(1)
57 #define AD5791_SWCTRL_RESET		BIT(2)
58 
59 #define AD5791_DAC_PWRDN_6K		0
60 #define AD5791_DAC_PWRDN_3STATE		1
61 
62 /**
63  * struct ad5791_chip_info - chip specific information
64  * @get_lin_comp:	function pointer to the device specific function
65  */
66 
67 struct ad5791_chip_info {
68 	int (*get_lin_comp)	(unsigned int span);
69 };
70 
71 /**
72  * struct ad5791_state - driver instance specific data
73  * @spi:			spi_device
74  * @reg_vdd:		positive supply regulator
75  * @reg_vss:		negative supply regulator
76  * @chip_info:		chip model specific constants
77  * @vref_mv:		actual reference voltage used
78  * @vref_neg_mv:	voltage of the negative supply
79  * @ctrl:		control register cache
80  * @pwr_down_mode:	current power down mode
81  * @pwr_down:		true if device is powered down
82  * @data:		spi transfer buffers
83  */
84 struct ad5791_state {
85 	struct spi_device		*spi;
86 	struct regulator		*reg_vdd;
87 	struct regulator		*reg_vss;
88 	const struct ad5791_chip_info	*chip_info;
89 	unsigned short			vref_mv;
90 	unsigned int			vref_neg_mv;
91 	unsigned			ctrl;
92 	unsigned			pwr_down_mode;
93 	bool				pwr_down;
94 
95 	union {
96 		__be32 d32;
97 		u8 d8[4];
98 	} data[3] __aligned(IIO_DMA_MINALIGN);
99 };
100 
101 enum ad5791_supported_device_ids {
102 	ID_AD5760,
103 	ID_AD5780,
104 	ID_AD5781,
105 	ID_AD5791,
106 };
107 
ad5791_spi_write(struct ad5791_state * st,u8 addr,u32 val)108 static int ad5791_spi_write(struct ad5791_state *st, u8 addr, u32 val)
109 {
110 	st->data[0].d32 = cpu_to_be32(AD5791_CMD_WRITE |
111 			      AD5791_ADDR(addr) |
112 			      (val & AD5791_DAC_MASK));
113 
114 	return spi_write(st->spi, &st->data[0].d8[1], 3);
115 }
116 
ad5791_spi_read(struct ad5791_state * st,u8 addr,u32 * val)117 static int ad5791_spi_read(struct ad5791_state *st, u8 addr, u32 *val)
118 {
119 	int ret;
120 	struct spi_transfer xfers[] = {
121 		{
122 			.tx_buf = &st->data[0].d8[1],
123 			.bits_per_word = 8,
124 			.len = 3,
125 			.cs_change = 1,
126 		}, {
127 			.tx_buf = &st->data[1].d8[1],
128 			.rx_buf = &st->data[2].d8[1],
129 			.bits_per_word = 8,
130 			.len = 3,
131 		},
132 	};
133 
134 	st->data[0].d32 = cpu_to_be32(AD5791_CMD_READ |
135 			      AD5791_ADDR(addr));
136 	st->data[1].d32 = cpu_to_be32(AD5791_ADDR(AD5791_ADDR_NOOP));
137 
138 	ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers));
139 
140 	*val = be32_to_cpu(st->data[2].d32);
141 
142 	return ret;
143 }
144 
145 static const char * const ad5791_powerdown_modes[] = {
146 	"6kohm_to_gnd",
147 	"three_state",
148 };
149 
ad5791_get_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan)150 static int ad5791_get_powerdown_mode(struct iio_dev *indio_dev,
151 	const struct iio_chan_spec *chan)
152 {
153 	struct ad5791_state *st = iio_priv(indio_dev);
154 
155 	return st->pwr_down_mode;
156 }
157 
ad5791_set_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,unsigned int mode)158 static int ad5791_set_powerdown_mode(struct iio_dev *indio_dev,
159 	const struct iio_chan_spec *chan, unsigned int mode)
160 {
161 	struct ad5791_state *st = iio_priv(indio_dev);
162 
163 	st->pwr_down_mode = mode;
164 
165 	return 0;
166 }
167 
168 static const struct iio_enum ad5791_powerdown_mode_enum = {
169 	.items = ad5791_powerdown_modes,
170 	.num_items = ARRAY_SIZE(ad5791_powerdown_modes),
171 	.get = ad5791_get_powerdown_mode,
172 	.set = ad5791_set_powerdown_mode,
173 };
174 
ad5791_read_dac_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,char * buf)175 static ssize_t ad5791_read_dac_powerdown(struct iio_dev *indio_dev,
176 	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
177 {
178 	struct ad5791_state *st = iio_priv(indio_dev);
179 
180 	return sysfs_emit(buf, "%d\n", st->pwr_down);
181 }
182 
ad5791_write_dac_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,const char * buf,size_t len)183 static ssize_t ad5791_write_dac_powerdown(struct iio_dev *indio_dev,
184 	 uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
185 	 size_t len)
186 {
187 	bool pwr_down;
188 	int ret;
189 	struct ad5791_state *st = iio_priv(indio_dev);
190 
191 	ret = kstrtobool(buf, &pwr_down);
192 	if (ret)
193 		return ret;
194 
195 	if (!pwr_down) {
196 		st->ctrl &= ~(AD5791_CTRL_OPGND | AD5791_CTRL_DACTRI);
197 	} else {
198 		if (st->pwr_down_mode == AD5791_DAC_PWRDN_6K)
199 			st->ctrl |= AD5791_CTRL_OPGND;
200 		else if (st->pwr_down_mode == AD5791_DAC_PWRDN_3STATE)
201 			st->ctrl |= AD5791_CTRL_DACTRI;
202 	}
203 	st->pwr_down = pwr_down;
204 
205 	ret = ad5791_spi_write(st, AD5791_ADDR_CTRL, st->ctrl);
206 
207 	return ret ? ret : len;
208 }
209 
ad5791_get_lin_comp(unsigned int span)210 static int ad5791_get_lin_comp(unsigned int span)
211 {
212 	if (span <= 10000)
213 		return AD5791_LINCOMP_0_10;
214 	else if (span <= 12000)
215 		return AD5791_LINCOMP_10_12;
216 	else if (span <= 16000)
217 		return AD5791_LINCOMP_12_16;
218 	else if (span <= 19000)
219 		return AD5791_LINCOMP_16_19;
220 	else
221 		return AD5791_LINCOMP_19_20;
222 }
223 
ad5780_get_lin_comp(unsigned int span)224 static int ad5780_get_lin_comp(unsigned int span)
225 {
226 	if (span <= 10000)
227 		return AD5780_LINCOMP_0_10;
228 	else
229 		return AD5780_LINCOMP_10_20;
230 }
231 static const struct ad5791_chip_info ad5791_chip_info_tbl[] = {
232 	[ID_AD5760] = {
233 		.get_lin_comp = ad5780_get_lin_comp,
234 	},
235 	[ID_AD5780] = {
236 		.get_lin_comp = ad5780_get_lin_comp,
237 	},
238 	[ID_AD5781] = {
239 		.get_lin_comp = ad5791_get_lin_comp,
240 	},
241 	[ID_AD5791] = {
242 		.get_lin_comp = ad5791_get_lin_comp,
243 	},
244 };
245 
ad5791_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long m)246 static int ad5791_read_raw(struct iio_dev *indio_dev,
247 			   struct iio_chan_spec const *chan,
248 			   int *val,
249 			   int *val2,
250 			   long m)
251 {
252 	struct ad5791_state *st = iio_priv(indio_dev);
253 	u64 val64;
254 	int ret;
255 
256 	switch (m) {
257 	case IIO_CHAN_INFO_RAW:
258 		ret = ad5791_spi_read(st, chan->address, val);
259 		if (ret)
260 			return ret;
261 		*val &= AD5791_DAC_MASK;
262 		*val >>= chan->scan_type.shift;
263 		return IIO_VAL_INT;
264 	case IIO_CHAN_INFO_SCALE:
265 		*val = st->vref_mv;
266 		*val2 = (1 << chan->scan_type.realbits) - 1;
267 		return IIO_VAL_FRACTIONAL;
268 	case IIO_CHAN_INFO_OFFSET:
269 		val64 = (((u64)st->vref_neg_mv) << chan->scan_type.realbits);
270 		do_div(val64, st->vref_mv);
271 		*val = -val64;
272 		return IIO_VAL_INT;
273 	default:
274 		return -EINVAL;
275 	}
276 
277 };
278 
279 static const struct iio_chan_spec_ext_info ad5791_ext_info[] = {
280 	{
281 		.name = "powerdown",
282 		.shared = IIO_SHARED_BY_TYPE,
283 		.read = ad5791_read_dac_powerdown,
284 		.write = ad5791_write_dac_powerdown,
285 	},
286 	IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE,
287 		 &ad5791_powerdown_mode_enum),
288 	IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE, &ad5791_powerdown_mode_enum),
289 	{ },
290 };
291 
292 #define AD5791_CHAN(bits, _shift) {			\
293 	.type = IIO_VOLTAGE,				\
294 	.output = 1,					\
295 	.indexed = 1,					\
296 	.address = AD5791_ADDR_DAC0,			\
297 	.channel = 0,					\
298 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
299 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |	\
300 		BIT(IIO_CHAN_INFO_OFFSET),		\
301 	.scan_type = {					\
302 		.sign = 'u',				\
303 		.realbits = (bits),			\
304 		.storagebits = 24,			\
305 		.shift = (_shift),			\
306 	},						\
307 	.ext_info = ad5791_ext_info,			\
308 }
309 
310 static const struct iio_chan_spec ad5791_channels[] = {
311 	[ID_AD5760] = AD5791_CHAN(16, 4),
312 	[ID_AD5780] = AD5791_CHAN(18, 2),
313 	[ID_AD5781] = AD5791_CHAN(18, 2),
314 	[ID_AD5791] = AD5791_CHAN(20, 0)
315 };
316 
ad5791_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)317 static int ad5791_write_raw(struct iio_dev *indio_dev,
318 			    struct iio_chan_spec const *chan,
319 			    int val,
320 			    int val2,
321 			    long mask)
322 {
323 	struct ad5791_state *st = iio_priv(indio_dev);
324 
325 	switch (mask) {
326 	case IIO_CHAN_INFO_RAW:
327 		val &= GENMASK(chan->scan_type.realbits - 1, 0);
328 		val <<= chan->scan_type.shift;
329 
330 		return ad5791_spi_write(st, chan->address, val);
331 
332 	default:
333 		return -EINVAL;
334 	}
335 }
336 
337 static const struct iio_info ad5791_info = {
338 	.read_raw = &ad5791_read_raw,
339 	.write_raw = &ad5791_write_raw,
340 };
341 
ad5791_probe(struct spi_device * spi)342 static int ad5791_probe(struct spi_device *spi)
343 {
344 	struct ad5791_platform_data *pdata = spi->dev.platform_data;
345 	struct iio_dev *indio_dev;
346 	struct ad5791_state *st;
347 	int ret, pos_voltage_uv = 0, neg_voltage_uv = 0;
348 
349 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
350 	if (!indio_dev)
351 		return -ENOMEM;
352 	st = iio_priv(indio_dev);
353 	st->reg_vdd = devm_regulator_get(&spi->dev, "vdd");
354 	if (!IS_ERR(st->reg_vdd)) {
355 		ret = regulator_enable(st->reg_vdd);
356 		if (ret)
357 			return ret;
358 
359 		ret = regulator_get_voltage(st->reg_vdd);
360 		if (ret < 0)
361 			goto error_disable_reg_pos;
362 
363 		pos_voltage_uv = ret;
364 	}
365 
366 	st->reg_vss = devm_regulator_get(&spi->dev, "vss");
367 	if (!IS_ERR(st->reg_vss)) {
368 		ret = regulator_enable(st->reg_vss);
369 		if (ret)
370 			goto error_disable_reg_pos;
371 
372 		ret = regulator_get_voltage(st->reg_vss);
373 		if (ret < 0)
374 			goto error_disable_reg_neg;
375 
376 		neg_voltage_uv = ret;
377 	}
378 
379 	st->pwr_down = true;
380 	st->spi = spi;
381 
382 	if (!IS_ERR(st->reg_vss) && !IS_ERR(st->reg_vdd)) {
383 		st->vref_mv = (pos_voltage_uv + neg_voltage_uv) / 1000;
384 		st->vref_neg_mv = neg_voltage_uv / 1000;
385 	} else if (pdata) {
386 		st->vref_mv = pdata->vref_pos_mv + pdata->vref_neg_mv;
387 		st->vref_neg_mv = pdata->vref_neg_mv;
388 	} else {
389 		dev_warn(&spi->dev, "reference voltage unspecified\n");
390 	}
391 
392 	ret = ad5791_spi_write(st, AD5791_ADDR_SW_CTRL, AD5791_SWCTRL_RESET);
393 	if (ret)
394 		goto error_disable_reg_neg;
395 
396 	st->chip_info =	&ad5791_chip_info_tbl[spi_get_device_id(spi)
397 					      ->driver_data];
398 
399 
400 	st->ctrl = AD5761_CTRL_LINCOMP(st->chip_info->get_lin_comp(st->vref_mv))
401 		  | ((pdata && pdata->use_rbuf_gain2) ? 0 : AD5791_CTRL_RBUF) |
402 		  AD5791_CTRL_BIN2SC;
403 
404 	ret = ad5791_spi_write(st, AD5791_ADDR_CTRL, st->ctrl |
405 		AD5791_CTRL_OPGND | AD5791_CTRL_DACTRI);
406 	if (ret)
407 		goto error_disable_reg_neg;
408 
409 	spi_set_drvdata(spi, indio_dev);
410 	indio_dev->info = &ad5791_info;
411 	indio_dev->modes = INDIO_DIRECT_MODE;
412 	indio_dev->channels
413 		= &ad5791_channels[spi_get_device_id(spi)->driver_data];
414 	indio_dev->num_channels = 1;
415 	indio_dev->name = spi_get_device_id(st->spi)->name;
416 	ret = iio_device_register(indio_dev);
417 	if (ret)
418 		goto error_disable_reg_neg;
419 
420 	return 0;
421 
422 error_disable_reg_neg:
423 	if (!IS_ERR(st->reg_vss))
424 		regulator_disable(st->reg_vss);
425 error_disable_reg_pos:
426 	if (!IS_ERR(st->reg_vdd))
427 		regulator_disable(st->reg_vdd);
428 	return ret;
429 }
430 
ad5791_remove(struct spi_device * spi)431 static void ad5791_remove(struct spi_device *spi)
432 {
433 	struct iio_dev *indio_dev = spi_get_drvdata(spi);
434 	struct ad5791_state *st = iio_priv(indio_dev);
435 
436 	iio_device_unregister(indio_dev);
437 	if (!IS_ERR(st->reg_vdd))
438 		regulator_disable(st->reg_vdd);
439 
440 	if (!IS_ERR(st->reg_vss))
441 		regulator_disable(st->reg_vss);
442 }
443 
444 static const struct spi_device_id ad5791_id[] = {
445 	{"ad5760", ID_AD5760},
446 	{"ad5780", ID_AD5780},
447 	{"ad5781", ID_AD5781},
448 	{"ad5790", ID_AD5791},
449 	{"ad5791", ID_AD5791},
450 	{}
451 };
452 MODULE_DEVICE_TABLE(spi, ad5791_id);
453 
454 static struct spi_driver ad5791_driver = {
455 	.driver = {
456 		   .name = "ad5791",
457 		   },
458 	.probe = ad5791_probe,
459 	.remove = ad5791_remove,
460 	.id_table = ad5791_id,
461 };
462 module_spi_driver(ad5791_driver);
463 
464 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
465 MODULE_DESCRIPTION("Analog Devices AD5760/AD5780/AD5781/AD5790/AD5791 DAC");
466 MODULE_LICENSE("GPL v2");
467