1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * LTC2632 Digital to analog convertors spi driver
4 *
5 * Copyright 2017 Maxime Roussin-Bélanger
6 * expanded by Silvan Murer <silvan.murer@gmail.com>
7 */
8
9 #include <linux/device.h>
10 #include <linux/spi/spi.h>
11 #include <linux/module.h>
12 #include <linux/iio/iio.h>
13 #include <linux/property.h>
14 #include <linux/regulator/consumer.h>
15
16 #include <asm/unaligned.h>
17
18 #define LTC2632_CMD_WRITE_INPUT_N 0x0
19 #define LTC2632_CMD_UPDATE_DAC_N 0x1
20 #define LTC2632_CMD_WRITE_INPUT_N_UPDATE_ALL 0x2
21 #define LTC2632_CMD_WRITE_INPUT_N_UPDATE_N 0x3
22 #define LTC2632_CMD_POWERDOWN_DAC_N 0x4
23 #define LTC2632_CMD_POWERDOWN_CHIP 0x5
24 #define LTC2632_CMD_INTERNAL_REFER 0x6
25 #define LTC2632_CMD_EXTERNAL_REFER 0x7
26
27 /**
28 * struct ltc2632_chip_info - chip specific information
29 * @channels: channel spec for the DAC
30 * @num_channels: DAC channel count of the chip
31 * @vref_mv: internal reference voltage
32 */
33 struct ltc2632_chip_info {
34 const struct iio_chan_spec *channels;
35 const size_t num_channels;
36 const int vref_mv;
37 };
38
39 /**
40 * struct ltc2632_state - driver instance specific data
41 * @spi_dev: pointer to the spi_device struct
42 * @powerdown_cache_mask: used to show current channel powerdown state
43 * @vref_mv: used reference voltage (internal or external)
44 * @vref_reg: regulator for the reference voltage
45 */
46 struct ltc2632_state {
47 struct spi_device *spi_dev;
48 unsigned int powerdown_cache_mask;
49 int vref_mv;
50 struct regulator *vref_reg;
51 };
52
53 enum ltc2632_supported_device_ids {
54 ID_LTC2632L12,
55 ID_LTC2632L10,
56 ID_LTC2632L8,
57 ID_LTC2632H12,
58 ID_LTC2632H10,
59 ID_LTC2632H8,
60 ID_LTC2634L12,
61 ID_LTC2634L10,
62 ID_LTC2634L8,
63 ID_LTC2634H12,
64 ID_LTC2634H10,
65 ID_LTC2634H8,
66 ID_LTC2636L12,
67 ID_LTC2636L10,
68 ID_LTC2636L8,
69 ID_LTC2636H12,
70 ID_LTC2636H10,
71 ID_LTC2636H8,
72 };
73
ltc2632_spi_write(struct spi_device * spi,u8 cmd,u8 addr,u16 val,u8 shift)74 static int ltc2632_spi_write(struct spi_device *spi,
75 u8 cmd, u8 addr, u16 val, u8 shift)
76 {
77 u32 data;
78 u8 msg[3];
79
80 /*
81 * The input shift register is 24 bits wide.
82 * The next four are the command bits, C3 to C0,
83 * followed by the 4-bit DAC address, A3 to A0, and then the
84 * 12-, 10-, 8-bit data-word. The data-word comprises the 12-,
85 * 10-, 8-bit input code followed by 4, 6, or 8 don't care bits.
86 */
87 data = (cmd << 20) | (addr << 16) | (val << shift);
88 put_unaligned_be24(data, &msg[0]);
89
90 return spi_write(spi, msg, sizeof(msg));
91 }
92
ltc2632_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long m)93 static int ltc2632_read_raw(struct iio_dev *indio_dev,
94 struct iio_chan_spec const *chan,
95 int *val,
96 int *val2,
97 long m)
98 {
99 const struct ltc2632_state *st = iio_priv(indio_dev);
100
101 switch (m) {
102 case IIO_CHAN_INFO_SCALE:
103 *val = st->vref_mv;
104 *val2 = chan->scan_type.realbits;
105 return IIO_VAL_FRACTIONAL_LOG2;
106 }
107 return -EINVAL;
108 }
109
ltc2632_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)110 static int ltc2632_write_raw(struct iio_dev *indio_dev,
111 struct iio_chan_spec const *chan,
112 int val,
113 int val2,
114 long mask)
115 {
116 struct ltc2632_state *st = iio_priv(indio_dev);
117
118 switch (mask) {
119 case IIO_CHAN_INFO_RAW:
120 if (val >= (1 << chan->scan_type.realbits) || val < 0)
121 return -EINVAL;
122
123 return ltc2632_spi_write(st->spi_dev,
124 LTC2632_CMD_WRITE_INPUT_N_UPDATE_N,
125 chan->address, val,
126 chan->scan_type.shift);
127 default:
128 return -EINVAL;
129 }
130 }
131
ltc2632_read_dac_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,char * buf)132 static ssize_t ltc2632_read_dac_powerdown(struct iio_dev *indio_dev,
133 uintptr_t private,
134 const struct iio_chan_spec *chan,
135 char *buf)
136 {
137 struct ltc2632_state *st = iio_priv(indio_dev);
138
139 return sysfs_emit(buf, "%d\n",
140 !!(st->powerdown_cache_mask & (1 << chan->channel)));
141 }
142
ltc2632_write_dac_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,const char * buf,size_t len)143 static ssize_t ltc2632_write_dac_powerdown(struct iio_dev *indio_dev,
144 uintptr_t private,
145 const struct iio_chan_spec *chan,
146 const char *buf,
147 size_t len)
148 {
149 bool pwr_down;
150 int ret;
151 struct ltc2632_state *st = iio_priv(indio_dev);
152
153 ret = kstrtobool(buf, &pwr_down);
154 if (ret)
155 return ret;
156
157 if (pwr_down)
158 st->powerdown_cache_mask |= (1 << chan->channel);
159 else
160 st->powerdown_cache_mask &= ~(1 << chan->channel);
161
162 ret = ltc2632_spi_write(st->spi_dev,
163 LTC2632_CMD_POWERDOWN_DAC_N,
164 chan->channel, 0, 0);
165
166 return ret ? ret : len;
167 }
168
169 static const struct iio_info ltc2632_info = {
170 .write_raw = ltc2632_write_raw,
171 .read_raw = ltc2632_read_raw,
172 };
173
174 static const struct iio_chan_spec_ext_info ltc2632_ext_info[] = {
175 {
176 .name = "powerdown",
177 .read = ltc2632_read_dac_powerdown,
178 .write = ltc2632_write_dac_powerdown,
179 .shared = IIO_SEPARATE,
180 },
181 { },
182 };
183
184 #define LTC2632_CHANNEL(_chan, _bits) { \
185 .type = IIO_VOLTAGE, \
186 .indexed = 1, \
187 .output = 1, \
188 .channel = (_chan), \
189 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
190 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
191 .address = (_chan), \
192 .scan_type = { \
193 .realbits = (_bits), \
194 .shift = 16 - (_bits), \
195 }, \
196 .ext_info = ltc2632_ext_info, \
197 }
198
199 #define DECLARE_LTC2632_CHANNELS(_name, _bits) \
200 const struct iio_chan_spec _name ## _channels[] = { \
201 LTC2632_CHANNEL(0, _bits), \
202 LTC2632_CHANNEL(1, _bits), \
203 LTC2632_CHANNEL(2, _bits), \
204 LTC2632_CHANNEL(3, _bits), \
205 LTC2632_CHANNEL(4, _bits), \
206 LTC2632_CHANNEL(5, _bits), \
207 LTC2632_CHANNEL(6, _bits), \
208 LTC2632_CHANNEL(7, _bits), \
209 }
210
211 static DECLARE_LTC2632_CHANNELS(ltc2632x12, 12);
212 static DECLARE_LTC2632_CHANNELS(ltc2632x10, 10);
213 static DECLARE_LTC2632_CHANNELS(ltc2632x8, 8);
214
215 static const struct ltc2632_chip_info ltc2632_chip_info_tbl[] = {
216 [ID_LTC2632L12] = {
217 .channels = ltc2632x12_channels,
218 .num_channels = 2,
219 .vref_mv = 2500,
220 },
221 [ID_LTC2632L10] = {
222 .channels = ltc2632x10_channels,
223 .num_channels = 2,
224 .vref_mv = 2500,
225 },
226 [ID_LTC2632L8] = {
227 .channels = ltc2632x8_channels,
228 .num_channels = 2,
229 .vref_mv = 2500,
230 },
231 [ID_LTC2632H12] = {
232 .channels = ltc2632x12_channels,
233 .num_channels = 2,
234 .vref_mv = 4096,
235 },
236 [ID_LTC2632H10] = {
237 .channels = ltc2632x10_channels,
238 .num_channels = 2,
239 .vref_mv = 4096,
240 },
241 [ID_LTC2632H8] = {
242 .channels = ltc2632x8_channels,
243 .num_channels = 2,
244 .vref_mv = 4096,
245 },
246 [ID_LTC2634L12] = {
247 .channels = ltc2632x12_channels,
248 .num_channels = 4,
249 .vref_mv = 2500,
250 },
251 [ID_LTC2634L10] = {
252 .channels = ltc2632x10_channels,
253 .num_channels = 4,
254 .vref_mv = 2500,
255 },
256 [ID_LTC2634L8] = {
257 .channels = ltc2632x8_channels,
258 .num_channels = 4,
259 .vref_mv = 2500,
260 },
261 [ID_LTC2634H12] = {
262 .channels = ltc2632x12_channels,
263 .num_channels = 4,
264 .vref_mv = 4096,
265 },
266 [ID_LTC2634H10] = {
267 .channels = ltc2632x10_channels,
268 .num_channels = 4,
269 .vref_mv = 4096,
270 },
271 [ID_LTC2634H8] = {
272 .channels = ltc2632x8_channels,
273 .num_channels = 4,
274 .vref_mv = 4096,
275 },
276 [ID_LTC2636L12] = {
277 .channels = ltc2632x12_channels,
278 .num_channels = 8,
279 .vref_mv = 2500,
280 },
281 [ID_LTC2636L10] = {
282 .channels = ltc2632x10_channels,
283 .num_channels = 8,
284 .vref_mv = 2500,
285 },
286 [ID_LTC2636L8] = {
287 .channels = ltc2632x8_channels,
288 .num_channels = 8,
289 .vref_mv = 2500,
290 },
291 [ID_LTC2636H12] = {
292 .channels = ltc2632x12_channels,
293 .num_channels = 8,
294 .vref_mv = 4096,
295 },
296 [ID_LTC2636H10] = {
297 .channels = ltc2632x10_channels,
298 .num_channels = 8,
299 .vref_mv = 4096,
300 },
301 [ID_LTC2636H8] = {
302 .channels = ltc2632x8_channels,
303 .num_channels = 8,
304 .vref_mv = 4096,
305 },
306 };
307
ltc2632_probe(struct spi_device * spi)308 static int ltc2632_probe(struct spi_device *spi)
309 {
310 struct ltc2632_state *st;
311 struct iio_dev *indio_dev;
312 struct ltc2632_chip_info *chip_info;
313 int ret;
314
315 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
316 if (!indio_dev)
317 return -ENOMEM;
318
319 st = iio_priv(indio_dev);
320
321 spi_set_drvdata(spi, indio_dev);
322 st->spi_dev = spi;
323
324 chip_info = (struct ltc2632_chip_info *)
325 spi_get_device_id(spi)->driver_data;
326
327 st->vref_reg = devm_regulator_get_optional(&spi->dev, "vref");
328 if (PTR_ERR(st->vref_reg) == -ENODEV) {
329 /* use internal reference voltage */
330 st->vref_reg = NULL;
331 st->vref_mv = chip_info->vref_mv;
332
333 ret = ltc2632_spi_write(spi, LTC2632_CMD_INTERNAL_REFER,
334 0, 0, 0);
335 if (ret) {
336 dev_err(&spi->dev,
337 "Set internal reference command failed, %d\n",
338 ret);
339 return ret;
340 }
341 } else if (IS_ERR(st->vref_reg)) {
342 dev_err(&spi->dev,
343 "Error getting voltage reference regulator\n");
344 return PTR_ERR(st->vref_reg);
345 } else {
346 /* use external reference voltage */
347 ret = regulator_enable(st->vref_reg);
348 if (ret) {
349 dev_err(&spi->dev,
350 "enable reference regulator failed, %d\n",
351 ret);
352 return ret;
353 }
354 st->vref_mv = regulator_get_voltage(st->vref_reg) / 1000;
355
356 ret = ltc2632_spi_write(spi, LTC2632_CMD_EXTERNAL_REFER,
357 0, 0, 0);
358 if (ret) {
359 dev_err(&spi->dev,
360 "Set external reference command failed, %d\n",
361 ret);
362 return ret;
363 }
364 }
365
366 indio_dev->name = fwnode_get_name(dev_fwnode(&spi->dev)) ?: spi_get_device_id(spi)->name;
367 indio_dev->info = <c2632_info;
368 indio_dev->modes = INDIO_DIRECT_MODE;
369 indio_dev->channels = chip_info->channels;
370 indio_dev->num_channels = chip_info->num_channels;
371
372 return iio_device_register(indio_dev);
373 }
374
ltc2632_remove(struct spi_device * spi)375 static void ltc2632_remove(struct spi_device *spi)
376 {
377 struct iio_dev *indio_dev = spi_get_drvdata(spi);
378 struct ltc2632_state *st = iio_priv(indio_dev);
379
380 iio_device_unregister(indio_dev);
381
382 if (st->vref_reg)
383 regulator_disable(st->vref_reg);
384 }
385
386 static const struct spi_device_id ltc2632_id[] = {
387 { "ltc2632-l12", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632L12] },
388 { "ltc2632-l10", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632L10] },
389 { "ltc2632-l8", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632L8] },
390 { "ltc2632-h12", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632H12] },
391 { "ltc2632-h10", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632H10] },
392 { "ltc2632-h8", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632H8] },
393 { "ltc2634-l12", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2634L12] },
394 { "ltc2634-l10", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2634L10] },
395 { "ltc2634-l8", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2634L8] },
396 { "ltc2634-h12", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2634H12] },
397 { "ltc2634-h10", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2634H10] },
398 { "ltc2634-h8", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2634H8] },
399 { "ltc2636-l12", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2636L12] },
400 { "ltc2636-l10", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2636L10] },
401 { "ltc2636-l8", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2636L8] },
402 { "ltc2636-h12", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2636H12] },
403 { "ltc2636-h10", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2636H10] },
404 { "ltc2636-h8", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2636H8] },
405 {}
406 };
407 MODULE_DEVICE_TABLE(spi, ltc2632_id);
408
409 static const struct of_device_id ltc2632_of_match[] = {
410 {
411 .compatible = "lltc,ltc2632-l12",
412 .data = <c2632_chip_info_tbl[ID_LTC2632L12]
413 }, {
414 .compatible = "lltc,ltc2632-l10",
415 .data = <c2632_chip_info_tbl[ID_LTC2632L10]
416 }, {
417 .compatible = "lltc,ltc2632-l8",
418 .data = <c2632_chip_info_tbl[ID_LTC2632L8]
419 }, {
420 .compatible = "lltc,ltc2632-h12",
421 .data = <c2632_chip_info_tbl[ID_LTC2632H12]
422 }, {
423 .compatible = "lltc,ltc2632-h10",
424 .data = <c2632_chip_info_tbl[ID_LTC2632H10]
425 }, {
426 .compatible = "lltc,ltc2632-h8",
427 .data = <c2632_chip_info_tbl[ID_LTC2632H8]
428 }, {
429 .compatible = "lltc,ltc2634-l12",
430 .data = <c2632_chip_info_tbl[ID_LTC2634L12]
431 }, {
432 .compatible = "lltc,ltc2634-l10",
433 .data = <c2632_chip_info_tbl[ID_LTC2634L10]
434 }, {
435 .compatible = "lltc,ltc2634-l8",
436 .data = <c2632_chip_info_tbl[ID_LTC2634L8]
437 }, {
438 .compatible = "lltc,ltc2634-h12",
439 .data = <c2632_chip_info_tbl[ID_LTC2634H12]
440 }, {
441 .compatible = "lltc,ltc2634-h10",
442 .data = <c2632_chip_info_tbl[ID_LTC2634H10]
443 }, {
444 .compatible = "lltc,ltc2634-h8",
445 .data = <c2632_chip_info_tbl[ID_LTC2634H8]
446 }, {
447 .compatible = "lltc,ltc2636-l12",
448 .data = <c2632_chip_info_tbl[ID_LTC2636L12]
449 }, {
450 .compatible = "lltc,ltc2636-l10",
451 .data = <c2632_chip_info_tbl[ID_LTC2636L10]
452 }, {
453 .compatible = "lltc,ltc2636-l8",
454 .data = <c2632_chip_info_tbl[ID_LTC2636L8]
455 }, {
456 .compatible = "lltc,ltc2636-h12",
457 .data = <c2632_chip_info_tbl[ID_LTC2636H12]
458 }, {
459 .compatible = "lltc,ltc2636-h10",
460 .data = <c2632_chip_info_tbl[ID_LTC2636H10]
461 }, {
462 .compatible = "lltc,ltc2636-h8",
463 .data = <c2632_chip_info_tbl[ID_LTC2636H8]
464 },
465 {}
466 };
467 MODULE_DEVICE_TABLE(of, ltc2632_of_match);
468
469 static struct spi_driver ltc2632_driver = {
470 .driver = {
471 .name = "ltc2632",
472 .of_match_table = ltc2632_of_match,
473 },
474 .probe = ltc2632_probe,
475 .remove = ltc2632_remove,
476 .id_table = ltc2632_id,
477 };
478 module_spi_driver(ltc2632_driver);
479
480 MODULE_AUTHOR("Maxime Roussin-Belanger <maxime.roussinbelanger@gmail.com>");
481 MODULE_DESCRIPTION("LTC2632 DAC SPI driver");
482 MODULE_LICENSE("GPL v2");
483
