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/regulator/consumer.h>
14
15 #define LTC2632_DAC_CHANNELS 2
16
17 #define LTC2632_ADDR_DAC0 0x0
18 #define LTC2632_ADDR_DAC1 0x1
19
20 #define LTC2632_CMD_WRITE_INPUT_N 0x0
21 #define LTC2632_CMD_UPDATE_DAC_N 0x1
22 #define LTC2632_CMD_WRITE_INPUT_N_UPDATE_ALL 0x2
23 #define LTC2632_CMD_WRITE_INPUT_N_UPDATE_N 0x3
24 #define LTC2632_CMD_POWERDOWN_DAC_N 0x4
25 #define LTC2632_CMD_POWERDOWN_CHIP 0x5
26 #define LTC2632_CMD_INTERNAL_REFER 0x6
27 #define LTC2632_CMD_EXTERNAL_REFER 0x7
28
29 /**
30 * struct ltc2632_chip_info - chip specific information
31 * @channels: channel spec for the DAC
32 * @vref_mv: internal reference voltage
33 */
34 struct ltc2632_chip_info {
35 const struct iio_chan_spec *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 };
61
ltc2632_spi_write(struct spi_device * spi,u8 cmd,u8 addr,u16 val,u8 shift)62 static int ltc2632_spi_write(struct spi_device *spi,
63 u8 cmd, u8 addr, u16 val, u8 shift)
64 {
65 u32 data;
66 u8 msg[3];
67
68 /*
69 * The input shift register is 24 bits wide.
70 * The next four are the command bits, C3 to C0,
71 * followed by the 4-bit DAC address, A3 to A0, and then the
72 * 12-, 10-, 8-bit data-word. The data-word comprises the 12-,
73 * 10-, 8-bit input code followed by 4, 6, or 8 don't care bits.
74 */
75 data = (cmd << 20) | (addr << 16) | (val << shift);
76 msg[0] = data >> 16;
77 msg[1] = data >> 8;
78 msg[2] = data;
79
80 return spi_write(spi, msg, sizeof(msg));
81 }
82
ltc2632_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long m)83 static int ltc2632_read_raw(struct iio_dev *indio_dev,
84 struct iio_chan_spec const *chan,
85 int *val,
86 int *val2,
87 long m)
88 {
89 const struct ltc2632_state *st = iio_priv(indio_dev);
90
91 switch (m) {
92 case IIO_CHAN_INFO_SCALE:
93 *val = st->vref_mv;
94 *val2 = chan->scan_type.realbits;
95 return IIO_VAL_FRACTIONAL_LOG2;
96 }
97 return -EINVAL;
98 }
99
ltc2632_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)100 static int ltc2632_write_raw(struct iio_dev *indio_dev,
101 struct iio_chan_spec const *chan,
102 int val,
103 int val2,
104 long mask)
105 {
106 struct ltc2632_state *st = iio_priv(indio_dev);
107
108 switch (mask) {
109 case IIO_CHAN_INFO_RAW:
110 if (val >= (1 << chan->scan_type.realbits) || val < 0)
111 return -EINVAL;
112
113 return ltc2632_spi_write(st->spi_dev,
114 LTC2632_CMD_WRITE_INPUT_N_UPDATE_N,
115 chan->address, val,
116 chan->scan_type.shift);
117 default:
118 return -EINVAL;
119 }
120 }
121
ltc2632_read_dac_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,char * buf)122 static ssize_t ltc2632_read_dac_powerdown(struct iio_dev *indio_dev,
123 uintptr_t private,
124 const struct iio_chan_spec *chan,
125 char *buf)
126 {
127 struct ltc2632_state *st = iio_priv(indio_dev);
128
129 return sprintf(buf, "%d\n",
130 !!(st->powerdown_cache_mask & (1 << chan->channel)));
131 }
132
ltc2632_write_dac_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,const char * buf,size_t len)133 static ssize_t ltc2632_write_dac_powerdown(struct iio_dev *indio_dev,
134 uintptr_t private,
135 const struct iio_chan_spec *chan,
136 const char *buf,
137 size_t len)
138 {
139 bool pwr_down;
140 int ret;
141 struct ltc2632_state *st = iio_priv(indio_dev);
142
143 ret = strtobool(buf, &pwr_down);
144 if (ret)
145 return ret;
146
147 if (pwr_down)
148 st->powerdown_cache_mask |= (1 << chan->channel);
149 else
150 st->powerdown_cache_mask &= ~(1 << chan->channel);
151
152 ret = ltc2632_spi_write(st->spi_dev,
153 LTC2632_CMD_POWERDOWN_DAC_N,
154 chan->channel, 0, 0);
155
156 return ret ? ret : len;
157 }
158
159 static const struct iio_info ltc2632_info = {
160 .write_raw = ltc2632_write_raw,
161 .read_raw = ltc2632_read_raw,
162 };
163
164 static const struct iio_chan_spec_ext_info ltc2632_ext_info[] = {
165 {
166 .name = "powerdown",
167 .read = ltc2632_read_dac_powerdown,
168 .write = ltc2632_write_dac_powerdown,
169 .shared = IIO_SEPARATE,
170 },
171 { },
172 };
173
174 #define LTC2632_CHANNEL(_chan, _bits) { \
175 .type = IIO_VOLTAGE, \
176 .indexed = 1, \
177 .output = 1, \
178 .channel = (_chan), \
179 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
180 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
181 .address = (_chan), \
182 .scan_type = { \
183 .realbits = (_bits), \
184 .shift = 16 - (_bits), \
185 }, \
186 .ext_info = ltc2632_ext_info, \
187 }
188
189 #define DECLARE_LTC2632_CHANNELS(_name, _bits) \
190 const struct iio_chan_spec _name ## _channels[] = { \
191 LTC2632_CHANNEL(0, _bits), \
192 LTC2632_CHANNEL(1, _bits), \
193 }
194
195 static DECLARE_LTC2632_CHANNELS(ltc2632l12, 12);
196 static DECLARE_LTC2632_CHANNELS(ltc2632l10, 10);
197 static DECLARE_LTC2632_CHANNELS(ltc2632l8, 8);
198
199 static DECLARE_LTC2632_CHANNELS(ltc2632h12, 12);
200 static DECLARE_LTC2632_CHANNELS(ltc2632h10, 10);
201 static DECLARE_LTC2632_CHANNELS(ltc2632h8, 8);
202
203 static const struct ltc2632_chip_info ltc2632_chip_info_tbl[] = {
204 [ID_LTC2632L12] = {
205 .channels = ltc2632l12_channels,
206 .vref_mv = 2500,
207 },
208 [ID_LTC2632L10] = {
209 .channels = ltc2632l10_channels,
210 .vref_mv = 2500,
211 },
212 [ID_LTC2632L8] = {
213 .channels = ltc2632l8_channels,
214 .vref_mv = 2500,
215 },
216 [ID_LTC2632H12] = {
217 .channels = ltc2632h12_channels,
218 .vref_mv = 4096,
219 },
220 [ID_LTC2632H10] = {
221 .channels = ltc2632h10_channels,
222 .vref_mv = 4096,
223 },
224 [ID_LTC2632H8] = {
225 .channels = ltc2632h8_channels,
226 .vref_mv = 4096,
227 },
228 };
229
ltc2632_probe(struct spi_device * spi)230 static int ltc2632_probe(struct spi_device *spi)
231 {
232 struct ltc2632_state *st;
233 struct iio_dev *indio_dev;
234 struct ltc2632_chip_info *chip_info;
235 int ret;
236
237 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
238 if (!indio_dev)
239 return -ENOMEM;
240
241 st = iio_priv(indio_dev);
242
243 spi_set_drvdata(spi, indio_dev);
244 st->spi_dev = spi;
245
246 chip_info = (struct ltc2632_chip_info *)
247 spi_get_device_id(spi)->driver_data;
248
249 st->vref_reg = devm_regulator_get_optional(&spi->dev, "vref");
250 if (PTR_ERR(st->vref_reg) == -ENODEV) {
251 /* use internal reference voltage */
252 st->vref_reg = NULL;
253 st->vref_mv = chip_info->vref_mv;
254
255 ret = ltc2632_spi_write(spi, LTC2632_CMD_INTERNAL_REFER,
256 0, 0, 0);
257 if (ret) {
258 dev_err(&spi->dev,
259 "Set internal reference command failed, %d\n",
260 ret);
261 return ret;
262 }
263 } else if (IS_ERR(st->vref_reg)) {
264 dev_err(&spi->dev,
265 "Error getting voltage reference regulator\n");
266 return PTR_ERR(st->vref_reg);
267 } else {
268 /* use external reference voltage */
269 ret = regulator_enable(st->vref_reg);
270 if (ret) {
271 dev_err(&spi->dev,
272 "enable reference regulator failed, %d\n",
273 ret);
274 return ret;
275 }
276 st->vref_mv = regulator_get_voltage(st->vref_reg) / 1000;
277
278 ret = ltc2632_spi_write(spi, LTC2632_CMD_EXTERNAL_REFER,
279 0, 0, 0);
280 if (ret) {
281 dev_err(&spi->dev,
282 "Set external reference command failed, %d\n",
283 ret);
284 return ret;
285 }
286 }
287
288 indio_dev->dev.parent = &spi->dev;
289 indio_dev->name = dev_of_node(&spi->dev) ? dev_of_node(&spi->dev)->name
290 : spi_get_device_id(spi)->name;
291 indio_dev->info = <c2632_info;
292 indio_dev->modes = INDIO_DIRECT_MODE;
293 indio_dev->channels = chip_info->channels;
294 indio_dev->num_channels = LTC2632_DAC_CHANNELS;
295
296 return iio_device_register(indio_dev);
297 }
298
ltc2632_remove(struct spi_device * spi)299 static int ltc2632_remove(struct spi_device *spi)
300 {
301 struct iio_dev *indio_dev = spi_get_drvdata(spi);
302 struct ltc2632_state *st = iio_priv(indio_dev);
303
304 iio_device_unregister(indio_dev);
305
306 if (st->vref_reg)
307 regulator_disable(st->vref_reg);
308
309 return 0;
310 }
311
312 static const struct spi_device_id ltc2632_id[] = {
313 { "ltc2632-l12", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632L12] },
314 { "ltc2632-l10", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632L10] },
315 { "ltc2632-l8", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632L8] },
316 { "ltc2632-h12", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632H12] },
317 { "ltc2632-h10", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632H10] },
318 { "ltc2632-h8", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632H8] },
319 {}
320 };
321 MODULE_DEVICE_TABLE(spi, ltc2632_id);
322
323 static const struct of_device_id ltc2632_of_match[] = {
324 {
325 .compatible = "lltc,ltc2632-l12",
326 .data = <c2632_chip_info_tbl[ID_LTC2632L12]
327 }, {
328 .compatible = "lltc,ltc2632-l10",
329 .data = <c2632_chip_info_tbl[ID_LTC2632L10]
330 }, {
331 .compatible = "lltc,ltc2632-l8",
332 .data = <c2632_chip_info_tbl[ID_LTC2632L8]
333 }, {
334 .compatible = "lltc,ltc2632-h12",
335 .data = <c2632_chip_info_tbl[ID_LTC2632H12]
336 }, {
337 .compatible = "lltc,ltc2632-h10",
338 .data = <c2632_chip_info_tbl[ID_LTC2632H10]
339 }, {
340 .compatible = "lltc,ltc2632-h8",
341 .data = <c2632_chip_info_tbl[ID_LTC2632H8]
342 },
343 {}
344 };
345 MODULE_DEVICE_TABLE(of, ltc2632_of_match);
346
347 static struct spi_driver ltc2632_driver = {
348 .driver = {
349 .name = "ltc2632",
350 .of_match_table = of_match_ptr(ltc2632_of_match),
351 },
352 .probe = ltc2632_probe,
353 .remove = ltc2632_remove,
354 .id_table = ltc2632_id,
355 };
356 module_spi_driver(ltc2632_driver);
357
358 MODULE_AUTHOR("Maxime Roussin-Belanger <maxime.roussinbelanger@gmail.com>");
359 MODULE_DESCRIPTION("LTC2632 DAC SPI driver");
360 MODULE_LICENSE("GPL v2");
361
