1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * ti-dac082s085.c - Texas Instruments 8/10/12-bit 2/4-channel DAC driver
4 *
5 * Copyright (C) 2017 KUNBUS GmbH
6 *
7 * https://www.ti.com/lit/ds/symlink/dac082s085.pdf
8 * https://www.ti.com/lit/ds/symlink/dac102s085.pdf
9 * https://www.ti.com/lit/ds/symlink/dac122s085.pdf
10 * https://www.ti.com/lit/ds/symlink/dac084s085.pdf
11 * https://www.ti.com/lit/ds/symlink/dac104s085.pdf
12 * https://www.ti.com/lit/ds/symlink/dac124s085.pdf
13 */
14
15 #include <linux/iio/iio.h>
16 #include <linux/module.h>
17 #include <linux/mod_devicetable.h>
18 #include <linux/regulator/consumer.h>
19 #include <linux/spi/spi.h>
20
21 enum { dual_8bit, dual_10bit, dual_12bit, quad_8bit, quad_10bit, quad_12bit };
22
23 struct ti_dac_spec {
24 u8 num_channels;
25 u8 resolution;
26 };
27
28 static const struct ti_dac_spec ti_dac_spec[] = {
29 [dual_8bit] = { .num_channels = 2, .resolution = 8 },
30 [dual_10bit] = { .num_channels = 2, .resolution = 10 },
31 [dual_12bit] = { .num_channels = 2, .resolution = 12 },
32 [quad_8bit] = { .num_channels = 4, .resolution = 8 },
33 [quad_10bit] = { .num_channels = 4, .resolution = 10 },
34 [quad_12bit] = { .num_channels = 4, .resolution = 12 },
35 };
36
37 /**
38 * struct ti_dac_chip - TI DAC chip
39 * @lock: protects write sequences
40 * @vref: regulator generating Vref
41 * @mesg: SPI message to perform a write
42 * @xfer: SPI transfer used by @mesg
43 * @val: cached value of each output
44 * @powerdown: whether the chip is powered down
45 * @powerdown_mode: selected by the user
46 * @resolution: resolution of the chip
47 * @buf: buffer for @xfer
48 */
49 struct ti_dac_chip {
50 struct mutex lock;
51 struct regulator *vref;
52 struct spi_message mesg;
53 struct spi_transfer xfer;
54 u16 val[4];
55 bool powerdown;
56 u8 powerdown_mode;
57 u8 resolution;
58 u8 buf[2] __aligned(IIO_DMA_MINALIGN);
59 };
60
61 #define WRITE_NOT_UPDATE(chan) (0x00 | (chan) << 6)
62 #define WRITE_AND_UPDATE(chan) (0x10 | (chan) << 6)
63 #define WRITE_ALL_UPDATE 0x20
64 #define POWERDOWN(mode) (0x30 | ((mode) + 1) << 6)
65
ti_dac_cmd(struct ti_dac_chip * ti_dac,u8 cmd,u16 val)66 static int ti_dac_cmd(struct ti_dac_chip *ti_dac, u8 cmd, u16 val)
67 {
68 u8 shift = 12 - ti_dac->resolution;
69
70 ti_dac->buf[0] = cmd | (val >> (8 - shift));
71 ti_dac->buf[1] = (val << shift) & 0xff;
72 return spi_sync(ti_dac->mesg.spi, &ti_dac->mesg);
73 }
74
75 static const char * const ti_dac_powerdown_modes[] = {
76 "2.5kohm_to_gnd", "100kohm_to_gnd", "three_state",
77 };
78
ti_dac_get_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan)79 static int ti_dac_get_powerdown_mode(struct iio_dev *indio_dev,
80 const struct iio_chan_spec *chan)
81 {
82 struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
83
84 return ti_dac->powerdown_mode;
85 }
86
ti_dac_set_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,unsigned int mode)87 static int ti_dac_set_powerdown_mode(struct iio_dev *indio_dev,
88 const struct iio_chan_spec *chan,
89 unsigned int mode)
90 {
91 struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
92 int ret = 0;
93
94 if (ti_dac->powerdown_mode == mode)
95 return 0;
96
97 mutex_lock(&ti_dac->lock);
98 if (ti_dac->powerdown) {
99 ret = ti_dac_cmd(ti_dac, POWERDOWN(mode), 0);
100 if (ret)
101 goto out;
102 }
103 ti_dac->powerdown_mode = mode;
104
105 out:
106 mutex_unlock(&ti_dac->lock);
107 return ret;
108 }
109
110 static const struct iio_enum ti_dac_powerdown_mode = {
111 .items = ti_dac_powerdown_modes,
112 .num_items = ARRAY_SIZE(ti_dac_powerdown_modes),
113 .get = ti_dac_get_powerdown_mode,
114 .set = ti_dac_set_powerdown_mode,
115 };
116
ti_dac_read_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,char * buf)117 static ssize_t ti_dac_read_powerdown(struct iio_dev *indio_dev,
118 uintptr_t private,
119 const struct iio_chan_spec *chan,
120 char *buf)
121 {
122 struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
123
124 return sysfs_emit(buf, "%d\n", ti_dac->powerdown);
125 }
126
ti_dac_write_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,const char * buf,size_t len)127 static ssize_t ti_dac_write_powerdown(struct iio_dev *indio_dev,
128 uintptr_t private,
129 const struct iio_chan_spec *chan,
130 const char *buf, size_t len)
131 {
132 struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
133 bool powerdown;
134 int ret;
135
136 ret = kstrtobool(buf, &powerdown);
137 if (ret)
138 return ret;
139
140 if (ti_dac->powerdown == powerdown)
141 return len;
142
143 mutex_lock(&ti_dac->lock);
144 if (powerdown)
145 ret = ti_dac_cmd(ti_dac, POWERDOWN(ti_dac->powerdown_mode), 0);
146 else
147 ret = ti_dac_cmd(ti_dac, WRITE_AND_UPDATE(0), ti_dac->val[0]);
148 if (!ret)
149 ti_dac->powerdown = powerdown;
150 mutex_unlock(&ti_dac->lock);
151
152 return ret ? ret : len;
153 }
154
155 static const struct iio_chan_spec_ext_info ti_dac_ext_info[] = {
156 {
157 .name = "powerdown",
158 .read = ti_dac_read_powerdown,
159 .write = ti_dac_write_powerdown,
160 .shared = IIO_SHARED_BY_TYPE,
161 },
162 IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE, &ti_dac_powerdown_mode),
163 IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE, &ti_dac_powerdown_mode),
164 { },
165 };
166
167 #define TI_DAC_CHANNEL(chan) { \
168 .type = IIO_VOLTAGE, \
169 .channel = (chan), \
170 .address = (chan), \
171 .indexed = true, \
172 .output = true, \
173 .datasheet_name = (const char[]){ 'A' + (chan), 0 }, \
174 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
175 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
176 .ext_info = ti_dac_ext_info, \
177 }
178
179 static const struct iio_chan_spec ti_dac_channels[] = {
180 TI_DAC_CHANNEL(0),
181 TI_DAC_CHANNEL(1),
182 TI_DAC_CHANNEL(2),
183 TI_DAC_CHANNEL(3),
184 };
185
ti_dac_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)186 static int ti_dac_read_raw(struct iio_dev *indio_dev,
187 struct iio_chan_spec const *chan,
188 int *val, int *val2, long mask)
189 {
190 struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
191 int ret;
192
193 switch (mask) {
194 case IIO_CHAN_INFO_RAW:
195 *val = ti_dac->val[chan->channel];
196 ret = IIO_VAL_INT;
197 break;
198
199 case IIO_CHAN_INFO_SCALE:
200 ret = regulator_get_voltage(ti_dac->vref);
201 if (ret < 0)
202 return ret;
203
204 *val = ret / 1000;
205 *val2 = ti_dac->resolution;
206 ret = IIO_VAL_FRACTIONAL_LOG2;
207 break;
208
209 default:
210 ret = -EINVAL;
211 }
212
213 return ret;
214 }
215
ti_dac_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)216 static int ti_dac_write_raw(struct iio_dev *indio_dev,
217 struct iio_chan_spec const *chan,
218 int val, int val2, long mask)
219 {
220 struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
221 int ret;
222
223 switch (mask) {
224 case IIO_CHAN_INFO_RAW:
225 if (ti_dac->val[chan->channel] == val)
226 return 0;
227
228 if (val >= (1 << ti_dac->resolution) || val < 0)
229 return -EINVAL;
230
231 if (ti_dac->powerdown)
232 return -EBUSY;
233
234 mutex_lock(&ti_dac->lock);
235 ret = ti_dac_cmd(ti_dac, WRITE_AND_UPDATE(chan->channel), val);
236 if (!ret)
237 ti_dac->val[chan->channel] = val;
238 mutex_unlock(&ti_dac->lock);
239 break;
240
241 default:
242 ret = -EINVAL;
243 }
244
245 return ret;
246 }
247
ti_dac_write_raw_get_fmt(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,long mask)248 static int ti_dac_write_raw_get_fmt(struct iio_dev *indio_dev,
249 struct iio_chan_spec const *chan, long mask)
250 {
251 return IIO_VAL_INT;
252 }
253
254 static const struct iio_info ti_dac_info = {
255 .read_raw = ti_dac_read_raw,
256 .write_raw = ti_dac_write_raw,
257 .write_raw_get_fmt = ti_dac_write_raw_get_fmt,
258 };
259
ti_dac_probe(struct spi_device * spi)260 static int ti_dac_probe(struct spi_device *spi)
261 {
262 struct device *dev = &spi->dev;
263 const struct ti_dac_spec *spec;
264 struct ti_dac_chip *ti_dac;
265 struct iio_dev *indio_dev;
266 int ret;
267
268 indio_dev = devm_iio_device_alloc(dev, sizeof(*ti_dac));
269 if (!indio_dev)
270 return -ENOMEM;
271
272 indio_dev->info = &ti_dac_info;
273 indio_dev->name = spi->modalias;
274 indio_dev->modes = INDIO_DIRECT_MODE;
275 indio_dev->channels = ti_dac_channels;
276 spi_set_drvdata(spi, indio_dev);
277
278 ti_dac = iio_priv(indio_dev);
279 ti_dac->xfer.tx_buf = &ti_dac->buf;
280 ti_dac->xfer.len = sizeof(ti_dac->buf);
281 spi_message_init_with_transfers(&ti_dac->mesg, &ti_dac->xfer, 1);
282 ti_dac->mesg.spi = spi;
283
284 spec = &ti_dac_spec[spi_get_device_id(spi)->driver_data];
285 indio_dev->num_channels = spec->num_channels;
286 ti_dac->resolution = spec->resolution;
287
288 ti_dac->vref = devm_regulator_get(dev, "vref");
289 if (IS_ERR(ti_dac->vref))
290 return PTR_ERR(ti_dac->vref);
291
292 ret = regulator_enable(ti_dac->vref);
293 if (ret < 0)
294 return ret;
295
296 mutex_init(&ti_dac->lock);
297
298 ret = ti_dac_cmd(ti_dac, WRITE_ALL_UPDATE, 0);
299 if (ret) {
300 dev_err(dev, "failed to initialize outputs to 0\n");
301 goto err;
302 }
303
304 ret = iio_device_register(indio_dev);
305 if (ret)
306 goto err;
307
308 return 0;
309
310 err:
311 mutex_destroy(&ti_dac->lock);
312 regulator_disable(ti_dac->vref);
313 return ret;
314 }
315
ti_dac_remove(struct spi_device * spi)316 static void ti_dac_remove(struct spi_device *spi)
317 {
318 struct iio_dev *indio_dev = spi_get_drvdata(spi);
319 struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
320
321 iio_device_unregister(indio_dev);
322 mutex_destroy(&ti_dac->lock);
323 regulator_disable(ti_dac->vref);
324 }
325
326 static const struct of_device_id ti_dac_of_id[] = {
327 { .compatible = "ti,dac082s085" },
328 { .compatible = "ti,dac102s085" },
329 { .compatible = "ti,dac122s085" },
330 { .compatible = "ti,dac084s085" },
331 { .compatible = "ti,dac104s085" },
332 { .compatible = "ti,dac124s085" },
333 { }
334 };
335 MODULE_DEVICE_TABLE(of, ti_dac_of_id);
336
337 static const struct spi_device_id ti_dac_spi_id[] = {
338 { "dac082s085", dual_8bit },
339 { "dac102s085", dual_10bit },
340 { "dac122s085", dual_12bit },
341 { "dac084s085", quad_8bit },
342 { "dac104s085", quad_10bit },
343 { "dac124s085", quad_12bit },
344 { }
345 };
346 MODULE_DEVICE_TABLE(spi, ti_dac_spi_id);
347
348 static struct spi_driver ti_dac_driver = {
349 .driver = {
350 .name = "ti-dac082s085",
351 .of_match_table = ti_dac_of_id,
352 },
353 .probe = ti_dac_probe,
354 .remove = ti_dac_remove,
355 .id_table = ti_dac_spi_id,
356 };
357 module_spi_driver(ti_dac_driver);
358
359 MODULE_AUTHOR("Lukas Wunner <lukas@wunner.de>");
360 MODULE_DESCRIPTION("Texas Instruments 8/10/12-bit 2/4-channel DAC driver");
361 MODULE_LICENSE("GPL v2");
362