1 /*
2 * ti-dac082s085.c - Texas Instruments 8/10/12-bit 2/4-channel DAC driver
3 *
4 * Copyright (C) 2017 KUNBUS GmbH
5 *
6 * http://www.ti.com/lit/ds/symlink/dac082s085.pdf
7 * http://www.ti.com/lit/ds/symlink/dac102s085.pdf
8 * http://www.ti.com/lit/ds/symlink/dac122s085.pdf
9 * http://www.ti.com/lit/ds/symlink/dac084s085.pdf
10 * http://www.ti.com/lit/ds/symlink/dac104s085.pdf
11 * http://www.ti.com/lit/ds/symlink/dac124s085.pdf
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License (version 2) as
15 * published by the Free Software Foundation.
16 */
17
18 #include <linux/iio/iio.h>
19 #include <linux/module.h>
20 #include <linux/regulator/consumer.h>
21 #include <linux/spi/spi.h>
22
23 enum { dual_8bit, dual_10bit, dual_12bit, quad_8bit, quad_10bit, quad_12bit };
24
25 struct ti_dac_spec {
26 u8 num_channels;
27 u8 resolution;
28 };
29
30 static const struct ti_dac_spec ti_dac_spec[] = {
31 [dual_8bit] = { .num_channels = 2, .resolution = 8 },
32 [dual_10bit] = { .num_channels = 2, .resolution = 10 },
33 [dual_12bit] = { .num_channels = 2, .resolution = 12 },
34 [quad_8bit] = { .num_channels = 4, .resolution = 8 },
35 [quad_10bit] = { .num_channels = 4, .resolution = 10 },
36 [quad_12bit] = { .num_channels = 4, .resolution = 12 },
37 };
38
39 /**
40 * struct ti_dac_chip - TI DAC chip
41 * @lock: protects write sequences
42 * @vref: regulator generating Vref
43 * @mesg: SPI message to perform a write
44 * @xfer: SPI transfer used by @mesg
45 * @val: cached value of each output
46 * @powerdown: whether the chip is powered down
47 * @powerdown_mode: selected by the user
48 * @resolution: resolution of the chip
49 * @buf: buffer for @xfer
50 */
51 struct ti_dac_chip {
52 struct mutex lock;
53 struct regulator *vref;
54 struct spi_message mesg;
55 struct spi_transfer xfer;
56 u16 val[4];
57 bool powerdown;
58 u8 powerdown_mode;
59 u8 resolution;
60 u8 buf[2] ____cacheline_aligned;
61 };
62
63 #define WRITE_NOT_UPDATE(chan) (0x00 | (chan) << 6)
64 #define WRITE_AND_UPDATE(chan) (0x10 | (chan) << 6)
65 #define WRITE_ALL_UPDATE 0x20
66 #define POWERDOWN(mode) (0x30 | ((mode) + 1) << 6)
67
ti_dac_cmd(struct ti_dac_chip * ti_dac,u8 cmd,u16 val)68 static int ti_dac_cmd(struct ti_dac_chip *ti_dac, u8 cmd, u16 val)
69 {
70 u8 shift = 12 - ti_dac->resolution;
71
72 ti_dac->buf[0] = cmd | (val >> (8 - shift));
73 ti_dac->buf[1] = (val << shift) & 0xff;
74 return spi_sync(ti_dac->mesg.spi, &ti_dac->mesg);
75 }
76
77 static const char * const ti_dac_powerdown_modes[] = {
78 "2.5kohm_to_gnd", "100kohm_to_gnd", "three_state",
79 };
80
ti_dac_get_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan)81 static int ti_dac_get_powerdown_mode(struct iio_dev *indio_dev,
82 const struct iio_chan_spec *chan)
83 {
84 struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
85
86 return ti_dac->powerdown_mode;
87 }
88
ti_dac_set_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,unsigned int mode)89 static int ti_dac_set_powerdown_mode(struct iio_dev *indio_dev,
90 const struct iio_chan_spec *chan,
91 unsigned int mode)
92 {
93 struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
94 int ret = 0;
95
96 if (ti_dac->powerdown_mode == mode)
97 return 0;
98
99 mutex_lock(&ti_dac->lock);
100 if (ti_dac->powerdown) {
101 ret = ti_dac_cmd(ti_dac, POWERDOWN(mode), 0);
102 if (ret)
103 goto out;
104 }
105 ti_dac->powerdown_mode = mode;
106
107 out:
108 mutex_unlock(&ti_dac->lock);
109 return ret;
110 }
111
112 static const struct iio_enum ti_dac_powerdown_mode = {
113 .items = ti_dac_powerdown_modes,
114 .num_items = ARRAY_SIZE(ti_dac_powerdown_modes),
115 .get = ti_dac_get_powerdown_mode,
116 .set = ti_dac_set_powerdown_mode,
117 };
118
ti_dac_read_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,char * buf)119 static ssize_t ti_dac_read_powerdown(struct iio_dev *indio_dev,
120 uintptr_t private,
121 const struct iio_chan_spec *chan,
122 char *buf)
123 {
124 struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
125
126 return sprintf(buf, "%d\n", ti_dac->powerdown);
127 }
128
ti_dac_write_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,const char * buf,size_t len)129 static ssize_t ti_dac_write_powerdown(struct iio_dev *indio_dev,
130 uintptr_t private,
131 const struct iio_chan_spec *chan,
132 const char *buf, size_t len)
133 {
134 struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
135 bool powerdown;
136 int ret;
137
138 ret = strtobool(buf, &powerdown);
139 if (ret)
140 return ret;
141
142 if (ti_dac->powerdown == powerdown)
143 return len;
144
145 mutex_lock(&ti_dac->lock);
146 if (powerdown)
147 ret = ti_dac_cmd(ti_dac, POWERDOWN(ti_dac->powerdown_mode), 0);
148 else
149 ret = ti_dac_cmd(ti_dac, WRITE_AND_UPDATE(0), ti_dac->val[0]);
150 if (!ret)
151 ti_dac->powerdown = powerdown;
152 mutex_unlock(&ti_dac->lock);
153
154 return ret ? ret : len;
155 }
156
157 static const struct iio_chan_spec_ext_info ti_dac_ext_info[] = {
158 {
159 .name = "powerdown",
160 .read = ti_dac_read_powerdown,
161 .write = ti_dac_write_powerdown,
162 .shared = IIO_SHARED_BY_TYPE,
163 },
164 IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE, &ti_dac_powerdown_mode),
165 IIO_ENUM_AVAILABLE("powerdown_mode", &ti_dac_powerdown_mode),
166 { },
167 };
168
169 #define TI_DAC_CHANNEL(chan) { \
170 .type = IIO_VOLTAGE, \
171 .channel = (chan), \
172 .address = (chan), \
173 .indexed = true, \
174 .output = true, \
175 .datasheet_name = (const char[]){ 'A' + (chan), 0 }, \
176 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
177 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
178 .ext_info = ti_dac_ext_info, \
179 }
180
181 static const struct iio_chan_spec ti_dac_channels[] = {
182 TI_DAC_CHANNEL(0),
183 TI_DAC_CHANNEL(1),
184 TI_DAC_CHANNEL(2),
185 TI_DAC_CHANNEL(3),
186 };
187
ti_dac_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)188 static int ti_dac_read_raw(struct iio_dev *indio_dev,
189 struct iio_chan_spec const *chan,
190 int *val, int *val2, long mask)
191 {
192 struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
193 int ret;
194
195 switch (mask) {
196 case IIO_CHAN_INFO_RAW:
197 *val = ti_dac->val[chan->channel];
198 ret = IIO_VAL_INT;
199 break;
200
201 case IIO_CHAN_INFO_SCALE:
202 ret = regulator_get_voltage(ti_dac->vref);
203 if (ret < 0)
204 return ret;
205
206 *val = ret / 1000;
207 *val2 = ti_dac->resolution;
208 ret = IIO_VAL_FRACTIONAL_LOG2;
209 break;
210
211 default:
212 ret = -EINVAL;
213 }
214
215 return ret;
216 }
217
ti_dac_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)218 static int ti_dac_write_raw(struct iio_dev *indio_dev,
219 struct iio_chan_spec const *chan,
220 int val, int val2, long mask)
221 {
222 struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
223 int ret;
224
225 switch (mask) {
226 case IIO_CHAN_INFO_RAW:
227 if (ti_dac->val[chan->channel] == val)
228 return 0;
229
230 if (val >= (1 << ti_dac->resolution) || val < 0)
231 return -EINVAL;
232
233 if (ti_dac->powerdown)
234 return -EBUSY;
235
236 mutex_lock(&ti_dac->lock);
237 ret = ti_dac_cmd(ti_dac, WRITE_AND_UPDATE(chan->channel), val);
238 if (!ret)
239 ti_dac->val[chan->channel] = val;
240 mutex_unlock(&ti_dac->lock);
241 break;
242
243 default:
244 ret = -EINVAL;
245 }
246
247 return ret;
248 }
249
ti_dac_write_raw_get_fmt(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,long mask)250 static int ti_dac_write_raw_get_fmt(struct iio_dev *indio_dev,
251 struct iio_chan_spec const *chan, long mask)
252 {
253 return IIO_VAL_INT;
254 }
255
256 static const struct iio_info ti_dac_info = {
257 .read_raw = ti_dac_read_raw,
258 .write_raw = ti_dac_write_raw,
259 .write_raw_get_fmt = ti_dac_write_raw_get_fmt,
260 };
261
ti_dac_probe(struct spi_device * spi)262 static int ti_dac_probe(struct spi_device *spi)
263 {
264 struct device *dev = &spi->dev;
265 const struct ti_dac_spec *spec;
266 struct ti_dac_chip *ti_dac;
267 struct iio_dev *indio_dev;
268 int ret;
269
270 indio_dev = devm_iio_device_alloc(dev, sizeof(*ti_dac));
271 if (!indio_dev)
272 return -ENOMEM;
273
274 indio_dev->dev.parent = dev;
275 indio_dev->info = &ti_dac_info;
276 indio_dev->name = spi->modalias;
277 indio_dev->modes = INDIO_DIRECT_MODE;
278 indio_dev->channels = ti_dac_channels;
279 spi_set_drvdata(spi, indio_dev);
280
281 ti_dac = iio_priv(indio_dev);
282 ti_dac->xfer.tx_buf = &ti_dac->buf;
283 ti_dac->xfer.len = sizeof(ti_dac->buf);
284 spi_message_init_with_transfers(&ti_dac->mesg, &ti_dac->xfer, 1);
285 ti_dac->mesg.spi = spi;
286
287 spec = &ti_dac_spec[spi_get_device_id(spi)->driver_data];
288 indio_dev->num_channels = spec->num_channels;
289 ti_dac->resolution = spec->resolution;
290
291 ti_dac->vref = devm_regulator_get(dev, "vref");
292 if (IS_ERR(ti_dac->vref))
293 return PTR_ERR(ti_dac->vref);
294
295 ret = regulator_enable(ti_dac->vref);
296 if (ret < 0)
297 return ret;
298
299 mutex_init(&ti_dac->lock);
300
301 ret = ti_dac_cmd(ti_dac, WRITE_ALL_UPDATE, 0);
302 if (ret) {
303 dev_err(dev, "failed to initialize outputs to 0\n");
304 goto err;
305 }
306
307 ret = iio_device_register(indio_dev);
308 if (ret)
309 goto err;
310
311 return 0;
312
313 err:
314 mutex_destroy(&ti_dac->lock);
315 regulator_disable(ti_dac->vref);
316 return ret;
317 }
318
ti_dac_remove(struct spi_device * spi)319 static int ti_dac_remove(struct spi_device *spi)
320 {
321 struct iio_dev *indio_dev = spi_get_drvdata(spi);
322 struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
323
324 iio_device_unregister(indio_dev);
325 mutex_destroy(&ti_dac->lock);
326 regulator_disable(ti_dac->vref);
327
328 return 0;
329 }
330
331 #ifdef CONFIG_OF
332 static const struct of_device_id ti_dac_of_id[] = {
333 { .compatible = "ti,dac082s085" },
334 { .compatible = "ti,dac102s085" },
335 { .compatible = "ti,dac122s085" },
336 { .compatible = "ti,dac084s085" },
337 { .compatible = "ti,dac104s085" },
338 { .compatible = "ti,dac124s085" },
339 { }
340 };
341 MODULE_DEVICE_TABLE(of, ti_dac_of_id);
342 #endif
343
344 static const struct spi_device_id ti_dac_spi_id[] = {
345 { "dac082s085", dual_8bit },
346 { "dac102s085", dual_10bit },
347 { "dac122s085", dual_12bit },
348 { "dac084s085", quad_8bit },
349 { "dac104s085", quad_10bit },
350 { "dac124s085", quad_12bit },
351 { }
352 };
353 MODULE_DEVICE_TABLE(spi, ti_dac_spi_id);
354
355 static struct spi_driver ti_dac_driver = {
356 .driver = {
357 .name = "ti-dac082s085",
358 .of_match_table = of_match_ptr(ti_dac_of_id),
359 },
360 .probe = ti_dac_probe,
361 .remove = ti_dac_remove,
362 .id_table = ti_dac_spi_id,
363 };
364 module_spi_driver(ti_dac_driver);
365
366 MODULE_AUTHOR("Lukas Wunner <lukas@wunner.de>");
367 MODULE_DESCRIPTION("Texas Instruments 8/10/12-bit 2/4-channel DAC driver");
368 MODULE_LICENSE("GPL v2");
369