1 // SPDX-License-Identifier: GPL-2.0
2 /* ti-dac7311.c - Texas Instruments 8/10/12-bit 1-channel DAC driver
3 *
4 * Copyright (C) 2018 CMC NV
5 *
6 * https://www.ti.com/lit/ds/symlink/dac7311.pdf
7 */
8
9 #include <linux/iio/iio.h>
10 #include <linux/module.h>
11 #include <linux/regulator/consumer.h>
12 #include <linux/spi/spi.h>
13
14 enum {
15 ID_DAC5311 = 0,
16 ID_DAC6311,
17 ID_DAC7311,
18 };
19
20 enum {
21 POWER_1KOHM_TO_GND = 0,
22 POWER_100KOHM_TO_GND,
23 POWER_TRI_STATE,
24 };
25
26 struct ti_dac_spec {
27 u8 resolution;
28 };
29
30 static const struct ti_dac_spec ti_dac_spec[] = {
31 [ID_DAC5311] = { .resolution = 8 },
32 [ID_DAC6311] = { .resolution = 10 },
33 [ID_DAC7311] = { .resolution = 12 },
34 };
35
36 /**
37 * struct ti_dac_chip - TI DAC chip
38 * @lock: protects write sequences
39 * @vref: regulator generating Vref
40 * @spi: SPI device to send data to the device
41 * @val: cached value
42 * @powerdown: whether the chip is powered down
43 * @powerdown_mode: selected by the user
44 * @resolution: resolution of the chip
45 * @buf: buffer for transfer data
46 */
47 struct ti_dac_chip {
48 struct mutex lock;
49 struct regulator *vref;
50 struct spi_device *spi;
51 u16 val;
52 bool powerdown;
53 u8 powerdown_mode;
54 u8 resolution;
55 u8 buf[2] __aligned(IIO_DMA_MINALIGN);
56 };
57
ti_dac_get_power(struct ti_dac_chip * ti_dac,bool powerdown)58 static u8 ti_dac_get_power(struct ti_dac_chip *ti_dac, bool powerdown)
59 {
60 if (powerdown)
61 return ti_dac->powerdown_mode + 1;
62
63 return 0;
64 }
65
ti_dac_cmd(struct ti_dac_chip * ti_dac,u8 power,u16 val)66 static int ti_dac_cmd(struct ti_dac_chip *ti_dac, u8 power, u16 val)
67 {
68 u8 shift = 14 - ti_dac->resolution;
69
70 ti_dac->buf[0] = (val << shift) & 0xFF;
71 ti_dac->buf[1] = (power << 6) | (val >> (8 - shift));
72 return spi_write(ti_dac->spi, ti_dac->buf, 2);
73 }
74
75 static const char * const ti_dac_powerdown_modes[] = {
76 "1kohm_to_gnd",
77 "100kohm_to_gnd",
78 "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
95 ti_dac->powerdown_mode = mode;
96 return 0;
97 }
98
99 static const struct iio_enum ti_dac_powerdown_mode = {
100 .items = ti_dac_powerdown_modes,
101 .num_items = ARRAY_SIZE(ti_dac_powerdown_modes),
102 .get = ti_dac_get_powerdown_mode,
103 .set = ti_dac_set_powerdown_mode,
104 };
105
ti_dac_read_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,char * buf)106 static ssize_t ti_dac_read_powerdown(struct iio_dev *indio_dev,
107 uintptr_t private,
108 const struct iio_chan_spec *chan,
109 char *buf)
110 {
111 struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
112
113 return sysfs_emit(buf, "%d\n", ti_dac->powerdown);
114 }
115
ti_dac_write_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,const char * buf,size_t len)116 static ssize_t ti_dac_write_powerdown(struct iio_dev *indio_dev,
117 uintptr_t private,
118 const struct iio_chan_spec *chan,
119 const char *buf, size_t len)
120 {
121 struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
122 bool powerdown;
123 u8 power;
124 int ret;
125
126 ret = kstrtobool(buf, &powerdown);
127 if (ret)
128 return ret;
129
130 power = ti_dac_get_power(ti_dac, powerdown);
131
132 mutex_lock(&ti_dac->lock);
133 ret = ti_dac_cmd(ti_dac, power, 0);
134 if (!ret)
135 ti_dac->powerdown = powerdown;
136 mutex_unlock(&ti_dac->lock);
137
138 return ret ? ret : len;
139 }
140
141 static const struct iio_chan_spec_ext_info ti_dac_ext_info[] = {
142 {
143 .name = "powerdown",
144 .read = ti_dac_read_powerdown,
145 .write = ti_dac_write_powerdown,
146 .shared = IIO_SHARED_BY_TYPE,
147 },
148 IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE, &ti_dac_powerdown_mode),
149 IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE, &ti_dac_powerdown_mode),
150 { },
151 };
152
153 #define TI_DAC_CHANNEL(chan) { \
154 .type = IIO_VOLTAGE, \
155 .channel = (chan), \
156 .output = true, \
157 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
158 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
159 .ext_info = ti_dac_ext_info, \
160 }
161
162 static const struct iio_chan_spec ti_dac_channels[] = {
163 TI_DAC_CHANNEL(0),
164 };
165
ti_dac_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)166 static int ti_dac_read_raw(struct iio_dev *indio_dev,
167 struct iio_chan_spec const *chan,
168 int *val, int *val2, long mask)
169 {
170 struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
171 int ret;
172
173 switch (mask) {
174 case IIO_CHAN_INFO_RAW:
175 *val = ti_dac->val;
176 return IIO_VAL_INT;
177
178 case IIO_CHAN_INFO_SCALE:
179 ret = regulator_get_voltage(ti_dac->vref);
180 if (ret < 0)
181 return ret;
182
183 *val = ret / 1000;
184 *val2 = ti_dac->resolution;
185 return IIO_VAL_FRACTIONAL_LOG2;
186 }
187
188 return -EINVAL;
189 }
190
ti_dac_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)191 static int ti_dac_write_raw(struct iio_dev *indio_dev,
192 struct iio_chan_spec const *chan,
193 int val, int val2, long mask)
194 {
195 struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
196 u8 power = ti_dac_get_power(ti_dac, ti_dac->powerdown);
197 int ret;
198
199 switch (mask) {
200 case IIO_CHAN_INFO_RAW:
201 if (ti_dac->val == val)
202 return 0;
203
204 if (val >= (1 << ti_dac->resolution) || val < 0)
205 return -EINVAL;
206
207 if (ti_dac->powerdown)
208 return -EBUSY;
209
210 mutex_lock(&ti_dac->lock);
211 ret = ti_dac_cmd(ti_dac, power, val);
212 if (!ret)
213 ti_dac->val = val;
214 mutex_unlock(&ti_dac->lock);
215 break;
216
217 default:
218 ret = -EINVAL;
219 }
220
221 return ret;
222 }
223
ti_dac_write_raw_get_fmt(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,long mask)224 static int ti_dac_write_raw_get_fmt(struct iio_dev *indio_dev,
225 struct iio_chan_spec const *chan, long mask)
226 {
227 return IIO_VAL_INT;
228 }
229
230 static const struct iio_info ti_dac_info = {
231 .read_raw = ti_dac_read_raw,
232 .write_raw = ti_dac_write_raw,
233 .write_raw_get_fmt = ti_dac_write_raw_get_fmt,
234 };
235
ti_dac_probe(struct spi_device * spi)236 static int ti_dac_probe(struct spi_device *spi)
237 {
238 struct device *dev = &spi->dev;
239 const struct ti_dac_spec *spec;
240 struct ti_dac_chip *ti_dac;
241 struct iio_dev *indio_dev;
242 int ret;
243
244 indio_dev = devm_iio_device_alloc(dev, sizeof(*ti_dac));
245 if (!indio_dev) {
246 dev_err(dev, "can not allocate iio device\n");
247 return -ENOMEM;
248 }
249
250 spi->mode = SPI_MODE_1;
251 spi->bits_per_word = 16;
252 spi_setup(spi);
253
254 indio_dev->info = &ti_dac_info;
255 indio_dev->name = spi_get_device_id(spi)->name;
256 indio_dev->modes = INDIO_DIRECT_MODE;
257 indio_dev->channels = ti_dac_channels;
258 spi_set_drvdata(spi, indio_dev);
259
260 ti_dac = iio_priv(indio_dev);
261 ti_dac->powerdown = false;
262 ti_dac->spi = spi;
263
264 spec = &ti_dac_spec[spi_get_device_id(spi)->driver_data];
265 indio_dev->num_channels = 1;
266 ti_dac->resolution = spec->resolution;
267
268 ti_dac->vref = devm_regulator_get(dev, "vref");
269 if (IS_ERR(ti_dac->vref))
270 return dev_err_probe(dev, PTR_ERR(ti_dac->vref),
271 "error to get regulator\n");
272
273 ret = regulator_enable(ti_dac->vref);
274 if (ret < 0) {
275 dev_err(dev, "can not enable regulator\n");
276 return ret;
277 }
278
279 mutex_init(&ti_dac->lock);
280
281 ret = iio_device_register(indio_dev);
282 if (ret) {
283 dev_err(dev, "fail to register iio device: %d\n", ret);
284 goto err;
285 }
286
287 return 0;
288
289 err:
290 mutex_destroy(&ti_dac->lock);
291 regulator_disable(ti_dac->vref);
292 return ret;
293 }
294
ti_dac_remove(struct spi_device * spi)295 static void ti_dac_remove(struct spi_device *spi)
296 {
297 struct iio_dev *indio_dev = spi_get_drvdata(spi);
298 struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
299
300 iio_device_unregister(indio_dev);
301 mutex_destroy(&ti_dac->lock);
302 regulator_disable(ti_dac->vref);
303 }
304
305 static const struct of_device_id ti_dac_of_id[] = {
306 { .compatible = "ti,dac5311" },
307 { .compatible = "ti,dac6311" },
308 { .compatible = "ti,dac7311" },
309 { }
310 };
311 MODULE_DEVICE_TABLE(of, ti_dac_of_id);
312
313 static const struct spi_device_id ti_dac_spi_id[] = {
314 { "dac5311", ID_DAC5311 },
315 { "dac6311", ID_DAC6311 },
316 { "dac7311", ID_DAC7311 },
317 { }
318 };
319 MODULE_DEVICE_TABLE(spi, ti_dac_spi_id);
320
321 static struct spi_driver ti_dac_driver = {
322 .driver = {
323 .name = "ti-dac7311",
324 .of_match_table = ti_dac_of_id,
325 },
326 .probe = ti_dac_probe,
327 .remove = ti_dac_remove,
328 .id_table = ti_dac_spi_id,
329 };
330 module_spi_driver(ti_dac_driver);
331
332 MODULE_AUTHOR("Charles-Antoine Couret <charles-antoine.couret@essensium.com>");
333 MODULE_DESCRIPTION("Texas Instruments 8/10/12-bit 1-channel DAC driver");
334 MODULE_LICENSE("GPL v2");
335