1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * iio/dac/max5821.c
4 * Copyright (C) 2014 Philippe Reynes
5 */
6
7 #include <linux/kernel.h>
8 #include <linux/module.h>
9 #include <linux/i2c.h>
10 #include <linux/iio/iio.h>
11 #include <linux/regulator/consumer.h>
12
13 #define MAX5821_MAX_DAC_CHANNELS 2
14
15 /* command bytes */
16 #define MAX5821_LOAD_DAC_A_IN_REG_B 0x00
17 #define MAX5821_LOAD_DAC_B_IN_REG_A 0x10
18 #define MAX5821_EXTENDED_COMMAND_MODE 0xf0
19 #define MAX5821_READ_DAC_A_COMMAND 0xf1
20 #define MAX5821_READ_DAC_B_COMMAND 0xf2
21
22 #define MAX5821_EXTENDED_POWER_UP 0x00
23 #define MAX5821_EXTENDED_POWER_DOWN_MODE0 0x01
24 #define MAX5821_EXTENDED_POWER_DOWN_MODE1 0x02
25 #define MAX5821_EXTENDED_POWER_DOWN_MODE2 0x03
26 #define MAX5821_EXTENDED_DAC_A 0x04
27 #define MAX5821_EXTENDED_DAC_B 0x08
28
29 enum max5821_device_ids {
30 ID_MAX5821,
31 };
32
33 struct max5821_data {
34 struct i2c_client *client;
35 unsigned short vref_mv;
36 bool powerdown[MAX5821_MAX_DAC_CHANNELS];
37 u8 powerdown_mode[MAX5821_MAX_DAC_CHANNELS];
38 struct mutex lock;
39 };
40
41 static const char * const max5821_powerdown_modes[] = {
42 "three_state",
43 "1kohm_to_gnd",
44 "100kohm_to_gnd",
45 };
46
47 enum {
48 MAX5821_THREE_STATE,
49 MAX5821_1KOHM_TO_GND,
50 MAX5821_100KOHM_TO_GND
51 };
52
max5821_get_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan)53 static int max5821_get_powerdown_mode(struct iio_dev *indio_dev,
54 const struct iio_chan_spec *chan)
55 {
56 struct max5821_data *st = iio_priv(indio_dev);
57
58 return st->powerdown_mode[chan->channel];
59 }
60
max5821_set_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,unsigned int mode)61 static int max5821_set_powerdown_mode(struct iio_dev *indio_dev,
62 const struct iio_chan_spec *chan,
63 unsigned int mode)
64 {
65 struct max5821_data *st = iio_priv(indio_dev);
66
67 st->powerdown_mode[chan->channel] = mode;
68
69 return 0;
70 }
71
72 static const struct iio_enum max5821_powerdown_mode_enum = {
73 .items = max5821_powerdown_modes,
74 .num_items = ARRAY_SIZE(max5821_powerdown_modes),
75 .get = max5821_get_powerdown_mode,
76 .set = max5821_set_powerdown_mode,
77 };
78
max5821_read_dac_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,char * buf)79 static ssize_t max5821_read_dac_powerdown(struct iio_dev *indio_dev,
80 uintptr_t private,
81 const struct iio_chan_spec *chan,
82 char *buf)
83 {
84 struct max5821_data *st = iio_priv(indio_dev);
85
86 return sysfs_emit(buf, "%d\n", st->powerdown[chan->channel]);
87 }
88
max5821_sync_powerdown_mode(struct max5821_data * data,const struct iio_chan_spec * chan)89 static int max5821_sync_powerdown_mode(struct max5821_data *data,
90 const struct iio_chan_spec *chan)
91 {
92 u8 outbuf[2];
93
94 outbuf[0] = MAX5821_EXTENDED_COMMAND_MODE;
95
96 if (chan->channel == 0)
97 outbuf[1] = MAX5821_EXTENDED_DAC_A;
98 else
99 outbuf[1] = MAX5821_EXTENDED_DAC_B;
100
101 if (data->powerdown[chan->channel])
102 outbuf[1] |= data->powerdown_mode[chan->channel] + 1;
103 else
104 outbuf[1] |= MAX5821_EXTENDED_POWER_UP;
105
106 return i2c_master_send(data->client, outbuf, 2);
107 }
108
max5821_write_dac_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,const char * buf,size_t len)109 static ssize_t max5821_write_dac_powerdown(struct iio_dev *indio_dev,
110 uintptr_t private,
111 const struct iio_chan_spec *chan,
112 const char *buf, size_t len)
113 {
114 struct max5821_data *data = iio_priv(indio_dev);
115 bool powerdown;
116 int ret;
117
118 ret = kstrtobool(buf, &powerdown);
119 if (ret)
120 return ret;
121
122 data->powerdown[chan->channel] = powerdown;
123
124 ret = max5821_sync_powerdown_mode(data, chan);
125 if (ret < 0)
126 return ret;
127
128 return len;
129 }
130
131 static const struct iio_chan_spec_ext_info max5821_ext_info[] = {
132 {
133 .name = "powerdown",
134 .read = max5821_read_dac_powerdown,
135 .write = max5821_write_dac_powerdown,
136 .shared = IIO_SEPARATE,
137 },
138 IIO_ENUM("powerdown_mode", IIO_SEPARATE, &max5821_powerdown_mode_enum),
139 IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE, &max5821_powerdown_mode_enum),
140 { },
141 };
142
143 #define MAX5821_CHANNEL(chan) { \
144 .type = IIO_VOLTAGE, \
145 .indexed = 1, \
146 .output = 1, \
147 .channel = (chan), \
148 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
149 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE), \
150 .ext_info = max5821_ext_info, \
151 }
152
153 static const struct iio_chan_spec max5821_channels[] = {
154 MAX5821_CHANNEL(0),
155 MAX5821_CHANNEL(1)
156 };
157
158 static const u8 max5821_read_dac_command[] = {
159 MAX5821_READ_DAC_A_COMMAND,
160 MAX5821_READ_DAC_B_COMMAND
161 };
162
163 static const u8 max5821_load_dac_command[] = {
164 MAX5821_LOAD_DAC_A_IN_REG_B,
165 MAX5821_LOAD_DAC_B_IN_REG_A
166 };
167
max5821_get_value(struct iio_dev * indio_dev,int * val,int channel)168 static int max5821_get_value(struct iio_dev *indio_dev,
169 int *val, int channel)
170 {
171 struct max5821_data *data = iio_priv(indio_dev);
172 struct i2c_client *client = data->client;
173 u8 outbuf[1];
174 u8 inbuf[2];
175 int ret;
176
177 if ((channel != 0) && (channel != 1))
178 return -EINVAL;
179
180 outbuf[0] = max5821_read_dac_command[channel];
181
182 mutex_lock(&data->lock);
183
184 ret = i2c_master_send(client, outbuf, 1);
185 if (ret < 0) {
186 mutex_unlock(&data->lock);
187 return ret;
188 } else if (ret != 1) {
189 mutex_unlock(&data->lock);
190 return -EIO;
191 }
192
193 ret = i2c_master_recv(client, inbuf, 2);
194 if (ret < 0) {
195 mutex_unlock(&data->lock);
196 return ret;
197 } else if (ret != 2) {
198 mutex_unlock(&data->lock);
199 return -EIO;
200 }
201
202 mutex_unlock(&data->lock);
203
204 *val = ((inbuf[0] & 0x0f) << 6) | (inbuf[1] >> 2);
205
206 return IIO_VAL_INT;
207 }
208
max5821_set_value(struct iio_dev * indio_dev,int val,int channel)209 static int max5821_set_value(struct iio_dev *indio_dev,
210 int val, int channel)
211 {
212 struct max5821_data *data = iio_priv(indio_dev);
213 struct i2c_client *client = data->client;
214 u8 outbuf[2];
215 int ret;
216
217 if ((val < 0) || (val > 1023))
218 return -EINVAL;
219
220 if ((channel != 0) && (channel != 1))
221 return -EINVAL;
222
223 outbuf[0] = max5821_load_dac_command[channel];
224 outbuf[0] |= val >> 6;
225 outbuf[1] = (val & 0x3f) << 2;
226
227 ret = i2c_master_send(client, outbuf, 2);
228 if (ret < 0)
229 return ret;
230 else if (ret != 2)
231 return -EIO;
232 else
233 return 0;
234 }
235
max5821_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)236 static int max5821_read_raw(struct iio_dev *indio_dev,
237 struct iio_chan_spec const *chan,
238 int *val, int *val2, long mask)
239 {
240 struct max5821_data *data = iio_priv(indio_dev);
241
242 switch (mask) {
243 case IIO_CHAN_INFO_RAW:
244 return max5821_get_value(indio_dev, val, chan->channel);
245 case IIO_CHAN_INFO_SCALE:
246 *val = data->vref_mv;
247 *val2 = 10;
248 return IIO_VAL_FRACTIONAL_LOG2;
249 default:
250 return -EINVAL;
251 }
252 }
253
max5821_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)254 static int max5821_write_raw(struct iio_dev *indio_dev,
255 struct iio_chan_spec const *chan,
256 int val, int val2, long mask)
257 {
258 if (val2 != 0)
259 return -EINVAL;
260
261 switch (mask) {
262 case IIO_CHAN_INFO_RAW:
263 return max5821_set_value(indio_dev, val, chan->channel);
264 default:
265 return -EINVAL;
266 }
267 }
268
max5821_suspend(struct device * dev)269 static int max5821_suspend(struct device *dev)
270 {
271 u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE,
272 MAX5821_EXTENDED_DAC_A |
273 MAX5821_EXTENDED_DAC_B |
274 MAX5821_EXTENDED_POWER_DOWN_MODE2 };
275
276 return i2c_master_send(to_i2c_client(dev), outbuf, 2);
277 }
278
max5821_resume(struct device * dev)279 static int max5821_resume(struct device *dev)
280 {
281 u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE,
282 MAX5821_EXTENDED_DAC_A |
283 MAX5821_EXTENDED_DAC_B |
284 MAX5821_EXTENDED_POWER_UP };
285
286 return i2c_master_send(to_i2c_client(dev), outbuf, 2);
287 }
288
289 static DEFINE_SIMPLE_DEV_PM_OPS(max5821_pm_ops, max5821_suspend,
290 max5821_resume);
291
292 static const struct iio_info max5821_info = {
293 .read_raw = max5821_read_raw,
294 .write_raw = max5821_write_raw,
295 };
296
max5821_probe(struct i2c_client * client)297 static int max5821_probe(struct i2c_client *client)
298 {
299 const struct i2c_device_id *id = i2c_client_get_device_id(client);
300 struct max5821_data *data;
301 struct iio_dev *indio_dev;
302 u32 tmp;
303 int ret;
304
305 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
306 if (!indio_dev)
307 return -ENOMEM;
308 data = iio_priv(indio_dev);
309 data->client = client;
310 mutex_init(&data->lock);
311
312 /* max5821 start in powerdown mode 100Kohm to ground */
313 for (tmp = 0; tmp < MAX5821_MAX_DAC_CHANNELS; tmp++) {
314 data->powerdown[tmp] = true;
315 data->powerdown_mode[tmp] = MAX5821_100KOHM_TO_GND;
316 }
317
318 ret = devm_regulator_get_enable_read_voltage(&client->dev, "vref");
319 if (ret)
320 return dev_err_probe(&client->dev, ret,
321 "Failed to get vref regulator voltage\n");
322
323 data->vref_mv = ret / 1000;
324
325 indio_dev->name = id->name;
326 indio_dev->num_channels = ARRAY_SIZE(max5821_channels);
327 indio_dev->channels = max5821_channels;
328 indio_dev->modes = INDIO_DIRECT_MODE;
329 indio_dev->info = &max5821_info;
330
331 return devm_iio_device_register(&client->dev, indio_dev);
332 }
333
334 static const struct i2c_device_id max5821_id[] = {
335 { "max5821", ID_MAX5821 },
336 { }
337 };
338 MODULE_DEVICE_TABLE(i2c, max5821_id);
339
340 static const struct of_device_id max5821_of_match[] = {
341 { .compatible = "maxim,max5821" },
342 { }
343 };
344 MODULE_DEVICE_TABLE(of, max5821_of_match);
345
346 static struct i2c_driver max5821_driver = {
347 .driver = {
348 .name = "max5821",
349 .of_match_table = max5821_of_match,
350 .pm = pm_sleep_ptr(&max5821_pm_ops),
351 },
352 .probe = max5821_probe,
353 .id_table = max5821_id,
354 };
355 module_i2c_driver(max5821_driver);
356
357 MODULE_AUTHOR("Philippe Reynes <[email protected]>");
358 MODULE_DESCRIPTION("MAX5821 DAC");
359 MODULE_LICENSE("GPL v2");
360