1 // SPDX-License-Identifier: GPL-2.0-only
3 * Support for Microchip MCP4728
5 * Copyright (C) 2023 Andrea Collamati <andrea.collamati@gmail.com>
7 * Based on mcp4725 by Peter Meerwald <pmeerw@pmeerw.net>
9 * Driver for the Microchip I2C 12-bit digital-to-analog quad channels
12 * (7-bit I2C slave address 0x60, the three LSBs can be configured in
16 #include <linux/bitfield.h>
17 #include <linux/delay.h>
18 #include <linux/err.h>
19 #include <linux/i2c.h>
20 #include <linux/iio/iio.h>
21 #include <linux/iio/sysfs.h>
22 #include <linux/module.h>
23 #include <linux/mod_devicetable.h>
24 #include <linux/property.h>
25 #include <linux/regulator/consumer.h>
27 #define MCP4728_RESOLUTION 12
28 #define MCP4728_N_CHANNELS 4
30 #define MCP4728_CMD_MASK GENMASK(7, 3)
31 #define MCP4728_CHSEL_MASK GENMASK(2, 1)
32 #define MCP4728_UDAC_MASK BIT(0)
34 #define MCP4728_VREF_MASK BIT(7)
35 #define MCP4728_PDMODE_MASK GENMASK(6, 5)
36 #define MCP4728_GAIN_MASK BIT(4)
38 #define MCP4728_DAC_H_MASK GENMASK(3, 0)
39 #define MCP4728_DAC_L_MASK GENMASK(7, 0)
41 #define MCP4728_RDY_MASK BIT(7)
43 #define MCP4728_MW_CMD 0x08 /* Multiwrite Command */
44 #define MCP4728_SW_CMD 0x0A /* Sequential Write Command with EEPROM */
46 #define MCP4728_READ_RESPONSE_LEN (MCP4728_N_CHANNELS * 3 * 2)
47 #define MCP4728_WRITE_EEPROM_LEN (1 + MCP4728_N_CHANNELS * 2)
50 MCP4728_VREF_EXTERNAL_VDD = 0,
51 MCP4728_VREF_INTERNAL_2048mV = 1,
59 enum iio_powerdown_mode {
65 struct mcp4728_channel_data {
66 enum vref_mode ref_mode;
67 enum iio_powerdown_mode pd_mode;
68 enum gain_mode g_mode;
72 /* MCP4728 Full Scale Ranges
73 * the device available ranges are
74 * - VREF = VDD FSR = from 0.0V to VDD
75 * - VREF = Internal Gain = 1 FSR = from 0.0V to VREF
76 * - VREF = Internal Gain = 2 FSR = from 0.0V to 2*VREF
80 MCP4728_SCALE_VINT_NO_GAIN,
81 MCP4728_SCALE_VINT_GAIN_X2,
86 struct i2c_client *client;
87 struct regulator *vdd_reg;
89 int scales_avail[MCP4728_N_SCALES * 2];
90 struct mcp4728_channel_data chdata[MCP4728_N_CHANNELS];
93 #define MCP4728_CHAN(chan) { \
94 .type = IIO_VOLTAGE, \
98 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
99 BIT(IIO_CHAN_INFO_SCALE), \
100 .info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SCALE), \
101 .ext_info = mcp4728_ext_info, \
104 static int mcp4728_suspend(struct device *dev);
105 static int mcp4728_resume(struct device *dev);
107 static ssize_t mcp4728_store_eeprom(struct device *dev,
108 struct device_attribute *attr,
109 const char *buf, size_t len)
111 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
112 struct mcp4728_data *data = iio_priv(indio_dev);
113 u8 outbuf[MCP4728_WRITE_EEPROM_LEN];
120 ret = kstrtobool(buf, &state);
127 outbuf[0] = FIELD_PREP(MCP4728_CMD_MASK, MCP4728_SW_CMD);
129 for (i = 0; i < MCP4728_N_CHANNELS; i++) {
130 struct mcp4728_channel_data *ch = &data->chdata[i];
131 int offset = 1 + i * 2;
133 outbuf[offset] = FIELD_PREP(MCP4728_VREF_MASK, ch->ref_mode);
135 if (data->powerdown) {
136 u8 mcp4728_pd_mode = ch->pd_mode + 1;
138 outbuf[offset] |= FIELD_PREP(MCP4728_PDMODE_MASK,
142 outbuf[offset] |= FIELD_PREP(MCP4728_GAIN_MASK, ch->g_mode);
144 FIELD_PREP(MCP4728_DAC_H_MASK, ch->dac_value >> 8);
146 FIELD_PREP(MCP4728_DAC_L_MASK, ch->dac_value);
149 ret = i2c_master_send(data->client, outbuf, MCP4728_WRITE_EEPROM_LEN);
152 else if (ret != MCP4728_WRITE_EEPROM_LEN)
155 /* wait RDY signal for write complete, takes up to 50ms */
158 ret = i2c_master_recv(data->client, inbuf, 3);
164 if (FIELD_GET(MCP4728_RDY_MASK, inbuf[0]))
169 dev_err(&data->client->dev, "%s failed, incomplete\n",
176 static IIO_DEVICE_ATTR(store_eeprom, 0200, NULL, mcp4728_store_eeprom, 0);
178 static struct attribute *mcp4728_attributes[] = {
179 &iio_dev_attr_store_eeprom.dev_attr.attr,
183 static const struct attribute_group mcp4728_attribute_group = {
184 .attrs = mcp4728_attributes,
187 static int mcp4728_program_channel_cfg(int channel, struct iio_dev *indio_dev)
189 struct mcp4728_data *data = iio_priv(indio_dev);
190 struct mcp4728_channel_data *ch = &data->chdata[channel];
194 outbuf[0] = FIELD_PREP(MCP4728_CMD_MASK, MCP4728_MW_CMD);
195 outbuf[0] |= FIELD_PREP(MCP4728_CHSEL_MASK, channel);
196 outbuf[0] |= FIELD_PREP(MCP4728_UDAC_MASK, 0);
198 outbuf[1] = FIELD_PREP(MCP4728_VREF_MASK, ch->ref_mode);
201 outbuf[1] |= FIELD_PREP(MCP4728_PDMODE_MASK, ch->pd_mode + 1);
203 outbuf[1] |= FIELD_PREP(MCP4728_GAIN_MASK, ch->g_mode);
204 outbuf[1] |= FIELD_PREP(MCP4728_DAC_H_MASK, ch->dac_value >> 8);
205 outbuf[2] = FIELD_PREP(MCP4728_DAC_L_MASK, ch->dac_value);
207 ret = i2c_master_send(data->client, outbuf, 3);
216 static const char *const mcp4728_powerdown_modes[] = { "1kohm_to_gnd",
220 static int mcp4728_get_powerdown_mode(struct iio_dev *indio_dev,
221 const struct iio_chan_spec *chan)
223 struct mcp4728_data *data = iio_priv(indio_dev);
225 return data->chdata[chan->channel].pd_mode;
228 static int mcp4728_set_powerdown_mode(struct iio_dev *indio_dev,
229 const struct iio_chan_spec *chan,
232 struct mcp4728_data *data = iio_priv(indio_dev);
234 data->chdata[chan->channel].pd_mode = mode;
239 static ssize_t mcp4728_read_powerdown(struct iio_dev *indio_dev,
241 const struct iio_chan_spec *chan,
244 struct mcp4728_data *data = iio_priv(indio_dev);
246 return sysfs_emit(buf, "%d\n", data->powerdown);
249 static ssize_t mcp4728_write_powerdown(struct iio_dev *indio_dev,
251 const struct iio_chan_spec *chan,
252 const char *buf, size_t len)
254 struct mcp4728_data *data = iio_priv(indio_dev);
258 ret = kstrtobool(buf, &state);
263 ret = mcp4728_suspend(&data->client->dev);
265 ret = mcp4728_resume(&data->client->dev);
273 static const struct iio_enum mcp4728_powerdown_mode_enum = {
274 .items = mcp4728_powerdown_modes,
275 .num_items = ARRAY_SIZE(mcp4728_powerdown_modes),
276 .get = mcp4728_get_powerdown_mode,
277 .set = mcp4728_set_powerdown_mode,
280 static const struct iio_chan_spec_ext_info mcp4728_ext_info[] = {
283 .read = mcp4728_read_powerdown,
284 .write = mcp4728_write_powerdown,
285 .shared = IIO_SEPARATE,
287 IIO_ENUM("powerdown_mode", IIO_SEPARATE, &mcp4728_powerdown_mode_enum),
288 IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
289 &mcp4728_powerdown_mode_enum),
293 static const struct iio_chan_spec mcp4728_channels[MCP4728_N_CHANNELS] = {
300 static void mcp4728_get_scale_avail(enum mcp4728_scale scale,
301 struct mcp4728_data *data, int *val,
304 *val = data->scales_avail[scale * 2];
305 *val2 = data->scales_avail[scale * 2 + 1];
308 static void mcp4728_get_scale(int channel, struct mcp4728_data *data, int *val,
311 int ref_mode = data->chdata[channel].ref_mode;
312 int g_mode = data->chdata[channel].g_mode;
314 if (ref_mode == MCP4728_VREF_EXTERNAL_VDD) {
315 mcp4728_get_scale_avail(MCP4728_SCALE_VDD, data, val, val2);
317 if (g_mode == MCP4728_GAIN_X1) {
318 mcp4728_get_scale_avail(MCP4728_SCALE_VINT_NO_GAIN,
321 mcp4728_get_scale_avail(MCP4728_SCALE_VINT_GAIN_X2,
327 static int mcp4728_find_matching_scale(struct mcp4728_data *data, int val,
330 for (int i = 0; i < MCP4728_N_SCALES; i++) {
331 if (data->scales_avail[i * 2] == val &&
332 data->scales_avail[i * 2 + 1] == val2)
338 static int mcp4728_set_scale(int channel, struct mcp4728_data *data, int val,
341 int scale = mcp4728_find_matching_scale(data, val, val2);
347 case MCP4728_SCALE_VDD:
348 data->chdata[channel].ref_mode = MCP4728_VREF_EXTERNAL_VDD;
350 case MCP4728_SCALE_VINT_NO_GAIN:
351 data->chdata[channel].ref_mode = MCP4728_VREF_INTERNAL_2048mV;
352 data->chdata[channel].g_mode = MCP4728_GAIN_X1;
354 case MCP4728_SCALE_VINT_GAIN_X2:
355 data->chdata[channel].ref_mode = MCP4728_VREF_INTERNAL_2048mV;
356 data->chdata[channel].g_mode = MCP4728_GAIN_X2;
363 static int mcp4728_read_raw(struct iio_dev *indio_dev,
364 struct iio_chan_spec const *chan, int *val,
365 int *val2, long mask)
367 struct mcp4728_data *data = iio_priv(indio_dev);
370 case IIO_CHAN_INFO_RAW:
371 *val = data->chdata[chan->channel].dac_value;
373 case IIO_CHAN_INFO_SCALE:
374 mcp4728_get_scale(chan->channel, data, val, val2);
375 return IIO_VAL_INT_PLUS_MICRO;
380 static int mcp4728_write_raw(struct iio_dev *indio_dev,
381 struct iio_chan_spec const *chan, int val,
384 struct mcp4728_data *data = iio_priv(indio_dev);
388 case IIO_CHAN_INFO_RAW:
389 if (val < 0 || val > GENMASK(MCP4728_RESOLUTION - 1, 0))
391 data->chdata[chan->channel].dac_value = val;
392 return mcp4728_program_channel_cfg(chan->channel, indio_dev);
393 case IIO_CHAN_INFO_SCALE:
394 ret = mcp4728_set_scale(chan->channel, data, val, val2);
398 return mcp4728_program_channel_cfg(chan->channel, indio_dev);
404 static void mcp4728_init_scale_avail(enum mcp4728_scale scale, int vref_mv,
405 struct mcp4728_data *data)
411 tmp = (s64)vref_mv * 1000000LL >> MCP4728_RESOLUTION;
412 value_int = div_s64_rem(tmp, 1000000LL, &value_micro);
414 data->scales_avail[scale * 2] = value_int;
415 data->scales_avail[scale * 2 + 1] = value_micro;
418 static int mcp4728_init_scales_avail(struct mcp4728_data *data)
422 ret = regulator_get_voltage(data->vdd_reg);
426 mcp4728_init_scale_avail(MCP4728_SCALE_VDD, ret / 1000, data);
427 mcp4728_init_scale_avail(MCP4728_SCALE_VINT_NO_GAIN, 2048, data);
428 mcp4728_init_scale_avail(MCP4728_SCALE_VINT_GAIN_X2, 4096, data);
433 static int mcp4728_read_avail(struct iio_dev *indio_dev,
434 struct iio_chan_spec const *chan,
435 const int **vals, int *type, int *length,
438 struct mcp4728_data *data = iio_priv(indio_dev);
441 case IIO_CHAN_INFO_SCALE:
442 *type = IIO_VAL_INT_PLUS_MICRO;
444 switch (chan->type) {
446 *vals = data->scales_avail;
447 *length = MCP4728_N_SCALES * 2;
448 return IIO_AVAIL_LIST;
457 static const struct iio_info mcp4728_info = {
458 .read_raw = mcp4728_read_raw,
459 .write_raw = mcp4728_write_raw,
460 .read_avail = &mcp4728_read_avail,
461 .attrs = &mcp4728_attribute_group,
464 static int mcp4728_suspend(struct device *dev)
466 struct iio_dev *indio_dev = dev_get_drvdata(dev);
467 struct mcp4728_data *data = iio_priv(indio_dev);
470 data->powerdown = true;
472 for (i = 0; i < MCP4728_N_CHANNELS; i++) {
473 int err = mcp4728_program_channel_cfg(i, indio_dev);
481 static int mcp4728_resume(struct device *dev)
483 struct iio_dev *indio_dev = dev_get_drvdata(dev);
484 struct mcp4728_data *data = iio_priv(indio_dev);
488 data->powerdown = false;
490 for (i = 0; i < MCP4728_N_CHANNELS; i++) {
491 int ret = mcp4728_program_channel_cfg(i, indio_dev);
499 static DEFINE_SIMPLE_DEV_PM_OPS(mcp4728_pm_ops, mcp4728_suspend,
502 static int mcp4728_init_channels_data(struct mcp4728_data *data)
504 u8 inbuf[MCP4728_READ_RESPONSE_LEN];
508 ret = i2c_master_recv(data->client, inbuf, MCP4728_READ_RESPONSE_LEN);
510 return dev_err_probe(&data->client->dev, ret,
511 "failed to read mcp4728 conf.\n");
512 } else if (ret != MCP4728_READ_RESPONSE_LEN) {
513 return dev_err_probe(&data->client->dev, -EIO,
514 "failed to read mcp4728 conf. Wrong Response Len ret=%d\n",
518 for (i = 0; i < MCP4728_N_CHANNELS; i++) {
519 struct mcp4728_channel_data *ch = &data->chdata[i];
520 u8 r2 = inbuf[i * 6 + 1];
521 u8 r3 = inbuf[i * 6 + 2];
523 ch->dac_value = FIELD_GET(MCP4728_DAC_H_MASK, r2) << 8 |
524 FIELD_GET(MCP4728_DAC_L_MASK, r3);
525 ch->ref_mode = FIELD_GET(MCP4728_VREF_MASK, r2);
526 ch->pd_mode = FIELD_GET(MCP4728_PDMODE_MASK, r2);
527 ch->g_mode = FIELD_GET(MCP4728_GAIN_MASK, r2);
533 static void mcp4728_reg_disable(void *reg)
535 regulator_disable(reg);
538 static int mcp4728_probe(struct i2c_client *client)
540 const struct i2c_device_id *id = i2c_client_get_device_id(client);
541 struct mcp4728_data *data;
542 struct iio_dev *indio_dev;
545 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
549 data = iio_priv(indio_dev);
550 i2c_set_clientdata(client, indio_dev);
551 data->client = client;
553 data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
554 if (IS_ERR(data->vdd_reg))
555 return PTR_ERR(data->vdd_reg);
557 err = regulator_enable(data->vdd_reg);
561 err = devm_add_action_or_reset(&client->dev, mcp4728_reg_disable,
567 * MCP4728 has internal EEPROM that save each channel boot
568 * configuration. It means that device configuration is unknown to the
569 * driver at kernel boot. mcp4728_init_channels_data() reads back DAC
570 * settings and stores them in data structure.
572 err = mcp4728_init_channels_data(data);
574 return dev_err_probe(&client->dev, err,
575 "failed to read mcp4728 current configuration\n");
578 err = mcp4728_init_scales_avail(data);
580 return dev_err_probe(&client->dev, err,
581 "failed to init scales\n");
584 indio_dev->name = id->name;
585 indio_dev->info = &mcp4728_info;
586 indio_dev->channels = mcp4728_channels;
587 indio_dev->num_channels = MCP4728_N_CHANNELS;
588 indio_dev->modes = INDIO_DIRECT_MODE;
590 return devm_iio_device_register(&client->dev, indio_dev);
593 static const struct i2c_device_id mcp4728_id[] = {
597 MODULE_DEVICE_TABLE(i2c, mcp4728_id);
599 static const struct of_device_id mcp4728_of_match[] = {
600 { .compatible = "microchip,mcp4728" },
603 MODULE_DEVICE_TABLE(of, mcp4728_of_match);
605 static struct i2c_driver mcp4728_driver = {
608 .of_match_table = mcp4728_of_match,
609 .pm = pm_sleep_ptr(&mcp4728_pm_ops),
611 .probe = mcp4728_probe,
612 .id_table = mcp4728_id,
614 module_i2c_driver(mcp4728_driver);
616 MODULE_AUTHOR("Andrea Collamati <andrea.collamati@gmail.com>");
617 MODULE_DESCRIPTION("MCP4728 12-bit DAC");
618 MODULE_LICENSE("GPL");