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iio: add MCP4728 I2C DAC driver

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MCP4728 is a 12-bit quad channel DAC with I2C interface.

support for:
 * per-channel gain
 * per-channel power state
 * per-channel power down mode control
 * per-channel vref selection internal/vdd
 * store current state to on-chip EEPROM

Signed-off-by: Andrea Collamati <andrea.collamati@gmail.com>
Link: https://lore.kernel.org/r/a0933003ed3c855f9d80d6ce0a40add2b6f0ba36.1691066050.git.andrea.collamati@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Andrea Collamati 2023-08-03 14:56:35 +02:00 committed by Jonathan Cameron
parent 74d4cd7a91
commit 7b24a034ad
3 changed files with 630 additions and 0 deletions
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11
drivers/iio/dac/Kconfig
View File

@ -389,6 +389,17 @@ config MCP4725
To compile this driver as a module, choose M here: the module
will be called mcp4725.
config MCP4728
tristate "MCP4728 DAC driver"
depends on I2C
help
Say Y here if you want to build a driver for the Microchip
MCP4728 quad channel, 12-bit digital-to-analog converter (DAC)
with I2C interface.
To compile this driver as a module, choose M here: the module
will be called mcp4728.
config MCP4922
tristate "MCP4902, MCP4912, MCP4922 DAC driver"
depends on SPI

1
drivers/iio/dac/Makefile
View File

@ -41,6 +41,7 @@ obj-$(CONFIG_MAX517) += max517.o
obj-$(CONFIG_MAX5522) += max5522.o
obj-$(CONFIG_MAX5821) += max5821.o
obj-$(CONFIG_MCP4725) += mcp4725.o
obj-$(CONFIG_MCP4728) += mcp4728.o
obj-$(CONFIG_MCP4922) += mcp4922.o
obj-$(CONFIG_STM32_DAC_CORE) += stm32-dac-core.o
obj-$(CONFIG_STM32_DAC) += stm32-dac.o

618
drivers/iio/dac/mcp4728.c Normal file
View File

@ -0,0 +1,618 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* Support for Microchip MCP4728
*
* Copyright (C) 2023 Andrea Collamati <andrea.collamati@gmail.com>
*
* Based on mcp4725 by Peter Meerwald <pmeerw@pmeerw.net>
*
* Driver for the Microchip I2C 12-bit digital-to-analog quad channels
* converter (DAC).
*
* (7-bit I2C slave address 0x60, the three LSBs can be configured in
* hardware)
*/
#include <linux/bitfield.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/property.h>
#include <linux/regulator/consumer.h>
#define MCP4728_RESOLUTION 12
#define MCP4728_N_CHANNELS 4
#define MCP4728_CMD_MASK GENMASK(7, 3)
#define MCP4728_CHSEL_MASK GENMASK(2, 1)
#define MCP4728_UDAC_MASK BIT(0)
#define MCP4728_VREF_MASK BIT(7)
#define MCP4728_PDMODE_MASK GENMASK(6, 5)
#define MCP4728_GAIN_MASK BIT(4)
#define MCP4728_DAC_H_MASK GENMASK(3, 0)
#define MCP4728_DAC_L_MASK GENMASK(7, 0)
#define MCP4728_RDY_MASK BIT(7)
#define MCP4728_MW_CMD 0x08 /* Multiwrite Command */
#define MCP4728_SW_CMD 0x0A /* Sequential Write Command with EEPROM */
#define MCP4728_READ_RESPONSE_LEN (MCP4728_N_CHANNELS * 3 * 2)
#define MCP4728_WRITE_EEPROM_LEN (1 + MCP4728_N_CHANNELS * 2)
enum vref_mode {
MCP4728_VREF_EXTERNAL_VDD = 0,
MCP4728_VREF_INTERNAL_2048mV = 1,
};
enum gain_mode {
MCP4728_GAIN_X1 = 0,
MCP4728_GAIN_X2 = 1,
};
enum iio_powerdown_mode {
MCP4728_IIO_1K,
MCP4728_IIO_100K,
MCP4728_IIO_500K,
};
struct mcp4728_channel_data {
enum vref_mode ref_mode;
enum iio_powerdown_mode pd_mode;
enum gain_mode g_mode;
u16 dac_value;
};
/* MCP4728 Full Scale Ranges
* the device available ranges are
* - VREF = VDD FSR = from 0.0V to VDD
* - VREF = Internal Gain = 1 FSR = from 0.0V to VREF
* - VREF = Internal Gain = 2 FSR = from 0.0V to 2*VREF
*/
enum mcp4728_scale {
MCP4728_SCALE_VDD,
MCP4728_SCALE_VINT_NO_GAIN,
MCP4728_SCALE_VINT_GAIN_X2,
MCP4728_N_SCALES
};
struct mcp4728_data {
struct i2c_client *client;
struct regulator *vdd_reg;
bool powerdown;
int scales_avail[MCP4728_N_SCALES * 2];
struct mcp4728_channel_data chdata[MCP4728_N_CHANNELS];
};
#define MCP4728_CHAN(chan) { \
.type = IIO_VOLTAGE, \
.output = 1, \
.indexed = 1, \
.channel = chan, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
BIT(IIO_CHAN_INFO_SCALE), \
.info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SCALE), \
.ext_info = mcp4728_ext_info, \
}
static int mcp4728_suspend(struct device *dev);
static int mcp4728_resume(struct device *dev);
static ssize_t mcp4728_store_eeprom(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct mcp4728_data *data = iio_priv(indio_dev);
u8 outbuf[MCP4728_WRITE_EEPROM_LEN];
int tries = 20;
u8 inbuf[3];
bool state;
int ret;
unsigned int i;
ret = kstrtobool(buf, &state);
if (ret < 0)
return ret;
if (!state)
return 0;
outbuf[0] = FIELD_PREP(MCP4728_CMD_MASK, MCP4728_SW_CMD);
for (i = 0; i < MCP4728_N_CHANNELS; i++) {
struct mcp4728_channel_data *ch = &data->chdata[i];
int offset = 1 + i * 2;
outbuf[offset] = FIELD_PREP(MCP4728_VREF_MASK, ch->ref_mode);
if (data->powerdown) {
u8 mcp4728_pd_mode = ch->pd_mode + 1;
outbuf[offset] |= FIELD_PREP(MCP4728_PDMODE_MASK,
mcp4728_pd_mode);
}
outbuf[offset] |= FIELD_PREP(MCP4728_GAIN_MASK, ch->g_mode);
outbuf[offset] |=
FIELD_PREP(MCP4728_DAC_H_MASK, ch->dac_value >> 8);
outbuf[offset + 1] =
FIELD_PREP(MCP4728_DAC_L_MASK, ch->dac_value);
}
ret = i2c_master_send(data->client, outbuf, MCP4728_WRITE_EEPROM_LEN);
if (ret < 0)
return ret;
else if (ret != MCP4728_WRITE_EEPROM_LEN)
return -EIO;
/* wait RDY signal for write complete, takes up to 50ms */
while (tries--) {
msleep(20);
ret = i2c_master_recv(data->client, inbuf, 3);
if (ret < 0)
return ret;
else if (ret != 3)
return -EIO;
if (FIELD_GET(MCP4728_RDY_MASK, inbuf[0]))
break;
}
if (tries < 0) {
dev_err(&data->client->dev, "%s failed, incomplete\n",
__func__);
return -EIO;
}
return len;
}
static IIO_DEVICE_ATTR(store_eeprom, 0200, NULL, mcp4728_store_eeprom, 0);
static struct attribute *mcp4728_attributes[] = {
&iio_dev_attr_store_eeprom.dev_attr.attr,
NULL,
};
static const struct attribute_group mcp4728_attribute_group = {
.attrs = mcp4728_attributes,
};
static int mcp4728_program_channel_cfg(int channel, struct iio_dev *indio_dev)
{
struct mcp4728_data *data = iio_priv(indio_dev);
struct mcp4728_channel_data *ch = &data->chdata[channel];
u8 outbuf[3];
int ret;
outbuf[0] = FIELD_PREP(MCP4728_CMD_MASK, MCP4728_MW_CMD);
outbuf[0] |= FIELD_PREP(MCP4728_CHSEL_MASK, channel);
outbuf[0] |= FIELD_PREP(MCP4728_UDAC_MASK, 0);
outbuf[1] = FIELD_PREP(MCP4728_VREF_MASK, ch->ref_mode);
if (data->powerdown)
outbuf[1] |= FIELD_PREP(MCP4728_PDMODE_MASK, ch->pd_mode + 1);
outbuf[1] |= FIELD_PREP(MCP4728_GAIN_MASK, ch->g_mode);
outbuf[1] |= FIELD_PREP(MCP4728_DAC_H_MASK, ch->dac_value >> 8);
outbuf[2] = FIELD_PREP(MCP4728_DAC_L_MASK, ch->dac_value);
ret = i2c_master_send(data->client, outbuf, 3);
if (ret < 0)
return ret;
else if (ret != 3)
return -EIO;
return 0;
}
static const char *const mcp4728_powerdown_modes[] = { "1kohm_to_gnd",
"100kohm_to_gnd",
"500kohm_to_gnd" };
static int mcp4728_get_powerdown_mode(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan)
{
struct mcp4728_data *data = iio_priv(indio_dev);
return data->chdata[chan->channel].pd_mode;
}
static int mcp4728_set_powerdown_mode(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan,
unsigned int mode)
{
struct mcp4728_data *data = iio_priv(indio_dev);
data->chdata[chan->channel].pd_mode = mode;
return 0;
}
static ssize_t mcp4728_read_powerdown(struct iio_dev *indio_dev,
uintptr_t private,
const struct iio_chan_spec *chan,
char *buf)
{
struct mcp4728_data *data = iio_priv(indio_dev);
return sysfs_emit(buf, "%d\n", data->powerdown);
}
static ssize_t mcp4728_write_powerdown(struct iio_dev *indio_dev,
uintptr_t private,
const struct iio_chan_spec *chan,
const char *buf, size_t len)
{
struct mcp4728_data *data = iio_priv(indio_dev);
bool state;
int ret;
ret = kstrtobool(buf, &state);
if (ret)
return ret;
if (state)
ret = mcp4728_suspend(&data->client->dev);
else
ret = mcp4728_resume(&data->client->dev);
if (ret < 0)
return ret;
return len;
}
static const struct iio_enum mcp4728_powerdown_mode_enum = {
.items = mcp4728_powerdown_modes,
.num_items = ARRAY_SIZE(mcp4728_powerdown_modes),
.get = mcp4728_get_powerdown_mode,
.set = mcp4728_set_powerdown_mode,
};
static const struct iio_chan_spec_ext_info mcp4728_ext_info[] = {
{
.name = "powerdown",
.read = mcp4728_read_powerdown,
.write = mcp4728_write_powerdown,
.shared = IIO_SEPARATE,
},
IIO_ENUM("powerdown_mode", IIO_SEPARATE, &mcp4728_powerdown_mode_enum),
IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
&mcp4728_powerdown_mode_enum),
{},
};
static const struct iio_chan_spec mcp4728_channels[MCP4728_N_CHANNELS] = {
MCP4728_CHAN(0),
MCP4728_CHAN(1),
MCP4728_CHAN(2),
MCP4728_CHAN(3),
};
static void mcp4728_get_scale_avail(enum mcp4728_scale scale,
struct mcp4728_data *data, int *val,
int *val2)
{
*val = data->scales_avail[scale * 2];
*val2 = data->scales_avail[scale * 2 + 1];
}
static void mcp4728_get_scale(int channel, struct mcp4728_data *data, int *val,
int *val2)
{
int ref_mode = data->chdata[channel].ref_mode;
int g_mode = data->chdata[channel].g_mode;
if (ref_mode == MCP4728_VREF_EXTERNAL_VDD) {
mcp4728_get_scale_avail(MCP4728_SCALE_VDD, data, val, val2);
} else {
if (g_mode == MCP4728_GAIN_X1) {
mcp4728_get_scale_avail(MCP4728_SCALE_VINT_NO_GAIN,
data, val, val2);
} else {
mcp4728_get_scale_avail(MCP4728_SCALE_VINT_GAIN_X2,
data, val, val2);
}
}
}
static int mcp4728_find_matching_scale(struct mcp4728_data *data, int val,
int val2)
{
for (int i = 0; i < MCP4728_N_SCALES; i++) {
if (data->scales_avail[i * 2] == val &&
data->scales_avail[i * 2 + 1] == val2)
return i;
}
return -EINVAL;
}
static int mcp4728_set_scale(int channel, struct mcp4728_data *data, int val,
int val2)
{
int scale = mcp4728_find_matching_scale(data, val, val2);
if (scale < 0)
return scale;
switch (scale) {
case MCP4728_SCALE_VDD:
data->chdata[channel].ref_mode = MCP4728_VREF_EXTERNAL_VDD;
return 0;
case MCP4728_SCALE_VINT_NO_GAIN:
data->chdata[channel].ref_mode = MCP4728_VREF_INTERNAL_2048mV;
data->chdata[channel].g_mode = MCP4728_GAIN_X1;
return 0;
case MCP4728_SCALE_VINT_GAIN_X2:
data->chdata[channel].ref_mode = MCP4728_VREF_INTERNAL_2048mV;
data->chdata[channel].g_mode = MCP4728_GAIN_X2;
return 0;
default:
return -EINVAL;
}
}
static int mcp4728_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val,
int *val2, long mask)
{
struct mcp4728_data *data = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_RAW:
*val = data->chdata[chan->channel].dac_value;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
mcp4728_get_scale(chan->channel, data, val, val2);
return IIO_VAL_INT_PLUS_MICRO;
}
return -EINVAL;
}
static int mcp4728_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int val,
int val2, long mask)
{
struct mcp4728_data *data = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
if (val < 0 || val > GENMASK(MCP4728_RESOLUTION - 1, 0))
return -EINVAL;
data->chdata[chan->channel].dac_value = val;
return mcp4728_program_channel_cfg(chan->channel, indio_dev);
case IIO_CHAN_INFO_SCALE:
ret = mcp4728_set_scale(chan->channel, data, val, val2);
if (ret)
return ret;
return mcp4728_program_channel_cfg(chan->channel, indio_dev);
default:
return -EINVAL;
}
}
static void mcp4728_init_scale_avail(enum mcp4728_scale scale, int vref_mv,
struct mcp4728_data *data)
{
s64 tmp;
int value_micro;
int value_int;
tmp = (s64)vref_mv * 1000000LL >> MCP4728_RESOLUTION;
value_int = div_s64_rem(tmp, 1000000LL, &value_micro);
data->scales_avail[scale * 2] = value_int;
data->scales_avail[scale * 2 + 1] = value_micro;
}
static int mcp4728_init_scales_avail(struct mcp4728_data *data)
{
int ret;
ret = regulator_get_voltage(data->vdd_reg);
if (ret < 0)
return ret;
mcp4728_init_scale_avail(MCP4728_SCALE_VDD, ret / 1000, data);
mcp4728_init_scale_avail(MCP4728_SCALE_VINT_NO_GAIN, 2048, data);
mcp4728_init_scale_avail(MCP4728_SCALE_VINT_GAIN_X2, 4096, data);
return 0;
}
static int mcp4728_read_avail(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
const int **vals, int *type, int *length,
long info)
{
struct mcp4728_data *data = iio_priv(indio_dev);
switch (info) {
case IIO_CHAN_INFO_SCALE:
*type = IIO_VAL_INT_PLUS_MICRO;
switch (chan->type) {
case IIO_VOLTAGE:
*vals = data->scales_avail;
*length = MCP4728_N_SCALES * 2;
return IIO_AVAIL_LIST;
default:
return -EINVAL;
}
default:
return -EINVAL;
}
}
static const struct iio_info mcp4728_info = {
.read_raw = mcp4728_read_raw,
.write_raw = mcp4728_write_raw,
.read_avail = &mcp4728_read_avail,
.attrs = &mcp4728_attribute_group,
};
static int mcp4728_suspend(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct mcp4728_data *data = iio_priv(indio_dev);
unsigned int i;
data->powerdown = true;
for (i = 0; i < MCP4728_N_CHANNELS; i++) {
int err = mcp4728_program_channel_cfg(i, indio_dev);
if (err)
return err;
}
return 0;
}
static int mcp4728_resume(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct mcp4728_data *data = iio_priv(indio_dev);
int err = 0;
unsigned int i;
data->powerdown = false;
for (i = 0; i < MCP4728_N_CHANNELS; i++) {
int ret = mcp4728_program_channel_cfg(i, indio_dev);
if (ret)
err = ret;
}
return err;
}
static DEFINE_SIMPLE_DEV_PM_OPS(mcp4728_pm_ops, mcp4728_suspend,
mcp4728_resume);
static int mcp4728_init_channels_data(struct mcp4728_data *data)
{
u8 inbuf[MCP4728_READ_RESPONSE_LEN];
int ret;
unsigned int i;
ret = i2c_master_recv(data->client, inbuf, MCP4728_READ_RESPONSE_LEN);
if (ret < 0) {
return dev_err_probe(&data->client->dev, ret,
"failed to read mcp4728 conf.\n");
} else if (ret != MCP4728_READ_RESPONSE_LEN) {
return dev_err_probe(&data->client->dev, -EIO,
"failed to read mcp4728 conf. Wrong Response Len ret=%d\n",
ret);
}
for (i = 0; i < MCP4728_N_CHANNELS; i++) {
struct mcp4728_channel_data *ch = &data->chdata[i];
u8 r2 = inbuf[i * 6 + 1];
u8 r3 = inbuf[i * 6 + 2];
ch->dac_value = FIELD_GET(MCP4728_DAC_H_MASK, r2) << 8 |
FIELD_GET(MCP4728_DAC_L_MASK, r3);
ch->ref_mode = FIELD_GET(MCP4728_VREF_MASK, r2);
ch->pd_mode = FIELD_GET(MCP4728_PDMODE_MASK, r2);
ch->g_mode = FIELD_GET(MCP4728_GAIN_MASK, r2);
}
return 0;
}
static void mcp4728_reg_disable(void *reg)
{
regulator_disable(reg);
}
static int mcp4728_probe(struct i2c_client *client)
{
const struct i2c_device_id *id = i2c_client_get_device_id(client);
struct mcp4728_data *data;
struct iio_dev *indio_dev;
int err;
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
data = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
data->client = client;
data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
if (IS_ERR(data->vdd_reg))
return PTR_ERR(data->vdd_reg);
err = regulator_enable(data->vdd_reg);
if (err)
return err;
err = devm_add_action_or_reset(&client->dev, mcp4728_reg_disable,
data->vdd_reg);
if (err)
return err;
/*
* MCP4728 has internal EEPROM that save each channel boot
* configuration. It means that device configuration is unknown to the
* driver at kernel boot. mcp4728_init_channels_data() reads back DAC
* settings and stores them in data structure.
*/
err = mcp4728_init_channels_data(data);
if (err) {
return dev_err_probe(&client->dev, err,
"failed to read mcp4728 current configuration\n");
}
err = mcp4728_init_scales_avail(data);
if (err) {
return dev_err_probe(&client->dev, err,
"failed to init scales\n");
}
indio_dev->name = id->name;
indio_dev->info = &mcp4728_info;
indio_dev->channels = mcp4728_channels;
indio_dev->num_channels = MCP4728_N_CHANNELS;
indio_dev->modes = INDIO_DIRECT_MODE;
return devm_iio_device_register(&client->dev, indio_dev);
}
static const struct i2c_device_id mcp4728_id[] = {
{ "mcp4728", 0 },
{}
};
MODULE_DEVICE_TABLE(i2c, mcp4728_id);
static const struct of_device_id mcp4728_of_match[] = {
{ .compatible = "microchip,mcp4728" },
{}
};
MODULE_DEVICE_TABLE(of, mcp4728_of_match);
static struct i2c_driver mcp4728_driver = {
.driver = {
.name = "mcp4728",
.of_match_table = mcp4728_of_match,
.pm = pm_sleep_ptr(&mcp4728_pm_ops),
},
.probe = mcp4728_probe,
.id_table = mcp4728_id,
};
module_i2c_driver(mcp4728_driver);
MODULE_AUTHOR("Andrea Collamati <andrea.collamati@gmail.com>");
MODULE_DESCRIPTION("MCP4728 12-bit DAC");
MODULE_LICENSE("GPL");