#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/regulator/consumer.h>
#define MAX5821_MAX_DAC_CHANNELS 2
#define MAX5821_LOAD_DAC_A_IN_REG_B 0x00
#define MAX5821_LOAD_DAC_B_IN_REG_A 0x10
#define MAX5821_EXTENDED_COMMAND_MODE 0xf0
#define MAX5821_READ_DAC_A_COMMAND 0xf1
#define MAX5821_READ_DAC_B_COMMAND 0xf2
#define MAX5821_EXTENDED_POWER_UP 0x00
#define MAX5821_EXTENDED_POWER_DOWN_MODE0 0x01
#define MAX5821_EXTENDED_POWER_DOWN_MODE1 0x02
#define MAX5821_EXTENDED_POWER_DOWN_MODE2 0x03
#define MAX5821_EXTENDED_DAC_A 0x04
#define MAX5821_EXTENDED_DAC_B 0x08
enum max5821_device_ids {
ID_MAX5821,
};
struct max5821_data {
struct i2c_client *client;
unsigned short vref_mv;
bool powerdown[MAX5821_MAX_DAC_CHANNELS];
u8 powerdown_mode[MAX5821_MAX_DAC_CHANNELS];
struct mutex lock;
};
static const char * const max5821_powerdown_modes[] = {
"three_state",
"1kohm_to_gnd",
"100kohm_to_gnd",
};
enum {
MAX5821_THREE_STATE,
MAX5821_1KOHM_TO_GND,
MAX5821_100KOHM_TO_GND
};
static int max5821_get_powerdown_mode(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan)
{
struct max5821_data *st = iio_priv(indio_dev);
return st->powerdown_mode[chan->channel];
}
static int max5821_set_powerdown_mode(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan,
unsigned int mode)
{
struct max5821_data *st = iio_priv(indio_dev);
st->powerdown_mode[chan->channel] = mode;
return 0;
}
static const struct iio_enum max5821_powerdown_mode_enum = {
.items = max5821_powerdown_modes,
.num_items = ARRAY_SIZE(max5821_powerdown_modes),
.get = max5821_get_powerdown_mode,
.set = max5821_set_powerdown_mode,
};
static ssize_t max5821_read_dac_powerdown(struct iio_dev *indio_dev,
uintptr_t private,
const struct iio_chan_spec *chan,
char *buf)
{
struct max5821_data *st = iio_priv(indio_dev);
return sysfs_emit(buf, "%d\n", st->powerdown[chan->channel]);
}
static int max5821_sync_powerdown_mode(struct max5821_data *data,
const struct iio_chan_spec *chan)
{
u8 outbuf[2];
outbuf[0] = MAX5821_EXTENDED_COMMAND_MODE;
if (chan->channel == 0)
outbuf[1] = MAX5821_EXTENDED_DAC_A;
else
outbuf[1] = MAX5821_EXTENDED_DAC_B;
if (data->powerdown[chan->channel])
outbuf[1] |= data->powerdown_mode[chan->channel] + 1;
else
outbuf[1] |= MAX5821_EXTENDED_POWER_UP;
return i2c_master_send(data->client, outbuf, 2);
}
static ssize_t max5821_write_dac_powerdown(struct iio_dev *indio_dev,
uintptr_t private,
const struct iio_chan_spec *chan,
const char *buf, size_t len)
{
struct max5821_data *data = iio_priv(indio_dev);
bool powerdown;
int ret;
ret = kstrtobool(buf, &powerdown);
if (ret)
return ret;
data->powerdown[chan->channel] = powerdown;
ret = max5821_sync_powerdown_mode(data, chan);
if (ret < 0)
return ret;
return len;
}
static const struct iio_chan_spec_ext_info max5821_ext_info[] = {
{
.name = "powerdown",
.read = max5821_read_dac_powerdown,
.write = max5821_write_dac_powerdown,
.shared = IIO_SEPARATE,
},
IIO_ENUM("powerdown_mode", IIO_SEPARATE, &max5821_powerdown_mode_enum),
IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE, &max5821_powerdown_mode_enum),
{ }
};
#define MAX5821_CHANNEL(chan) { \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.output = 1, \
.channel = (chan), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE), \
.ext_info = max5821_ext_info, \
}
static const struct iio_chan_spec max5821_channels[] = {
MAX5821_CHANNEL(0),
MAX5821_CHANNEL(1)
};
static const u8 max5821_read_dac_command[] = {
MAX5821_READ_DAC_A_COMMAND,
MAX5821_READ_DAC_B_COMMAND
};
static const u8 max5821_load_dac_command[] = {
MAX5821_LOAD_DAC_A_IN_REG_B,
MAX5821_LOAD_DAC_B_IN_REG_A
};
static int max5821_get_value(struct iio_dev *indio_dev,
int *val, int channel)
{
struct max5821_data *data = iio_priv(indio_dev);
struct i2c_client *client = data->client;
u8 outbuf[1];
u8 inbuf[2];
int ret;
if ((channel != 0) && (channel != 1))
return -EINVAL;
outbuf[0] = max5821_read_dac_command[channel];
mutex_lock(&data->lock);
ret = i2c_master_send(client, outbuf, 1);
if (ret < 0) {
mutex_unlock(&data->lock);
return ret;
} else if (ret != 1) {
mutex_unlock(&data->lock);
return -EIO;
}
ret = i2c_master_recv(client, inbuf, 2);
if (ret < 0) {
mutex_unlock(&data->lock);
return ret;
} else if (ret != 2) {
mutex_unlock(&data->lock);
return -EIO;
}
mutex_unlock(&data->lock);
*val = ((inbuf[0] & 0x0f) << 6) | (inbuf[1] >> 2);
return IIO_VAL_INT;
}
static int max5821_set_value(struct iio_dev *indio_dev,
int val, int channel)
{
struct max5821_data *data = iio_priv(indio_dev);
struct i2c_client *client = data->client;
u8 outbuf[2];
int ret;
if ((val < 0) || (val > 1023))
return -EINVAL;
if ((channel != 0) && (channel != 1))
return -EINVAL;
outbuf[0] = max5821_load_dac_command[channel];
outbuf[0] |= val >> 6;
outbuf[1] = (val & 0x3f) << 2;
ret = i2c_master_send(client, outbuf, 2);
if (ret < 0)
return ret;
else if (ret != 2)
return -EIO;
else
return 0;
}
static int max5821_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct max5821_data *data = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_RAW:
return max5821_get_value(indio_dev, val, chan->channel);
case IIO_CHAN_INFO_SCALE:
*val = data->vref_mv;
*val2 = 10;
return IIO_VAL_FRACTIONAL_LOG2;
default:
return -EINVAL;
}
}
static int max5821_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
if (val2 != 0)
return -EINVAL;
switch (mask) {
case IIO_CHAN_INFO_RAW:
return max5821_set_value(indio_dev, val, chan->channel);
default:
return -EINVAL;
}
}
static int max5821_suspend(struct device *dev)
{
u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE,
MAX5821_EXTENDED_DAC_A |
MAX5821_EXTENDED_DAC_B |
MAX5821_EXTENDED_POWER_DOWN_MODE2 };
return i2c_master_send(to_i2c_client(dev), outbuf, 2);
}
static int max5821_resume(struct device *dev)
{
u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE,
MAX5821_EXTENDED_DAC_A |
MAX5821_EXTENDED_DAC_B |
MAX5821_EXTENDED_POWER_UP };
return i2c_master_send(to_i2c_client(dev), outbuf, 2);
}
static DEFINE_SIMPLE_DEV_PM_OPS(max5821_pm_ops, max5821_suspend,
max5821_resume);
static const struct iio_info max5821_info = {
.read_raw = max5821_read_raw,
.write_raw = max5821_write_raw,
};
static int max5821_probe(struct i2c_client *client)
{
const struct i2c_device_id *id = i2c_client_get_device_id(client);
struct max5821_data *data;
struct iio_dev *indio_dev;
u32 tmp;
int ret;
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
data = iio_priv(indio_dev);
data->client = client;
mutex_init(&data->lock);
for (tmp = 0; tmp < MAX5821_MAX_DAC_CHANNELS; tmp++) {
data->powerdown[tmp] = true;
data->powerdown_mode[tmp] = MAX5821_100KOHM_TO_GND;
}
ret = devm_regulator_get_enable_read_voltage(&client->dev, "vref");
if (ret)
return dev_err_probe(&client->dev, ret,
"Failed to get vref regulator voltage\n");
data->vref_mv = ret / 1000;
indio_dev->name = id->name;
indio_dev->num_channels = ARRAY_SIZE(max5821_channels);
indio_dev->channels = max5821_channels;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &max5821_info;
return devm_iio_device_register(&client->dev, indio_dev);
}
static const struct i2c_device_id max5821_id[] = {
{ "max5821", ID_MAX5821 },
{ }
};
MODULE_DEVICE_TABLE(i2c, max5821_id);
static const struct of_device_id max5821_of_match[] = {
{ .compatible = "maxim,max5821" },
{ }
};
MODULE_DEVICE_TABLE(of, max5821_of_match);
static struct i2c_driver max5821_driver = {
.driver = {
.name = "max5821",
.of_match_table = max5821_of_match,
.pm = pm_sleep_ptr(&max5821_pm_ops),
},
.probe = max5821_probe,
.id_table = max5821_id,
};
module_i2c_driver(max5821_driver);
MODULE_AUTHOR("Philippe Reynes <tremyfr@yahoo.fr>");
MODULE_DESCRIPTION("MAX5821 DAC");
MODULE_LICENSE("GPL v2");
