/*
* LTC2632 Digital to analog convertors spi driver
*
* Copyright 2017 Maxime Roussin-Bélanger
* expanded by Silvan Murer <silvan.murer@gmail.com>
*
* Licensed under the GPL-2.
*/
#include <linux/device.h>
#include <linux/spi/spi.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/regulator/consumer.h>
#define LTC2632_DAC_CHANNELS 2
#define LTC2632_ADDR_DAC0 0x0
#define LTC2632_ADDR_DAC1 0x1
#define LTC2632_CMD_WRITE_INPUT_N 0x0
#define LTC2632_CMD_UPDATE_DAC_N 0x1
#define LTC2632_CMD_WRITE_INPUT_N_UPDATE_ALL 0x2
#define LTC2632_CMD_WRITE_INPUT_N_UPDATE_N 0x3
#define LTC2632_CMD_POWERDOWN_DAC_N 0x4
#define LTC2632_CMD_POWERDOWN_CHIP 0x5
#define LTC2632_CMD_INTERNAL_REFER 0x6
#define LTC2632_CMD_EXTERNAL_REFER 0x7
/**
* struct ltc2632_chip_info - chip specific information
* @channels: channel spec for the DAC
* @vref_mv: internal reference voltage
*/
struct ltc2632_chip_info {
const struct iio_chan_spec *channels;
const int vref_mv;
};
/**
* struct ltc2632_state - driver instance specific data
* @spi_dev: pointer to the spi_device struct
* @powerdown_cache_mask used to show current channel powerdown state
* @vref_mv used reference voltage (internal or external)
* @vref_reg regulator for the reference voltage
*/
struct ltc2632_state {
struct spi_device *spi_dev;
unsigned int powerdown_cache_mask;
int vref_mv;
struct regulator *vref_reg;
};
enum ltc2632_supported_device_ids {
ID_LTC2632L12,
ID_LTC2632L10,
ID_LTC2632L8,
ID_LTC2632H12,
ID_LTC2632H10,
ID_LTC2632H8,
};
static int ltc2632_spi_write(struct spi_device *spi,
u8 cmd, u8 addr, u16 val, u8 shift)
{
u32 data;
u8 msg[3];
/*
* The input shift register is 24 bits wide.
* The next four are the command bits, C3 to C0,
* followed by the 4-bit DAC address, A3 to A0, and then the
* 12-, 10-, 8-bit data-word. The data-word comprises the 12-,
* 10-, 8-bit input code followed by 4, 6, or 8 don't care bits.
*/
data = (cmd << 20) | (addr << 16) | (val << shift);
msg[0] = data >> 16;
msg[1] = data >> 8;
msg[2] = data;
return spi_write(spi, msg, sizeof(msg));
}
static int ltc2632_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val,
int *val2,
long m)
{
const struct ltc2632_state *st = iio_priv(indio_dev);
switch (m) {
case IIO_CHAN_INFO_SCALE:
*val = st->vref_mv;
*val2 = chan->scan_type.realbits;
return IIO_VAL_FRACTIONAL_LOG2;
}
return -EINVAL;
}
static int ltc2632_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val,
int val2,
long mask)
{
struct ltc2632_state *st = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_RAW:
if (val >= (1 << chan->scan_type.realbits) || val < 0)
return -EINVAL;
return ltc2632_spi_write(st->spi_dev,
LTC2632_CMD_WRITE_INPUT_N_UPDATE_N,
chan->address, val,
chan->scan_type.shift);
default:
return -EINVAL;
}
}
static ssize_t ltc2632_read_dac_powerdown(struct iio_dev *indio_dev,
uintptr_t private,
const struct iio_chan_spec *chan,
char *buf)
{
struct ltc2632_state *st = iio_priv(indio_dev);
return sprintf(buf, "%d\n",
!!(st->powerdown_cache_mask & (1 << chan->channel)));
}
static ssize_t ltc2632_write_dac_powerdown(struct iio_dev *indio_dev,
uintptr_t private,
const struct iio_chan_spec *chan,
const char *buf,
size_t len)
{
bool pwr_down;
int ret;
struct ltc2632_state *st = iio_priv(indio_dev);
ret = strtobool(buf, &pwr_down);
if (ret)
return ret;
if (pwr_down)
st->powerdown_cache_mask |= (1 << chan->channel);
else
st->powerdown_cache_mask &= ~(1 << chan->channel);
ret = ltc2632_spi_write(st->spi_dev,
LTC2632_CMD_POWERDOWN_DAC_N,
chan->channel, 0, 0);
return ret ? ret : len;
}
static const struct iio_info ltc2632_info = {
.write_raw = ltc2632_write_raw,
.read_raw = ltc2632_read_raw,
};
static const struct iio_chan_spec_ext_info ltc2632_ext_info[] = {
{
.name = "powerdown",
.read = ltc2632_read_dac_powerdown,
.write = ltc2632_write_dac_powerdown,
.shared = IIO_SEPARATE,
},
{ },
};
#define LTC2632_CHANNEL(_chan, _bits) { \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.output = 1, \
.channel = (_chan), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.address = (_chan), \
.scan_type = { \
.realbits = (_bits), \
.shift = 16 - (_bits), \
}, \
.ext_info = ltc2632_ext_info, \
}
#define DECLARE_LTC2632_CHANNELS(_name, _bits) \
const struct iio_chan_spec _name ## _channels[] = { \
LTC2632_CHANNEL(0, _bits), \
LTC2632_CHANNEL(1, _bits), \
}
static DECLARE_LTC2632_CHANNELS(ltc2632l12, 12);
static DECLARE_LTC2632_CHANNELS(ltc2632l10, 10);
static DECLARE_LTC2632_CHANNELS(ltc2632l8, 8);
static DECLARE_LTC2632_CHANNELS(ltc2632h12, 12);
static DECLARE_LTC2632_CHANNELS(ltc2632h10, 10);
static DECLARE_LTC2632_CHANNELS(ltc2632h8, 8);
static const struct ltc2632_chip_info ltc2632_chip_info_tbl[] = {
[ID_LTC2632L12] = {
.channels = ltc2632l12_channels,
.vref_mv = 2500,
},
[ID_LTC2632L10] = {
.channels = ltc2632l10_channels,
.vref_mv = 2500,
},
[ID_LTC2632L8] = {
.channels = ltc2632l8_channels,
.vref_mv = 2500,
},
[ID_LTC2632H12] = {
.channels = ltc2632h12_channels,
.vref_mv = 4096,
},
[ID_LTC2632H10] = {
.channels = ltc2632h10_channels,
.vref_mv = 4096,
},
[ID_LTC2632H8] = {
.channels = ltc2632h8_channels,
.vref_mv = 4096,
},
};
static int ltc2632_probe(struct spi_device *spi)
{
struct ltc2632_state *st;
struct iio_dev *indio_dev;
struct ltc2632_chip_info *chip_info;
int ret;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
st = iio_priv(indio_dev);
spi_set_drvdata(spi, indio_dev);
st->spi_dev = spi;
chip_info = (struct ltc2632_chip_info *)
spi_get_device_id(spi)->driver_data;
st->vref_reg = devm_regulator_get_optional(&spi->dev, "vref");
if (PTR_ERR(st->vref_reg) == -ENODEV) {
/* use internal reference voltage */
st->vref_reg = NULL;
st->vref_mv = chip_info->vref_mv;
ret = ltc2632_spi_write(spi, LTC2632_CMD_INTERNAL_REFER,
0, 0, 0);
if (ret) {
dev_err(&spi->dev,
"Set internal reference command failed, %d\n",
ret);
return ret;
}
} else if (IS_ERR(st->vref_reg)) {
dev_err(&spi->dev,
"Error getting voltage reference regulator\n");
return PTR_ERR(st->vref_reg);
} else {
/* use external reference voltage */
ret = regulator_enable(st->vref_reg);
if (ret) {
dev_err(&spi->dev,
"enable reference regulator failed, %d\n",
ret);
return ret;
}
st->vref_mv = regulator_get_voltage(st->vref_reg) / 1000;
ret = ltc2632_spi_write(spi, LTC2632_CMD_EXTERNAL_REFER,
0, 0, 0);
if (ret) {
dev_err(&spi->dev,
"Set external reference command failed, %d\n",
ret);
return ret;
}
}
indio_dev->dev.parent = &spi->dev;
indio_dev->name = dev_of_node(&spi->dev) ? dev_of_node(&spi->dev)->name
: spi_get_device_id(spi)->name;
indio_dev->info = <c2632_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = chip_info->channels;
indio_dev->num_channels = LTC2632_DAC_CHANNELS;
return iio_device_register(indio_dev);
}
static int ltc2632_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct ltc2632_state *st = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
if (st->vref_reg)
regulator_disable(st->vref_reg);
return 0;
}
static const struct spi_device_id ltc2632_id[] = {
{ "ltc2632-l12", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632L12] },
{ "ltc2632-l10", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632L10] },
{ "ltc2632-l8", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632L8] },
{ "ltc2632-h12", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632H12] },
{ "ltc2632-h10", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632H10] },
{ "ltc2632-h8", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632H8] },
{}
};
MODULE_DEVICE_TABLE(spi, ltc2632_id);
static const struct of_device_id ltc2632_of_match[] = {
{
.compatible = "lltc,ltc2632-l12",
.data = <c2632_chip_info_tbl[ID_LTC2632L12]
}, {
.compatible = "lltc,ltc2632-l10",
.data = <c2632_chip_info_tbl[ID_LTC2632L10]
}, {
.compatible = "lltc,ltc2632-l8",
.data = <c2632_chip_info_tbl[ID_LTC2632L8]
}, {
.compatible = "lltc,ltc2632-h12",
.data = <c2632_chip_info_tbl[ID_LTC2632H12]
}, {
.compatible = "lltc,ltc2632-h10",
.data = <c2632_chip_info_tbl[ID_LTC2632H10]
}, {
.compatible = "lltc,ltc2632-h8",
.data = <c2632_chip_info_tbl[ID_LTC2632H8]
},
{}
};
MODULE_DEVICE_TABLE(of, ltc2632_of_match);
static struct spi_driver ltc2632_driver = {
.driver = {
.name = "ltc2632",
.of_match_table = of_match_ptr(ltc2632_of_match),
},
.probe = ltc2632_probe,
.remove = ltc2632_remove,
.id_table = ltc2632_id,
};
module_spi_driver(ltc2632_driver);
MODULE_AUTHOR("Maxime Roussin-Belanger <maxime.roussinbelanger@gmail.com>");
MODULE_DESCRIPTION("LTC2632 DAC SPI driver");
MODULE_LICENSE("GPL v2");
