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iio: dac: add support for ltc1660

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LTC1665/LTC1660 is a 8/10-bit Digital-to-Analog Converter
(DAC) with eight individual channels.

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Marcus Folkesson 2018-08-21 21:31:24 +02:00 committed by Jonathan Cameron
parent 7ec040af6c
commit 8316cebd1e
3 changed files with 261 additions and 0 deletions
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10
drivers/iio/dac/Kconfig
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@ -120,6 +120,16 @@ config AD5624R_SPI
Say yes here to build support for Analog Devices AD5624R, AD5644R and
AD5664R converters (DAC). This driver uses the common SPI interface.
config LTC1660
tristate "Linear Technology LTC1660/LTC1665 DAC SPI driver"
depends on SPI
help
Say yes here to build support for Linear Technology
LTC1660 and LTC1665 Digital to Analog Converters.
To compile this driver as a module, choose M here: the
module will be called ltc1660.
config LTC2632
tristate "Linear Technology LTC2632-12/10/8 DAC spi driver"
depends on SPI

1
drivers/iio/dac/Makefile
View File

@ -29,6 +29,7 @@ obj-$(CONFIG_CIO_DAC) += cio-dac.o
obj-$(CONFIG_DPOT_DAC) += dpot-dac.o
obj-$(CONFIG_DS4424) += ds4424.o
obj-$(CONFIG_LPC18XX_DAC) += lpc18xx_dac.o
obj-$(CONFIG_LTC1660) += ltc1660.o
obj-$(CONFIG_LTC2632) += ltc2632.o
obj-$(CONFIG_M62332) += m62332.o
obj-$(CONFIG_MAX517) += max517.o

250
drivers/iio/dac/ltc1660.c Normal file
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@ -0,0 +1,250 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Driver for Linear Technology LTC1665/LTC1660, 8 channels DAC
*
* Copyright (C) 2018 Marcus Folkesson <marcus.folkesson@gmail.com>
*/
#include <linux/bitops.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/regulator/consumer.h>
#include <linux/regmap.h>
#include <linux/spi/spi.h>
#define LTC1660_REG_WAKE 0x0
#define LTC1660_REG_DAC_A 0x1
#define LTC1660_REG_DAC_B 0x2
#define LTC1660_REG_DAC_C 0x3
#define LTC1660_REG_DAC_D 0x4
#define LTC1660_REG_DAC_E 0x5
#define LTC1660_REG_DAC_F 0x6
#define LTC1660_REG_DAC_G 0x7
#define LTC1660_REG_DAC_H 0x8
#define LTC1660_REG_SLEEP 0xe
#define LTC1660_NUM_CHANNELS 8
static const struct regmap_config ltc1660_regmap_config = {
.reg_bits = 4,
.val_bits = 12,
};
enum ltc1660_supported_device_ids {
ID_LTC1660,
ID_LTC1665,
};
struct ltc1660_priv {
struct spi_device *spi;
struct regmap *regmap;
struct regulator *vref_reg;
unsigned int value[LTC1660_NUM_CHANNELS];
unsigned int vref_mv;
};
static int ltc1660_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val,
int *val2,
long mask)
{
struct ltc1660_priv *priv = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_RAW:
*val = priv->value[chan->channel];
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*val = regulator_get_voltage(priv->vref_reg);
if (*val < 0) {
dev_err(&priv->spi->dev, "failed to read vref regulator: %d\n",
*val);
return *val;
}
/* Convert to mV */
*val /= 1000;
*val2 = chan->scan_type.realbits;
return IIO_VAL_FRACTIONAL_LOG2;
default:
return -EINVAL;
}
}
static int ltc1660_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val,
int val2,
long mask)
{
struct ltc1660_priv *priv = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
if (val2 != 0)
return -EINVAL;
if (val < 0 || val > GENMASK(chan->scan_type.realbits - 1, 0))
return -EINVAL;
ret = regmap_write(priv->regmap, chan->channel,
(val << chan->scan_type.shift));
if (!ret)
priv->value[chan->channel] = val;
return ret;
default:
return -EINVAL;
}
}
#define LTC1660_CHAN(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), \
.scan_type = { \
.sign = 'u', \
.realbits = (bits), \
.storagebits = 16, \
.shift = 12 - (bits), \
}, \
}
#define LTC1660_OCTAL_CHANNELS(bits) { \
LTC1660_CHAN(LTC1660_REG_DAC_A, bits), \
LTC1660_CHAN(LTC1660_REG_DAC_B, bits), \
LTC1660_CHAN(LTC1660_REG_DAC_C, bits), \
LTC1660_CHAN(LTC1660_REG_DAC_D, bits), \
LTC1660_CHAN(LTC1660_REG_DAC_E, bits), \
LTC1660_CHAN(LTC1660_REG_DAC_F, bits), \
LTC1660_CHAN(LTC1660_REG_DAC_G, bits), \
LTC1660_CHAN(LTC1660_REG_DAC_H, bits), \
}
static const struct iio_chan_spec ltc1660_channels[][LTC1660_NUM_CHANNELS] = {
[ID_LTC1660] = LTC1660_OCTAL_CHANNELS(10),
[ID_LTC1665] = LTC1660_OCTAL_CHANNELS(8),
};
static const struct iio_info ltc1660_info = {
.read_raw = &ltc1660_read_raw,
.write_raw = &ltc1660_write_raw,
};
static int __maybe_unused ltc1660_suspend(struct device *dev)
{
struct ltc1660_priv *priv = iio_priv(spi_get_drvdata(
to_spi_device(dev)));
return regmap_write(priv->regmap, LTC1660_REG_SLEEP, 0x00);
}
static int __maybe_unused ltc1660_resume(struct device *dev)
{
struct ltc1660_priv *priv = iio_priv(spi_get_drvdata(
to_spi_device(dev)));
return regmap_write(priv->regmap, LTC1660_REG_WAKE, 0x00);
}
static SIMPLE_DEV_PM_OPS(ltc1660_pm_ops, ltc1660_suspend, ltc1660_resume);
static int ltc1660_probe(struct spi_device *spi)
{
struct iio_dev *indio_dev;
struct ltc1660_priv *priv;
const struct spi_device_id *id = spi_get_device_id(spi);
int ret;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*priv));
if (indio_dev == NULL)
return -ENOMEM;
priv = iio_priv(indio_dev);
priv->regmap = devm_regmap_init_spi(spi, &ltc1660_regmap_config);
if (IS_ERR(priv->regmap)) {
dev_err(&spi->dev, "failed to register spi regmap %ld\n",
PTR_ERR(priv->regmap));
return PTR_ERR(priv->regmap);
}
priv->vref_reg = devm_regulator_get(&spi->dev, "vref");
if (IS_ERR(priv->vref_reg)) {
dev_err(&spi->dev, "vref regulator not specified\n");
return PTR_ERR(priv->vref_reg);
}
ret = regulator_enable(priv->vref_reg);
if (ret) {
dev_err(&spi->dev, "failed to enable vref regulator: %d\n",
ret);
return ret;
}
priv->spi = spi;
spi_set_drvdata(spi, indio_dev);
indio_dev->dev.parent = &spi->dev;
indio_dev->info = &ltc1660_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = ltc1660_channels[id->driver_data];
indio_dev->num_channels = LTC1660_NUM_CHANNELS;
indio_dev->name = id->name;
ret = iio_device_register(indio_dev);
if (ret) {
dev_err(&spi->dev, "failed to register iio device: %d\n",
ret);
goto error_disable_reg;
}
return 0;
error_disable_reg:
regulator_disable(priv->vref_reg);
return ret;
}
static int ltc1660_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct ltc1660_priv *priv = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
regulator_disable(priv->vref_reg);
return 0;
}
static const struct of_device_id ltc1660_dt_ids[] = {
{ .compatible = "lltc,ltc1660", .data = (void *)ID_LTC1660 },
{ .compatible = "lltc,ltc1665", .data = (void *)ID_LTC1665 },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, ltc1660_dt_ids);
static const struct spi_device_id ltc1660_id[] = {
{"ltc1660", ID_LTC1660},
{"ltc1665", ID_LTC1665},
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(spi, ltc1660_id);
static struct spi_driver ltc1660_driver = {
.driver = {
.name = "ltc1660",
.of_match_table = ltc1660_dt_ids,
.pm = &ltc1660_pm_ops,
},
.probe = ltc1660_probe,
.remove = ltc1660_remove,
.id_table = ltc1660_id,
};
module_spi_driver(ltc1660_driver);
MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>");
MODULE_DESCRIPTION("Linear Technology LTC1660/LTC1665 DAC");
MODULE_LICENSE("GPL v2");