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git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
iio: dac: Support ROHM BD79703 DAC
The ROHM BD79703 is a 6 channel digital to analog converter.
Based on the data-sheet examples the hardware would support setting the
DAC word without changing the actual output. The data-sheet is not too
specific on how the enabling the output of new voltage set by DAC
should be done - hence this is not implemented by the driver.
The BD79703 would also support two specific "PULL_DOWN" modes. These
aren't currently supported by the driver either.
Add a very basic support for controlling the channel outputs one-by-one.
Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Link: https://patch.msgid.link/bc77d7b979ca28408a216f597082fcd94ec63be7.1734608215.git.mazziesaccount@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
authored by
Matti Vaittinen
and committed by
Jonathan Cameron
af6aca65
f6ed0ca1
+171
+8
drivers/iio/dac/Kconfig
+8
drivers/iio/dac/Kconfig
···
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To compile this driver as a module choose M here: the module will be called
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ad8801.
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config BD79703
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tristate "ROHM Semiconductor BD79703 DAC driver"
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depends on SPI
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select REGMAP_SPI
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help
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Say yes here to build support for ROHM Semiconductor BD79703 Digital
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to Analog Converter (DAC).
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config CIO_DAC
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tristate "Measurement Computing CIO-DAC IIO driver"
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depends on X86 && (ISA_BUS || PC104)
+1
drivers/iio/dac/Makefile
+1
drivers/iio/dac/Makefile
···
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obj-$(CONFIG_AD8801) += ad8801.o
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obj-$(CONFIG_AD9739A) += ad9739a.o
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obj-$(CONFIG_ADI_AXI_DAC) += adi-axi-dac.o
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obj-$(CONFIG_BD79703) += rohm-bd79703.o
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obj-$(CONFIG_CIO_DAC) += cio-dac.o
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obj-$(CONFIG_DPOT_DAC) += dpot-dac.o
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obj-$(CONFIG_DS4424) += ds4424.o
+162
drivers/iio/dac/rohm-bd79703.c
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drivers/iio/dac/rohm-bd79703.c
···
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* BD79703 ROHM Digital to Analog converter
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*
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* Copyright (c) 2024, ROHM Semiconductor.
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*/
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#include <linux/bits.h>
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#include <linux/device.h>
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#include <linux/module.h>
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#include <linux/regmap.h>
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#include <linux/regulator/consumer.h>
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#include <linux/spi/spi.h>
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#include <linux/iio/iio.h>
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+
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#define BD79703_MAX_REGISTER 0xf
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#define BD79703_DAC_BITS 8
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#define BD79703_REG_OUT_ALL GENMASK(2, 0)
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/*
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* The BD79703 uses 12-bit SPI commands. First four bits (high bits) define
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* channel(s) which are operated on, and also the mode. The mode can be to set
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* a DAC word only, or set DAC word and output. The data-sheet is not very
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* specific on how a previously set DAC word can be 'taken in to use'. Thus
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* this driver only uses the 'set DAC and output it' -mode.
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*
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* The BD79703 latches last 12-bits when the chip-select is toggled. Thus we
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* can use 16-bit transfers which should be widely supported. To simplify this
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* further, we treat the last 8 bits as a value, and first 8 bits as an
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* address. This allows us to separate channels/mode by address and treat the
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* 8-bit register value as DAC word. The highest 4 bits of address will be
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* discarded when the transfer is latched.
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*/
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static const struct regmap_config bd79703_regmap_config = {
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.reg_bits = 8,
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.val_bits = 8,
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.max_register = BD79703_MAX_REGISTER,
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.cache_type = REGCACHE_RBTREE,
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};
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struct bd79703_data {
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struct regmap *regmap;
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int vfs;
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};
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static int bd79703_read_raw(struct iio_dev *idev,
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struct iio_chan_spec const *chan, int *val,
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int *val2, long mask)
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{
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struct bd79703_data *data = iio_priv(idev);
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if (mask != IIO_CHAN_INFO_SCALE)
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return -EINVAL;
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*val = data->vfs / 1000;
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*val2 = BD79703_DAC_BITS;
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return IIO_VAL_FRACTIONAL_LOG2;
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}
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static int bd79703_write_raw(struct iio_dev *idev,
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struct iio_chan_spec const *chan, int val,
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int val2, long mask)
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{
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struct bd79703_data *data = iio_priv(idev);
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if (val < 0 || val >= 1 << BD79703_DAC_BITS)
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return -EINVAL;
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return regmap_write(data->regmap, chan->channel + 1, val);
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};
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static const struct iio_info bd79703_info = {
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.read_raw = bd79703_read_raw,
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.write_raw = bd79703_write_raw,
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};
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#define BD79703_CHAN(_chan) { \
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.type = IIO_VOLTAGE, \
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.indexed = 1, \
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.output = 1, \
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.channel = (_chan), \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
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.address = (_chan), \
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}
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static const struct iio_chan_spec bd79703_channels[] = {
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BD79703_CHAN(0),
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BD79703_CHAN(1),
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BD79703_CHAN(2),
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BD79703_CHAN(3),
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BD79703_CHAN(4),
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BD79703_CHAN(5),
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};
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static int bd79703_probe(struct spi_device *spi)
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{
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struct device *dev = &spi->dev;
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struct bd79703_data *data;
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struct iio_dev *idev;
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int ret;
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idev = devm_iio_device_alloc(dev, sizeof(*data));
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if (!idev)
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return -ENOMEM;
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data = iio_priv(idev);
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data->regmap = devm_regmap_init_spi(spi, &bd79703_regmap_config);
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if (IS_ERR(data->regmap))
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return dev_err_probe(dev, PTR_ERR(data->regmap),
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"Failed to initialize Regmap\n");
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ret = devm_regulator_get_enable(dev, "vcc");
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if (ret)
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return dev_err_probe(dev, ret, "Failed to enable VCC\n");
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ret = devm_regulator_get_enable_read_voltage(dev, "vfs");
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if (ret < 0)
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return dev_err_probe(dev, ret, "Failed to get Vfs\n");
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data->vfs = ret;
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idev->channels = bd79703_channels;
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idev->num_channels = ARRAY_SIZE(bd79703_channels);
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idev->modes = INDIO_DIRECT_MODE;
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idev->info = &bd79703_info;
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idev->name = "bd79703";
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/* Initialize all to output zero */
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ret = regmap_write(data->regmap, BD79703_REG_OUT_ALL, 0);
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if (ret)
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return ret;
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return devm_iio_device_register(dev, idev);
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}
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static const struct spi_device_id bd79703_id[] = {
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{ "bd79703", },
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{ }
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};
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MODULE_DEVICE_TABLE(spi, bd79703_id);
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static const struct of_device_id bd79703_of_match[] = {
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{ .compatible = "rohm,bd79703", },
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{ }
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};
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MODULE_DEVICE_TABLE(of, bd79703_of_match);
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static struct spi_driver bd79703_driver = {
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.driver = {
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.name = "bd79703",
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.of_match_table = bd79703_of_match,
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},
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.probe = bd79703_probe,
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.id_table = bd79703_id,
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};
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module_spi_driver(bd79703_driver);
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MODULE_AUTHOR("Matti Vaittinen <mazziesaccount@gmail.com>");
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MODULE_DESCRIPTION("ROHM BD79703 DAC driver");
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MODULE_LICENSE("GPL");