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Wed, 25 Mar 2026 04:01:52 -0700 (PDT) Message-ID: <1920a90a223c1394004d269895df54eee720125a.camel@gmail.com> Subject: Re: [PATCH v3 2/2] iio: dac: ad5706r: Add support for AD5706R DAC From: Nuno =?ISO-8859-1?Q?S=E1?= To: Alexis Czezar Torreno , Lars-Peter Clausen , Michael Hennerich , Jonathan Cameron , David Lechner , Nuno =?ISO-8859-1?Q?S=E1?= , Andy Shevchenko , Rob Herring , Krzysztof Kozlowski , Conor Dooley Cc: linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 25 Mar 2026 11:02:38 +0000 In-Reply-To: <20260318-dev_ad5706r-v3-2-5d078f41e988@analog.com> References: <20260318-dev_ad5706r-v3-0-5d078f41e988@analog.com> <20260318-dev_ad5706r-v3-2-5d078f41e988@analog.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.58.3 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Wed, 2026-03-18 at 13:13 +0800, Alexis Czezar Torreno wrote: > Add support for the Analog Devices AD5706R, a 4-channel 16-bit > current output digital-to-analog converter with SPI interface. >=20 > Features: > =C2=A0 - 4 independent DAC channels > =C2=A0 - Hardware and software LDAC trigger > =C2=A0 - Configurable output range > =C2=A0 - PWM-based LDAC control > =C2=A0 - Dither and toggle modes > =C2=A0 - Dynamically configurable SPI speed >=20 > Signed-off-by: Alexis Czezar Torreno >=20 > --- Not sure if everyone is aware of this but AI review in: https://sashiko.dev/#/patchset/20260318-dev_ad5706r-v3-0-5d078f41e988%40ana= log.com The DMA comment is an interesting one. Likely it needs improvement in the r= eview-prompt repo given it's one of those case we know what we're doing (at least we think we know = :)).=C2=A0Still has a point in that IIO_DMA_MINALIGN should be used. At some point we need to add some IIO specific bits :) - Nuno S=C3=A1 > Changes since v1: > =C2=A0 - Removed PWM, GPIO, clock generator, debugfs, regmap, IIO_BUFFER > =C2=A0 - Removed all custom ext_info sysfs attributes > =C2=A0 - Simplified to basic raw read/write and read-only scale > =C2=A0 - SPI read/write can handle multibyte registers > --- > --- > =C2=A0MAINTAINERS=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 |=C2=A0=C2=A0 1 + > =C2=A0drivers/iio/dac/Kconfig=C2=A0=C2=A0 |=C2=A0 10 +++ > =C2=A0drivers/iio/dac/Makefile=C2=A0 |=C2=A0=C2=A0 1 + > =C2=A0drivers/iio/dac/ad5706r.c | 222 +++++++++++++++++++++++++++++++++++= +++++++++++ > =C2=A04 files changed, 234 insertions(+) >=20 > diff --git a/MAINTAINERS b/MAINTAINERS > index 17a3d2d45fccb9cd3c93fd35666fb85d17d53cde..3d7bd98b4d1b55836e40687a9= a3ac9f4935a8acb 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -1502,6 +1502,7 @@ L: linux-iio@vger.kernel.org > =C2=A0S: Supported > =C2=A0W: https://ez.analog.com/linux-software-drivers > =C2=A0F: Documentation/devicetree/bindings/iio/dac/adi,ad5706r.yaml > +F: drivers/iio/dac/ad5706r.c > =C2=A0 > =C2=A0ANALOG DEVICES INC AD7091R DRIVER > =C2=A0M: Marcelo Schmitt > diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig > index db9f5c711b3df90641f017652fbbef594cc1627d..8ccbdf6dfbca8640a47bf05b4= afc6b4bf90a7e26 100644 > --- a/drivers/iio/dac/Kconfig > +++ b/drivers/iio/dac/Kconfig > @@ -178,6 +178,16 @@ config AD5624R_SPI > =C2=A0 =C2=A0 Say yes here to build support for Analog Devices AD5624R, A= D5644R and > =C2=A0 =C2=A0 AD5664R converters (DAC). This driver uses the common SPI i= nterface. > =C2=A0 > +config AD5706R > + tristate "Analog Devices AD5706R DAC driver" > + depends on SPI > + help > + =C2=A0 Say yes here to build support for Analog Devices AD5706R 4-chann= el, > + =C2=A0 16-bit current output DAC. > + > + =C2=A0 To compile this driver as a module, choose M here: the > + =C2=A0 module will be called ad5706r. > + > =C2=A0config AD9739A > =C2=A0 tristate "Analog Devices AD9739A RF DAC spi driver" > =C2=A0 depends on SPI > diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile > index 2a80bbf4e80ad557da79ed916027cedff286984b..0034317984985035f7987a744= 899924bfd4612e3 100644 > --- a/drivers/iio/dac/Makefile > +++ b/drivers/iio/dac/Makefile > @@ -21,6 +21,7 @@ obj-$(CONFIG_AD5449) +=3D ad5449.o > =C2=A0obj-$(CONFIG_AD5592R_BASE) +=3D ad5592r-base.o > =C2=A0obj-$(CONFIG_AD5592R) +=3D ad5592r.o > =C2=A0obj-$(CONFIG_AD5593R) +=3D ad5593r.o > +obj-$(CONFIG_AD5706R) +=3D ad5706r.o > =C2=A0obj-$(CONFIG_AD5755) +=3D ad5755.o > =C2=A0obj-$(CONFIG_AD5758) +=3D ad5758.o > =C2=A0obj-$(CONFIG_AD5761) +=3D ad5761.o > diff --git a/drivers/iio/dac/ad5706r.c b/drivers/iio/dac/ad5706r.c > new file mode 100644 > index 0000000000000000000000000000000000000000..840ee7b6db2e05ea35b27ff77= 6f0c5c8a961d9c1 > --- /dev/null > +++ b/drivers/iio/dac/ad5706r.c > @@ -0,0 +1,222 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * AD5706R 16-bit Current Output Digital to Analog Converter > + * > + * Copyright 2026 Analog Devices Inc. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +/* SPI frame layout */ > +#define AD5706R_RD_MASK BIT(15) > +#define AD5706R_ADDR_MASK GENMASK(11, 0) > + > +/* Registers */ > +#define AD5706R_REG_DAC_INPUT_A_CH(x) (0x60 + ((x) * 2)) > +#define AD5706R_REG_DAC_DATA_READBACK_CH(x) (0x68 + ((x) * 2)) > + > +#define AD5706R_DAC_RESOLUTION 16 > +#define AD5706R_DAC_MAX_CODE BIT(16) > +#define AD5706R_MULTIBYTE_REG_START 0x14 > +#define AD5706R_MULTIBYTE_REG_END 0x71 > +#define AD5706R_SINGLE_BYTE_LEN 1 > +#define AD5706R_DOUBLE_BYTE_LEN 2 > + > +struct ad5706r_state { > + struct spi_device *spi; > + struct mutex lock; /* Protects SPI transfers */ > + > + u8 tx_buf[4] __aligned(ARCH_DMA_MINALIGN); > + u8 rx_buf[2]; > +}; > + > +static int ad5706r_reg_len(unsigned int reg) > +{ > + if (reg >=3D AD5706R_MULTIBYTE_REG_START && reg <=3D AD5706R_MULTIBYTE_= REG_END) > + return AD5706R_DOUBLE_BYTE_LEN; > + > + return AD5706R_SINGLE_BYTE_LEN; > +} > + > +static int ad5706r_spi_write(struct ad5706r_state *st, u16 reg, u16 val) > +{ > + unsigned int num_bytes =3D ad5706r_reg_len(reg); > + struct spi_transfer xfer =3D { > + .tx_buf =3D st->tx_buf, > + .len =3D num_bytes + 2, > + }; > + > + put_unaligned_be16(reg, &st->tx_buf[0]); > + > + if (num_bytes =3D=3D 1) > + st->tx_buf[2] =3D val; > + else if (num_bytes =3D=3D 2) > + put_unaligned_be16(val, &st->tx_buf[2]); > + else > + return -EINVAL; > + > + return spi_sync_transfer(st->spi, &xfer, 1); > +} > + > +static int ad5706r_spi_read(struct ad5706r_state *st, u16 reg, u16 *val) > +{ > + unsigned int num_bytes =3D ad5706r_reg_len(reg); > + u16 cmd; > + int ret; > + > + struct spi_transfer xfer[] =3D { > + { > + .tx_buf =3D st->tx_buf, > + .len =3D 2, > + }, > + { > + .rx_buf =3D st->rx_buf, > + .len =3D num_bytes, > + }, > + }; > + > + cmd =3D AD5706R_RD_MASK | (reg & AD5706R_ADDR_MASK); > + put_unaligned_be16(cmd, &st->tx_buf[0]); > + > + ret =3D spi_sync_transfer(st->spi, xfer, ARRAY_SIZE(xfer)); > + if (ret) > + return ret; > + > + if (num_bytes =3D=3D 1) > + *val =3D st->rx_buf[0]; > + else if (num_bytes =3D=3D 2) > + *val =3D get_unaligned_be16(st->rx_buf); > + else > + return -EINVAL; > + > + return 0; > +} > + > +static int ad5706r_read_raw(struct iio_dev *indio_dev, > + =C2=A0=C2=A0=C2=A0 struct iio_chan_spec const *chan, int *val, > + =C2=A0=C2=A0=C2=A0 int *val2, long mask) > +{ > + struct ad5706r_state *st =3D iio_priv(indio_dev); > + u16 reg_val; > + int ret; > + > + switch (mask) { > + case IIO_CHAN_INFO_RAW: > + scoped_guard(mutex, &st->lock) { > + ret =3D ad5706r_spi_read(st, AD5706R_REG_DAC_DATA_READBACK_CH(chan- > >channel), > + =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 ®_val); > + > + if (ret) > + return ret; > + > + *val =3D reg_val; > + } > + return IIO_VAL_INT; > + case IIO_CHAN_INFO_SCALE: > + *val =3D 50; > + *val2 =3D AD5706R_DAC_RESOLUTION; > + return IIO_VAL_FRACTIONAL_LOG2; > + } > + > + return -EINVAL; > +} > + > +static int ad5706r_write_raw(struct iio_dev *indio_dev, > + =C2=A0=C2=A0=C2=A0=C2=A0 struct iio_chan_spec const *chan, int val, > + =C2=A0=C2=A0=C2=A0=C2=A0 int val2, long mask) > +{ > + struct ad5706r_state *st =3D iio_priv(indio_dev); > + > + switch (mask) { > + case IIO_CHAN_INFO_RAW: > + if (val < 0 || val >=3D AD5706R_DAC_MAX_CODE) > + return -EINVAL; > + > + guard(mutex)(&st->lock); > + return ad5706r_spi_write(st, > + AD5706R_REG_DAC_INPUT_A_CH(chan->channel), > + val); > + default: > + return -EINVAL; > + } > +} > + > +static const struct iio_info ad5706r_info =3D { > + .read_raw =3D ad5706r_read_raw, > + .write_raw =3D ad5706r_write_raw, > +}; > + > +#define AD5706R_CHAN(_channel) { \ > + .type =3D IIO_CURRENT, \ > + .info_mask_separate =3D BIT(IIO_CHAN_INFO_RAW) | \ > + =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 BIT(IIO_CHAN_INFO_SCALE), \ > + .output =3D 1, \ > + .indexed =3D 1, \ > + .channel =3D _channel, \ > +} > + > +static const struct iio_chan_spec ad5706r_channels[] =3D { > + AD5706R_CHAN(0), > + AD5706R_CHAN(1), > + AD5706R_CHAN(2), > + AD5706R_CHAN(3), > +}; > + > +static int ad5706r_probe(struct spi_device *spi) > +{ > + struct iio_dev *indio_dev; > + struct ad5706r_state *st; > + int ret; > + > + indio_dev =3D devm_iio_device_alloc(&spi->dev, sizeof(*st)); > + if (!indio_dev) > + return -ENOMEM; > + > + st =3D iio_priv(indio_dev); > + st->spi =3D spi; > + > + ret =3D devm_mutex_init(&spi->dev, &st->lock); > + if (ret) > + return ret; > + > + indio_dev->name =3D "ad5706r"; > + indio_dev->info =3D &ad5706r_info; > + indio_dev->modes =3D INDIO_DIRECT_MODE; > + indio_dev->channels =3D ad5706r_channels; > + indio_dev->num_channels =3D ARRAY_SIZE(ad5706r_channels); > + > + return devm_iio_device_register(&spi->dev, indio_dev); > +} > + > +static const struct of_device_id ad5706r_of_match[] =3D { > + { .compatible =3D "adi,ad5706r" }, > + {} > +}; > +MODULE_DEVICE_TABLE(of, ad5706r_of_match); > + > +static const struct spi_device_id ad5706r_id[] =3D { > + { "ad5706r" }, > + {} > +}; > +MODULE_DEVICE_TABLE(spi, ad5706r_id); > + > +static struct spi_driver ad5706r_driver =3D { > + .driver =3D { > + .name =3D "ad5706r", > + .of_match_table =3D ad5706r_of_match, > + }, > + .probe =3D ad5706r_probe, > + .id_table =3D ad5706r_id, > +}; > +module_spi_driver(ad5706r_driver); > + > +MODULE_AUTHOR("Alexis Czezar Torreno ")= ; > +MODULE_DESCRIPTION("AD5706R 16-bit Current Output DAC driver"); > +MODULE_LICENSE("GPL");