On Tue, 2024-06-25 at 18:55 -0300, Marcelo Schmitt wrote: > Add support for AD4000 series of low noise, low power, high speed, > successive approximation register (SAR) ADCs. > > Signed-off-by: Marcelo Schmitt <marcelo.schmitt@xxxxxxxxxx> > --- > MAINTAINERS | 1 + > drivers/iio/adc/Kconfig | 12 + > drivers/iio/adc/Makefile | 1 + > drivers/iio/adc/ad4000.c | 711 +++++++++++++++++++++++++++++++++++++++ > 4 files changed, 725 insertions(+) > create mode 100644 drivers/iio/adc/ad4000.c > > diff --git a/MAINTAINERS b/MAINTAINERS > index 9aa6531f7cf2..f4ffedada8ea 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -1205,6 +1205,7 @@ L: linux-iio@xxxxxxxxxxxxxxx > S: Supported > W: https://ez.analog.com/linux-software-drivers > F: Documentation/devicetree/bindings/iio/adc/adi,ad4000.yaml > +F: drivers/iio/adc/ad4000.c > > ANALOG DEVICES INC AD4130 DRIVER > M: Cosmin Tanislav <cosmin.tanislav@xxxxxxxxxx> > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig > index b8184706c7d1..5bbe843916a3 100644 > --- a/drivers/iio/adc/Kconfig > +++ b/drivers/iio/adc/Kconfig > @@ -21,6 +21,18 @@ config AD_SIGMA_DELTA > select IIO_BUFFER > select IIO_TRIGGERED_BUFFER > > +config AD4000 > + tristate "Analog Devices AD4000 ADC Driver" > + depends on SPI > + select IIO_BUFFER > + select IIO_TRIGGERED_BUFFER > + help > + Say yes here to build support for Analog Devices AD4000 high speed > + SPI analog to digital converters (ADC). > + > + To compile this driver as a module, choose M here: the module will > be > + called ad4000. > + > config AD4130 > tristate "Analog Device AD4130 ADC Driver" > depends on SPI > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile > index 51298c52b223..f4361df40cca 100644 > --- a/drivers/iio/adc/Makefile > +++ b/drivers/iio/adc/Makefile > @@ -6,6 +6,7 @@ > # When adding new entries keep the list in alphabetical order > obj-$(CONFIG_AB8500_GPADC) += ab8500-gpadc.o > obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o > +obj-$(CONFIG_AD4000) += ad4000.o > obj-$(CONFIG_AD4130) += ad4130.o > obj-$(CONFIG_AD7091R) += ad7091r-base.o > obj-$(CONFIG_AD7091R5) += ad7091r5.o > diff --git a/drivers/iio/adc/ad4000.c b/drivers/iio/adc/ad4000.c > new file mode 100644 > index 000000000000..0b6293db68dc > --- /dev/null > +++ b/drivers/iio/adc/ad4000.c > @@ -0,0 +1,711 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * AD4000 SPI ADC driver > + * > + * Copyright 2024 Analog Devices Inc. > + */ > +#include <linux/bits.h> > +#include <linux/bitfield.h> > +#include <linux/byteorder/generic.h> > +#include <linux/device.h> > +#include <linux/err.h> > +#include <linux/math.h> > +#include <linux/module.h> > +#include <linux/mod_devicetable.h> > +#include <linux/gpio/consumer.h> > +#include <linux/regulator/consumer.h> > +#include <linux/spi/spi.h> > +#include <linux/units.h> > +#include <linux/util_macros.h> > +#include <linux/iio/iio.h> > + > +#include <linux/iio/buffer.h> > +#include <linux/iio/triggered_buffer.h> > +#include <linux/iio/trigger_consumer.h> > + > ... > + > +static int ad4000_read_reg(struct ad4000_state *st, unsigned int *val) > +{ > + struct spi_transfer t = { > + .tx_buf = st->tx_buf, > + .rx_buf = st->rx_buf, > + .len = 2, > + }; > + int ret; > + > + st->tx_buf[0] = AD4000_READ_COMMAND; > + ret = spi_sync_transfer(st->spi, &t, 1); > + if (ret < 0) > + return ret; > + > + *val = st->tx_buf[1]; I'm puzzled... tx_buf? > + return ret; > +} > + > +/* > + * This executes a data sample transfer for when the device connections are > + * in "3-wire" mode, selected when the adi,sdi-pin device tree property is > + * absent or set to "high". In this connection mode, the ADC SDI pin is > + * connected to MOSI or to VIO and ADC CNV pin is connected either to a SPI > + * controller CS or to a GPIO. > + * AD4000 series of devices initiate conversions on the rising edge of CNV > pin. > + * > + * If the CNV pin is connected to an SPI controller CS line (which is by > default > + * active low), the ADC readings would have a latency (delay) of one read. > + * Moreover, since we also do ADC sampling for filling the buffer on > triggered > + * buffer mode, the timestamps of buffer readings would be disarranged. > + * To prevent the read latency and reduce the time discrepancy between the > + * sample read request and the time of actual sampling by the ADC, do a > + * preparatory transfer to pulse the CS/CNV line. > + */ > +static int ad4000_prepare_3wire_mode_message(struct ad4000_state *st, > + const struct iio_chan_spec > *chan) > +{ > + unsigned int cnv_pulse_time = st->turbo_mode ? AD4000_TQUIET1_NS > + : AD4000_TCONV_NS; > + struct spi_transfer *xfers = st->xfers; > + > + xfers[0].cs_change = 1; > + xfers[0].cs_change_delay.value = cnv_pulse_time; > + xfers[0].cs_change_delay.unit = SPI_DELAY_UNIT_NSECS; > + > + xfers[1].rx_buf = &st->scan.data; > + xfers[1].len = BITS_TO_BYTES(chan->scan_type.storagebits); > + xfers[1].delay.value = AD4000_TQUIET2_NS; > + xfers[1].delay.unit = SPI_DELAY_UNIT_NSECS; > + > + spi_message_init_with_transfers(&st->msg, st->xfers, 2); > + > + return devm_spi_optimize_message(st->spi, &st->msg); > +} > + > +/* > + * This executes a data sample transfer for when the device connections are > + * in "4-wire" mode, selected when the adi,sdi-pin device tree property is > + * set to "cs". In this connection mode, the controller CS pin is connected > to > + * ADC SDI pin and a GPIO is connected to ADC CNV pin. > + * The GPIO connected to ADC CNV pin is set outside of the SPI transfer. > + */ > +static int ad4000_prepare_4wire_mode_message(struct ad4000_state *st, > + const struct iio_chan_spec > *chan) > +{ > + unsigned int cnv_to_sdi_time = st->turbo_mode ? AD4000_TQUIET1_NS > + : AD4000_TCONV_NS; > + struct spi_transfer *xfers = st->xfers; > + > + /* > + * Dummy transfer to cause enough delay between CNV going high and > SDI > + * going low. > + */ > + xfers[0].cs_off = 1; > + xfers[0].delay.value = cnv_to_sdi_time; > + xfers[0].delay.unit = SPI_DELAY_UNIT_NSECS; > + > + xfers[1].rx_buf = &st->scan.data; > + xfers[1].len = BITS_TO_BYTES(chan->scan_type.storagebits); > + > + spi_message_init_with_transfers(&st->msg, st->xfers, 2); > + > + return devm_spi_optimize_message(st->spi, &st->msg); > +} nit: you could reduce the scope of the above prepare functions... > + > +static int ad4000_convert_and_acquire(struct ad4000_state *st) > +{ > + int ret; > + > + /* > + * In 4-wire mode, the CNV line is held high for the entire > conversion > + * and acquisition process. In other modes, the CNV GPIO is optional > + * and, if provided, replaces controller CS. If CNV GPIO is not > defined > + * gpiod_set_value_cansleep() has no effect. > + */ > + gpiod_set_value_cansleep(st->cnv_gpio, 1); > + ret = spi_sync(st->spi, &st->msg); > + gpiod_set_value_cansleep(st->cnv_gpio, 0); > + > + return ret; > +} > + > +static int ad4000_single_conversion(struct iio_dev *indio_dev, > + const struct iio_chan_spec *chan, int > *val) > +{ > + struct ad4000_state *st = iio_priv(indio_dev); > + u32 sample; > + int ret; > + > + ret = ad4000_convert_and_acquire(st); > + if (ret < 0) > + return ret; > + > + if (chan->scan_type.storagebits > 16) > + sample = be32_to_cpu(st->scan.data.sample_buf32); Just a minor note regarding your comment in the cover. FWIW, I prefer you leave it like this. Yes, with 24 bits you save some space but then you need an unaligned access... To me that space savings are really a micro optimization so I would definitely go with the simpler form. > + else > + sample = be16_to_cpu(st->scan.data.sample_buf16); > + > + sample >>= chan->scan_type.shift; > + > + if (chan->scan_type.sign == 's') > + *val = sign_extend32(sample, chan->scan_type.realbits - 1); > + > + return IIO_VAL_INT; > +} > + > +static int ad4000_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, int *val, > + int *val2, long info) > +{ > + struct ad4000_state *st = iio_priv(indio_dev); > + > + switch (info) { > + case IIO_CHAN_INFO_RAW: > + iio_device_claim_direct_scoped(return -EBUSY, indio_dev) > + return ad4000_single_conversion(indio_dev, chan, > val); > + unreachable(); > + case IIO_CHAN_INFO_SCALE: > + *val = st->scale_tbl[st->span_comp][0]; > + *val2 = st->scale_tbl[st->span_comp][1]; > + return IIO_VAL_INT_PLUS_NANO; > + case IIO_CHAN_INFO_OFFSET: > + *val = 0; > + if (st->span_comp) > + *val = mult_frac(st->vref_mv, 1, 10); > + > + return IIO_VAL_INT; > + default: > + return -EINVAL; > + } > +} > + > +static int ad4000_read_avail(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + const int **vals, int *type, int *length, > + long info) > +{ > + struct ad4000_state *st = iio_priv(indio_dev); > + > + switch (info) { > + case IIO_CHAN_INFO_SCALE: > + *vals = (int *)st->scale_tbl; > + *length = AD4000_SCALE_OPTIONS * 2; > + *type = IIO_VAL_INT_PLUS_NANO; > + return IIO_AVAIL_LIST; > + default: > + return -EINVAL; > + } > +} > + > +static int ad4000_write_raw_get_fmt(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, long > mask) > +{ > + switch (mask) { > + case IIO_CHAN_INFO_SCALE: > + return IIO_VAL_INT_PLUS_NANO; > + default: > + return IIO_VAL_INT_PLUS_MICRO; > + } > +} > + > +static int ad4000_write_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, int val, int > val2, > + long mask) > +{ > + struct ad4000_state *st = iio_priv(indio_dev); > + unsigned int reg_val; > + bool span_comp_en; > + int ret; > + > + switch (mask) { > + case IIO_CHAN_INFO_SCALE: > + ret = iio_device_claim_direct_mode(indio_dev); iio_device_claim_direct_scoped()? > + if (ret < 0) > + return ret; > + > + mutex_lock(&st->lock); guard()? > + ret = ad4000_read_reg(st, ®_val); > + if (ret < 0) > + goto err_unlock; > + > + span_comp_en = val2 == st->scale_tbl[1][1]; > + reg_val &= ~AD4000_CFG_SPAN_COMP; > + reg_val |= FIELD_PREP(AD4000_CFG_SPAN_COMP, span_comp_en); > + > + ret = ad4000_write_reg(st, reg_val); > + if (ret < 0) > + goto err_unlock; > + > + st->span_comp = span_comp_en; > +err_unlock: > + iio_device_release_direct_mode(indio_dev); > + mutex_unlock(&st->lock); > + return ret; > + default: > + return -EINVAL; > + } > +} > + > +static irqreturn_t ad4000_trigger_handler(int irq, void *p) > +{ > + struct iio_poll_func *pf = p; > + struct iio_dev *indio_dev = pf->indio_dev; > + struct ad4000_state *st = iio_priv(indio_dev); > + int ret; > + > + ret = ad4000_convert_and_acquire(st); > + if (ret < 0) > + goto err_out; > + > + iio_push_to_buffers_with_timestamp(indio_dev, &st->scan, pf- > >timestamp); > + > +err_out: > + iio_trigger_notify_done(indio_dev->trig); > + return IRQ_HANDLED; > +} > + > +static const struct iio_info ad4000_reg_access_info = { > + .read_raw = &ad4000_read_raw, > + .read_avail = &ad4000_read_avail, > + .write_raw = &ad4000_write_raw, > + .write_raw_get_fmt = &ad4000_write_raw_get_fmt, > +}; > + > +static const struct iio_info ad4000_info = { > + .read_raw = &ad4000_read_raw, > +}; > + > +static int ad4000_config(struct ad4000_state *st) > +{ > + unsigned int reg_val = AD4000_CONFIG_REG_DEFAULT; > + > + if (device_property_present(&st->spi->dev, "adi,high-z-input")) > + reg_val |= FIELD_PREP(AD4000_CFG_HIGHZ, 1); > + > + return ad4000_write_reg(st, reg_val); > +} > + > +static int ad4000_probe(struct spi_device *spi) > +{ > + const struct ad4000_chip_info *chip; > + struct device *dev = &spi->dev; > + struct iio_dev *indio_dev; > + struct ad4000_state *st; > + int ret; > + > + indio_dev = devm_iio_device_alloc(dev, sizeof(*st)); > + if (!indio_dev) > + return -ENOMEM; > + > + chip = spi_get_device_match_data(spi); > + if (!chip) > + return -EINVAL; > + > + st = iio_priv(indio_dev); > + st->spi = spi; > + > + ret = devm_regulator_get_enable(dev, "vdd"); > + if (ret) > + return dev_err_probe(dev, ret, "Failed to enable VDD > supply\n"); > + > + ret = devm_regulator_get_enable(dev, "vio"); > + if (ret) > + return dev_err_probe(dev, ret, "Failed to enable VIO > supply\n"); devm_regulator_bulk_get_enable()? Do we have any ordering constrains? > + > + ret = devm_regulator_get_enable_read_voltage(dev, "ref"); > + if (ret < 0) > + return dev_err_probe(dev, ret, > + "Failed to get ref regulator > reference\n"); > + st->vref_mv = ret / 1000; > + > + st->cnv_gpio = devm_gpiod_get_optional(dev, "cnv", GPIOD_OUT_HIGH); > + if (IS_ERR(st->cnv_gpio)) > + return dev_err_probe(dev, PTR_ERR(st->cnv_gpio), > + "Failed to get CNV GPIO"); > + > + ret = device_property_match_property_string(dev, "adi,sdi-pin", > + ad4000_sdi_pin, > + > ARRAY_SIZE(ad4000_sdi_pin)); > + if (ret < 0 && ret != -EINVAL) > + return dev_err_probe(dev, ret, > + "getting adi,sdi-pin property > failed\n"); > + > + /* Default to usual SPI connections if pin properties are not present > */ > + st->sdi_pin = ret == -EINVAL ? AD4000_SDI_MOSI : ret; > + switch (st->sdi_pin) { > + case AD4000_SDI_MOSI: > + indio_dev->info = &ad4000_reg_access_info; > + indio_dev->channels = &chip->reg_access_chan_spec; > + > + /* > + * In "3-wire mode", the ADC SDI line must be kept high when > + * data is not being clocked out of the controller. > + * Request the SPI controller to make MOSI idle high. > + */ > + spi->mode |= SPI_MOSI_IDLE_HIGH; > + ret = spi_setup(spi); > + if (ret < 0) > + return ret; > + > + ret = ad4000_prepare_3wire_mode_message(st, indio_dev- > >channels); > + if (ret) > + return ret; > + > + ret = ad4000_config(st); > + if (ret < 0) > + dev_warn(dev, "Failed to config device\n"); > + Should this be a warning? Very suspicious :) > + break; > + case AD4000_SDI_VIO: > + indio_dev->info = &ad4000_info; > + indio_dev->channels = &chip->chan_spec; > + ret = ad4000_prepare_3wire_mode_message(st, indio_dev- > >channels); > + if (ret) > + return ret; > + > + break; > + case AD4000_SDI_CS: > + indio_dev->info = &ad4000_info; > + indio_dev->channels = &chip->chan_spec; > + ret = ad4000_prepare_4wire_mode_message(st, indio_dev- > >channels); > + if (ret) > + return ret; > + > + break; > + default: > + return dev_err_probe(dev, -EINVAL, "Unrecognized connection > mode\n"); > + } > + > + indio_dev->name = chip->dev_name; > + indio_dev->num_channels = 1; > + > + devm_mutex_init(dev, &st->lock); > + > + st->gain_milli = 1000; > + if (chip->has_hardware_gain) { > + if (device_property_present(dev, "adi,gain-milli")) { > + ret = device_property_read_u16(dev, "adi,gain-milli", > + &st->gain_milli); > + if (ret) > + return dev_err_probe(dev, ret, > + "Failed to read gain > property\n"); > + } > the above looks odd. Why not? ret = device_property_read_u16(dev, "adi,gain-milli", &st->gain_milli); if (!ret) { ... } Note that you're also allowing any value for gain_milli when we just allow some of them (according to the bindings). Hence you should make sure we get supported values from FW. - Nuno Sá
