[PATCH v3 6/6] iio: adc: Add support for AD4000

From: Marcelo Schmitt
Date: Wed Jun 05 2024 - 07:15:41 EST

Add support for AD4000 series of low noise, low power, high speed,
successive aproximation 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 | 735 +++++++++++++++++++++++++++++++++++++++
4 files changed, 749 insertions(+)
create mode 100644 drivers/iio/adc/ad4000.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 1f052b9cd912..c732cf13f511 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1206,6 +1206,7 @@ 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 5030319249c5..dcc49d9711a4 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 37ac689a0209..c32bd0ef6128 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..55dc36fbd549
--- /dev/null
+++ b/drivers/iio/adc/ad4000.c
@@ -0,0 +1,735 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * AD4000 SPI ADC driver
+ *
+ * Copyright 2024 Analog Devices Inc.
+ */
+#include <asm/unaligned.h>
+#include <linux/bits.h>
+#include <linux/bitfield.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/kernel.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/sysfs.h>
+#include <linux/units.h>
+#include <linux/util_macros.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+
+#define AD4000_READ_COMMAND 0x54
+#define AD4000_WRITE_COMMAND 0x14
+
+#define AD4000_CONFIG_REG_MSK 0xFF
+
+/* AD4000 Configuration Register programmable bits */
+#define AD4000_CFG_STATUS BIT(4) /* Status bits output */
+#define AD4000_CFG_SPAN_COMP BIT(3) /* Input span compression */
+#define AD4000_CFG_HIGHZ BIT(2) /* High impedance mode */
+#define AD4000_CFG_TURBO BIT(1) /* Turbo mode */
+
+#define AD4000_TQUIET1_NS 190
+#define AD4000_TQUIET2_NS 60
+#define AD4000_TCONV_NS 320
+
+#define AD4000_18BIT_MSK GENMASK(31, 14)
+#define AD4000_20BIT_MSK GENMASK(31, 12)
+
+#define AD4000_DIFF_CHANNEL(_sign, _real_bits) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .differential = 1, \
+ .channel = 0, \
+ .channel2 = 1, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+ BIT(IIO_CHAN_INFO_SCALE), \
+ .info_mask_separate_available = BIT(IIO_CHAN_INFO_SCALE),\
+ .scan_type = { \
+ .sign = _sign, \
+ .realbits = _real_bits, \
+ .storagebits = _real_bits > 16 ? 32 : 16, \
+ .shift = _real_bits > 16 ? 32 - _real_bits : 0, \
+ .endianness = IIO_BE, \
+ }, \
+ } \
+
+#define AD4000_PSEUDO_DIFF_CHANNEL(_sign, _real_bits) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = 0, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+ BIT(IIO_CHAN_INFO_SCALE) | \
+ BIT(IIO_CHAN_INFO_OFFSET), \
+ .info_mask_separate_available = BIT(IIO_CHAN_INFO_SCALE),\
+ .scan_type = { \
+ .sign = _sign, \
+ .realbits = _real_bits, \
+ .storagebits = _real_bits > 16 ? 32 : 16, \
+ .shift = _real_bits > 16 ? 32 - _real_bits : 0, \
+ .endianness = IIO_BE, \
+ }, \
+ } \
+
+enum ad4000_ids {
+ ID_AD4000,
+ ID_AD4001,
+ ID_AD4002,
+ ID_AD4003,
+ ID_AD4004,
+ ID_AD4005,
+ ID_AD4006,
+ ID_AD4007,
+ ID_AD4008,
+ ID_AD4010,
+ ID_AD4011,
+ ID_AD4020,
+ ID_AD4021,
+ ID_AD4022,
+ ID_ADAQ4001,
+ ID_ADAQ4003,
+};
+
+enum ad4000_spi_mode {
+ /* datasheet calls this "4-wire mode" (controller CS goes to ADC SDI!) */
+ AD4000_SPI_MODE_DEFAULT,
+ /* datasheet calls this "3-wire mode" (not related to SPI_3WIRE!) */
+ AD4000_SPI_MODE_SINGLE,
+};
+
+/* maps adi,spi-mode property value to enum */
+static const char * const ad4000_spi_modes[] = {
+ [AD4000_SPI_MODE_DEFAULT] = "",
+ [AD4000_SPI_MODE_SINGLE] = "single",
+};
+
+struct ad4000_chip_info {
+ const char *dev_name;
+ struct iio_chan_spec chan_spec;
+};
+
+static const struct ad4000_chip_info ad4000_chips[] = {
+ [ID_AD4000] = {
+ .dev_name = "ad4000",
+ .chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16),
+ },
+ [ID_AD4001] = {
+ .dev_name = "ad4001",
+ .chan_spec = AD4000_DIFF_CHANNEL('s', 16),
+ },
+ [ID_AD4002] = {
+ .dev_name = "ad4002",
+ .chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 18),
+ },
+ [ID_AD4003] = {
+ .dev_name = "ad4003",
+ .chan_spec = AD4000_DIFF_CHANNEL('s', 18),
+ },
+ [ID_AD4004] = {
+ .dev_name = "ad4004",
+ .chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16),
+ },
+ [ID_AD4005] = {
+ .dev_name = "ad4005",
+ .chan_spec = AD4000_DIFF_CHANNEL('s', 16),
+ },
+ [ID_AD4006] = {
+ .dev_name = "ad4006",
+ .chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 18),
+ },
+ [ID_AD4007] = {
+ .dev_name = "ad4007",
+ .chan_spec = AD4000_DIFF_CHANNEL('s', 18),
+ },
+ [ID_AD4008] = {
+ .dev_name = "ad4008",
+ .chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16),
+ },
+ [ID_AD4010] = {
+ .dev_name = "ad4010",
+ .chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 18),
+ },
+ [ID_AD4011] = {
+ .dev_name = "ad4011",
+ .chan_spec = AD4000_DIFF_CHANNEL('s', 18),
+ },
+ [ID_AD4020] = {
+ .dev_name = "ad4020",
+ .chan_spec = AD4000_DIFF_CHANNEL('s', 20),
+ },
+ [ID_AD4021] = {
+ .dev_name = "ad4021",
+ .chan_spec = AD4000_DIFF_CHANNEL('s', 20),
+ },
+ [ID_AD4022] = {
+ .dev_name = "ad4022",
+ .chan_spec = AD4000_DIFF_CHANNEL('s', 20),
+ },
+ [ID_ADAQ4001] = {
+ .dev_name = "adaq4001",
+ .chan_spec = AD4000_DIFF_CHANNEL('s', 16),
+ },
+ [ID_ADAQ4003] = {
+ .dev_name = "adaq4003",
+ .chan_spec = AD4000_DIFF_CHANNEL('s', 18),
+ },
+};
+
+struct ad4000_state {
+ struct spi_device *spi;
+ struct gpio_desc *cnv_gpio;
+ struct spi_transfer xfers[2];
+ struct spi_message msg;
+ int vref;
+ enum ad4000_spi_mode spi_mode;
+ bool span_comp;
+ bool turbo_mode;
+ int gain_milli;
+ int scale_tbl[2][2];
+
+ /*
+ * DMA (thus cache coherency maintenance) requires the
+ * transfer buffers to live in their own cache lines.
+ */
+ struct {
+ union {
+ __be16 sample_buf16;
+ __be32 sample_buf32;
+ } data;
+ s64 timestamp __aligned(8);
+ } scan __aligned(IIO_DMA_MINALIGN);
+ __be16 tx_buf;
+ __be16 rx_buf;
+};
+
+static void ad4000_fill_scale_tbl(struct ad4000_state *st, int scale_bits,
+ const struct ad4000_chip_info *chip)
+{
+ int diff = chip->chan_spec.differential;
+ int val, val2, tmp0, tmp1;
+ u64 tmp2;
+
+ val2 = scale_bits;
+ val = st->vref / 1000;
+ /*
+ * The gain is stored as a fraction of 1000 and, as we need to
+ * divide vref by gain, we invert the gain/1000 fraction.
+ * Also multiply by an extra MILLI to avoid losing precision.
+ */
+ val = mult_frac(val, MILLI * MILLI, st->gain_milli);
+ /* Would multiply by NANO here but we multiplied by extra MILLI */
+ tmp2 = shift_right((u64)val * MICRO, val2);
+ tmp0 = (int)div_s64_rem(tmp2, NANO, &tmp1);
+ /* Store scale for when span compression is disabled */
+ st->scale_tbl[0][0] = tmp0; /* Integer part */
+ st->scale_tbl[0][1] = abs(tmp1); /* Fractional part */
+ /* Store scale for when span compression is enabled */
+ st->scale_tbl[1][0] = tmp0;
+ /* The integer part is always zero so don't bother to divide it. */
+ if (diff)
+ st->scale_tbl[1][1] = DIV_ROUND_CLOSEST(abs(tmp1) * 4, 5);
+ else
+ st->scale_tbl[1][1] = DIV_ROUND_CLOSEST(abs(tmp1) * 9, 10);
+}
+
+static int ad4000_write_reg(struct ad4000_state *st, uint8_t val)
+{
+ st->tx_buf = cpu_to_be16(AD4000_WRITE_COMMAND << BITS_PER_BYTE | val);
+ return spi_write(st->spi, &st->tx_buf, 2);
+}
+
+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 = cpu_to_be16(AD4000_READ_COMMAND << BITS_PER_BYTE);
+ ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
+ if (ret < 0)
+ return ret;
+
+ *val = be16_to_cpu(st->rx_buf);
+
+ return ret;
+}
+
+static void ad4000_unoptimize_msg(void *msg)
+{
+ spi_unoptimize_message(msg);
+}
+
+/*
+ * This executes a data sample transfer for when the device connections are
+ * in "3-wire" mode, selected by setting the adi,spi-mode device tree property
+ * to "single". 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;
+ int ret;
+
+ 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);
+
+ ret = spi_optimize_message(st->spi, &st->msg);
+ if (ret)
+ return ret;
+
+ return devm_add_action_or_reset(&st->spi->dev, ad4000_unoptimize_msg,
+ &st->msg);
+}
+
+/*
+ * This executes a data sample transfer for when the device connections are
+ * in "4-wire" mode, selected when the adi,spi-mode device tree
+ * property is absent or empty. 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;
+ int ret;
+
+ /*
+ * 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);
+
+ ret = spi_optimize_message(st->spi, &st->msg);
+ if (ret)
+ return ret;
+
+ return devm_add_action_or_reset(&st->spi->dev, ad4000_unoptimize_msg,
+ &st->msg);
+}
+
+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 st->cnv_gpio is NULL and is
+ * ignored (CS is wired to CNV in those cases).
+ */
+ 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 (chan->scan_type.storagebits > 16)
+ sample = be32_to_cpu(st->scan.data.sample_buf32);
+ else
+ sample = be16_to_cpu(st->scan.data.sample_buf16);
+
+ switch (chan->scan_type.realbits) {
+ case 16:
+ break;
+ case 18:
+ sample = FIELD_GET(AD4000_18BIT_MSK, sample);
+ break;
+ case 20:
+ sample = FIELD_GET(AD4000_20BIT_MSK, sample);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ 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 / 1000, 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 = 2 * 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:
+ iio_device_claim_direct_scoped(return -EBUSY, indio_dev) {
+ ret = ad4000_read_reg(st, &reg_val);
+ if (ret < 0)
+ return ret;
+
+ 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)
+ return ret;
+
+ st->span_comp = span_comp_en;
+ return 0;
+ }
+ unreachable();
+ 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,
+ iio_get_time_ns(indio_dev));
+
+err_out:
+ iio_trigger_notify_done(indio_dev->trig);
+ return IRQ_HANDLED;
+}
+
+static int ad4000_reg_access(struct iio_dev *indio_dev, unsigned int reg,
+ unsigned int writeval, unsigned int *readval)
+{
+ struct ad4000_state *st = iio_priv(indio_dev);
+ int ret;
+
+ if (readval)
+ ret = ad4000_read_reg(st, readval);
+ else
+ ret = ad4000_write_reg(st, writeval);
+
+ return ret;
+}
+
+static const struct iio_info ad4000_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,
+ .debugfs_reg_access = &ad4000_reg_access,
+
+};
+
+static int ad4000_config(struct ad4000_state *st)
+{
+ unsigned int reg_val;
+
+ if (device_property_present(&st->spi->dev, "adi,high-z-input"))
+ reg_val |= FIELD_PREP(AD4000_CFG_HIGHZ, 1);
+
+ /*
+ * The ADC SDI pin might be connected to controller CS line in which
+ * case the write might fail. This, however, does not prevent the device
+ * from functioning even though in a configuration other than the
+ * requested one.
+ */
+ return ad4000_write_reg(st, reg_val);
+}
+
+static void ad4000_regulator_disable(void *reg)
+{
+ regulator_disable(reg);
+}
+
+static int ad4000_probe(struct spi_device *spi)
+{
+ const struct ad4000_chip_info *chip;
+ struct regulator *vref_reg;
+ struct iio_dev *indio_dev;
+ struct ad4000_state *st;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&spi->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(&spi->dev, "vdd");
+ if (ret)
+ return dev_err_probe(&spi->dev, ret, "Failed to enable VDD supply\n");
+
+ ret = devm_regulator_get_enable(&spi->dev, "vio");
+ if (ret)
+ return dev_err_probe(&spi->dev, ret, "Failed to enable VIO supply\n");
+
+ vref_reg = devm_regulator_get(&spi->dev, "ref");
+ if (IS_ERR(vref_reg))
+ return dev_err_probe(&spi->dev, PTR_ERR(vref_reg),
+ "Failed to get vref regulator\n");
+
+ ret = regulator_enable(vref_reg);
+ if (ret < 0)
+ return dev_err_probe(&spi->dev, ret,
+ "Failed to enable voltage regulator\n");
+
+ ret = devm_add_action_or_reset(&spi->dev, ad4000_regulator_disable, vref_reg);
+ if (ret)
+ return dev_err_probe(&spi->dev, ret,
+ "Failed to add regulator disable action\n");
+
+ st->vref = regulator_get_voltage(vref_reg);
+ if (st->vref < 0)
+ return dev_err_probe(&spi->dev, st->vref, "Failed to get vref\n");
+
+ st->cnv_gpio = devm_gpiod_get_optional(&spi->dev, "cnv", GPIOD_OUT_HIGH);
+ if (IS_ERR(st->cnv_gpio))
+ return dev_err_probe(&spi->dev, PTR_ERR(st->cnv_gpio),
+ "Failed to get CNV GPIO");
+
+ ret = device_property_match_property_string(&spi->dev, "adi,spi-mode",
+ ad4000_spi_modes,
+ ARRAY_SIZE(ad4000_spi_modes));
+ /* Default to 4-wire mode if adi,spi-mode property is not present */
+ if (ret == -EINVAL)
+ st->spi_mode = AD4000_SPI_MODE_DEFAULT;
+ else if (ret < 0)
+ return dev_err_probe(&spi->dev, ret,
+ "getting adi,spi-mode property failed\n");
+ else
+ st->spi_mode = ret;
+
+ switch (st->spi_mode) {
+ case AD4000_SPI_MODE_DEFAULT:
+ ret = ad4000_prepare_4wire_mode_message(st, &chip->chan_spec);
+ if (ret)
+ return ret;
+
+ break;
+ case AD4000_SPI_MODE_SINGLE:
+ ret = ad4000_prepare_3wire_mode_message(st, &chip->chan_spec);
+ if (ret)
+ return ret;
+
+ /*
+ * 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_MODE_0 | SPI_MOSI_IDLE_HIGH;
+ if (spi_setup(spi))
+ dev_warn(&st->spi->dev, "SPI controller setup failed\n");
+
+ break;
+ }
+
+ ret = ad4000_config(st);
+ if (ret < 0)
+ dev_dbg(&st->spi->dev, "Failed to config device\n");
+
+ indio_dev->name = chip->dev_name;
+ indio_dev->info = &ad4000_info;
+ indio_dev->channels = &chip->chan_spec;
+ indio_dev->num_channels = 1;
+
+ /* Hardware gain only applies to ADAQ devices */
+ st->gain_milli = 1000;
+ if (device_property_present(&spi->dev, "adi,gain-milli")) {
+
+ ret = device_property_read_u32(&spi->dev, "adi,gain-milli",
+ &st->gain_milli);
+ if (ret)
+ return dev_err_probe(&spi->dev, ret,
+ "Failed to read gain property\n");
+ }
+
+ /*
+ * ADCs that output two's complement code have one less bit to express
+ * voltage magnitude.
+ */
+ if (chip->chan_spec.scan_type.sign == 's')
+ ad4000_fill_scale_tbl(st, chip->chan_spec.scan_type.realbits - 1,
+ chip);
+ else
+ ad4000_fill_scale_tbl(st, chip->chan_spec.scan_type.realbits,
+ chip);
+
+ ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
+ &iio_pollfunc_store_time,
+ &ad4000_trigger_handler, NULL);
+ if (ret)
+ return ret;
+
+ return devm_iio_device_register(&spi->dev, indio_dev);
+}
+
+static const struct spi_device_id ad4000_id[] = {
+ { "ad4000", (kernel_ulong_t)&ad4000_chips[ID_AD4000] },
+ { "ad4001", (kernel_ulong_t)&ad4000_chips[ID_AD4001] },
+ { "ad4002", (kernel_ulong_t)&ad4000_chips[ID_AD4002] },
+ { "ad4003", (kernel_ulong_t)&ad4000_chips[ID_AD4003] },
+ { "ad4004", (kernel_ulong_t)&ad4000_chips[ID_AD4004] },
+ { "ad4005", (kernel_ulong_t)&ad4000_chips[ID_AD4005] },
+ { "ad4006", (kernel_ulong_t)&ad4000_chips[ID_AD4006] },
+ { "ad4007", (kernel_ulong_t)&ad4000_chips[ID_AD4007] },
+ { "ad4008", (kernel_ulong_t)&ad4000_chips[ID_AD4008] },
+ { "ad4010", (kernel_ulong_t)&ad4000_chips[ID_AD4010] },
+ { "ad4011", (kernel_ulong_t)&ad4000_chips[ID_AD4011] },
+ { "ad4020", (kernel_ulong_t)&ad4000_chips[ID_AD4020] },
+ { "ad4021", (kernel_ulong_t)&ad4000_chips[ID_AD4021] },
+ { "ad4022", (kernel_ulong_t)&ad4000_chips[ID_AD4022] },
+ { "adaq4001", (kernel_ulong_t)&ad4000_chips[ID_ADAQ4001] },
+ { "adaq4003", (kernel_ulong_t)&ad4000_chips[ID_ADAQ4003] },
+ { }
+};
+MODULE_DEVICE_TABLE(spi, ad4000_id);
+
+static const struct of_device_id ad4000_of_match[] = {
+ { .compatible = "adi,ad4000", .data = &ad4000_chips[ID_AD4000] },
+ { .compatible = "adi,ad4001", .data = &ad4000_chips[ID_AD4001] },
+ { .compatible = "adi,ad4002", .data = &ad4000_chips[ID_AD4002] },
+ { .compatible = "adi,ad4003", .data = &ad4000_chips[ID_AD4003] },
+ { .compatible = "adi,ad4004", .data = &ad4000_chips[ID_AD4004] },
+ { .compatible = "adi,ad4005", .data = &ad4000_chips[ID_AD4005] },
+ { .compatible = "adi,ad4006", .data = &ad4000_chips[ID_AD4006] },
+ { .compatible = "adi,ad4007", .data = &ad4000_chips[ID_AD4007] },
+ { .compatible = "adi,ad4008", .data = &ad4000_chips[ID_AD4008] },
+ { .compatible = "adi,ad4010", .data = &ad4000_chips[ID_AD4010] },
+ { .compatible = "adi,ad4011", .data = &ad4000_chips[ID_AD4011] },
+ { .compatible = "adi,ad4020", .data = &ad4000_chips[ID_AD4020] },
+ { .compatible = "adi,ad4021", .data = &ad4000_chips[ID_AD4021] },
+ { .compatible = "adi,ad4022", .data = &ad4000_chips[ID_AD4022] },
+ { .compatible = "adi,adaq4001", .data = &ad4000_chips[ID_ADAQ4001] },
+ { .compatible = "adi,adaq4003", .data = &ad4000_chips[ID_ADAQ4003] },
+ { }
+};
+MODULE_DEVICE_TABLE(of, ad4000_of_match);
+
+static struct spi_driver ad4000_driver = {
+ .driver = {
+ .name = "ad4000",
+ .of_match_table = ad4000_of_match,
+ },
+ .probe = ad4000_probe,
+ .id_table = ad4000_id,
+};
+module_spi_driver(ad4000_driver);
+
+MODULE_AUTHOR("Marcelo Schmitt <marcelo.schmitt@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Analog Devices AD4000 ADC driver");
+MODULE_LICENSE("GPL");
--
2.43.0