[PATCH RFC 2/5] iio: adc: ad4030: add driver for ad4030-24

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This adds a new driver for the Analog Devices INC. AD4030-24 ADC.

The driver implements basic support for the AD4030-24 1 channel
differential ADC with hardware gain and offset control.

Signed-off-by: Esteban Blanc <eblanc@xxxxxxxxxxxx>
---
 MAINTAINERS              |   1 +
 drivers/iio/adc/Kconfig  |  13 +
 drivers/iio/adc/Makefile |   1 +
 drivers/iio/adc/ad4030.c | 822 +++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 837 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 8ca5b2e09b69..8df171c62d37 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -419,6 +419,7 @@ R:	Esteban Blanc <eblanc@xxxxxxxxxxxx>
 S:	Supported
 W:	https://ez.analog.com/linux-software-drivers
 F:	Documentation/devicetree/bindings/iio/adc/adi,ad4630.yaml
+F:	drivers/iio/adc/ad4030.c
 
 AD5110 ANALOG DEVICES DIGITAL POTENTIOMETERS DRIVER
 M:	Mugilraj Dhavachelvan <dmugil2000@xxxxxxxxx>
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 3d91015af6ea..e71ac1e49acb 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -21,6 +21,19 @@ config AD_SIGMA_DELTA
 	select IIO_BUFFER
 	select IIO_TRIGGERED_BUFFER
 
+config AD4030
+	tristate "Analog Device AD4630 ADC Driver"
+	depends on SPI
+	depends on GPIOLIB
+	select REGMAP_SPI
+	select IIO_BUFFER
+	help
+	  Say yes here to build support for Analog Devices AD4030 and AD4630 high speed
+	  SPI analog to digital converters (ADC).
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called ad4030.
+
 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..7a8945559589 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-$(CONFIG_AD4030) += ad4030.o
 obj-$(CONFIG_AD4130) += ad4130.o
 obj-$(CONFIG_AD7091R) += ad7091r-base.o
 obj-$(CONFIG_AD7091R5) += ad7091r5.o
diff --git a/drivers/iio/adc/ad4030.c b/drivers/iio/adc/ad4030.c
new file mode 100644
index 000000000000..6d537e531d6f
--- /dev/null
+++ b/drivers/iio/adc/ad4030.c
@@ -0,0 +1,822 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Analog Devices AD4030 and AD4630 ADC family driver.
+ *
+ * Copyright 2024 Analog Devices, Inc.
+ * Copyright 2024 BayLibre, SAS
+ *
+ * based on code from:
+ *	Analog Devices, Inc.
+ *	  Sergiu Cuciurean <sergiu.cuciurean@xxxxxxxxxx>
+ *	  Nuno Sa <nuno.sa@xxxxxxxxxx>
+ *	  Marcelo Schmitt <marcelo.schmitt@xxxxxxxxxx>
+ *	  Liviu Adace <liviu.adace@xxxxxxxxxx>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/units.h>
+#include <linux/clk.h>
+#include <linux/spi/spi.h>
+#include <linux/regmap.h>
+#include <linux/iio/iio.h>
+#include <linux/regulator/consumer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+#define AD4030_REG_INTERFACE_CONFIG_A				0x00
+#define     AD4030_REG_INTERFACE_CONFIG_A_SW_RESET		(BIT(0) | BIT(7))
+#define AD4030_REG_INTERFACE_CONFIG_B				0x01
+#define AD4030_REG_DEVICE_CONFIG				0x02
+#define AD4030_REG_CHIP_TYPE					0x03
+#define AD4030_REG_PRODUCT_ID_L					0x04
+#define AD4030_REG_PRODUCT_ID_H					0x05
+#define AD4030_REG_CHIP_GRADE					0x06
+#define     AD4030_REG_CHIP_GRADE_AD4030_24_GRADE		0x10
+#define     AD4030_REG_CHIP_GRADE_MASK_CHIP_GRADE		GENMASK(7, 3)
+#define AD4030_REG_SCRATCH_PAD					0x0A
+#define AD4030_REG_SPI_REVISION					0x0B
+#define AD4030_REG_VENDOR_L					0x0C
+#define AD4030_REG_VENDOR_H					0x0D
+#define AD4030_REG_STREAM_MODE					0x0E
+#define AD4030_REG_INTERFACE_CONFIG_C				0x10
+#define AD4030_REG_INTERFACE_STATUS_A				0x11
+#define AD4030_REG_EXIT_CFG_MODE				0x14
+#define     AD4030_REG_EXIT_CFG_MODE_MASK_EXIT_CONFIG_MD	BIT(0)
+#define AD4030_REG_AVG						0x15
+#define     AD4030_REG_AVG_MASK_AVG_SYNC			BIT(7)
+#define     AD4030_REG_AVG_MASK_AVG_VAL				GENMASK(4, 0)
+#define AD4030_REG_OFFSET_X0_0					0x16
+#define AD4030_REG_OFFSET_X0_1					0x17
+#define AD4030_REG_OFFSET_X0_2					0x18
+#define AD4030_REG_OFFSET_X1_0					0x19
+#define AD4030_REG_OFFSET_X1_1					0x1A
+#define AD4030_REG_OFFSET_X1_2					0x1B
+#define     AD4030_REG_OFFSET_BYTES_NB				3
+#define     AD4030_REG_OFFSET_CHAN(ch)				(AD4030_REG_OFFSET_X0_2 +	\
+								(AD4030_REG_OFFSET_BYTES_NB *	\
+								(ch)))
+#define AD4030_REG_GAIN_X0_LSB					0x1C
+#define AD4030_REG_GAIN_X0_MSB					0x1D
+#define AD4030_REG_GAIN_X1_LSB					0x1E
+#define AD4030_REG_GAIN_X1_MSB					0x1F
+#define     AD4030_REG_GAIN_MAX_GAIN				1999970
+#define     AD4030_REG_GAIN_BYTES_NB				2
+#define     AD4030_REG_GAIN_CHAN(ch)				(AD4030_REG_GAIN_X0_MSB +	\
+								(AD4030_REG_GAIN_BYTES_NB *	\
+								(ch)))
+#define AD4030_REG_MODES					0x20
+#define     AD4030_REG_MODES_MASK_OUT_DATA_MODE			GENMASK(2, 0)
+#define     AD4030_REG_MODES_MASK_LANE_MODE			GENMASK(7, 6)
+#define AD4030_REG_OSCILATOR					0x21
+#define AD4030_REG_IO						0x22
+#define     AD4030_REG_IO_MASK_IO2X				BIT(1)
+#define AD4030_REG_PAT0						0x23
+#define AD4030_REG_PAT1						0x24
+#define AD4030_REG_PAT2						0x25
+#define AD4030_REG_PAT3						0x26
+#define AD4030_REG_DIG_DIAG					0x34
+#define AD4030_REG_DIG_ERR					0x35
+
+/* Sequence starting with "1 0 1" to enable reg access */
+#define AD4030_REG_ACCESS		0xa0
+
+#define AD4030_MAX_DIFF_CHANNEL_NB	2
+#define AD4030_MAX_COMMON_CHANNEL_NB	AD4030_MAX_DIFF_CHANNEL_NB
+#define AD4030_MAX_TIMESTAMP_CHANNEL_NB	1
+#define AD4030_ALL_CHANNELS_NB		(AD4030_MAX_DIFF_CHANNEL_NB +	\
+					AD4030_MAX_COMMON_CHANNEL_NB +	\
+					AD4030_MAX_TIMESTAMP_CHANNEL_NB)
+#define AD4030_VREF_MIN_UV		(4096 * MILLI)
+#define AD4030_VREF_MAX_UV		(5000 * MILLI)
+#define AD4030_VIO_THRESHOLD_UV		(1400 * MILLI)
+
+#define AD4030_SPI_MAX_XFER_LEN		8
+#define AD4030_SPI_MAX_REG_XFER_SPEED	(80 * MEGA)
+#define AD4030_TCNVH_NS			10
+#define AD4030_TCNVL_NS			20
+#define AD4030_TCONV_NS			(300 - (AD4030_TCNVH_NS +	\
+					AD4030_TCNVL_NS))
+#define AD4030_TRESET_PW_NS		50
+#define AD4030_TRESET_COM_DELAY_MS	750
+
+enum ad4030_out_mode {
+	AD4030_OUT_DATA_MD_16_DIFF = 0x00,
+	AD4030_OUT_DATA_MD_24_DIFF = 0x00,
+	AD4030_OUT_DATA_MD_16_DIFF_8_COM = 0x01,
+	AD4030_OUT_DATA_MD_24_DIFF_8_COM = 0x02,
+	AD4030_OUT_DATA_MD_30_AVERAGED_DIFF = 0x03,
+	AD4030_OUT_DATA_MD_32_PATTERN = 0x04
+};
+
+struct ad4030_chip_info {
+	const char *name;
+	const unsigned long *available_masks;
+	unsigned int available_masks_len;
+	const struct iio_chan_spec channels[AD4030_ALL_CHANNELS_NB];
+	u8 grade;
+	u8 precision_bits;
+	int num_channels;
+};
+
+struct ad4030_state {
+	struct spi_device *spi;
+	struct regmap *regmap;
+	const struct ad4030_chip_info *chip;
+	struct gpio_desc *cnv_gpio;
+	int vref_uv;
+	int vio_uv;
+	int min_offset;
+	int max_offset;
+	int offset_avail[3];
+	u32 conversion_speed_hz;
+	enum ad4030_out_mode mode;
+
+	/*
+	 * DMA (thus cache coherency maintenance) requires the transfer buffers
+	 * to live in their own cache lines.
+	 */
+	u8 tx_data[AD4030_SPI_MAX_XFER_LEN] __aligned(IIO_DMA_MINALIGN);
+	struct {
+		union {
+			/*
+			 * Make the buffer large enough for MAX_NUM_CHANNELS 32-bit samples and
+			 * one 64-bit aligned 64-bit timestamp.
+			 */
+			u8 raw[ALIGN(AD4030_MAX_DIFF_CHANNEL_NB * sizeof(u32) +
+			       AD4030_MAX_COMMON_CHANNEL_NB * sizeof(u8),
+			       sizeof(u64)) + sizeof(u64)];
+			struct {
+				s32 val[AD4030_MAX_DIFF_CHANNEL_NB];
+				u8 common[AD4030_MAX_COMMON_CHANNEL_NB];
+			};
+		};
+	} rx_data __aligned(IIO_DMA_MINALIGN);
+};
+
+#define AD4030_CHAN_CMO(_idx)  {					\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),			\
+	.type = IIO_VOLTAGE,						\
+	.indexed = 1,							\
+	.channel = _idx,						\
+	.scan_index = _idx,						\
+	.scan_type = {							\
+		.sign = 'u',						\
+		.storagebits = 8,					\
+		.realbits = 8,						\
+		.endianness = IIO_BE,					\
+	},								\
+}
+
+#define AD4030_CHAN_IN(_idx, _storage, _real, _shift) {			\
+	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE),		\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_CALIBSCALE) |		\
+		BIT(IIO_CHAN_INFO_CALIBBIAS) |				\
+		BIT(IIO_CHAN_INFO_RAW),					\
+	.info_mask_separate_available = BIT(IIO_CHAN_INFO_CALIBBIAS) |	\
+		BIT(IIO_CHAN_INFO_CALIBSCALE),				\
+	.type = IIO_VOLTAGE,						\
+	.indexed = 1,							\
+	.channel = _idx,						\
+	.scan_index = _idx,						\
+	.scan_type = {							\
+		.sign = 's',						\
+		.storagebits = _storage,				\
+		.realbits = _real,					\
+		.shift = _shift,					\
+		.endianness = IIO_BE,					\
+	},								\
+}
+
+static int ad4030_spi_read(void *context, const void *reg, size_t reg_size,
+			   void *val, size_t val_size)
+{
+	struct ad4030_state *st = context;
+
+	struct spi_transfer xfer = {
+		.tx_buf = st->tx_data,
+		.rx_buf = st->rx_data.raw,
+		.len = reg_size + val_size,
+	};
+	int ret;
+
+	memcpy(st->tx_data, reg, reg_size);
+
+	ret = spi_sync_transfer(st->spi, &xfer, 1);
+	if (ret)
+		return ret;
+
+	memcpy(val, &st->rx_data.raw[reg_size], val_size);
+
+	return ret;
+}
+
+static int ad4030_spi_write(void *context, const void *data, size_t count)
+{
+	const struct ad4030_state *st = context;
+
+	return spi_write(st->spi, data, count);
+}
+
+static const struct regmap_bus ad4030_regmap_bus = {
+	.read = ad4030_spi_read,
+	.write = ad4030_spi_write,
+	.reg_format_endian_default = REGMAP_ENDIAN_BIG,
+};
+
+static const struct regmap_range ad4030_regmap_rd_range[] = {
+	regmap_reg_range(AD4030_REG_INTERFACE_CONFIG_A, AD4030_REG_CHIP_GRADE),
+	regmap_reg_range(AD4030_REG_SCRATCH_PAD, AD4030_REG_STREAM_MODE),
+	regmap_reg_range(AD4030_REG_INTERFACE_CONFIG_C, AD4030_REG_INTERFACE_STATUS_A),
+	regmap_reg_range(AD4030_REG_EXIT_CFG_MODE, AD4030_REG_PAT3),
+	regmap_reg_range(AD4030_REG_DIG_DIAG, AD4030_REG_DIG_ERR),
+};
+
+static const struct regmap_range ad4030_regmap_wr_range[] = {
+	regmap_reg_range(AD4030_REG_CHIP_TYPE, AD4030_REG_CHIP_GRADE),
+	regmap_reg_range(AD4030_REG_SPI_REVISION, AD4030_REG_VENDOR_H),
+};
+
+static const struct regmap_access_table ad4030_regmap_rd_table = {
+	.yes_ranges = ad4030_regmap_rd_range,
+	.n_yes_ranges = ARRAY_SIZE(ad4030_regmap_rd_range),
+};
+
+static const struct regmap_access_table ad4030_regmap_wr_table = {
+	.no_ranges = ad4030_regmap_wr_range,
+	.n_no_ranges = ARRAY_SIZE(ad4030_regmap_wr_range),
+};
+
+static const struct regmap_config ad4030_regmap_config = {
+	.reg_bits = 16,
+	.val_bits = 8,
+	.read_flag_mask = 0x80,
+	.rd_table = &ad4030_regmap_rd_table,
+	.wr_table = &ad4030_regmap_wr_table,
+	.max_register = AD4030_REG_DIG_ERR,
+};
+
+static int ad4030_enter_config_mode(struct ad4030_state *st)
+{
+	st->rx_data.raw[0] = AD4030_REG_ACCESS;
+
+	return spi_write(st->spi, st->rx_data.raw, 1);
+}
+
+static int ad4030_exit_config_mode(struct ad4030_state *st)
+{
+	return regmap_write(st->regmap, AD4030_REG_EXIT_CFG_MODE,
+		     AD4030_REG_EXIT_CFG_MODE_MASK_EXIT_CONFIG_MD);
+}
+
+static int ad4030_get_chan_gain(struct iio_dev *indio_dev, int ch, int *val,
+				int *val2)
+{
+	struct ad4030_state *st = iio_priv(indio_dev);
+	u16 gain;
+	int ret;
+
+	ret = regmap_bulk_read(st->regmap, AD4030_REG_GAIN_CHAN(ch), &gain,
+			       AD4030_REG_GAIN_BYTES_NB);
+	if (ret)
+		return ret;
+
+	gain = be16_to_cpu(gain);
+
+	/* From datasheet: multiplied output = input × gain word/0x8000 */
+	*val = gain / 0x8000;
+	*val2 = mul_u64_u32_div(gain % 0x8000, MICRO, 0x8000);
+
+	return 0;
+}
+
+/*
+ * @brief Returns the offset where 1 LSB = (VREF/2^precision_bits - 1)/gain
+ */
+static int ad4030_get_chan_offset(struct iio_dev *indio_dev, int ch, int *val)
+{
+	struct ad4030_state *st = iio_priv(indio_dev);
+	__be32 offset;
+	int ret;
+
+	ret = regmap_bulk_read(st->regmap, AD4030_REG_OFFSET_CHAN(ch), &offset,
+			       AD4030_REG_OFFSET_BYTES_NB);
+	if (ret)
+		return ret;
+
+	if (st->chip->precision_bits == 16)
+		offset <<= 16;
+	else
+		offset <<= 8;
+
+	*val = be32_to_cpu(offset);
+
+	return 0;
+}
+
+static int ad4030_set_chan_gain(struct iio_dev *indio_dev, int ch, int gain_int,
+				int gain_frac)
+{
+	struct ad4030_state *st = iio_priv(indio_dev);
+	__be16 val;
+	u64 gain;
+
+	gain = mul_u32_u32(gain_int, MICRO) + gain_frac;
+
+	if (gain > AD4030_REG_GAIN_MAX_GAIN)
+		return -EINVAL;
+
+	val = cpu_to_be16(DIV_ROUND_CLOSEST_ULL(gain * 0x8000, MICRO));
+
+	return regmap_bulk_write(st->regmap, AD4030_REG_GAIN_CHAN(ch), &val,
+			  AD4030_REG_GAIN_BYTES_NB);
+}
+
+static int ad4030_set_chan_offset(struct iio_dev *indio_dev, int ch, int offset)
+{
+	struct ad4030_state *st = iio_priv(indio_dev);
+	__be32 val;
+
+	if (offset < st->min_offset || offset > st->max_offset)
+		return -EINVAL;
+
+	val = cpu_to_be32(offset);
+	if (st->chip->precision_bits == 16)
+		val >>= 16;
+	else
+		val >>= 8;
+
+	return regmap_bulk_write(st->regmap, AD4030_REG_OFFSET_CHAN(ch), &val, 3);
+}
+
+static bool ad4030_is_common_byte_asked(struct ad4030_state *st,
+					unsigned int mask)
+{
+	return mask & BIT(st->chip->num_channels);
+}
+
+static int ad4030_set_mode(struct iio_dev *indio_dev, unsigned long mask)
+{
+	struct ad4030_state *st = iio_priv(indio_dev);
+
+	if (ad4030_is_common_byte_asked(st, mask))
+		st->mode = st->chip->precision_bits == 24 ?
+			AD4030_OUT_DATA_MD_24_DIFF_8_COM :
+			AD4030_OUT_DATA_MD_16_DIFF_8_COM;
+	else
+		st->mode = AD4030_OUT_DATA_MD_24_DIFF;
+
+	return regmap_update_bits(st->regmap, AD4030_REG_MODES,
+				AD4030_REG_MODES_MASK_OUT_DATA_MODE,
+				st->mode);
+}
+
+static int ad4030_conversion(struct ad4030_state *st, const struct iio_chan_spec *chan)
+{
+	unsigned int bytes_to_read = (BITS_TO_BYTES(chan->scan_type.realbits) +
+			     ((st->mode == AD4030_OUT_DATA_MD_24_DIFF_8_COM ||
+			     st->mode == AD4030_OUT_DATA_MD_16_DIFF_8_COM) ? 1 : 0)) *
+			     st->chip->num_channels;
+	struct spi_transfer xfer = {
+		.rx_buf = st->rx_data.raw,
+		.len = bytes_to_read,
+	};
+	unsigned char byte_index;
+	unsigned int i;
+	int ret;
+
+	gpiod_set_value_cansleep(st->cnv_gpio, 1);
+	ndelay(AD4030_TCNVH_NS);
+	gpiod_set_value_cansleep(st->cnv_gpio, 0);
+	ndelay(AD4030_TCNVL_NS + AD4030_TCONV_NS);
+
+	ret = spi_sync_transfer(st->spi, &xfer, 1);
+	if (ret || (st->mode != AD4030_OUT_DATA_MD_16_DIFF_8_COM &&
+		    st->mode != AD4030_OUT_DATA_MD_24_DIFF_8_COM))
+		return ret;
+
+	byte_index = st->chip->precision_bits == 16 ? 3 : 4;
+	for (i = 0; i < st->chip->num_channels; i++)
+		st->rx_data.common[i] = ((u8 *)&st->rx_data.val[i])[byte_index];
+
+	return 0;
+}
+
+static int ad4030_single_conversion(struct iio_dev *indio_dev,
+				    const struct iio_chan_spec *chan, int *val)
+{
+	struct ad4030_state *st = iio_priv(indio_dev);
+	int ret;
+
+	ret = ad4030_set_mode(indio_dev, BIT(chan->channel));
+	if (ret)
+		return ret;
+
+	ret = ad4030_exit_config_mode(st);
+	if (ret)
+		goto out_error;
+
+	ret = ad4030_conversion(st, chan);
+	if (ret)
+		goto out_error;
+
+	if (chan->channel < st->chip->num_channels)
+		*val = st->rx_data.val[chan->channel];
+	else
+		*val = st->rx_data.common[chan->channel - st->chip->num_channels];
+
+out_error:
+	ad4030_enter_config_mode(st);
+
+	return IIO_VAL_INT;
+}
+
+static irqreturn_t ad4030_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct ad4030_state *st = iio_priv(indio_dev);
+	int ret;
+
+	ret = ad4030_conversion(st, indio_dev->channels);
+	if (ret)
+		goto out;
+
+	iio_push_to_buffers_with_timestamp(indio_dev, st->rx_data.raw,
+					   pf->timestamp);
+
+out:
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static const int *ad4030_get_offset_avail(struct ad4030_state *st)
+{
+	return st->offset_avail;
+}
+
+static const int ad4030_gain_avail[3][2] = {
+	{0, 0},
+	{0, 30},
+	{1, 999969},
+};
+
+static int ad4030_read_avail(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *channel,
+			     const int **vals, int *type,
+			     int *length, long mask)
+{
+	struct ad4030_state *st = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_CALIBBIAS:
+		*vals = ad4030_get_offset_avail(st);
+		*type = IIO_VAL_INT;
+		return IIO_AVAIL_RANGE;
+
+	case IIO_CHAN_INFO_CALIBSCALE:
+		*vals = (void *)ad4030_gain_avail;
+		*type = IIO_VAL_INT_PLUS_MICRO;
+		return IIO_AVAIL_RANGE;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ad4030_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan, int *val,
+			   int *val2, long info)
+{
+	struct ad4030_state *st = iio_priv(indio_dev);
+	int ret;
+
+	iio_device_claim_direct_scoped(return -EBUSY, indio_dev) {
+		switch (info) {
+		case IIO_CHAN_INFO_RAW:
+			return ad4030_single_conversion(indio_dev, chan, val);
+
+		case IIO_CHAN_INFO_SCALE:
+			*val = (st->vref_uv * 2) / MILLI;
+			*val2 = st->chip->precision_bits;
+			return IIO_VAL_FRACTIONAL_LOG2;
+
+		case IIO_CHAN_INFO_CALIBSCALE:
+			ret = ad4030_get_chan_gain(indio_dev, chan->channel,
+						   val, val2);
+			if (ret)
+				return ret;
+			return IIO_VAL_INT_PLUS_MICRO;
+
+		case IIO_CHAN_INFO_CALIBBIAS:
+			ret = ad4030_get_chan_offset(indio_dev, chan->channel,
+						     val);
+			if (ret)
+				return ret;
+			return IIO_VAL_INT;
+
+		default:
+			return -EINVAL;
+		}
+	}
+
+	unreachable();
+}
+
+static int ad4030_write_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan, int val,
+			    int val2, long info)
+{
+	iio_device_claim_direct_scoped(return -EBUSY, indio_dev) {
+		switch (info) {
+		case IIO_CHAN_INFO_CALIBSCALE:
+			return ad4030_set_chan_gain(indio_dev, chan->channel,
+						    val, val2);
+
+		case IIO_CHAN_INFO_CALIBBIAS:
+			return ad4030_set_chan_offset(indio_dev, chan->channel,
+						      val);
+
+		default:
+			return -EINVAL;
+		}
+	}
+
+	unreachable();
+}
+
+static int ad4030_reg_access(struct iio_dev *indio_dev, unsigned int reg,
+			     unsigned int writeval, unsigned int *readval)
+{
+	const struct ad4030_state *st = iio_priv(indio_dev);
+
+	iio_device_claim_direct_scoped(return -EBUSY, indio_dev) {
+		if (readval)
+			return regmap_read(st->regmap, reg, readval);
+
+		return regmap_write(st->regmap, reg, writeval);
+	}
+
+	unreachable();
+}
+
+static const struct iio_info ad4030_iio_info = {
+	.read_avail = ad4030_read_avail,
+	.read_raw = ad4030_read_raw,
+	.write_raw = ad4030_write_raw,
+	.debugfs_reg_access = ad4030_reg_access,
+};
+
+static int ad4030_buffer_preenable(struct iio_dev *indio_dev)
+{
+	struct ad4030_state *st = iio_priv(indio_dev);
+	int ret;
+
+	ret = ad4030_set_mode(indio_dev, *indio_dev->active_scan_mask);
+	if (ret)
+		return ret;
+
+	ret = ad4030_exit_config_mode(st);
+	if (ret)
+		return ret;
+
+	/* Restore SPI max speed for conversion */
+	st->spi->max_speed_hz = st->conversion_speed_hz;
+
+	return 0;
+}
+
+static int ad4030_buffer_postdisable(struct iio_dev *indio_dev)
+{
+	struct ad4030_state *st = iio_priv(indio_dev);
+
+	/* Make sure the SPI clock is within range to read register */
+	if (st->spi->max_speed_hz > AD4030_SPI_MAX_REG_XFER_SPEED)
+		st->spi->max_speed_hz = AD4030_SPI_MAX_REG_XFER_SPEED;
+
+	return ad4030_enter_config_mode(st);
+}
+
+static const struct iio_buffer_setup_ops ad4030_buffer_setup_ops = {
+	.preenable = ad4030_buffer_preenable,
+	.postdisable = ad4030_buffer_postdisable,
+};
+
+static int ad4030_regulators_get(struct ad4030_state *st)
+{
+	struct device *dev = &st->spi->dev;
+	static const char * const ids[] = {"vdd-5v", "vdd-1v8"};
+	int ret;
+
+	ret = devm_regulator_bulk_get_enable(dev, ARRAY_SIZE(ids), ids);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to enable regulators\n");
+
+	st->vio_uv = devm_regulator_get_enable_read_voltage(dev, "vio");
+	if (st->vio_uv < 0)
+		return dev_err_probe(dev, st->vio_uv,
+				     "Failed to enable and read vio voltage");
+
+	st->vref_uv = devm_regulator_get_enable_read_voltage(dev, "ref");
+	if (st->vref_uv < 0) {
+		if (st->vref_uv != -ENODEV)
+			return dev_err_probe(dev, st->vref_uv,
+					     "Failed to read vref voltage");
+
+		/* if not using optional REF, the internal REFIN must be used */
+		st->vref_uv = devm_regulator_get_enable_read_voltage(dev, "refin");
+		if (st->vref_uv < 0)
+			return dev_err_probe(dev, st->vref_uv,
+					     "Failed to read vrefin voltage");
+	}
+
+	if (st->vref_uv < AD4030_VREF_MIN_UV || st->vref_uv > AD4030_VREF_MAX_UV)
+		return dev_err_probe(dev, -EINVAL,
+				     "vref(%d) must be in the range [%lu %lu]\n",
+				     st->vref_uv, AD4030_VREF_MIN_UV,
+				     AD4030_VREF_MAX_UV);
+
+	return 0;
+}
+
+static int ad4030_reset(struct ad4030_state *st)
+{
+	struct device *dev = &st->spi->dev;
+	struct gpio_desc *reset;
+	int ret;
+
+	/* Use GPIO if available ... */
+	reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(reset))
+		return dev_err_probe(dev, PTR_ERR(reset),
+				"Failed to get reset GPIO\n");
+
+	if (reset) {
+		ndelay(50);
+		gpiod_set_value_cansleep(reset, 0);
+		goto reset_end;
+	}
+
+	/* ... falback to software reset otherwise */
+	ret = ad4030_enter_config_mode(st);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(st->regmap, AD4030_REG_INTERFACE_CONFIG_A,
+			   AD4030_REG_INTERFACE_CONFIG_A_SW_RESET);
+	if (ret)
+		return ret;
+
+reset_end:
+	/* Wait for reset to complete before communicating to it */
+	fsleep(AD4030_TRESET_COM_DELAY_MS);
+
+	/* After reset, conversion mode is enabled. Switch to reg access */
+	return ad4030_enter_config_mode(st);
+}
+
+static int ad4030_detect_chip_info(const struct ad4030_state *st)
+{
+	unsigned int grade;
+	int ret;
+
+	ret = regmap_read(st->regmap, AD4030_REG_CHIP_GRADE, &grade);
+	if (ret)
+		return ret;
+
+	grade = FIELD_GET(AD4030_REG_CHIP_GRADE_MASK_CHIP_GRADE, grade);
+	if (grade != st->chip->grade)
+		return dev_err_probe(&st->spi->dev, -EINVAL,
+				"Unknown grade(%u) for %s\n", grade,
+				st->chip->name);
+
+	return 0;
+}
+
+static int ad4030_config(struct ad4030_state *st)
+{
+	st->min_offset = (int)BIT(st->chip->precision_bits) * -1;
+	st->max_offset = BIT(st->chip->precision_bits) - 1;
+	st->offset_avail[0] = st->min_offset;
+	st->offset_avail[1] = 1;
+	st->offset_avail[2] = st->max_offset;
+
+	if (st->vio_uv < AD4030_VIO_THRESHOLD_UV)
+		return regmap_write(st->regmap, AD4030_REG_IO,
+				AD4030_REG_IO_MASK_IO2X);
+
+	return 0;
+}
+
+static int ad4030_probe(struct spi_device *spi)
+{
+	struct device *dev = &spi->dev;
+	struct iio_dev *indio_dev;
+	struct ad4030_state *st;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	st = iio_priv(indio_dev);
+	st->spi = spi;
+
+	/* Make sure the SPI clock is within range to read register */
+	st->conversion_speed_hz = spi->max_speed_hz;
+	if (spi->max_speed_hz > AD4030_SPI_MAX_REG_XFER_SPEED)
+		spi->max_speed_hz = AD4030_SPI_MAX_REG_XFER_SPEED;
+
+	st->regmap = devm_regmap_init(&spi->dev, &ad4030_regmap_bus, st,
+				      &ad4030_regmap_config);
+	if (IS_ERR(st->regmap))
+		dev_err_probe(&spi->dev, PTR_ERR(st->regmap),
+			      "Failed to initialize regmap\n");
+
+	st->chip = spi_get_device_match_data(spi);
+	if (!st->chip)
+		return -EINVAL;
+
+	ret = ad4030_regulators_get(st);
+	if (ret)
+		return ret;
+
+	ret = ad4030_reset(st);
+	if (ret)
+		return ret;
+
+	ret = ad4030_detect_chip_info(st);
+	if (ret)
+		return ret;
+
+	ret = ad4030_config(st);
+	if (ret)
+		return ret;
+
+	st->cnv_gpio = devm_gpiod_get(dev, "cnv", GPIOD_OUT_LOW);
+	if (IS_ERR(st->cnv_gpio))
+		return dev_err_probe(dev, PTR_ERR(st->cnv_gpio),
+				     "Failed to get cnv gpio");
+
+	indio_dev->name = st->chip->name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &ad4030_iio_info;
+	indio_dev->channels = st->chip->channels;
+	indio_dev->num_channels =  2 * st->chip->num_channels + 1;
+	indio_dev->available_scan_masks = st->chip->available_masks;
+	indio_dev->masklength = st->chip->available_masks_len;
+
+	ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
+					      iio_pollfunc_store_time,
+					      ad4030_trigger_handler,
+					      &ad4030_buffer_setup_ops);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to setup triggered buffer\n");
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+
+static const unsigned long ad4030_channel_masks[] = {
+	BIT(0),
+	GENMASK(1, 0),
+	0,
+};
+
+static const struct ad4030_chip_info ad4030_24_chip_info = {
+	.name = "ad4030-24",
+	.available_masks = ad4030_channel_masks,
+	.available_masks_len = ARRAY_SIZE(ad4030_channel_masks),
+	.channels = {
+		AD4030_CHAN_IN(0, 32, 24, 8),
+		AD4030_CHAN_CMO(1),
+		IIO_CHAN_SOFT_TIMESTAMP(2),
+	},
+	.grade = AD4030_REG_CHIP_GRADE_AD4030_24_GRADE,
+	.precision_bits = 24,
+	.num_channels = 1,
+};
+
+static const struct spi_device_id ad4030_id_table[] = {
+	{ "ad4030-24", (kernel_ulong_t)&ad4030_24_chip_info },
+	{}
+};
+MODULE_DEVICE_TABLE(spi, ad4030_id_table);
+
+static const struct of_device_id ad4030_of_match[] = {
+	{ .compatible = "adi,ad4030-24", .data = &ad4030_24_chip_info },
+	{}
+};
+MODULE_DEVICE_TABLE(of, ad4030_of_match);
+
+static struct spi_driver ad4030_driver = {
+	.driver = {
+		.name = "ad4030",
+		.of_match_table = ad4030_of_match,
+	},
+	.probe = ad4030_probe,
+	.id_table = ad4030_id_table,
+};
+module_spi_driver(ad4030_driver);
+
+MODULE_AUTHOR("Esteban Blanc <eblanc@xxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Analog Devices AD4630 ADC family driver");
+MODULE_LICENSE("GPL");

-- 
2.44.1





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