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Subject[PATCH v4 7/8] iio: adc: ad9467: add support AD9467 ADC
Date
From: Michael Hennerich <michael.hennerich@analog.com>

The AD9467 is a 16-bit, monolithic, IF sampling analog-to-digital converter
(ADC). It is optimized for high performanceover wide bandwidths and ease of
use. The product operates at a 250 MSPS conversion rate and is designed for
wireless receivers, instrumentation, and test equipment that require a high
dynamic range. The ADC requires 1.8 V and 3.3 V power supplies and a low
voltage differential input clock for full performance operation. No
external reference or driver components are required for many applications.
Data outputs are LVDS compatible (ANSI-644 compatible) and include the
means to reduce the overall current needed for short trace distances.

Since the chip can operate at such high sample-rates (much higher than
classical interfaces), it requires that a DMA controller be used to
interface directly to the chip and push data into memory.
Typically, the AXI ADC IP core is used to interface with it.

Link: https://www.analog.com/media/en/technical-documentation/data-sheets/AD9467.pdf

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
drivers/iio/adc/Kconfig | 15 ++
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/ad9467.c | 432 +++++++++++++++++++++++++++++++++++++++
3 files changed, 448 insertions(+)
create mode 100644 drivers/iio/adc/ad9467.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 11bfc079c543..3362ff8d22b7 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -246,6 +246,21 @@ config AD799X
To compile this driver as a module, choose M here: the module will be
called ad799x.

+config AD9467
+ tristate "Analog Devices AD9467 High Speed ADC driver"
+ depends on SPI
+ select ADI_AXI_ADC
+ help
+ Say yes here to build support for Analog Devices:
+ * AD9467 16-Bit, 200 MSPS/250 MSPS Analog-to-Digital Converter
+
+ The driver requires the assistance of the AXI ADC IP core to operate,
+ since SPI is used for configuration only, while data has to be
+ streamed into memory via DMA.
+
+ To compile this driver as a module, choose M here: the module will be
+ called ad9467.
+
config ADI_AXI_ADC
tristate "Analog Devices Generic AXI ADC IP core driver"
select IIO_BUFFER
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 7c6594d049f9..59722770a654 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_AD7793) += ad7793.o
obj-$(CONFIG_AD7887) += ad7887.o
obj-$(CONFIG_AD7949) += ad7949.o
obj-$(CONFIG_AD799X) += ad799x.o
+obj-$(CONFIG_AD9467) += ad9467.o
obj-$(CONFIG_ADI_AXI_ADC) += adi-axi-adc.o
obj-$(CONFIG_ASPEED_ADC) += aspeed_adc.o
obj-$(CONFIG_AT91_ADC) += at91_adc.o
diff --git a/drivers/iio/adc/ad9467.c b/drivers/iio/adc/ad9467.c
new file mode 100644
index 000000000000..35324bd1f0ee
--- /dev/null
+++ b/drivers/iio/adc/ad9467.c
@@ -0,0 +1,432 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Analog Devices AD9467 SPI ADC driver
+ *
+ * Copyright 2012-2020 Analog Devices Inc.
+ */
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/of.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#include <linux/clk.h>
+
+#include <linux/iio/adc/adi-axi-adc.h>
+
+/*
+ * ADI High-Speed ADC common spi interface registers
+ * See Application-Note AN-877:
+ * https://www.analog.com/media/en/technical-documentation/application-notes/AN-877.pdf
+ */
+
+#define AN877_ADC_REG_CHIP_PORT_CONF 0x00
+#define AN877_ADC_REG_CHIP_ID 0x01
+#define AN877_ADC_REG_CHIP_GRADE 0x02
+#define AN877_ADC_REG_CHAN_INDEX 0x05
+#define AN877_ADC_REG_TRANSFER 0xFF
+#define AN877_ADC_REG_MODES 0x08
+#define AN877_ADC_REG_TEST_IO 0x0D
+#define AN877_ADC_REG_ADC_INPUT 0x0F
+#define AN877_ADC_REG_OFFSET 0x10
+#define AN877_ADC_REG_OUTPUT_MODE 0x14
+#define AN877_ADC_REG_OUTPUT_ADJUST 0x15
+#define AN877_ADC_REG_OUTPUT_PHASE 0x16
+#define AN877_ADC_REG_OUTPUT_DELAY 0x17
+#define AN877_ADC_REG_VREF 0x18
+#define AN877_ADC_REG_ANALOG_INPUT 0x2C
+
+/* AN877_ADC_REG_TEST_IO */
+#define AN877_ADC_TESTMODE_OFF 0x0
+#define AN877_ADC_TESTMODE_MIDSCALE_SHORT 0x1
+#define AN877_ADC_TESTMODE_POS_FULLSCALE 0x2
+#define AN877_ADC_TESTMODE_NEG_FULLSCALE 0x3
+#define AN877_ADC_TESTMODE_ALT_CHECKERBOARD 0x4
+#define AN877_ADC_TESTMODE_PN23_SEQ 0x5
+#define AN877_ADC_TESTMODE_PN9_SEQ 0x6
+#define AN877_ADC_TESTMODE_ONE_ZERO_TOGGLE 0x7
+#define AN877_ADC_TESTMODE_USER 0x8
+#define AN877_ADC_TESTMODE_BIT_TOGGLE 0x9
+#define AN877_ADC_TESTMODE_SYNC 0xA
+#define AN877_ADC_TESTMODE_ONE_BIT_HIGH 0xB
+#define AN877_ADC_TESTMODE_MIXED_BIT_FREQUENCY 0xC
+#define AN877_ADC_TESTMODE_RAMP 0xF
+
+/* AN877_ADC_REG_TRANSFER */
+#define AN877_ADC_TRANSFER_SYNC 0x1
+
+/* AN877_ADC_REG_OUTPUT_MODE */
+#define AN877_ADC_OUTPUT_MODE_OFFSET_BINARY 0x0
+#define AN877_ADC_OUTPUT_MODE_TWOS_COMPLEMENT 0x1
+#define AN877_ADC_OUTPUT_MODE_GRAY_CODE 0x2
+
+/* AN877_ADC_REG_OUTPUT_PHASE */
+#define AN877_ADC_OUTPUT_EVEN_ODD_MODE_EN 0x20
+#define AN877_ADC_INVERT_DCO_CLK 0x80
+
+/* AN877_ADC_REG_OUTPUT_DELAY */
+#define AN877_ADC_DCO_DELAY_ENABLE 0x80
+
+/*
+ * Analog Devices AD9467 16-Bit, 200/250 MSPS ADC
+ */
+
+#define CHIPID_AD9467 0x50
+#define AD9467_DEF_OUTPUT_MODE 0x08
+#define AD9467_REG_VREF_MASK 0x0F
+
+enum {
+ ID_AD9467,
+};
+
+struct ad9467_state {
+ struct spi_device *spi;
+ struct clk *clk;
+ unsigned int output_mode;
+
+ struct gpio_desc *pwrdown_gpio;
+ struct gpio_desc *reset_gpio;
+};
+
+static int ad9467_spi_read(struct spi_device *spi, unsigned int reg)
+{
+ unsigned char buf[3];
+ int ret;
+
+ buf[0] = 0x80 | (reg >> 8);
+ buf[1] = reg & 0xFF;
+
+ ret = spi_write_then_read(spi, &buf[0], 2, &buf[2], 1);
+
+ if (ret < 0)
+ return ret;
+
+ return buf[2];
+}
+
+static int ad9467_spi_write(struct spi_device *spi, unsigned int reg,
+ unsigned int val)
+{
+ unsigned char buf[3];
+
+ buf[0] = reg >> 8;
+ buf[1] = reg & 0xFF;
+ buf[2] = val;
+
+ return spi_write(spi, buf, ARRAY_SIZE(buf));
+}
+
+static int ad9467_reg_access(struct adi_axi_adc_conv *conv, unsigned int reg,
+ unsigned int writeval, unsigned int *readval)
+{
+ struct ad9467_state *st = adi_axi_adc_conv_priv(conv);
+ struct spi_device *spi = st->spi;
+ int ret;
+
+ if (readval == NULL) {
+ ret = ad9467_spi_write(spi, reg, writeval);
+ ad9467_spi_write(spi, AN877_ADC_REG_TRANSFER,
+ AN877_ADC_TRANSFER_SYNC);
+ return ret;
+ }
+
+ ret = ad9467_spi_read(spi, reg);
+ if (ret < 0)
+ return ret;
+ *readval = ret;
+
+ return 0;
+}
+
+static const unsigned int ad9467_scale_table[][2] = {
+ {2000, 0}, {2100, 6}, {2200, 7},
+ {2300, 8}, {2400, 9}, {2500, 10},
+};
+
+static void __ad9467_get_scale(struct adi_axi_adc_conv *conv, int index,
+ unsigned int *val, unsigned int *val2)
+{
+ const struct adi_axi_adc_chip_info *info = conv->chip_info;
+ const struct iio_chan_spec *chan = &info->channels[0];
+ unsigned int tmp;
+
+ tmp = (info->scale_table[index][0] * 1000000ULL) >>
+ chan->scan_type.realbits;
+ *val = tmp / 1000000;
+ *val2 = tmp % 1000000;
+}
+
+#define AD9467_CHAN(_chan, _si, _bits, _sign) \
+{ \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = _chan, \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
+ BIT(IIO_CHAN_INFO_SAMP_FREQ), \
+ .scan_index = _si, \
+ .scan_type = { \
+ .sign = _sign, \
+ .realbits = _bits, \
+ .storagebits = 16, \
+ }, \
+}
+
+static const struct iio_chan_spec ad9467_channels[] = {
+ AD9467_CHAN(0, 0, 16, 'S'),
+};
+
+static const struct adi_axi_adc_chip_info ad9467_chip_info_tbl[] = {
+ [ID_AD9467] = {
+ .id = CHIPID_AD9467,
+ .max_rate = 250000000UL,
+ .scale_table = ad9467_scale_table,
+ .num_scales = ARRAY_SIZE(ad9467_scale_table),
+ .channels = ad9467_channels,
+ .num_channels = ARRAY_SIZE(ad9467_channels),
+ },
+};
+
+static int ad9467_get_scale(struct adi_axi_adc_conv *conv, int *val, int *val2)
+{
+ const struct adi_axi_adc_chip_info *info = conv->chip_info;
+ struct ad9467_state *st = adi_axi_adc_conv_priv(conv);
+ unsigned int i, vref_val, vref_mask;
+
+ vref_val = ad9467_spi_read(st->spi, AN877_ADC_REG_VREF);
+
+ switch (info->id) {
+ case CHIPID_AD9467:
+ vref_mask = AD9467_REG_VREF_MASK;
+ break;
+ default:
+ vref_mask = 0xFFFF;
+ break;
+ }
+
+ vref_val &= vref_mask;
+
+ for (i = 0; i < info->num_scales; i++) {
+ if (vref_val == info->scale_table[i][1])
+ break;
+ }
+
+ if (i == info->num_scales)
+ return -ERANGE;
+
+ __ad9467_get_scale(conv, i, val, val2);
+
+ return IIO_VAL_INT_PLUS_MICRO;
+}
+
+static int ad9467_set_scale(struct adi_axi_adc_conv *conv, int val, int val2)
+{
+ const struct adi_axi_adc_chip_info *info = conv->chip_info;
+ struct ad9467_state *st = adi_axi_adc_conv_priv(conv);
+ unsigned int scale_val[2];
+ unsigned int i;
+
+ if (val != 0)
+ return -EINVAL;
+
+ for (i = 0; i < info->num_scales; i++) {
+ __ad9467_get_scale(conv, i, &scale_val[0], &scale_val[1]);
+ if (scale_val[0] != val || scale_val[1] != val2)
+ continue;
+
+ ad9467_spi_write(st->spi, AN877_ADC_REG_VREF,
+ info->scale_table[i][1]);
+ ad9467_spi_write(st->spi, AN877_ADC_REG_TRANSFER,
+ AN877_ADC_TRANSFER_SYNC);
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static int ad9467_read_raw(struct adi_axi_adc_conv *conv,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long m)
+{
+ struct ad9467_state *st = adi_axi_adc_conv_priv(conv);
+
+ switch (m) {
+ case IIO_CHAN_INFO_SCALE:
+ return ad9467_get_scale(conv, val, val2);
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ if (!st->clk)
+ return -ENODEV;
+
+ *val = clk_get_rate(st->clk);
+
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int ad9467_write_raw(struct adi_axi_adc_conv *conv,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ const struct adi_axi_adc_chip_info *info = conv->chip_info;
+ struct ad9467_state *st = adi_axi_adc_conv_priv(conv);
+ unsigned long r_clk;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_SCALE:
+ return ad9467_set_scale(conv, val, val2);
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ if (!st->clk)
+ return -ENODEV;
+
+ if (chan->extend_name)
+ return -ENODEV;
+
+ r_clk = clk_round_rate(st->clk, val);
+ if (r_clk < 0 || r_clk > info->max_rate) {
+ dev_warn(&st->spi->dev,
+ "Error setting ADC sample rate %ld", r_clk);
+ return -EINVAL;
+ }
+
+ return clk_set_rate(st->clk, r_clk);
+ default:
+ return -EINVAL;
+ }
+}
+
+static int ad9467_outputmode_set(struct spi_device *spi, unsigned int mode)
+{
+ int ret;
+
+ ret = ad9467_spi_write(spi, AN877_ADC_REG_OUTPUT_MODE, mode);
+ if (ret < 0)
+ return ret;
+
+ return ad9467_spi_write(spi, AN877_ADC_REG_TRANSFER,
+ AN877_ADC_TRANSFER_SYNC);
+}
+
+static int ad9467_preenable_setup(struct adi_axi_adc_conv *conv)
+{
+ struct ad9467_state *st = adi_axi_adc_conv_priv(conv);
+
+ return ad9467_outputmode_set(st->spi, st->output_mode);
+}
+
+static int ad9467_setup(struct ad9467_state *st, unsigned int chip_id)
+{
+ switch (chip_id) {
+ case CHIPID_AD9467:
+ st->output_mode = AD9467_DEF_OUTPUT_MODE |
+ AN877_ADC_OUTPUT_MODE_TWOS_COMPLEMENT;
+ return 0;
+ default:
+ return -EINVAL;
+ }
+}
+
+static void ad9467_clk_disable(void *data)
+{
+ struct ad9467_state *st = data;
+
+ clk_disable_unprepare(st->clk);
+}
+
+static const struct of_device_id ad9467_of_match[] = {
+ { .compatible = "adi,ad9467", .data = (void *)ID_AD9467, },
+ {}
+};
+MODULE_DEVICE_TABLE(of, ad9467_of_match);
+
+static int ad9467_probe(struct spi_device *spi)
+{
+ const struct of_device_id *oid;
+ struct adi_axi_adc_conv *conv;
+ struct ad9467_state *st;
+ unsigned int id;
+ int ret;
+
+ if (!spi->dev.of_node) {
+ dev_err(&spi->dev, "DT node is null\n");
+ return -ENODEV;
+ }
+
+ oid = of_match_node(ad9467_of_match, spi->dev.of_node);
+ if (!oid)
+ return -ENODEV;
+
+ conv = devm_adi_axi_adc_conv_register(&spi->dev, sizeof(*st));
+ if (IS_ERR(conv))
+ return PTR_ERR(conv);
+
+ st = adi_axi_adc_conv_priv(conv);
+ st->spi = spi;
+
+ st->clk = devm_clk_get(&spi->dev, "adc-clk");
+ if (IS_ERR(st->clk))
+ return PTR_ERR(st->clk);
+
+ ret = clk_prepare_enable(st->clk);
+ if (ret < 0)
+ return ret;
+
+ ret = devm_add_action_or_reset(&spi->dev, ad9467_clk_disable, st);
+ if (ret)
+ return ret;
+
+ st->pwrdown_gpio = devm_gpiod_get_optional(&spi->dev, "powerdown",
+ GPIOD_OUT_LOW);
+ if (IS_ERR(st->pwrdown_gpio))
+ return PTR_ERR(st->pwrdown_gpio);
+
+ st->reset_gpio = devm_gpiod_get_optional(&spi->dev, "reset",
+ GPIOD_OUT_LOW);
+ if (IS_ERR(st->reset_gpio))
+ return PTR_ERR(st->reset_gpio);
+
+ if (st->reset_gpio) {
+ udelay(1);
+ ret = gpiod_direction_output(st->reset_gpio, 1);
+ mdelay(10);
+ }
+
+ spi_set_drvdata(spi, st);
+
+ id = (unsigned int)oid->data;
+ conv->chip_info = &ad9467_chip_info_tbl[id];
+
+ id = ad9467_spi_read(spi, AN877_ADC_REG_CHIP_ID);
+ if (id != conv->chip_info->id) {
+ dev_err(&spi->dev, "Unrecognized CHIP_ID 0x%X\n", id);
+ return -ENODEV;
+ }
+
+ conv->reg_access = ad9467_reg_access;
+ conv->write_raw = ad9467_write_raw;
+ conv->read_raw = ad9467_read_raw;
+ conv->preenable_setup = ad9467_preenable_setup;
+
+ return ad9467_setup(st, id);
+}
+
+static struct spi_driver ad9467_driver = {
+ .driver = {
+ .name = "ad9467",
+ .of_match_table = ad9467_of_match,
+ },
+ .probe = ad9467_probe,
+};
+module_spi_driver(ad9467_driver);
+
+MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD9467 ADC driver");
+MODULE_LICENSE("GPL v2");
--
2.20.1
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