Date:   Sat, 21 Mar 2020 17:23:21 +0000
From:   Jonathan Cameron <jic23@...nel.org>
To:     Alexandru Ardelean <alexandru.ardelean@...log.com>
Cc:     <linux-iio@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <robh+dt@...nel.org>,
        <Laszlo.Nagy@...log.com>, <Andrei.Grozav@...log.com>,
        <Michael.Hennerich@...log.com>, <Istvan.Csomortani@...log.com>,
        <Adrian.Costina@...log.com>, <Dragos.Bogdan@...log.com>,
        Lars-Peter Clausen <lars@...afoo.de>
Subject: Re: [PATCH v11 7/8] iio: adc: ad9467: add support AD9467 ADC

On Sat, 21 Mar 2020 10:53:14 +0200
Alexandru Ardelean <alexandru.ardelean@...log.com> wrote:

> From: Michael Hennerich <michael.hennerich@...log.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@...afoo.de>
> Signed-off-by: Michael Hennerich <michael.hennerich@...log.com>
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@...log.com>

Applied thanks.  

Jonathan

> ---
>  drivers/iio/adc/Kconfig  |  15 ++
>  drivers/iio/adc/Makefile |   1 +
>  drivers/iio/adc/ad9467.c | 420 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 436 insertions(+)
>  create mode 100644 drivers/iio/adc/ad9467.c
> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 445070abf376..a0796510f9d4 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..362993daedaf
> --- /dev/null
> +++ b/drivers/iio/adc/ad9467.c
> @@ -0,0 +1,420 @@
> +// 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_device.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 tbuf[2], rbuf[1];
> +	int ret;
> +
> +	tbuf[0] = 0x80 | (reg >> 8);
> +	tbuf[1] = reg & 0xFF;
> +
> +	ret = spi_write_then_read(spi,
> +				  tbuf, ARRAY_SIZE(tbuf),
> +				  rbuf, ARRAY_SIZE(rbuf));
> +
> +	if (ret < 0)
> +		return ret;
> +
> +	return rbuf[0];
> +}
> +
> +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_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:
> +		*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:
> +		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 = &ad9467_chip_tbl[ID_AD9467], },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, ad9467_of_match);
> +
> +static int ad9467_probe(struct spi_device *spi)
> +{
> +	const struct adi_axi_adc_chip_info *info;
> +	struct adi_axi_adc_conv *conv;
> +	struct ad9467_state *st;
> +	unsigned int id;
> +	int ret;
> +
> +	info = of_device_get_match_data(&spi->dev);
> +	if (!info)
> +		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);
> +
> +	conv->chip_info = info;
> +
> +	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@...log.com>");
> +MODULE_DESCRIPTION("Analog Devices AD9467 ADC driver");
> +MODULE_LICENSE("GPL v2");

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