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SubjectRe: [PATCH 4/5] iio: adc: ad9467: add support AD9467 ADC
On Wed, 26 Feb 2020 11:30:33 +0000
"Ardelean, Alexandru" <alexandru.Ardelean@analog.com> wrote:

> On Fri, 2020-02-21 at 12:57 +0000, Jonathan Cameron wrote:
> > On Thu, 20 Feb 2020 17:03:16 +0200
> > Alexandru Ardelean <alexandru.ardelean@analog.com> wrote:
> >
> > > 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>
> >
> > A few minor things inline.
> >
> > Jonathan
> > > ---
> > > drivers/iio/adc/Kconfig | 15 ++
> > > drivers/iio/adc/Makefile | 1 +
> > > drivers/iio/adc/ad9467.c | 447 +++++++++++++++++++++++++++++++++++++++
> > > 3 files changed, 463 insertions(+)
> > > create mode 100644 drivers/iio/adc/ad9467.c
> > >
> > > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> > > index 6cd48a256122..229b8bc6f9b6 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 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 ASPEED_ADC
> > > tristate "Aspeed ADC"
> > > depends on ARCH_ASPEED || COMPILE_TEST
> > > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> > > index e14fabd53246..5018220b8ec7 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_ASPEED_ADC) += aspeed_adc.o
> > > obj-$(CONFIG_AT91_ADC) += at91_adc.o
> > > obj-$(CONFIG_AT91_SAMA5D2_ADC) += at91-sama5d2_adc.o
> > > diff --git a/drivers/iio/adc/ad9467.c b/drivers/iio/adc/ad9467.c
> > > new file mode 100644
> > > index 000000000000..f268bbb6bcf6
> > > --- /dev/null
> > > +++ b/drivers/iio/adc/ad9467.c
> > > @@ -0,0 +1,447 @@
> > > +// 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/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 ADI_ADC_REG_CHIP_PORT_CONF 0x00
> > These prefixes should reflect the chip we are supporting here.
> > They aren't true for 'all' ADI parts.
> >
> > You could come up with some 'generic' but not to generic prefix
> > if you prefer.
>
> How about AN877_ADC ?

I guess that works.

>
> >
> > > +#define ADI_ADC_REG_CHIP_ID 0x01
> > > +#define ADI_ADC_REG_CHIP_GRADE 0x02
> > > +#define ADI_ADC_REG_CHAN_INDEX 0x05
> > > +#define ADI_ADC_REG_TRANSFER 0xFF
> > > +#define ADI_ADC_REG_MODES 0x08
> > > +#define ADI_ADC_REG_TEST_IO 0x0D
> > > +#define ADI_ADC_REG_ADC_INPUT 0x0F
> > > +#define ADI_ADC_REG_OFFSET 0x10
> > > +#define ADI_ADC_REG_OUTPUT_MODE 0x14
> > > +#define ADI_ADC_REG_OUTPUT_ADJUST 0x15
> > > +#define ADI_ADC_REG_OUTPUT_PHASE 0x16
> > > +#define ADI_ADC_REG_OUTPUT_DELAY 0x17
> > > +#define ADI_ADC_REG_VREF 0x18
> > > +#define ADI_ADC_REG_ANALOG_INPUT 0x2C
> > > +
> > > +/* ADI_ADC_REG_TEST_IO */
> > > +#define ADI_ADC_TESTMODE_OFF 0x0
> > > +#define ADI_ADC_TESTMODE_MIDSCALE_SHORT 0x1
> > > +#define ADI_ADC_TESTMODE_POS_FULLSCALE 0x2
> > > +#define ADI_ADC_TESTMODE_NEG_FULLSCALE 0x3
> > > +#define ADI_ADC_TESTMODE_ALT_CHECKERBOARD 0x4
> > > +#define ADI_ADC_TESTMODE_PN23_SEQ 0x5
> > > +#define ADI_ADC_TESTMODE_PN9_SEQ 0x6
> > > +#define ADI_ADC_TESTMODE_ONE_ZERO_TOGGLE 0x7
> > > +#define ADI_ADC_TESTMODE_USER 0x8
> > > +#define ADI_ADC_TESTMODE_BIT_TOGGLE 0x9
> > > +#define ADI_ADC_TESTMODE_SYNC 0xA
> > > +#define ADI_ADC_TESTMODE_ONE_BIT_HIGH 0xB
> > > +#define ADI_ADC_TESTMODE_MIXED_BIT_FREQUENCY 0xC
> > > +#define ADI_ADC_TESTMODE_RAMP 0xF
> > > +
> > > +/* ADI_ADC_REG_TRANSFER */
> > > +#define ADI_ADC_TRANSFER_SYNC 0x1
> > > +
> > > +/* ADI_ADC_REG_OUTPUT_MODE */
> > > +#define ADI_ADC_OUTPUT_MODE_OFFSET_BINARY 0x0
> > > +#define ADI_ADC_OUTPUT_MODE_TWOS_COMPLEMENT 0x1
> > > +#define ADI_ADC_OUTPUT_MODE_GRAY_CODE 0x2
> > > +
> > > +/* ADI_ADC_REG_OUTPUT_PHASE */
> > > +#define ADI_ADC_OUTPUT_EVEN_ODD_MODE_EN 0x20
> > > +#define ADI_ADC_INVERT_DCO_CLK 0x80
> > > +
> > > +/* ADI_ADC_REG_OUTPUT_DELAY */
> > > +#define ADI_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 axi_adc_conv *conv, unsigned int reg,
> > > + unsigned int writeval, unsigned int *readval)
> > > +{
> > > + struct ad9467_state *st = 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, ADI_ADC_REG_TRANSFER,
> > > + ADI_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 axi_adc_conv *conv, int index,
> > > + unsigned int *val, unsigned int *val2)
> > > +{
> > > + const struct axi_adc_chip_info *info = conv->chip_info;
> > > + const struct iio_chan_spec *chan = &info->channels[0].iio_chan;
> > > + 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_separate = BIT(IIO_CHAN_INFO_CALIBSCALE) | \
> > > + BIT(IIO_CHAN_INFO_CALIBBIAS) | \
> > > + BIT(IIO_CHAN_INFO_CALIBPHASE) | \
> >
> > These don't seem to be handled that I can see...
> >
> > > + BIT(IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY), \
> > > + .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, \
> > > + .shift = 0, \
> >
> > shift of 0 is the "obvious" default so no need to specify it...
> >
> > > + }, \
> > > +}
> > > +
> > > +static const struct axi_adc_chan_spec ad9467_channels[] = {
> > > + {
> > > + .iio_chan = AD9467_CHAN(0, 0, 16, 'S'),
> > > + .num_lanes = 8,
> > > + },
> > > +};
> > > +
> > > +static const struct 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 axi_adc_conv *conv, int *val, int *val2)
> > > +{
> > > + const struct axi_adc_chip_info *info = conv->chip_info;
> > > + struct ad9467_state *st = axi_adc_conv_priv(conv);
> > > + unsigned int i, vref_val, vref_mask;
> > > +
> > > + vref_val = ad9467_spi_read(st->spi, ADI_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 axi_adc_conv *conv, int val, int val2)
> > > +{
> > > + const struct axi_adc_chip_info *info = conv->chip_info;
> > > + struct ad9467_state *st = 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, ADI_ADC_REG_VREF,
> > > + info->scale_table[i][1]);
> > > + ad9467_spi_write(st->spi, ADI_ADC_REG_TRANSFER,
> > > + ADI_ADC_TRANSFER_SYNC);
> > > + return 0;
> > > + }
> > > +
> > > + return -EINVAL;
> > > +}
> > > +
> > > +static int ad9467_read_raw(struct axi_adc_conv *conv,
> > > + struct iio_chan_spec const *chan,
> > > + int *val, int *val2, long m)
> > > +{
> > > + struct ad9467_state *st = 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;
> > > +
> > > + }
> > > + return -EINVAL;
> >
> > I'd put that in a default in the switch as you may get warnings
> > from some static checkers otherwise.
> >
> > > +}
> > > +
> > > +static int ad9467_write_raw(struct axi_adc_conv *conv,
> > > + struct iio_chan_spec const *chan,
> > > + int val, int val2, long mask)
> > > +{
> > > + const struct axi_adc_chip_info *info = conv->chip_info;
> > > + struct ad9467_state *st = axi_adc_conv_priv(conv);
> > > + unsigned long r_clk;
> > > + int ret;
> > > +
> > > + 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;
> > > + }
> > > +
> > > + ret = clk_set_rate(st->clk, r_clk);
> > > + if (ret < 0)
> > > + return ret;
> > return clk_set_rate(st->clk, r_clk) is probably the same.
> > Might as well do early returns everywhere.
> >
> > > +
> > > + break;
> > > + default:
> > > + return -EINVAL;
> > > + }
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static int ad9467_outputmode_set(struct spi_device *spi, unsigned int mode)
> > > +{
> > > + int ret;
> > > +
> > > + ret = ad9467_spi_write(spi, ADI_ADC_REG_OUTPUT_MODE, mode);
> > > + if (ret < 0)
> > > + return ret;
> > > +
> > > + return ad9467_spi_write(spi, ADI_ADC_REG_TRANSFER,
> > > + ADI_ADC_TRANSFER_SYNC);
> > > +}
> > > +
> > > +static int ad9467_preenable_setup(struct axi_adc_conv *conv)
> > > +{
> > > + struct ad9467_state *st = 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 |
> > > + ADI_ADC_OUTPUT_MODE_TWOS_COMPLEMENT;
> > > + break;
> >
> > return 0 unless you are going to add anything after the switch statement.
> >
> > > + default:
> > > + return -EINVAL;
> > > + }
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static void ad9467_clk_disable(void *data)
> > > +{
> > > + struct ad9467_state *st = data;
> > > +
> > > + clk_disable_unprepare(st->clk);
> > > +}
> > > +
> > > +static int ad9467_probe(struct spi_device *spi)
> > > +{
> > > + struct axi_adc_conv *conv;
> > > + struct ad9467_state *st;
> > > + unsigned int id;
> > > + int ret;
> > > +
> > > + conv = devm_axi_adc_conv_register(&spi->dev, sizeof(*st));
> > > +
> >
> > No blank line between a call and it's error handler.
> >
> > > + if (IS_ERR(conv))
> > > + return PTR_ERR(conv);
> > > +
> > > + st = axi_adc_conv_priv(conv);
> > > + st->spi = spi;
> > > +
> > > + st->clk = devm_clk_get(&spi->dev, "sample-clock");
> > > + 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 = spi_get_device_id(spi)->driver_data;
> > > + conv->chip_info = &ad9467_chip_info_tbl[id];
> > > +
> > > + id = ad9467_spi_read(spi, ADI_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 const struct spi_device_id ad9467_id[] = {
> > > + { "ad9467", ID_AD9467 },
> > > + {}
> > > +};
> > > +MODULE_DEVICE_TABLE(spi, ad9467_id);
> > > +
> > > +static const struct of_device_id ad9467_of_match[] = {
> > > + { .compatible = "adi,ad9467" },
> > > + {}
> > > +};
> > > +MODULE_DEVICE_TABLE(of, ad9467_of_match);
> > > +
> > > +static struct spi_driver ad9467_driver = {
> > > + .driver = {
> > > + .name = "ad9467",
> > > + .of_match_table = ad9467_of_match,
> > > + },
> > > + .probe = ad9467_probe,
> > > + .id_table = ad9467_id,
> >
> > This is something I've only just started raising in reviews.
> > If a driver can't realistically be instantiated without firmware
> > bindings, there isn't really any point in providing the id_table
> > that I can think of so please remove.
> >
> > > +};
> > > +module_spi_driver(ad9467_driver);
> > > +
> > > +MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
> > > +MODULE_DESCRIPTION("Analog Devices AD9467 ADC driver");
> > > +MODULE_LICENSE("GPL v2");

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