Re: [PATCH v4 2/2] iio: adc: Add driver support for AD7292

Jonathan Cameron
2019-11-10T16:08:11Z

On Fri, 8 Nov 2019 10:56:50 -0300
Marcelo Schmitt <marcelo.schmitt1@gmail.com> wrote:

> The AD7292 is a 10-bit monitor and control system with ADC, DACs,
> temperature sensor, and GPIOs.
>
> Configure AD7292 devices in direct access mode, enabling single-ended
> ADC readings.
>
> Datasheet:
> Link: https://www.analog.com/media/en/technical-documentation/data-sheets/ad7292.pdf
>
> Signed-off-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
Looks good to me.

Applied to the togreg branch of iio.git and pushed out as testing for the
autobuilders to play with it.

Thanks,

Jonathan

> ---
> Changelog V3 -> V4:
> - added brackets to shield macro parameters
>
> MAINTAINERS | 1 +
> drivers/iio/adc/Kconfig | 10 ++
> drivers/iio/adc/Makefile | 1 +
> drivers/iio/adc/ad7292.c | 350 +++++++++++++++++++++++++++++++++++++++
> 4 files changed, 362 insertions(+)
> create mode 100644 drivers/iio/adc/ad7292.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 5d00e871c4c6..5941cfc0d6f7 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -818,6 +818,7 @@ M: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
> L: linux-iio@vger.kernel.org
> W: http://ez.analog.com/community/linux-device-drivers
> S: Supported
> +F: drivers/iio/adc/ad7292.c
> F: Documentation/devicetree/bindings/iio/adc/adi,ad7292.yaml
>
> ANALOG DEVICES INC AD7606 DRIVER
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 632b331429c6..02587c990cb5 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -59,6 +59,16 @@ config AD7291
> To compile this driver as a module, choose M here: the
> module will be called ad7291.
>
> +config AD7292
> + tristate "Analog Devices AD7292 ADC driver"
> + depends on SPI
> + help
> + Say yes here to build support for Analog Devices AD7292
> + 8 Channel ADC with temperature sensor.
> +
> + To compile this driver as a module, choose M here: the
> + module will be called ad7292.
> +
> config AD7298
> tristate "Analog Devices AD7298 ADC driver"
> depends on SPI
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index 4779ab3ff8fb..1818f2f66566 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -11,6 +11,7 @@ obj-$(CONFIG_AD7124) += ad7124.o
> obj-$(CONFIG_AD7173) += ad7173.o
> obj-$(CONFIG_AD7266) += ad7266.o
> obj-$(CONFIG_AD7291) += ad7291.o
> +obj-$(CONFIG_AD7292) += ad7292.o
> obj-$(CONFIG_AD7298) += ad7298.o
> obj-$(CONFIG_AD738X) += ad738x.o
> obj-$(CONFIG_AD7768) += ad7768-1.o
> diff --git a/drivers/iio/adc/ad7292.c b/drivers/iio/adc/ad7292.c
> new file mode 100644
> index 000000000000..a6798f7dfdb8
> --- /dev/null
> +++ b/drivers/iio/adc/ad7292.c
> @@ -0,0 +1,350 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Analog Devices AD7292 SPI ADC driver
> + *
> + * Copyright 2019 Analog Devices Inc.
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/device.h>
> +#include <linux/module.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/spi/spi.h>
> +
> +#include <linux/iio/iio.h>
> +
> +#define ADI_VENDOR_ID 0x0018
> +
> +/* AD7292 registers definition */
> +#define AD7292_REG_VENDOR_ID 0x00
> +#define AD7292_REG_CONF_BANK 0x05
> +#define AD7292_REG_CONV_COMM 0x0E
> +#define AD7292_REG_ADC_CH(x) (0x10 + (x))
> +
> +/* AD7292 configuration bank subregisters definition */
> +#define AD7292_BANK_REG_VIN_RNG0 0x10
> +#define AD7292_BANK_REG_VIN_RNG1 0x11
> +#define AD7292_BANK_REG_SAMP_MODE 0x12
> +
> +#define AD7292_RD_FLAG_MSK(x) (BIT(7) | ((x) & 0x3F))
> +
> +/* AD7292_REG_ADC_CONVERSION */
> +#define AD7292_ADC_DATA_MASK GENMASK(15, 6)
> +#define AD7292_ADC_DATA(x) FIELD_GET(AD7292_ADC_DATA_MASK, x)
> +
> +/* AD7292_CHANNEL_SAMPLING_MODE */
> +#define AD7292_CH_SAMP_MODE(reg, ch) (((reg) >> 8) & BIT(ch))
> +
> +/* AD7292_CHANNEL_VIN_RANGE */
> +#define AD7292_CH_VIN_RANGE(reg, ch) ((reg) & BIT(ch))
> +
> +#define AD7292_VOLTAGE_CHAN(_chan) \
> +{ \
> + .type = IIO_VOLTAGE, \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
> + BIT(IIO_CHAN_INFO_SCALE), \
> + .indexed = 1, \
> + .channel = _chan, \
> +}
> +
> +static const struct iio_chan_spec ad7292_channels[] = {
> + AD7292_VOLTAGE_CHAN(0),
> + AD7292_VOLTAGE_CHAN(1),
> + AD7292_VOLTAGE_CHAN(2),
> + AD7292_VOLTAGE_CHAN(3),
> + AD7292_VOLTAGE_CHAN(4),
> + AD7292_VOLTAGE_CHAN(5),
> + AD7292_VOLTAGE_CHAN(6),
> + AD7292_VOLTAGE_CHAN(7)
> +};
> +
> +static const struct iio_chan_spec ad7292_channels_diff[] = {
> + {
> + .type = IIO_VOLTAGE,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> + .indexed = 1,
> + .differential = 1,
> + .channel = 0,
> + .channel2 = 1,
> + },
> + AD7292_VOLTAGE_CHAN(2),
> + AD7292_VOLTAGE_CHAN(3),
> + AD7292_VOLTAGE_CHAN(4),
> + AD7292_VOLTAGE_CHAN(5),
> + AD7292_VOLTAGE_CHAN(6),
> + AD7292_VOLTAGE_CHAN(7)
> +};
> +
> +struct ad7292_state {
> + struct spi_device *spi;
> + struct regulator *reg;
> + unsigned short vref_mv;
> +
> + __be16 d16 ____cacheline_aligned;
> + u8 d8[2];
> +};
> +
> +static int ad7292_spi_reg_read(struct ad7292_state *st, unsigned int addr)
> +{
> + int ret;
> +
> + st->d8[0] = AD7292_RD_FLAG_MSK(addr);
> +
> + ret = spi_write_then_read(st->spi, st->d8, 1, &st->d16, 2);
> + if (ret < 0)
> + return ret;
> +
> + return be16_to_cpu(st->d16);
> +}
> +
> +static int ad7292_spi_subreg_read(struct ad7292_state *st, unsigned int addr,
> + unsigned int sub_addr, unsigned int len)
> +{
> + unsigned int shift = 16 - (8 * len);
> + int ret;
> +
> + st->d8[0] = AD7292_RD_FLAG_MSK(addr);
> + st->d8[1] = sub_addr;
> +
> + ret = spi_write_then_read(st->spi, st->d8, 2, &st->d16, len);
> + if (ret < 0)
> + return ret;
> +
> + return (be16_to_cpu(st->d16) >> shift);
> +}
> +
> +static int ad7292_single_conversion(struct ad7292_state *st,
> + unsigned int chan_addr)
> +{
> + int ret;
> +
> + struct spi_transfer t[] = {
> + {
> + .tx_buf = &st->d8,
> + .len = 4,
> + .delay_usecs = 6,
> + }, {
> + .rx_buf = &st->d16,
> + .len = 2,
> + },
> + };
> +
> + st->d8[0] = chan_addr;
> + st->d8[1] = AD7292_RD_FLAG_MSK(AD7292_REG_CONV_COMM);
> +
> + ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
> +
> + if (ret < 0)
> + return ret;
> +
> + return be16_to_cpu(st->d16);
> +}
> +
> +static int ad7292_vin_range_multiplier(struct ad7292_state *st, int channel)
> +{
> + int samp_mode, range0, range1, factor = 1;
> +
> + /*
> + * Every AD7292 ADC channel may have its input range adjusted according
> + * to the settings at the ADC sampling mode and VIN range subregisters.
> + * For a given channel, the minimum input range is equal to Vref, and it
> + * may be increased by a multiplier factor of 2 or 4 according to the
> + * following rule:
> + * If channel is being sampled with respect to AGND:
> + * factor = 4 if VIN range0 and VIN range1 equal 0
> + * factor = 2 if only one of VIN ranges equal 1
> + * factor = 1 if both VIN range0 and VIN range1 equal 1
> + * If channel is being sampled with respect to AVDD:
> + * factor = 4 if VIN range0 and VIN range1 equal 0
> + * Behavior is undefined if any of VIN range doesn't equal 0
> + */
> +
> + samp_mode = ad7292_spi_subreg_read(st, AD7292_REG_CONF_BANK,
> + AD7292_BANK_REG_SAMP_MODE, 2);
> +
> + if (samp_mode < 0)
> + return samp_mode;
> +
> + range0 = ad7292_spi_subreg_read(st, AD7292_REG_CONF_BANK,
> + AD7292_BANK_REG_VIN_RNG0, 2);
> +
> + if (range0 < 0)
> + return range0;
> +
> + range1 = ad7292_spi_subreg_read(st, AD7292_REG_CONF_BANK,
> + AD7292_BANK_REG_VIN_RNG1, 2);
> +
> + if (range1 < 0)
> + return range1;
> +
> + if (AD7292_CH_SAMP_MODE(samp_mode, channel)) {
> + /* Sampling with respect to AGND */
> + if (!AD7292_CH_VIN_RANGE(range0, channel))
> + factor *= 2;
> +
> + if (!AD7292_CH_VIN_RANGE(range1, channel))
> + factor *= 2;
> +
> + } else {
> + /* Sampling with respect to AVDD */
> + if (AD7292_CH_VIN_RANGE(range0, channel) ||
> + AD7292_CH_VIN_RANGE(range1, channel))
> + return -EPERM;
> +
> + factor = 4;
> + }
> +
> + return factor;
> +}
> +
> +static int ad7292_read_raw(struct iio_dev *indio_dev,
> + const struct iio_chan_spec *chan,
> + int *val, int *val2, long info)
> +{
> + struct ad7292_state *st = iio_priv(indio_dev);
> + unsigned int ch_addr;
> + int ret;
> +
> + switch (info) {
> + case IIO_CHAN_INFO_RAW:
> + ch_addr = AD7292_REG_ADC_CH(chan->channel);
> + ret = ad7292_single_conversion(st, ch_addr);
> + if (ret < 0)
> + return ret;
> +
> + *val = AD7292_ADC_DATA(ret);
> +
> + return IIO_VAL_INT;
> + case IIO_CHAN_INFO_SCALE:
> + /*
> + * To convert a raw value to standard units, the IIO defines
> + * this formula: Scaled value = (raw + offset) * scale.
> + * For the scale to be a correct multiplier for (raw + offset),
> + * it must be calculated as the input range divided by the
> + * number of possible distinct input values. Given the ADC data
> + * is 10 bit long, it may assume 2^10 distinct values.
> + * Hence, scale = range / 2^10. The IIO_VAL_FRACTIONAL_LOG2
> + * return type indicates to the IIO API to divide *val by 2 to
> + * the power of *val2 when returning from read_raw.
> + */
> +
> + ret = ad7292_vin_range_multiplier(st, chan->channel);
> + if (ret < 0)
> + return ret;
> +
> + *val = st->vref_mv * ret;
> + *val2 = 10;
> + return IIO_VAL_FRACTIONAL_LOG2;
> + default:
> + break;
> + }
> + return -EINVAL;
> +}
> +
> +static const struct iio_info ad7292_info = {
> + .read_raw = ad7292_read_raw,
> +};
> +
> +static void ad7292_regulator_disable(void *data)
> +{
> + struct ad7292_state *st = data;
> +
> + regulator_disable(st->reg);
> +}
> +
> +static int ad7292_probe(struct spi_device *spi)
> +{
> + struct ad7292_state *st;
> + struct iio_dev *indio_dev;
> + struct device_node *child;
> + bool diff_channels = 0;
> + 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;
> +
> + ret = ad7292_spi_reg_read(st, AD7292_REG_VENDOR_ID);
> + if (ret != ADI_VENDOR_ID) {
> + dev_err(&spi->dev, "Wrong vendor id 0x%x\n", ret);
> + return -EINVAL;
> + }
> +
> + spi_set_drvdata(spi, indio_dev);
> +
> + st->reg = devm_regulator_get_optional(&spi->dev, "vref");
> + if (!IS_ERR(st->reg)) {
> + ret = regulator_enable(st->reg);
> + if (ret) {
> + dev_err(&spi->dev,
> + "Failed to enable external vref supply\n");
> + return ret;
> + }
> +
> + ret = devm_add_action_or_reset(&spi->dev,
> + ad7292_regulator_disable, st);
> + if (ret) {
> + regulator_disable(st->reg);
> + return ret;
> + }
> +
> + ret = regulator_get_voltage(st->reg);
> + if (ret < 0)
> + return ret;
> +
> + st->vref_mv = ret / 1000;
> + } else {
> + /* Use the internal voltage reference. */
> + st->vref_mv = 1250;
> + }
> +
> + indio_dev->dev.parent = &spi->dev;
> + indio_dev->name = spi_get_device_id(spi)->name;
> + indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->info = &ad7292_info;
> +
> + for_each_available_child_of_node(spi->dev.of_node, child) {
> + diff_channels = of_property_read_bool(child, "diff-channels");
> + if (diff_channels)
> + break;
> + }
> +
> + if (diff_channels) {
> + indio_dev->num_channels = ARRAY_SIZE(ad7292_channels_diff);
> + indio_dev->channels = ad7292_channels_diff;
> + } else {
> + indio_dev->num_channels = ARRAY_SIZE(ad7292_channels);
> + indio_dev->channels = ad7292_channels;
> + }
> +
> + return devm_iio_device_register(&spi->dev, indio_dev);
> +}
> +
> +static const struct spi_device_id ad7292_id_table[] = {
> + { "ad7292", 0 },
> + {}
> +};
> +MODULE_DEVICE_TABLE(spi, ad7292_id_table);
> +
> +static const struct of_device_id ad7292_of_match[] = {
> + { .compatible = "adi,ad7292" },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, ad7292_of_match);
> +
> +static struct spi_driver ad7292_driver = {
> + .driver = {
> + .name = "ad7292",
> + .of_match_table = ad7292_of_match,
> + },
> + .probe = ad7292_probe,
> + .id_table = ad7292_id_table,
> +};
> +module_spi_driver(ad7292_driver);
> +
> +MODULE_AUTHOR("Marcelo Schmitt <marcelo.schmitt1@gmail.com>");
> +MODULE_DESCRIPTION("Analog Devices AD7292 ADC driver");
> +MODULE_LICENSE("GPL v2");