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iio: adc: ad7380: add support for adaq4370-4 and adaq4380-4
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adaq4370-4 (2MSPS) and adaq4380-4 (4MSPS) are quad-channel precision data
acquisition signal chain μModule solutions compatible with the ad738x
family, with the following differences:

- pin selectable gain in front of each 4 adc
- internal reference is 3V derived from refin-supply (5V)
- additional supplies

This implies that IIO_CHAN_INFO_SCALE can not be shared by type for
these new devices.

Signed-off-by: Julien Stephan <[email protected]>
Reviewed-by: David Lechner <[email protected]>
Link: https://patch.msgid.link/20241030-ad7380-add-adaq4380-4-support-v4-4-864ff02babae@baylibre.com
Signed-off-by: Jonathan Cameron <[email protected]>
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@justeph @nunojsa
justeph authored and nunojsa committed Dec 12, 2024
1 parent fd1d1d5 commit a4c3029
Showing 1 changed file with 126 additions and 4 deletions.
130 changes: 126 additions & 4 deletions drivers/iio/adc/ad7380.c
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,8 @@
* ad7381-4 : https://www.analog.com/media/en/technical-documentation/data-sheets/ad7381-4.pdf
* ad7383/4-4 : https://www.analog.com/media/en/technical-documentation/data-sheets/ad7383-4-ad7384-4.pdf
* ad7386/7/8-4 : https://www.analog.com/media/en/technical-documentation/data-sheets/ad7386-4-7387-4-7388-4.pdf
* adaq4370-4 : https://www.analog.com/media/en/technical-documentation/data-sheets/adaq4370-4.pdf
* adaq4380-4 : https://www.analog.com/media/en/technical-documentation/data-sheets/adaq4380-4.pdf
*/

#include <linux/align.h>
Expand All @@ -22,11 +24,14 @@
#include <linux/device.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/math.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/units.h>
#include <linux/util_macros.h>

#include <linux/iio/buffer.h>
#include <linux/iio/iio.h>
Expand All @@ -36,6 +41,8 @@
#define MAX_NUM_CHANNELS 8
/* 2.5V internal reference voltage */
#define AD7380_INTERNAL_REF_MV 2500
/* 3.3V internal reference voltage for ADAQ */
#define ADAQ4380_INTERNAL_REF_MV 3300

/* reading and writing registers is more reliable at lower than max speed */
#define AD7380_REG_WR_SPEED_HZ 10000000
Expand Down Expand Up @@ -82,6 +89,7 @@
* supports only 1 SDO line (standard SPI transaction)
*/
#define AD7380_NUM_SDO_LINES 1
#define AD7380_DEFAULT_GAIN_MILLI 1000

struct ad7380_timing_specs {
const unsigned int t_csh_ns; /* CS minimum high time */
Expand All @@ -92,10 +100,12 @@ struct ad7380_chip_info {
const struct iio_chan_spec *channels;
unsigned int num_channels;
unsigned int num_simult_channels;
bool has_hardware_gain;
bool has_mux;
const char * const *supplies;
unsigned int num_supplies;
bool external_ref_only;
bool adaq_internal_ref_only;
const char * const *vcm_supplies;
unsigned int num_vcm_supplies;
const unsigned long *available_scan_masks;
Expand Down Expand Up @@ -187,11 +197,12 @@ static const struct iio_scan_type ad7380_scan_type_16_u[] = {
},
};

#define AD7380_CHANNEL(index, bits, diff, sign) { \
#define _AD7380_CHANNEL(index, bits, diff, sign, gain) { \
.type = IIO_VOLTAGE, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
((gain) ? BIT(IIO_CHAN_INFO_SCALE) : 0) | \
((diff) ? 0 : BIT(IIO_CHAN_INFO_OFFSET)), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
.info_mask_shared_by_type = ((gain) ? 0 : BIT(IIO_CHAN_INFO_SCALE)) | \
BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
.info_mask_shared_by_type_available = \
BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
Expand All @@ -205,6 +216,12 @@ static const struct iio_scan_type ad7380_scan_type_16_u[] = {
.num_ext_scan_type = ARRAY_SIZE(ad7380_scan_type_##bits##_##sign), \
}

#define AD7380_CHANNEL(index, bits, diff, sign) \
_AD7380_CHANNEL(index, bits, diff, sign, false)

#define ADAQ4380_CHANNEL(index, bits, diff, sign) \
_AD7380_CHANNEL(index, bits, diff, sign, true)

#define DEFINE_AD7380_2_CHANNEL(name, bits, diff, sign) \
static const struct iio_chan_spec name[] = { \
AD7380_CHANNEL(0, bits, diff, sign), \
Expand All @@ -221,6 +238,15 @@ static const struct iio_chan_spec name[] = { \
IIO_CHAN_SOFT_TIMESTAMP(4), \
}

#define DEFINE_ADAQ4380_4_CHANNEL(name, bits, diff, sign) \
static const struct iio_chan_spec name[] = { \
ADAQ4380_CHANNEL(0, bits, diff, sign), \
ADAQ4380_CHANNEL(1, bits, diff, sign), \
ADAQ4380_CHANNEL(2, bits, diff, sign), \
ADAQ4380_CHANNEL(3, bits, diff, sign), \
IIO_CHAN_SOFT_TIMESTAMP(4), \
}

#define DEFINE_AD7380_8_CHANNEL(name, bits, diff, sign) \
static const struct iio_chan_spec name[] = { \
AD7380_CHANNEL(0, bits, diff, sign), \
Expand All @@ -239,6 +265,7 @@ DEFINE_AD7380_2_CHANNEL(ad7380_channels, 16, 1, s);
DEFINE_AD7380_2_CHANNEL(ad7381_channels, 14, 1, s);
DEFINE_AD7380_4_CHANNEL(ad7380_4_channels, 16, 1, s);
DEFINE_AD7380_4_CHANNEL(ad7381_4_channels, 14, 1, s);
DEFINE_ADAQ4380_4_CHANNEL(adaq4380_4_channels, 16, 1, s);
/* pseudo differential */
DEFINE_AD7380_2_CHANNEL(ad7383_channels, 16, 0, s);
DEFINE_AD7380_2_CHANNEL(ad7384_channels, 14, 0, s);
Expand All @@ -257,6 +284,10 @@ static const char * const ad7380_supplies[] = {
"vcc", "vlogic",
};

static const char * const adaq4380_supplies[] = {
"ldo", "vcc", "vlogic", "vs-p", "vs-n", "refin",
};

static const char * const ad7380_2_channel_vcm_supplies[] = {
"aina", "ainb",
};
Expand Down Expand Up @@ -347,6 +378,11 @@ static const int ad7380_oversampling_ratios[] = {
1, 2, 4, 8, 16, 32,
};

/* Gains stored as fractions of 1000 so they can be expressed by integers. */
static const int ad7380_gains[] = {
300, 600, 1000, 1600,
};

static const struct ad7380_chip_info ad7380_chip_info = {
.name = "ad7380",
.channels = ad7380_channels,
Expand Down Expand Up @@ -516,6 +552,32 @@ static const struct ad7380_chip_info ad7388_4_chip_info = {
.timing_specs = &ad7380_4_timing,
};

static const struct ad7380_chip_info adaq4370_4_chip_info = {
.name = "adaq4370-4",
.channels = adaq4380_4_channels,
.num_channels = ARRAY_SIZE(adaq4380_4_channels),
.num_simult_channels = 4,
.supplies = adaq4380_supplies,
.num_supplies = ARRAY_SIZE(adaq4380_supplies),
.adaq_internal_ref_only = true,
.has_hardware_gain = true,
.available_scan_masks = ad7380_4_channel_scan_masks,
.timing_specs = &ad7380_4_timing,
};

static const struct ad7380_chip_info adaq4380_4_chip_info = {
.name = "adaq4380-4",
.channels = adaq4380_4_channels,
.num_channels = ARRAY_SIZE(adaq4380_4_channels),
.num_simult_channels = 4,
.supplies = adaq4380_supplies,
.num_supplies = ARRAY_SIZE(adaq4380_supplies),
.adaq_internal_ref_only = true,
.has_hardware_gain = true,
.available_scan_masks = ad7380_4_channel_scan_masks,
.timing_specs = &ad7380_4_timing,
};

struct ad7380_state {
const struct ad7380_chip_info *chip_info;
struct spi_device *spi;
Expand All @@ -526,6 +588,7 @@ struct ad7380_state {
bool seq;
unsigned int vref_mv;
unsigned int vcm_mv[MAX_NUM_CHANNELS];
unsigned int gain_milli[MAX_NUM_CHANNELS];
/* xfers, message an buffer for reading sample data */
struct spi_transfer normal_xfer[2];
struct spi_message normal_msg;
Expand Down Expand Up @@ -876,8 +939,15 @@ static int ad7380_read_raw(struct iio_dev *indio_dev,
* * (2 × VREF) / 2^N, for differential chips
* * VREF / 2^N, for pseudo-differential chips
* where N is the ADC resolution (i.e realbits)
*
* The gain is stored as a fraction of 1000 and, as we need to
* divide vref_mv by the gain, we invert the gain/1000 fraction.
*/
*val = st->vref_mv;
if (st->chip_info->has_hardware_gain)
*val = mult_frac(st->vref_mv, MILLI,
st->gain_milli[chan->scan_index]);
else
*val = st->vref_mv;
*val2 = scan_type->realbits - chan->differential;

return IIO_VAL_FRACTIONAL_LOG2;
Expand Down Expand Up @@ -1059,7 +1129,19 @@ static int ad7380_probe(struct spi_device *spi)
"Failed to enable power supplies\n");
fsleep(T_POWERUP_US);

if (st->chip_info->external_ref_only) {
if (st->chip_info->adaq_internal_ref_only) {
/*
* ADAQ chips use fixed internal reference but still
* require a specific reference supply to power it.
* "refin" is already enabled with other power supplies
* in bulk_get_enable().
*/

st->vref_mv = ADAQ4380_INTERNAL_REF_MV;

/* these chips don't have a register bit for this */
external_ref_en = false;
} else if (st->chip_info->external_ref_only) {
ret = devm_regulator_get_enable_read_voltage(dev, "refin");
if (ret < 0)
return dev_err_probe(dev, ret,
Expand Down Expand Up @@ -1103,6 +1185,42 @@ static int ad7380_probe(struct spi_device *spi)
st->vcm_mv[i] = ret / 1000;
}

for (i = 0; i < MAX_NUM_CHANNELS; i++)
st->gain_milli[i] = AD7380_DEFAULT_GAIN_MILLI;

if (st->chip_info->has_hardware_gain) {
device_for_each_child_node_scoped(dev, node) {
unsigned int channel, gain;
int gain_idx;

ret = fwnode_property_read_u32(node, "reg", &channel);
if (ret)
return dev_err_probe(dev, ret,
"Failed to read reg property\n");

if (channel >= st->chip_info->num_channels - 1)
return dev_err_probe(dev, -EINVAL,
"Invalid channel number %i\n",
channel);

ret = fwnode_property_read_u32(node, "adi,gain-milli",
&gain);
if (ret && ret != -EINVAL)
return dev_err_probe(dev, ret,
"Failed to read gain for channel %i\n",
channel);
if (ret != -EINVAL) {
/*
* Match gain value from dt to one of supported
* gains
*/
gain_idx = find_closest(gain, ad7380_gains,
ARRAY_SIZE(ad7380_gains));
st->gain_milli[channel] = ad7380_gains[gain_idx];
}
}
}

st->regmap = devm_regmap_init(dev, NULL, st, &ad7380_regmap_config);
if (IS_ERR(st->regmap))
return dev_err_probe(dev, PTR_ERR(st->regmap),
Expand Down Expand Up @@ -1185,6 +1303,8 @@ static const struct of_device_id ad7380_of_match_table[] = {
{ .compatible = "adi,ad7386-4", .data = &ad7386_4_chip_info },
{ .compatible = "adi,ad7387-4", .data = &ad7387_4_chip_info },
{ .compatible = "adi,ad7388-4", .data = &ad7388_4_chip_info },
{ .compatible = "adi,adaq4370-4", .data = &adaq4370_4_chip_info },
{ .compatible = "adi,adaq4380-4", .data = &adaq4380_4_chip_info },
{ }
};

Expand All @@ -1203,6 +1323,8 @@ static const struct spi_device_id ad7380_id_table[] = {
{ "ad7386-4", (kernel_ulong_t)&ad7386_4_chip_info },
{ "ad7387-4", (kernel_ulong_t)&ad7387_4_chip_info },
{ "ad7388-4", (kernel_ulong_t)&ad7388_4_chip_info },
{ "adaq4370-4", (kernel_ulong_t)&adaq4370_4_chip_info },
{ "adaq4380-4", (kernel_ulong_t)&adaq4380_4_chip_info },
{ }
};
MODULE_DEVICE_TABLE(spi, ad7380_id_table);
Expand Down

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