iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

iio: amplifiers: ada4250: add support for ADA4250

Browse Source 
The ADA4250 is an instrumentation amplifier with SPI/pin-strap
progammable gains that is optimized for ultra-low power systems.
With a minimum supply voltage of 1.7V, 26uA of quiescent current,
a shutdown mode, a sleep mode, and a fast wake up settling time,
ADA4250 can be power cycled on a battery powered system for even
futher savings.

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Link: https://lore.kernel.org/r/20220223120112.8067-2-antoniu.miclaus@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Antoniu Miclaus 2022-02-23 14:01:11 +02:00 committed by Jonathan Cameron
parent 602744fa9f
commit 28b4c30bfa
3 changed files with 415 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
drivers/iio/amplifiers/Kconfig
View File

@ -23,6 +23,17 @@ config AD8366
To compile this driver as a module, choose M here: the
module will be called ad8366.
config ADA4250
tristate "Analog Devices ADA4250 Instrumentation Amplifier"
depends on SPI
help
Say yes here to build support for Analog Devices ADA4250
SPI Amplifier's support. The driver provides direct access via
sysfs.
To compile this driver as a module, choose M here: the
module will be called ada4250.
config HMC425
tristate "Analog Devices HMC425A and similar GPIO Gain Amplifiers"
depends on GPIOLIB

1
drivers/iio/amplifiers/Makefile
View File

@ -5,4 +5,5 @@
# When adding new entries keep the list in alphabetical order
obj-$(CONFIG_AD8366) += ad8366.o
obj-$(CONFIG_ADA4250) += ada4250.o
obj-$(CONFIG_HMC425) += hmc425a.o

403
drivers/iio/amplifiers/ada4250.c Normal file
View File

@ -0,0 +1,403 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* ADA4250 driver
*
* Copyright 2022 Analog Devices Inc.
*/
#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/device.h>
#include <linux/iio/iio.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>
#include <asm/unaligned.h>
/* ADA4250 Register Map */
#define ADA4250_REG_GAIN_MUX 0x00
#define ADA4250_REG_REFBUF_EN 0x01
#define ADA4250_REG_RESET 0x02
#define ADA4250_REG_SNSR_CAL_VAL 0x04
#define ADA4250_REG_SNSR_CAL_CNFG 0x05
#define ADA4250_REG_DIE_REV 0x18
#define ADA4250_REG_CHIP_ID 0x19
/* ADA4250_REG_GAIN_MUX Map */
#define ADA4250_GAIN_MUX_MSK GENMASK(2, 0)
/* ADA4250_REG_REFBUF Map */
#define ADA4250_REFBUF_MSK BIT(0)
/* ADA4250_REG_RESET Map */
#define ADA4250_RESET_MSK BIT(0)
/* ADA4250_REG_SNSR_CAL_VAL Map */
#define ADA4250_CAL_CFG_BIAS_MSK GENMASK(7, 0)
/* ADA4250_REG_SNSR_CAL_CNFG Bit Definition */
#define ADA4250_BIAS_SET_MSK GENMASK(3, 2)
#define ADA4250_RANGE_SET_MSK GENMASK(1, 0)
/* Miscellaneous definitions */
#define ADA4250_CHIP_ID 0x4250
#define ADA4250_RANGE1 0
#define ADA4250_RANGE4 3
/* ADA4250 current bias set */
enum ada4250_current_bias {
ADA4250_BIAS_DISABLED,
ADA4250_BIAS_BANDGAP,
ADA4250_BIAS_AVDD,
};
struct ada4250_state {
struct spi_device *spi;
struct regmap *regmap;
struct regulator *reg;
/* Protect against concurrent accesses to the device and data content */
struct mutex lock;
u8 bias;
u8 gain;
int offset_uv;
bool refbuf_en;
};
/* ADA4250 Current Bias Source Settings: Disabled, Bandgap Reference, AVDD */
static const int calibbias_table[] = {0, 1, 2};
/* ADA4250 Gain (V/V) values: 1, 2, 4, 8, 16, 32, 64, 128 */
static const int hwgain_table[] = {1, 2, 4, 8, 16, 32, 64, 128};
static const struct regmap_config ada4250_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
.read_flag_mask = BIT(7),
.max_register = 0x1A,
};
static int ada4250_set_offset_uv(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan,
int offset_uv)
{
struct ada4250_state *st = iio_priv(indio_dev);
int i, ret, x[8], max_vos, min_vos, voltage_v, vlsb = 0;
u8 offset_raw, range = ADA4250_RANGE1;
u32 lsb_coeff[6] = {1333, 2301, 4283, 8289, 16311, 31599};
if (st->bias == 0 || st->bias == 3)
return -EINVAL;
voltage_v = regulator_get_voltage(st->reg);
voltage_v = DIV_ROUND_CLOSEST(voltage_v, 1000000);
if (st->bias == ADA4250_BIAS_AVDD)
x[0] = voltage_v;
else
x[0] = 5;
x[1] = 126 * (x[0] - 1);
for (i = 0; i < 6; i++)
x[i + 2] = DIV_ROUND_CLOSEST(x[1] * 1000, lsb_coeff[i]);
if (st->gain == 0)
return -EINVAL;
/*
* Compute Range and Voltage per LSB for the Sensor Offset Calibration
* Example of computation for Range 1 and Range 2 (Curren Bias Set = AVDD):
* Range 1 Range 2
* Gain | Max Vos(mV) | LSB(mV) | Max Vos(mV) | LSB(mV) |
* 2 | X1*127 | X1=0.126(AVDD-1) | X1*3*127 | X1*3 |
* 4 | X2*127 | X2=X1/1.3333 | X2*3*127 | X2*3 |
* 8 | X3*127 | X3=X1/2.301 | X3*3*127 | X3*3 |
* 16 | X4*127 | X4=X1/4.283 | X4*3*127 | X4*3 |
* 32 | X5*127 | X5=X1/8.289 | X5*3*127 | X5*3 |
* 64 | X6*127 | X6=X1/16.311 | X6*3*127 | X6*3 |
* 128 | X7*127 | X7=X1/31.599 | X7*3*127 | X7*3 |
*/
for (i = ADA4250_RANGE1; i <= ADA4250_RANGE4; i++) {
max_vos = x[st->gain] * 127 * ((1 << (i + 1)) - 1);
min_vos = -1 * max_vos;
if (offset_uv > min_vos && offset_uv < max_vos) {
range = i;
vlsb = x[st->gain] * ((1 << (i + 1)) - 1);
break;
}
}
if (vlsb <= 0)
return -EINVAL;
offset_raw = DIV_ROUND_CLOSEST(abs(offset_uv), vlsb);
mutex_lock(&st->lock);
ret = regmap_update_bits(st->regmap, ADA4250_REG_SNSR_CAL_CNFG,
ADA4250_RANGE_SET_MSK,
FIELD_PREP(ADA4250_RANGE_SET_MSK, range));
if (ret)
goto exit;
st->offset_uv = offset_raw * vlsb;
/*
* To set the offset calibration value, use bits [6:0] and bit 7 as the
* polarity bit (set to "0" for a negative offset and "1" for a positive
* offset).
*/
if (offset_uv < 0) {
offset_raw |= BIT(7);
st->offset_uv *= (-1);
}
ret = regmap_write(st->regmap, ADA4250_REG_SNSR_CAL_VAL, offset_raw);
exit:
mutex_unlock(&st->lock);
return ret;
}
static int ada4250_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long info)
{
struct ada4250_state *st = iio_priv(indio_dev);
int ret;
switch (info) {
case IIO_CHAN_INFO_HARDWAREGAIN:
ret = regmap_read(st->regmap, ADA4250_REG_GAIN_MUX, val);
if (ret)
return ret;
*val = BIT(*val);
return IIO_VAL_INT;
case IIO_CHAN_INFO_OFFSET:
*val = st->offset_uv;
return IIO_VAL_INT;
case IIO_CHAN_INFO_CALIBBIAS:
ret = regmap_read(st->regmap, ADA4250_REG_SNSR_CAL_CNFG, val);
if (ret)
return ret;
*val = FIELD_GET(ADA4250_BIAS_SET_MSK, *val);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*val = 1;
*val2 = 1000000;
return IIO_VAL_FRACTIONAL;
default:
return -EINVAL;
}
}
static int ada4250_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long info)
{
struct ada4250_state *st = iio_priv(indio_dev);
int ret;
switch (info) {
case IIO_CHAN_INFO_HARDWAREGAIN:
ret = regmap_write(st->regmap, ADA4250_REG_GAIN_MUX,
FIELD_PREP(ADA4250_GAIN_MUX_MSK, ilog2(val)));
if (ret)
return ret;
st->gain = ilog2(val);
return ret;
case IIO_CHAN_INFO_OFFSET:
return ada4250_set_offset_uv(indio_dev, chan, val);
case IIO_CHAN_INFO_CALIBBIAS:
ret = regmap_update_bits(st->regmap, ADA4250_REG_SNSR_CAL_CNFG,
ADA4250_BIAS_SET_MSK,
FIELD_PREP(ADA4250_BIAS_SET_MSK, val));
if (ret)
return ret;
st->bias = val;
return ret;
default:
return -EINVAL;
}
}
static int ada4250_read_avail(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
const int **vals, int *type, int *length,
long mask)
{
switch (mask) {
case IIO_CHAN_INFO_CALIBBIAS:
*vals = calibbias_table;
*type = IIO_VAL_INT;
*length = ARRAY_SIZE(calibbias_table);
return IIO_AVAIL_LIST;
case IIO_CHAN_INFO_HARDWAREGAIN:
*vals = hwgain_table;
*type = IIO_VAL_INT;
*length = ARRAY_SIZE(hwgain_table);
return IIO_AVAIL_LIST;
default:
return -EINVAL;
}
}
static int ada4250_reg_access(struct iio_dev *indio_dev,
unsigned int reg,
unsigned int write_val,
unsigned int *read_val)
{
struct ada4250_state *st = iio_priv(indio_dev);
if (read_val)
return regmap_read(st->regmap, reg, read_val);
else
return regmap_write(st->regmap, reg, write_val);
}
static const struct iio_info ada4250_info = {
.read_raw = ada4250_read_raw,
.write_raw = ada4250_write_raw,
.read_avail = &ada4250_read_avail,
.debugfs_reg_access = &ada4250_reg_access,
};
static const struct iio_chan_spec ada4250_channels[] = {
{
.type = IIO_VOLTAGE,
.output = 1,
.indexed = 1,
.channel = 0,
.info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN) |
BIT(IIO_CHAN_INFO_OFFSET) |
BIT(IIO_CHAN_INFO_CALIBBIAS) |
BIT(IIO_CHAN_INFO_SCALE),
.info_mask_separate_available = BIT(IIO_CHAN_INFO_CALIBBIAS) |
BIT(IIO_CHAN_INFO_HARDWAREGAIN),
}
};
static void ada4250_reg_disable(void *data)
{
regulator_disable(data);
}
static int ada4250_init(struct ada4250_state *st)
{
int ret;
u16 chip_id;
u8 data[2] __aligned(8) = {};
struct spi_device *spi = st->spi;
st->refbuf_en = device_property_read_bool(&spi->dev, "adi,refbuf-enable");
st->reg = devm_regulator_get(&spi->dev, "avdd");
if (IS_ERR(st->reg))
return dev_err_probe(&spi->dev, PTR_ERR(st->reg),
"failed to get the AVDD voltage\n");
ret = regulator_enable(st->reg);
if (ret) {
dev_err(&spi->dev, "Failed to enable specified AVDD supply\n");
return ret;
}
ret = devm_add_action_or_reset(&spi->dev, ada4250_reg_disable, st->reg);
if (ret)
return ret;
ret = regmap_write(st->regmap, ADA4250_REG_RESET,
FIELD_PREP(ADA4250_RESET_MSK, 1));
if (ret)
return ret;
ret = regmap_bulk_read(st->regmap, ADA4250_REG_CHIP_ID, data, 2);
if (ret)
return ret;
chip_id = get_unaligned_le16(data);
if (chip_id != ADA4250_CHIP_ID) {
dev_err(&spi->dev, "Invalid chip ID.\n");
return -EINVAL;
}
return regmap_write(st->regmap, ADA4250_REG_REFBUF_EN,
FIELD_PREP(ADA4250_REFBUF_MSK, st->refbuf_en));
}
static int ada4250_probe(struct spi_device *spi)
{
struct iio_dev *indio_dev;
struct regmap *regmap;
struct ada4250_state *st;
int ret;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
regmap = devm_regmap_init_spi(spi, &ada4250_regmap_config);
if (IS_ERR(regmap))
return PTR_ERR(regmap);
st = iio_priv(indio_dev);
st->regmap = regmap;
st->spi = spi;
indio_dev->info = &ada4250_info;
indio_dev->name = "ada4250";
indio_dev->channels = ada4250_channels;
indio_dev->num_channels = ARRAY_SIZE(ada4250_channels);
mutex_init(&st->lock);
ret = ada4250_init(st);
if (ret) {
dev_err(&spi->dev, "ADA4250 init failed\n");
return ret;
}
return devm_iio_device_register(&spi->dev, indio_dev);
}
static const struct spi_device_id ada4250_id[] = {
{ "ada4250", 0 },
{}
};
MODULE_DEVICE_TABLE(spi, ada4250_id);
static const struct of_device_id ada4250_of_match[] = {
{ .compatible = "adi,ada4250" },
{},
};
MODULE_DEVICE_TABLE(of, ada4250_of_match);
static struct spi_driver ada4250_driver = {
.driver = {
.name = "ada4250",
.of_match_table = ada4250_of_match,
},
.probe = ada4250_probe,
.id_table = ada4250_id,
};
module_spi_driver(ada4250_driver);
MODULE_AUTHOR("Antoniu Miclaus <antoniu.miclaus@analog.com");
MODULE_DESCRIPTION("Analog Devices ADA4250");
MODULE_LICENSE("GPL v2");