404 lines
9.8 KiB
C
404 lines
9.8 KiB
C
// 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");
|