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iio: adc: max14001: New driver

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The MAX14001/MAX14002 is configurable, isolated 10-bit ADCs for multi-range
binary inputs. In addition to ADC readings, the MAX14001/MAX14002 offers
more features, like a binary comparator, a filtered reading that can
provide the average of the last 2, 4, or 8 ADC readings, and an inrush
comparator that triggers the inrush current. There is also a fault feature
that can diagnose seven possible fault conditions. And an option to select
an external or internal ADC voltage reference.

MAX14001/MAX14002 features implemented so far:
- Raw ADC reading.
- MV fault disable.
- Selection of external or internal ADC voltage reference, depending on
whether it is declared in the device tree.

Co-developed-by: Kim Seer Paller <kimseer.paller@analog.com>
Signed-off-by: Kim Seer Paller <kimseer.paller@analog.com>
Signed-off-by: Marilene Andrade Garcia <marilene.agarcia@gmail.com>
Tested-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
Reviewed-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Marilene Andrade Garcia
2025-10-15 02:12:08 -03:00
committed by Jonathan Cameron
parent 192e5bbf0a
commit 59795109fa
4 changed files with 403 additions and 0 deletions
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1
MAINTAINERS
View File

@@ -15181,6 +15181,7 @@ L: linux-iio@vger.kernel.org
S: Maintained
W: https://ez.analog.com/linux-software-drivers
F: Documentation/devicetree/bindings/iio/adc/adi,max14001.yaml
F: drivers/iio/adc/max14001.c
MAX15301 DRIVER
M: Daniel Nilsson <daniel.nilsson@flex.com>

10
drivers/iio/adc/Kconfig
View File

@@ -1020,6 +1020,16 @@ config MAX1363
To compile this driver as a module, choose M here: the module will be
called max1363.
config MAX14001
tristate "Analog Devices MAX14001/MAX14002 ADC driver"
depends on SPI
help
Say yes here to build support for Analog Devices MAX14001/MAX14002
Configurable, Isolated 10-bit ADCs for Multi-Range Binary Inputs.
To compile this driver as a module, choose M here: the module will be
called max14001.
config MAX34408
tristate "Maxim max34408/max344089 ADC driver"
depends on I2C

1
drivers/iio/adc/Makefile
View File

@@ -89,6 +89,7 @@ obj-$(CONFIG_MAX11205) += max11205.o
obj-$(CONFIG_MAX11410) += max11410.o
obj-$(CONFIG_MAX1241) += max1241.o
obj-$(CONFIG_MAX1363) += max1363.o
obj-$(CONFIG_MAX14001) += max14001.o
obj-$(CONFIG_MAX34408) += max34408.o
obj-$(CONFIG_MAX77541_ADC) += max77541-adc.o
obj-$(CONFIG_MAX9611) += max9611.o

391
drivers/iio/adc/max14001.c Normal file
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@@ -0,0 +1,391 @@
// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
/*
* Analog Devices MAX14001/MAX14002 ADC driver
*
* Copyright (C) 2023-2025 Analog Devices Inc.
* Copyright (C) 2023 Kim Seer Paller <kimseer.paller@analog.com>
* Copyright (c) 2025 Marilene Andrade Garcia <marilene.agarcia@gmail.com>
*
* Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/MAX14001-MAX14002.pdf
*/
#include <linux/array_size.h>
#include <linux/bitfield.h>
#include <linux/bitrev.h>
#include <linux/bits.h>
#include <linux/cleanup.h>
#include <linux/device.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>
#include <linux/types.h>
#include <linux/units.h>
#include <asm/byteorder.h>
#include <linux/iio/iio.h>
#include <linux/iio/types.h>
/* MAX14001 Registers Address */
#define MAX14001_REG_ADC 0x00
#define MAX14001_REG_FADC 0x01
#define MAX14001_REG_FLAGS 0x02
#define MAX14001_REG_FLTEN 0x03
#define MAX14001_REG_THL 0x04
#define MAX14001_REG_THU 0x05
#define MAX14001_REG_INRR 0x06
#define MAX14001_REG_INRT 0x07
#define MAX14001_REG_INRP 0x08
#define MAX14001_REG_CFG 0x09
#define MAX14001_REG_ENBL 0x0A
#define MAX14001_REG_ACT 0x0B
#define MAX14001_REG_WEN 0x0C
#define MAX14001_REG_VERIFICATION(x) ((x) + 0x10)
#define MAX14001_REG_CFG_BIT_EXRF BIT(5)
#define MAX14001_REG_WEN_VALUE_WRITE 0x294
#define MAX14001_MASK_ADDR GENMASK(15, 11)
#define MAX14001_MASK_WR BIT(10)
#define MAX14001_MASK_DATA GENMASK(9, 0)
struct max14001_state {
const struct max14001_chip_info *chip_info;
struct spi_device *spi;
struct regmap *regmap;
int vref_mV;
bool spi_hw_has_lsb_first;
/*
* The following buffers will be bit-reversed during device
* communication, because the device transmits and receives data
* LSB-first.
* DMA (thus cache coherency maintenance) requires the transfer
* buffers to live in their own cache lines.
*/
union {
__be16 be;
__le16 le;
} spi_tx_buffer __aligned(IIO_DMA_MINALIGN);
union {
__be16 be;
__le16 le;
} spi_rx_buffer;
};
struct max14001_chip_info {
const char *name;
};
static int max14001_read(void *context, unsigned int reg, unsigned int *val)
{
struct max14001_state *st = context;
struct spi_transfer xfers[] = {
{
.tx_buf = &st->spi_tx_buffer,
.len = sizeof(st->spi_tx_buffer),
.cs_change = 1,
}, {
.rx_buf = &st->spi_rx_buffer,
.len = sizeof(st->spi_rx_buffer),
},
};
int ret;
unsigned int addr, data;
/*
* Prepare SPI transmit buffer 16 bit-value and reverse bit order
* to align with the LSB-first input on SDI port in order to meet
* the device communication requirements. If the controller supports
* SPI_LSB_FIRST, this step will be handled by the SPI controller.
*/
addr = FIELD_PREP(MAX14001_MASK_ADDR, reg);
if (st->spi_hw_has_lsb_first)
st->spi_tx_buffer.le = cpu_to_le16(addr);
else
st->spi_tx_buffer.be = cpu_to_be16(bitrev16(addr));
ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers));
if (ret)
return ret;
/*
* Convert received 16-bit value to cpu-endian format and reverse
* bit order. If the controller supports SPI_LSB_FIRST, this step
* will be handled by the SPI controller.
*/
if (st->spi_hw_has_lsb_first)
data = le16_to_cpu(st->spi_rx_buffer.le);
else
data = bitrev16(be16_to_cpu(st->spi_rx_buffer.be));
*val = FIELD_GET(MAX14001_MASK_DATA, data);
return 0;
}
static int max14001_write(struct max14001_state *st, unsigned int reg, unsigned int val)
{
unsigned int addr;
/*
* Prepare SPI transmit buffer 16 bit-value and reverse bit order
* to align with the LSB-first input on SDI port in order to meet
* the device communication requirements. If the controller supports
* SPI_LSB_FIRST, this step will be handled by the SPI controller.
*/
addr = FIELD_PREP(MAX14001_MASK_ADDR, reg) |
FIELD_PREP(MAX14001_MASK_WR, 1) |
FIELD_PREP(MAX14001_MASK_DATA, val);
if (st->spi_hw_has_lsb_first)
st->spi_tx_buffer.le = cpu_to_le16(addr);
else
st->spi_tx_buffer.be = cpu_to_be16(bitrev16(addr));
return spi_write(st->spi, &st->spi_tx_buffer, sizeof(st->spi_tx_buffer));
}
static int max14001_write_single_reg(void *context, unsigned int reg, unsigned int val)
{
struct max14001_state *st = context;
int ret;
/* Enable writing to the SPI register. */
ret = max14001_write(st, MAX14001_REG_WEN, MAX14001_REG_WEN_VALUE_WRITE);
if (ret)
return ret;
/* Writing data into SPI register. */
ret = max14001_write(st, reg, val);
if (ret)
return ret;
/* Disable writing to the SPI register. */
return max14001_write(st, MAX14001_REG_WEN, 0);
}
static int max14001_write_verification_reg(struct max14001_state *st, unsigned int reg)
{
unsigned int val;
int ret;
ret = regmap_read(st->regmap, reg, &val);
if (ret)
return ret;
return max14001_write(st, MAX14001_REG_VERIFICATION(reg), val);
}
static int max14001_disable_mv_fault(struct max14001_state *st)
{
unsigned int reg;
int ret;
/* Enable writing to the SPI registers. */
ret = max14001_write(st, MAX14001_REG_WEN, MAX14001_REG_WEN_VALUE_WRITE);
if (ret)
return ret;
/*
* Reads all registers and writes the values to their appropriate
* verification registers to clear the Memory Validation fault.
*/
for (reg = MAX14001_REG_FLTEN; reg <= MAX14001_REG_ENBL; reg++) {
ret = max14001_write_verification_reg(st, reg);
if (ret)
return ret;
}
/* Disable writing to the SPI registers. */
return max14001_write(st, MAX14001_REG_WEN, 0);
}
static int max14001_debugfs_reg_access(struct iio_dev *indio_dev,
unsigned int reg, unsigned int writeval,
unsigned int *readval)
{
struct max14001_state *st = iio_priv(indio_dev);
if (readval)
return regmap_read(st->regmap, reg, readval);
return regmap_write(st->regmap, reg, writeval);
}
static int max14001_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct max14001_state *st = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = regmap_read(st->regmap, MAX14001_REG_ADC, val);
if (ret)
return ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*val = st->vref_mV;
*val2 = 10;
return IIO_VAL_FRACTIONAL_LOG2;
default:
return -EINVAL;
}
}
static const struct regmap_range max14001_regmap_rd_range[] = {
regmap_reg_range(MAX14001_REG_ADC, MAX14001_REG_ENBL),
regmap_reg_range(MAX14001_REG_WEN, MAX14001_REG_WEN),
regmap_reg_range(MAX14001_REG_VERIFICATION(MAX14001_REG_FLTEN),
MAX14001_REG_VERIFICATION(MAX14001_REG_ENBL)),
};
static const struct regmap_access_table max14001_regmap_rd_table = {
.yes_ranges = max14001_regmap_rd_range,
.n_yes_ranges = ARRAY_SIZE(max14001_regmap_rd_range),
};
static const struct regmap_range max14001_regmap_wr_range[] = {
regmap_reg_range(MAX14001_REG_FLTEN, MAX14001_REG_WEN),
regmap_reg_range(MAX14001_REG_VERIFICATION(MAX14001_REG_FLTEN),
MAX14001_REG_VERIFICATION(MAX14001_REG_ENBL)),
};
static const struct regmap_access_table max14001_regmap_wr_table = {
.yes_ranges = max14001_regmap_wr_range,
.n_yes_ranges = ARRAY_SIZE(max14001_regmap_wr_range),
};
static const struct regmap_config max14001_regmap_config = {
.reg_read = max14001_read,
.reg_write = max14001_write_single_reg,
.max_register = MAX14001_REG_VERIFICATION(MAX14001_REG_ENBL),
.rd_table = &max14001_regmap_rd_table,
.wr_table = &max14001_regmap_wr_table,
};
static const struct iio_info max14001_info = {
.read_raw = max14001_read_raw,
.debugfs_reg_access = max14001_debugfs_reg_access,
};
static const struct iio_chan_spec max14001_channel[] = {
{
.type = IIO_VOLTAGE,
.indexed = 1,
.channel = 0,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
},
};
static int max14001_probe(struct spi_device *spi)
{
struct device *dev = &spi->dev;
struct iio_dev *indio_dev;
struct max14001_state *st;
int ret;
bool use_ext_vrefin = false;
indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
st = iio_priv(indio_dev);
st->spi = spi;
st->spi_hw_has_lsb_first = spi->mode & SPI_LSB_FIRST;
st->chip_info = spi_get_device_match_data(spi);
if (!st->chip_info)
return -EINVAL;
indio_dev->name = st->chip_info->name;
indio_dev->info = &max14001_info;
indio_dev->channels = max14001_channel;
indio_dev->num_channels = ARRAY_SIZE(max14001_channel);
indio_dev->modes = INDIO_DIRECT_MODE;
st->regmap = devm_regmap_init(dev, NULL, st, &max14001_regmap_config);
if (IS_ERR(st->regmap))
return dev_err_probe(dev, PTR_ERR(st->regmap), "Failed to initialize regmap\n");
ret = devm_regulator_get_enable(dev, "vdd");
if (ret)
return dev_err_probe(dev, ret, "Failed to enable Vdd supply\n");
ret = devm_regulator_get_enable(dev, "vddl");
if (ret)
return dev_err_probe(dev, ret, "Failed to enable Vddl supply\n");
ret = devm_regulator_get_enable_read_voltage(dev, "refin");
if (ret < 0 && ret != -ENODEV)
return dev_err_probe(dev, ret, "Failed to get REFIN voltage\n");
if (ret == -ENODEV)
ret = 1250000;
else
use_ext_vrefin = true;
st->vref_mV = ret / (MICRO / MILLI);
if (use_ext_vrefin) {
/*
* Configure the MAX14001/MAX14002 to use an external voltage
* reference source by setting the bit 5 of the configuration register.
*/
ret = regmap_set_bits(st->regmap, MAX14001_REG_CFG,
MAX14001_REG_CFG_BIT_EXRF);
if (ret)
return dev_err_probe(dev, ret,
"Failed to set External REFIN in Configuration Register\n");
}
ret = max14001_disable_mv_fault(st);
if (ret)
return dev_err_probe(dev, ret, "Failed to disable MV Fault\n");
return devm_iio_device_register(dev, indio_dev);
}
static struct max14001_chip_info max14001_chip_info = {
.name = "max14001",
};
static struct max14001_chip_info max14002_chip_info = {
.name = "max14002",
};
static const struct spi_device_id max14001_id_table[] = {
{ "max14001", (kernel_ulong_t)&max14001_chip_info },
{ "max14002", (kernel_ulong_t)&max14002_chip_info },
{ }
};
static const struct of_device_id max14001_of_match[] = {
{ .compatible = "adi,max14001", .data = &max14001_chip_info },
{ .compatible = "adi,max14002", .data = &max14002_chip_info },
{ }
};
MODULE_DEVICE_TABLE(of, max14001_of_match);
static struct spi_driver max14001_driver = {
.driver = {
.name = "max14001",
.of_match_table = max14001_of_match,
},
.probe = max14001_probe,
.id_table = max14001_id_table,
};
module_spi_driver(max14001_driver);
MODULE_AUTHOR("Kim Seer Paller <kimseer.paller@analog.com>");
MODULE_AUTHOR("Marilene Andrade Garcia <marilene.agarcia@gmail.com>");
MODULE_DESCRIPTION("Analog Devices MAX14001/MAX14002 ADCs driver");
MODULE_LICENSE("GPL");