| Message ID | 20220214094115.48548-1-antoniu.miclaus@analog.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v3,1/3] iio:amplifiers:ada4250: add support for ADA4250 | expand |
On Mon, 14 Feb 2022 11:41:13 +0200 Antoniu Miclaus <antoniu.miclaus@analog.com> wrote: > 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> Hi Antoniu Just a few really small comments about comment syntax. If it's all that comes up in review I can just fix them up whilst applying. We need to give a little more time for review, including dt bindings so I'll not be picking this up today anyway. Thanks, Jonathan > --- > changes in v3: > - fix indent in Kconfig > - rename `ADA4250_SNSR_CAL_CFG_BIAS_MSK` > - use actual values for hwgain instead of raw register values > - VLSB -> Voltage per LSB > - add comment example for computing offset raw value > - add documentation comment about the offset polarity bit > - use __aligned(8) for data buffer > drivers/iio/amplifiers/Kconfig | 11 + > drivers/iio/amplifiers/Makefile | 1 + > drivers/iio/amplifiers/ada4250.c | 400 +++++++++++++++++++++++++++++++ > 3 files changed, 412 insertions(+) > create mode 100644 drivers/iio/amplifiers/ada4250.c > > diff --git a/drivers/iio/amplifiers/Kconfig b/drivers/iio/amplifiers/Kconfig > index 5eb1357a9c78..f217a2a1e958 100644 > --- a/drivers/iio/amplifiers/Kconfig > +++ b/drivers/iio/amplifiers/Kconfig > @@ -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 > diff --git a/drivers/iio/amplifiers/Makefile b/drivers/iio/amplifiers/Makefile > index cb551d82f56b..2126331129cf 100644 > --- a/drivers/iio/amplifiers/Makefile > +++ b/drivers/iio/amplifiers/Makefile > @@ -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 > diff --git a/drivers/iio/amplifiers/ada4250.c b/drivers/iio/amplifiers/ada4250.c > new file mode 100644 > index 000000000000..2d88c831a7ee > --- /dev/null > +++ b/drivers/iio/amplifiers/ada4250.c > @@ -0,0 +1,400 @@ > +// 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 */ Please use the standard multiline comment syntax of /* * Compute Range and ... * Example ... ... */ Reviewer's eyes get used to parsing a particular style so it is best to keep to it. > + /* 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). Please use /* * To set the... * pol... * offset */ syntax for multiline comments > + 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");
diff --git a/drivers/iio/amplifiers/Kconfig b/drivers/iio/amplifiers/Kconfig index 5eb1357a9c78..f217a2a1e958 100644 --- a/drivers/iio/amplifiers/Kconfig +++ b/drivers/iio/amplifiers/Kconfig @@ -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 diff --git a/drivers/iio/amplifiers/Makefile b/drivers/iio/amplifiers/Makefile index cb551d82f56b..2126331129cf 100644 --- a/drivers/iio/amplifiers/Makefile +++ b/drivers/iio/amplifiers/Makefile @@ -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 diff --git a/drivers/iio/amplifiers/ada4250.c b/drivers/iio/amplifiers/ada4250.c new file mode 100644 index 000000000000..2d88c831a7ee --- /dev/null +++ b/drivers/iio/amplifiers/ada4250.c @@ -0,0 +1,400 @@ +// 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");
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> --- changes in v3: - fix indent in Kconfig - rename `ADA4250_SNSR_CAL_CFG_BIAS_MSK` - use actual values for hwgain instead of raw register values - VLSB -> Voltage per LSB - add comment example for computing offset raw value - add documentation comment about the offset polarity bit - use __aligned(8) for data buffer drivers/iio/amplifiers/Kconfig | 11 + drivers/iio/amplifiers/Makefile | 1 + drivers/iio/amplifiers/ada4250.c | 400 +++++++++++++++++++++++++++++++ 3 files changed, 412 insertions(+) create mode 100644 drivers/iio/amplifiers/ada4250.c