Adding support for max11205 16-bit single-channel ultra-low power delta-sigma adc. The MAX11205 is compatible with the 2-wire interface and uses SCLK and RDY/DOUT for serial communications. In this mode, all controls are implemented by timing the high or low phase of the SCLK. The 2-wire serial interface only allows for data to be read out through the RDY/DOUT output. Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX11205.pdf Signed-off-by: Ramona Bolboaca <ramona.bolboaca@xxxxxxxxxx> --- changes in v2: - add chip_info null pointer check - add support for probing with ACPI table - remove function for module removal - remove irq flag from max11205_sigma_delta_info - add missing commas and missing spaces - remove redundant blank line - wrap text to 75-80 chars - removed typos in commit message drivers/iio/adc/Kconfig | 14 +++ drivers/iio/adc/Makefile | 1 + drivers/iio/adc/max11205.c | 183 +++++++++++++++++++++++++++++++++++++ 3 files changed, 198 insertions(+) create mode 100644 drivers/iio/adc/max11205.c diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig index 7fe5930891e0..0c8f376b65d8 100644 --- a/drivers/iio/adc/Kconfig +++ b/drivers/iio/adc/Kconfig @@ -653,6 +653,20 @@ config MAX1118 To compile this driver as a module, choose M here: the module will be called max1118. +config MAX11205 + tristate "Maxim max11205 ADC driver" + depends on SPI + select AD_SIGMA_DELTA + select IIO_BUFFER + select IIO_TRIGGERED_BUFFER + + help + Say yes here to build support for Maxim max11205 16-bit, single-channel + ultra-low power delta-sigma ADC. + + To compile this driver as a module, choose M here: the module will be + called max11205. + config MAX1241 tristate "Maxim max1241 ADC driver" depends on SPI_MASTER diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile index 1772a549a3c8..bb681844e497 100644 --- a/drivers/iio/adc/Makefile +++ b/drivers/iio/adc/Makefile @@ -61,6 +61,7 @@ obj-$(CONFIG_LTC2497) += ltc2497.o ltc2497-core.o obj-$(CONFIG_MAX1027) += max1027.o obj-$(CONFIG_MAX11100) += max11100.o obj-$(CONFIG_MAX1118) += max1118.o +obj-$(CONFIG_MAX11205) += max11205.o obj-$(CONFIG_MAX1241) += max1241.o obj-$(CONFIG_MAX1363) += max1363.o obj-$(CONFIG_MAX9611) += max9611.o diff --git a/drivers/iio/adc/max11205.c b/drivers/iio/adc/max11205.c new file mode 100644 index 000000000000..68e6082e70e5 --- /dev/null +++ b/drivers/iio/adc/max11205.c @@ -0,0 +1,183 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * max11205 16-Bit Delta-Sigma ADC + * + * Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX1240-max11205.pdf + * Copyright (C) 2022 Analog Devices, Inc. + * Author: Ramona Bolboaca <ramona.bolboaca@xxxxxxxxxx> + */ + +#include <linux/device.h> +#include <linux/module.h> +#include <linux/regulator/consumer.h> +#include <linux/spi/spi.h> + +#include <linux/iio/iio.h> +#include <linux/iio/adc/ad_sigma_delta.h> + +#define MAX11205_BIT_SCALE 15 +#define MAX11205A_OUT_DATA_RATE 116 +#define MAX11205B_OUT_DATA_RATE 13 + +enum chip_type { + TYPE_MAX11205A, + TYPE_MAX11205B, +}; + +struct chip_info { + unsigned int out_data_rate; + const char *name; +}; + +struct max11205_state { + const struct chip_info *chip_info; + struct regulator *vref; + struct ad_sigma_delta sd; +}; + +static const struct ad_sigma_delta_info max11205_sigma_delta_info = { + .has_registers = false, +}; + +static int max11205_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct max11205_state *st = iio_priv(indio_dev); + int reg_mv; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + return ad_sigma_delta_single_conversion(indio_dev, chan, val); + case IIO_CHAN_INFO_SCALE: + reg_mv = regulator_get_voltage(st->vref); + if (reg_mv < 0) + return reg_mv; + reg_mv /= 1000; + *val = reg_mv; + *val2 = MAX11205_BIT_SCALE; + return IIO_VAL_FRACTIONAL_LOG2; + case IIO_CHAN_INFO_SAMP_FREQ: + *val = st->chip_info->out_data_rate; + return IIO_VAL_INT; + default: + return -EINVAL; + } +} + +static const struct iio_info max11205_iio_info = { + .read_raw = max11205_read_raw, + .validate_trigger = ad_sd_validate_trigger, +}; + +static const struct iio_chan_spec max11205_channels[] = { + { + .type = IIO_VOLTAGE, + .indexed = 1, + .scan_type = { + .sign = 's', + .realbits = 16, + .storagebits = 16, + .endianness = IIO_BE + }, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_SAMP_FREQ) | + BIT(IIO_CHAN_INFO_SCALE), + }, +}; + +static const struct chip_info max11205_chip_info[] = { + [TYPE_MAX11205A] = { + .out_data_rate = MAX11205A_OUT_DATA_RATE, + .name = "max11205a", + }, + [TYPE_MAX11205B] = { + .out_data_rate = MAX11205B_OUT_DATA_RATE, + .name = "max11205b", + }, +}; + +static void max11205_reg_disable(void *reg) +{ + regulator_disable(reg); +} + +static int max11205_probe(struct spi_device *spi) +{ + struct max11205_state *st; + struct iio_dev *indio_dev; + int ret; + + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); + if (!indio_dev) + return -ENOMEM; + + st = iio_priv(indio_dev); + + ad_sd_init(&st->sd, indio_dev, spi, &max11205_sigma_delta_info); + + st->chip_info = device_get_match_data(&spi->dev); + + if (!st->chip_info) + st->chip_info = (const struct chip_info *)spi_get_device_id(spi)->driver_data; + + indio_dev->name = st->chip_info->name; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = max11205_channels; + indio_dev->num_channels = 1; + indio_dev->info = &max11205_iio_info; + + st->vref = devm_regulator_get(&spi->dev, "vref"); + if (IS_ERR(st->vref)) + return dev_err_probe(&spi->dev, PTR_ERR(st->vref), + "Failed to get vref regulator\n"); + + ret = regulator_enable(st->vref); + if (ret) + return ret; + + ret = devm_add_action_or_reset(&spi->dev, max11205_reg_disable, st->vref); + if (ret) + return ret; + + ret = devm_ad_sd_setup_buffer_and_trigger(&spi->dev, indio_dev); + if (ret) + return ret; + + return devm_iio_device_register(&spi->dev, indio_dev); +} + +static const struct spi_device_id max11205_spi_ids[] = { + { "max11205a", (kernel_ulong_t)&max11205_chip_info[TYPE_MAX11205A] }, + { "max11205b", (kernel_ulong_t)&max11205_chip_info[TYPE_MAX11205B] }, + { } +}; +MODULE_DEVICE_TABLE(spi, max11205_spi_ids); + +static const struct of_device_id max11205_dt_ids[] = { + { + .compatible = "maxim,max11205a", + .data = &max11205_chip_info[TYPE_MAX11205A], + }, + { + .compatible = "maxim,max11205b", + .data = &max11205_chip_info[TYPE_MAX11205B], + }, + { } +}; +MODULE_DEVICE_TABLE(of, max11205_dt_ids); + +static struct spi_driver max11205_spi_driver = { + .driver = { + .name = "max11205", + .of_match_table = max11205_dt_ids, + }, + .probe = max11205_probe, + .id_table = max11205_spi_ids, +}; +module_spi_driver(max11205_spi_driver); + +MODULE_AUTHOR("Ramona Bolboaca <ramona.bolboaca@xxxxxxxxxx>"); +MODULE_DESCRIPTION("MAX11205 ADC driver"); +MODULE_LICENSE("GPL v2"); +MODULE_IMPORT_NS(IIO_AD_SIGMA_DELTA); -- 2.25.1
