The MAX14001 is configurable, isolated 10-bit ADCs for multi-range binary inputs. Signed-off-by: Kim Seer Paller <kimseer.paller@xxxxxxxxxx> --- V8 -> V9: Changed SPI buffer data types to __le16, removed force cast and modified spi buffers bit sequence. Removed max14001_reg_update function and directly handled its functionality within the caller. Removed unused headers. V7 -> V8: Added a bitwise OR operation to combine the bitfield element with the reg_data value. V6 -> V7: Swapped ADC external vref source and regulator_get_voltage calls. Added forced cast and comment to addressed endian warning. V5 -> V6: Replaced fixed length assignment with dynamic size assignment in xfers struct initialization. Removed .channel assignment in max14001_channels definition. V4 -> V5: No changes. V3 -> V4: Removed regmap setup, structures, and include. MAINTAINERS | 1 + drivers/iio/adc/Kconfig | 10 ++ drivers/iio/adc/Makefile | 1 + drivers/iio/adc/max14001.c | 325 +++++++++++++++++++++++++++++++++++++ 4 files changed, 337 insertions(+) create mode 100644 drivers/iio/adc/max14001.c diff --git a/MAINTAINERS b/MAINTAINERS index 0253058c345b..bd4bbe4f1749 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -12797,6 +12797,7 @@ L: linux-iio@xxxxxxxxxxxxxxx S: Supported W: https://ez.analog.com/linux-software-drivers F: Documentation/devicetree/bindings/iio/adc/adi,max14001.yaml +F: drivers/iio/adc/max14001.c MAXBOTIX ULTRASONIC RANGER IIO DRIVER M: Andreas Klinger <ak@xxxxxxxxxxxxx> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig index dc14bde31ac1..bdd5033b0733 100644 --- a/drivers/iio/adc/Kconfig +++ b/drivers/iio/adc/Kconfig @@ -706,6 +706,16 @@ config MAX11410 To compile this driver as a module, choose M here: the module will be called max11410. +config MAX14001 + tristate "Analog Devices MAX14001 ADC driver" + depends on SPI + help + Say yes here to build support for Analog Devices MAX14001 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 MAX1241 tristate "Maxim max1241 ADC driver" depends on SPI_MASTER diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile index eb6e891790fb..5a825cf9066f 100644 --- a/drivers/iio/adc/Makefile +++ b/drivers/iio/adc/Makefile @@ -65,6 +65,7 @@ obj-$(CONFIG_MAX11100) += max11100.o obj-$(CONFIG_MAX1118) += max1118.o obj-$(CONFIG_MAX11205) += max11205.o obj-$(CONFIG_MAX11410) += max11410.o +obj-$(CONFIG_MAX14001) += max14001.o obj-$(CONFIG_MAX1241) += max1241.o obj-$(CONFIG_MAX1363) += max1363.o obj-$(CONFIG_MAX77541_ADC) += max77541-adc.o diff --git a/drivers/iio/adc/max14001.c b/drivers/iio/adc/max14001.c new file mode 100644 index 000000000000..09686a9faa2e --- /dev/null +++ b/drivers/iio/adc/max14001.c @@ -0,0 +1,325 @@ +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause) +/* + * Analog Devices MAX14001 ADC driver + * + * Copyright 2023 Analog Devices Inc. + */ + +#include <linux/bitfield.h> +#include <linux/bitrev.h> +#include <linux/device.h> +#include <linux/iio/iio.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/regulator/consumer.h> +#include <linux/spi/spi.h> +#include <linux/types.h> + +/* MAX14001 Registers Address */ +#define MAX14001_ADC 0x00 +#define MAX14001_FADC 0x01 +#define MAX14001_FLAGS 0x02 +#define MAX14001_FLTEN 0x03 +#define MAX14001_THL 0x04 +#define MAX14001_THU 0x05 +#define MAX14001_INRR 0x06 +#define MAX14001_INRT 0x07 +#define MAX14001_INRP 0x08 +#define MAX14001_CFG 0x09 +#define MAX14001_ENBL 0x0A +#define MAX14001_ACT 0x0B +#define MAX14001_WEN 0x0C + +#define MAX14001_VERIFICATION_REG(x) ((x) + 0x10) + +#define MAX14001_CFG_EXRF BIT(5) + +#define MAX14001_ADDR_MASK GENMASK(15, 11) +#define MAX14001_DATA_MASK GENMASK(9, 0) +#define MAX14001_FILTER_MASK GENMASK(3, 2) + +#define MAX14001_SET_WRITE_BIT BIT(10) +#define MAX14001_WRITE_WEN 0x294 + +struct max14001_state { + struct spi_device *spi; + /* + * lock protect against multiple concurrent accesses, RMW sequence, and + * SPI transfer + */ + struct mutex lock; + int vref_mv; + /* + * DMA (thus cache coherency maintenance) requires the + * transfer buffers to live in their own cache lines. + */ + __le16 spi_tx_buffer __aligned(IIO_DMA_MINALIGN); + __le16 spi_rx_buffer; +}; + +static int max14001_read(void *context, unsigned int reg_addr, unsigned int *data) +{ + struct max14001_state *st = context; + int ret; + + 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), + }, + }; + + /* + * Prepare SPI transmit buffer 16 bit-value to big-endian format and + * reverses bit order to align with the LSB-first input on SDI port. + */ + st->spi_tx_buffer = bitrev16(cpu_to_be16(FIELD_PREP(MAX14001_ADDR_MASK, + reg_addr))); + + ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers)); + if (ret) + return ret; + + /* + * Convert received 16-bit value from big-endian to little-endian format + * and reverses bit order. + */ + *data = bitrev16(be16_to_cpu(st->spi_rx_buffer)); + + return 0; +} + +static int max14001_write(void *context, unsigned int reg_addr, unsigned int data) +{ + struct max14001_state *st = context; + + /* + * Prepare SPI transmit buffer 16 bit-value to big-endian format and + * reverses bit order to align with the LSB-first input on SDI port. + */ + st->spi_tx_buffer = bitrev16(cpu_to_be16( + FIELD_PREP(MAX14001_ADDR_MASK, reg_addr) | + FIELD_PREP(MAX14001_SET_WRITE_BIT, 1) | + FIELD_PREP(MAX14001_DATA_MASK, data))); + + return spi_write(st->spi, &st->spi_tx_buffer, sizeof(st->spi_tx_buffer)); +} + +static int max14001_write_verification_reg(struct max14001_state *st, + unsigned int reg_addr) +{ + unsigned int reg_data; + int ret; + + ret = max14001_read(st, reg_addr, ®_data); + if (ret) + return ret; + + return max14001_write(st, MAX14001_VERIFICATION_REG(reg_addr), reg_data); +} + +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); + unsigned int data; + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + mutex_lock(&st->lock); + ret = max14001_read(st, MAX14001_ADC, &data); + mutex_unlock(&st->lock); + if (ret < 0) + return ret; + + *val = data; + + 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 iio_info max14001_info = { + .read_raw = max14001_read_raw, +}; + +static const struct iio_chan_spec max14001_channels[] = { + { + .type = IIO_VOLTAGE, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_SCALE), + } +}; + +static void max14001_regulator_disable(void *data) +{ + struct regulator *reg = data; + + regulator_disable(reg); +} + +static int max14001_init(struct max14001_state *st) +{ + int ret; + + /* Enable SPI Registers Write */ + ret = max14001_write(st, MAX14001_WEN, MAX14001_WRITE_WEN); + if (ret) + return ret; + + /* + * Reads all registers and writes the values back to their appropriate + * verification registers to clear the Memory Validation fault. + */ + ret = max14001_write_verification_reg(st, MAX14001_FLTEN); + if (ret) + return ret; + + ret = max14001_write_verification_reg(st, MAX14001_THL); + if (ret) + return ret; + + ret = max14001_write_verification_reg(st, MAX14001_THU); + if (ret) + return ret; + + ret = max14001_write_verification_reg(st, MAX14001_INRR); + if (ret) + return ret; + + ret = max14001_write_verification_reg(st, MAX14001_INRT); + if (ret) + return ret; + + ret = max14001_write_verification_reg(st, MAX14001_INRP); + if (ret) + return ret; + + ret = max14001_write_verification_reg(st, MAX14001_CFG); + if (ret) + return ret; + + ret = max14001_write_verification_reg(st, MAX14001_ENBL); + if (ret) + return ret; + + /* Disable SPI Registers Write */ + return max14001_write(st, MAX14001_WEN, 0); +} + +static int max14001_probe(struct spi_device *spi) +{ + struct iio_dev *indio_dev; + struct max14001_state *st; + struct regulator *vref; + struct device *dev = &spi->dev; + unsigned int reg_data; + int ret; + + indio_dev = devm_iio_device_alloc(dev, sizeof(*st)); + if (!indio_dev) + return -ENOMEM; + + st = iio_priv(indio_dev); + st->spi = spi; + + indio_dev->name = "max14001"; + indio_dev->info = &max14001_info; + indio_dev->channels = max14001_channels; + indio_dev->num_channels = ARRAY_SIZE(max14001_channels); + indio_dev->modes = INDIO_DIRECT_MODE; + + ret = max14001_init(st); + if (ret) + return ret; + + vref = devm_regulator_get_optional(dev, "vref"); + if (IS_ERR(vref)) { + if (PTR_ERR(vref) != -ENODEV) + return dev_err_probe(dev, PTR_ERR(vref), + "Failed to get vref regulator"); + + /* internal reference */ + st->vref_mv = 1250; + } else { + ret = regulator_enable(vref); + if (ret) + return dev_err_probe(dev, ret, + "Failed to enable vref regulators\n"); + + ret = devm_add_action_or_reset(dev, max14001_regulator_disable, + vref); + if (ret) + return ret; + + ret = regulator_get_voltage(vref); + if (ret < 0) + return dev_err_probe(dev, ret, + "Failed to get vref\n"); + + st->vref_mv = ret / 1000; + + /* + * Enable SPI registers write and select external voltage + * reference source for the ADC. + */ + ret = max14001_write(st, MAX14001_WEN, MAX14001_WRITE_WEN); + if (ret) + return ret; + + ret = max14001_read(st, MAX14001_CFG, ®_data); + if (ret) + return ret; + + reg_data |= FIELD_PREP(MAX14001_CFG_EXRF, 1); + + ret = max14001_write(st, MAX14001_CFG, reg_data); + if (ret) + return ret; + + /* Write Verification Register */ + ret = max14001_write_verification_reg(st, MAX14001_CFG); + if (ret) + return ret; + + /* Disable SPI Registers Write */ + ret = max14001_write(st, MAX14001_WEN, 0); + if (ret) + return ret; + } + + mutex_init(&st->lock); + + return devm_iio_device_register(dev, indio_dev); +} + +static const struct of_device_id max14001_of_match[] = { + { .compatible = "adi,max14001" }, + { } +}; +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, +}; +module_spi_driver(max14001_driver); + +MODULE_AUTHOR("Kim Seer Paller"); +MODULE_DESCRIPTION("MAX14001 ADC driver"); +MODULE_LICENSE("GPL"); -- 2.34.1
