// 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 * Copyright (c) 2025 Marilene Andrade Garcia * * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/MAX14001-MAX14002.pdf */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* 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 "); MODULE_AUTHOR("Marilene Andrade Garcia "); MODULE_DESCRIPTION("Analog Devices MAX14001/MAX14002 ADCs driver"); MODULE_LICENSE("GPL");