From: Marcelo Schmitt Date: Wed, 7 Jan 2026 14:47:59 +0000 (-0300) Subject: iio: adc: Initial support for AD4134 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e0bc6d7e258486c10bb11e31fd4421c134063b1d;p=thirdparty%2Fkernel%2Flinux.git iio: adc: Initial support for AD4134 AD4134 is a 24-bit, 4-channel, simultaneous sampling, precision analog-to-digital converter (ADC). The device can be managed through SPI or direct control of pin logical levels (pin control mode). The AD4134 design also features a dedicated bus for ADC sample data output. Though, this initial driver for AD4134 only supports usual SPI connections. Add basic support for AD4134 that enables single-shot ADC sample read. Signed-off-by: Marcelo Schmitt Reviewed-by: Andy Shevchenko Signed-off-by: Jonathan Cameron --- diff --git a/MAINTAINERS b/MAINTAINERS index 3f9f6dd96ae4..4dd9f758a871 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -1464,6 +1464,7 @@ L: linux-iio@vger.kernel.org S: Supported W: https://ez.analog.com/linux-software-drivers F: Documentation/devicetree/bindings/iio/adc/adi,ad4134.yaml +F: drivers/iio/adc/ad4134.c ANALOG DEVICES INC AD4170-4 DRIVER M: Marcelo Schmitt diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig index 89a6486135f6..b4295aa415bf 100644 --- a/drivers/iio/adc/Kconfig +++ b/drivers/iio/adc/Kconfig @@ -112,6 +112,17 @@ config AD4130 To compile this driver as a module, choose M here: the module will be called ad4130. +config AD4134 + tristate "Analog Device AD4134 ADC Driver" + depends on SPI + select REGMAP_SPI + select CRC8 + help + Say yes here to build support for Analog Devices AD4134 SPI analog to + digital converters (ADC). + + To compile this driver as a module, choose M here: the module will be + called ad4134_spi. config AD4170_4 tristate "Analog Device AD4170-4 ADC Driver" diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile index 0a199630c081..c76550415ff1 100644 --- a/drivers/iio/adc/Makefile +++ b/drivers/iio/adc/Makefile @@ -14,6 +14,7 @@ obj-$(CONFIG_AD4030) += ad4030.o obj-$(CONFIG_AD4062) += ad4062.o obj-$(CONFIG_AD4080) += ad4080.o obj-$(CONFIG_AD4130) += ad4130.o +obj-$(CONFIG_AD4134) += ad4134.o obj-$(CONFIG_AD4170_4) += ad4170-4.o obj-$(CONFIG_AD4695) += ad4695.o obj-$(CONFIG_AD4851) += ad4851.o diff --git a/drivers/iio/adc/ad4134.c b/drivers/iio/adc/ad4134.c new file mode 100644 index 000000000000..e42ee328fcbf --- /dev/null +++ b/drivers/iio/adc/ad4134.c @@ -0,0 +1,500 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2026 Analog Devices, Inc. + * Author: Marcelo Schmitt + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define AD4134_RESET_TIME_US (10 * USEC_PER_SEC) + +#define AD4134_REG_READ_MASK BIT(7) +#define AD4134_SPI_MAX_XFER_LEN 3 + +#define AD4134_EXT_CLOCK_MHZ (48 * HZ_PER_MHZ) + +#define AD4134_NUM_CHANNELS 4 +#define AD4134_CHAN_PRECISION_BITS 24 + +#define AD4134_IFACE_CONFIG_A_REG 0x00 +#define AD4134_IFACE_CONFIG_B_REG 0x01 +#define AD4134_IFACE_CONFIG_B_SINGLE_INSTR BIT(7) + +#define AD4134_DEVICE_CONFIG_REG 0x02 +#define AD4134_DEVICE_CONFIG_POWER_MODE_MASK BIT(0) +#define AD4134_POWER_MODE_HIGH_PERF 0x1 + +#define AD4134_SILICON_REV_REG 0x07 +#define AD4134_SCRATCH_PAD_REG 0x0A +#define AD4134_STREAM_MODE_REG 0x0E +#define AD4134_SDO_PIN_SRC_SEL_REG 0x10 +#define AD4134_SDO_PIN_SRC_SEL_SDO_SEL_MASK BIT(2) + +#define AD4134_DATA_PACKET_CONFIG_REG 0x11 +#define AD4134_DATA_PACKET_CONFIG_FRAME_MASK GENMASK(5, 4) +#define AD4134_DATA_PACKET_24BIT_FRAME 0x2 + +#define AD4134_DIG_IF_CFG_REG 0x12 +#define AD4134_DIF_IF_CFG_FORMAT_MASK GENMASK(1, 0) +#define AD4134_DATA_FORMAT_SINGLE_CH_MODE 0x0 + +#define AD4134_PW_DOWN_CTRL_REG 0x13 +#define AD4134_DEVICE_STATUS_REG 0x15 +#define AD4134_ODR_VAL_INT_LSB_REG 0x16 +#define AD4134_CH3_OFFSET_MSB_REG 0x3E +#define AD4134_AIN_OR_ERROR_REG 0x48 + +/* + * AD4134 register map ends at address 0x48 and there is no register for + * retrieving ADC sample data. Though, to make use of Linux regmap API both + * for register access and sample read, we define one virtual register for each + * ADC channel. AD4134_CH_VREG(x) maps a channel number to it's virtual register + * address while AD4134_VREG_CH(x) tells which channel given the address. + */ +#define AD4134_CH_VREG(x) ((x) + 0x50) +#define AD4134_VREG_CH(x) ((x) - 0x50) + +#define AD4134_SPI_CRC_POLYNOM 0x07 +#define AD4134_SPI_CRC_INIT_VALUE 0xA5 +static unsigned char ad4134_spi_crc_table[CRC8_TABLE_SIZE]; + +#define AD4134_CHANNEL(_index) { \ + .type = IIO_VOLTAGE, \ + .indexed = 1, \ + .channel = (_index), \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ +} + +static const struct iio_chan_spec ad4134_chan_set[] = { + AD4134_CHANNEL(0), + AD4134_CHANNEL(1), + AD4134_CHANNEL(2), + AD4134_CHANNEL(3), +}; + +struct ad4134_state { + struct spi_device *spi; + struct regmap *regmap; + unsigned long sys_clk_hz; + struct gpio_desc *odr_gpio; + int refin_mv; + /* + * DMA (thus cache coherency maintenance) requires the transfer buffers + * to live in their own cache lines. + */ + u8 rx_buf[AD4134_SPI_MAX_XFER_LEN] __aligned(IIO_DMA_MINALIGN); + u8 tx_buf[AD4134_SPI_MAX_XFER_LEN]; +}; + +static const struct regmap_range ad4134_regmap_rd_range[] = { + regmap_reg_range(AD4134_IFACE_CONFIG_A_REG, AD4134_SILICON_REV_REG), + regmap_reg_range(AD4134_SCRATCH_PAD_REG, AD4134_PW_DOWN_CTRL_REG), + regmap_reg_range(AD4134_DEVICE_STATUS_REG, AD4134_AIN_OR_ERROR_REG), + regmap_reg_range(AD4134_CH_VREG(0), AD4134_CH_VREG(AD4134_NUM_CHANNELS)), +}; + +static const struct regmap_range ad4134_regmap_wr_range[] = { + regmap_reg_range(AD4134_IFACE_CONFIG_A_REG, AD4134_DEVICE_CONFIG_REG), + regmap_reg_range(AD4134_SCRATCH_PAD_REG, AD4134_SCRATCH_PAD_REG), + regmap_reg_range(AD4134_STREAM_MODE_REG, AD4134_PW_DOWN_CTRL_REG), + regmap_reg_range(AD4134_ODR_VAL_INT_LSB_REG, AD4134_CH3_OFFSET_MSB_REG), +}; + +static const struct regmap_access_table ad4134_regmap_rd_table = { + .yes_ranges = ad4134_regmap_rd_range, + .n_yes_ranges = ARRAY_SIZE(ad4134_regmap_rd_range), +}; + +static const struct regmap_access_table ad4134_regmap_wr_table = { + .yes_ranges = ad4134_regmap_wr_range, + .n_yes_ranges = ARRAY_SIZE(ad4134_regmap_wr_range), +}; + +static int ad4134_calc_spi_crc(u8 inst, u8 data) +{ + u8 buf[] = { inst, data }; + + return crc8(ad4134_spi_crc_table, buf, ARRAY_SIZE(buf), + AD4134_SPI_CRC_INIT_VALUE); +} + +static void ad4134_prepare_spi_tx_buf(u8 inst, u8 data, u8 *buf) +{ + buf[0] = inst; + buf[1] = data; + buf[2] = ad4134_calc_spi_crc(inst, data); +} + +static int ad4134_reg_write(void *context, unsigned int reg, unsigned int val) +{ + struct ad4134_state *st = context; + struct spi_transfer xfer = { + .tx_buf = st->tx_buf, + .rx_buf = st->rx_buf, + .len = AD4134_SPI_MAX_XFER_LEN, + }; + int ret; + + ad4134_prepare_spi_tx_buf(reg, val, st->tx_buf); + + ret = spi_sync_transfer(st->spi, &xfer, 1); + if (ret) + return ret; + + if (st->rx_buf[2] != st->tx_buf[2]) + dev_dbg(&st->spi->dev, "reg write CRC check failed\n"); + + return 0; +} + +static int ad4134_data_read(struct ad4134_state *st, unsigned int reg, + unsigned int *val) +{ + unsigned int i; + int ret; + + /* + * To be able to read data from all 4 channels through a single line, we + * set DOUTx output format to 0 in the digital interface config register + * (0x12). With that, data from all four channels is serialized and + * output on DOUT0. During the probe, we also set SDO_PIN_SRC_SEL in + * DEVICE_CONFIG_1 register to duplicate DOUT0 on the SDO pin. Combined, + * those configurations enable ADC data read through a conventional SPI + * interface. Now we read data from all channels but keep only the bits + * from the requested one. + */ + for (i = 0; i < ARRAY_SIZE(ad4134_chan_set); i++) { + ret = spi_write_then_read(st->spi, NULL, 0, st->rx_buf, + BITS_TO_BYTES(AD4134_CHAN_PRECISION_BITS)); + if (ret) + return ret; + + /* + * AD4134 has a built-in feature that flags when data transfers + * don't run enough clock cycles to read the entire data frame. + * Clock out data from all channels to avoid that. + */ + if (i == AD4134_VREG_CH(reg)) + *val = get_unaligned_be24(st->rx_buf); + } + + return 0; +} + +static int ad4134_register_read(struct ad4134_state *st, unsigned int reg, + unsigned int *val) +{ + struct spi_transfer xfer = { + .tx_buf = st->tx_buf, + .rx_buf = st->rx_buf, + .len = AD4134_SPI_MAX_XFER_LEN, + }; + unsigned int inst; + int ret; + + inst = AD4134_REG_READ_MASK | reg; + ad4134_prepare_spi_tx_buf(inst, 0, st->tx_buf); + + ret = spi_sync_transfer(st->spi, &xfer, 1); + if (ret) + return ret; + + *val = st->rx_buf[1]; + + /* Check CRC */ + if (st->rx_buf[2] != st->tx_buf[2]) + dev_dbg(&st->spi->dev, "reg read CRC check failed\n"); + + return 0; +} + +static int ad4134_reg_read(void *context, unsigned int reg, unsigned int *val) +{ + struct ad4134_state *st = context; + + if (reg >= AD4134_CH_VREG(0)) + return ad4134_data_read(st, reg, val); + + return ad4134_register_read(st, reg, val); +} + +static const struct regmap_config ad4134_regmap_config = { + .reg_read = ad4134_reg_read, + .reg_write = ad4134_reg_write, + .rd_table = &ad4134_regmap_rd_table, + .wr_table = &ad4134_regmap_wr_table, + .max_register = AD4134_CH_VREG(ARRAY_SIZE(ad4134_chan_set)), +}; + +static int ad4134_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long info) +{ + struct ad4134_state *st = iio_priv(indio_dev); + int ret; + + switch (info) { + case IIO_CHAN_INFO_RAW: + gpiod_set_value_cansleep(st->odr_gpio, 1); + /* + * For slave mode gated DCLK (data sheet page 11), the minimum + * ODR high time is 3 * tDIGCLK. The internal digital clock + * period is tDIGCLK = 1/fDIGCLK = 2/fSYSCLK. + * The System clock frequency (fSYSCLK) is typically 48 MHz. + * Thus, ODR high time = 3 * (2 / (48 * HZ_PER_MHZ)) + * ODR high time = 0.000000125 s = 125 ns + * 1 micro second should be more than enough. Not worth it + * tweaking for shorter dealy since this is not a fast data path. + */ + fsleep(1); + gpiod_set_value_cansleep(st->odr_gpio, 0); + ret = regmap_read(st->regmap, AD4134_CH_VREG(chan->channel), val); + if (ret) + return ret; + + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + *val = st->refin_mv; + *val2 = AD4134_CHAN_PRECISION_BITS - 1; + + return IIO_VAL_FRACTIONAL_LOG2; + default: + return -EINVAL; + } +} + +static int ad4134_debugfs_reg_access(struct iio_dev *indio_dev, + unsigned int reg, unsigned int writeval, + unsigned int *readval) +{ + struct ad4134_state *st = iio_priv(indio_dev); + + if (readval) + return regmap_read(st->regmap, reg, readval); + + return regmap_write(st->regmap, reg, writeval); +} + +static int ad4134_min_io_mode_setup(struct ad4134_state *st) +{ + struct device *dev = &st->spi->dev; + int ret; + + st->odr_gpio = devm_gpiod_get(dev, "odr", GPIOD_OUT_LOW); + if (IS_ERR(st->odr_gpio)) + return dev_err_probe(dev, PTR_ERR(st->odr_gpio), + "failed to get ODR GPIO\n"); + + ret = regmap_update_bits(st->regmap, AD4134_DIG_IF_CFG_REG, + AD4134_DIF_IF_CFG_FORMAT_MASK, + FIELD_PREP(AD4134_DIF_IF_CFG_FORMAT_MASK, + AD4134_DATA_FORMAT_SINGLE_CH_MODE)); + if (ret) + return dev_err_probe(dev, ret, + "failed to set single channel mode\n"); + + ret = regmap_set_bits(st->regmap, AD4134_SDO_PIN_SRC_SEL_REG, + AD4134_SDO_PIN_SRC_SEL_SDO_SEL_MASK); + if (ret) + return dev_err_probe(dev, ret, + "failed to set SDO source selection\n"); + + return regmap_set_bits(st->regmap, AD4134_IFACE_CONFIG_B_REG, + AD4134_IFACE_CONFIG_B_SINGLE_INSTR); +} + +static const struct iio_info ad4134_info = { + .read_raw = ad4134_read_raw, + .debugfs_reg_access = ad4134_debugfs_reg_access, +}; + +static const char * const ad4143_required_regulators[] = { + "avdd5", "dvdd5", "iovdd", +}; + +static const char * const ad4143_optional_regulators[] = { + "avdd1v8", "dvdd1v8", "clkvdd", +}; + +static int ad4134_regulator_setup(struct ad4134_state *st) +{ + struct device *dev = &st->spi->dev; + int ret; + + ret = devm_regulator_bulk_get_enable(dev, ARRAY_SIZE(ad4143_required_regulators), + ad4143_required_regulators); + if (ret) + return dev_err_probe(dev, ret, "failed to enable power supplies\n"); + + /* Required regulator that we need to read the voltage */ + ret = devm_regulator_get_enable_read_voltage(dev, "refin"); + if (ret < 0) + return dev_err_probe(dev, ret, "failed to get REFIN voltage.\n"); + + st->refin_mv = ret / (MICRO / MILLI); + + ret = devm_regulator_get_enable_optional(dev, "ldoin"); + if (ret < 0 && ret != -ENODEV) + return dev_err_probe(dev, ret, "failed to enable ldoin supply\n"); + + /* If ldoin was provided, then use the use the internal LDO regulators */ + if (ret == 0) + return 0; + + /* + * If ldoin is not provided, then avdd1v8, dvdd1v8, and clkvdd are + * required. + */ + ret = devm_regulator_bulk_get_enable(dev, ARRAY_SIZE(ad4143_optional_regulators), + ad4143_optional_regulators); + if (ret) + return dev_err_probe(dev, ret, "failed to enable 1V8 power supplies\n"); + + return 0; +} + +static int ad4134_clock_select(struct ad4134_state *st) +{ + struct device *dev = &st->spi->dev; + struct clk *xtal_clk, *clkin_clk; + + /* + * AD4134 requires one external clock source and only one external clock + * source can be provided at a time. Try to get a crystal provided clock. + * If that fails, try to get a CMOS clock. + */ + xtal_clk = devm_clk_get_optional_enabled(dev, "xtal"); + if (!xtal_clk) + xtal_clk = devm_clk_get_optional_enabled(dev, "xtal"); + if (IS_ERR(xtal_clk)) + return dev_err_probe(dev, PTR_ERR(xtal_clk), + "failed to get xtal\n"); + + clkin_clk = devm_clk_get_optional_enabled(dev, "clkin"); + if (!clkin_clk) + clkin_clk = devm_clk_get_optional_enabled(dev, "clkin"); + if (IS_ERR(clkin_clk)) + return dev_err_probe(dev, PTR_ERR(clkin_clk), + "failed to get clkin\n"); + + st->sys_clk_hz = clk_get_rate(xtal_clk) | clk_get_rate(clkin_clk); + if (st->sys_clk_hz != AD4134_EXT_CLOCK_MHZ) + dev_warn(dev, "invalid external clock frequency %lu\n", + st->sys_clk_hz); + + return 0; +} + +static int ad4134_probe(struct spi_device *spi) +{ + struct device *dev = &spi->dev; + struct reset_control *rst; + struct iio_dev *indio_dev; + struct ad4134_state *st; + 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 = "ad4134"; + indio_dev->channels = ad4134_chan_set; + indio_dev->num_channels = ARRAY_SIZE(ad4134_chan_set); + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->info = &ad4134_info; + + ret = ad4134_regulator_setup(st); + if (ret) + return ret; + + ret = ad4134_clock_select(st); + if (ret) + return ret; + + rst = devm_reset_control_get_optional_exclusive_deasserted(dev, NULL); + if (IS_ERR(rst)) + return dev_err_probe(dev, PTR_ERR(rst), + "failed to get and deassert reset\n"); + + crc8_populate_msb(ad4134_spi_crc_table, AD4134_SPI_CRC_POLYNOM); + + st->regmap = devm_regmap_init(dev, NULL, st, &ad4134_regmap_config); + if (IS_ERR(st->regmap)) + return dev_err_probe(dev, PTR_ERR(st->regmap), + "failed to initialize regmap"); + + ret = ad4134_min_io_mode_setup(st); + if (ret) + return dev_err_probe(dev, ret, + "failed to setup minimum I/O mode\n"); + + /* Bump precision to 24-bit */ + ret = regmap_update_bits(st->regmap, AD4134_DATA_PACKET_CONFIG_REG, + AD4134_DATA_PACKET_CONFIG_FRAME_MASK, + FIELD_PREP(AD4134_DATA_PACKET_CONFIG_FRAME_MASK, + AD4134_DATA_PACKET_24BIT_FRAME)); + if (ret) + return ret; + + /* Set high performance power mode */ + ret = regmap_update_bits(st->regmap, AD4134_DEVICE_CONFIG_REG, + AD4134_DEVICE_CONFIG_POWER_MODE_MASK, + FIELD_PREP(AD4134_DEVICE_CONFIG_POWER_MODE_MASK, + AD4134_POWER_MODE_HIGH_PERF)); + if (ret) + return ret; + + return devm_iio_device_register(dev, indio_dev); +} + +static const struct spi_device_id ad4134_id[] = { + { "ad4134" }, + { } +}; +MODULE_DEVICE_TABLE(spi, ad4134_id); + +static const struct of_device_id ad4134_of_match[] = { + { .compatible = "adi,ad4134" }, + { } +}; +MODULE_DEVICE_TABLE(of, ad4134_of_match); + +static struct spi_driver ad4134_driver = { + .driver = { + .name = "ad4134", + .of_match_table = ad4134_of_match, + }, + .probe = ad4134_probe, + .id_table = ad4134_id, +}; +module_spi_driver(ad4134_driver); + +MODULE_AUTHOR("Marcelo Schmitt "); +MODULE_DESCRIPTION("Analog Devices AD4134 SPI driver"); +MODULE_LICENSE("GPL"); +MODULE_IMPORT_NS("IIO_AD4134");