--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AD5706R 16-bit Current Output Digital to Analog Converter
+ *
+ * Copyright 2026 Analog Devices Inc.
+ */
+
+#include <linux/array_size.h>
+#include <linux/bits.h>
+#include <linux/dev_printk.h>
+#include <linux/err.h>
+#include <linux/iio/iio.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+#include <linux/types.h>
+#include <linux/unaligned.h>
+
+/* SPI frame layout */
+#define AD5706R_RD_MASK BIT(15)
+#define AD5706R_ADDR_MASK GENMASK(11, 0)
+
+/* Registers */
+#define AD5706R_REG_DAC_INPUT_A_CH(x) (0x60 + ((x) * 2))
+#define AD5706R_REG_DAC_DATA_READBACK_CH(x) (0x68 + ((x) * 2))
+
+#define AD5706R_DAC_RESOLUTION 16
+#define AD5706R_DAC_MAX_CODE GENMASK(15, 0)
+#define AD5706R_MULTIBYTE_REG_START 0x14
+#define AD5706R_MULTIBYTE_REG_END 0x71
+#define AD5706R_MAX_REG 0x77
+
+struct ad5706r_state {
+ struct spi_device *spi;
+ struct regmap *regmap;
+
+ u8 tx_buf[4] __aligned(IIO_DMA_MINALIGN);
+ u8 rx_buf[4];
+};
+
+static int ad5706r_reg_len(unsigned int reg)
+{
+ if (reg >= AD5706R_MULTIBYTE_REG_START && reg <= AD5706R_MULTIBYTE_REG_END)
+ return 2;
+
+ return 1;
+}
+
+static int ad5706r_regmap_write(void *context, const void *data, size_t count)
+{
+ struct ad5706r_state *st = context;
+ unsigned int num_bytes;
+ u16 reg, val;
+
+ if (count != 4)
+ return -EINVAL;
+
+ reg = get_unaligned_be16(data);
+ val = get_unaligned_be16(data + 2);
+ num_bytes = ad5706r_reg_len(reg);
+
+ struct spi_transfer xfer = {
+ .tx_buf = st->tx_buf,
+ .len = num_bytes + 2,
+ };
+
+ put_unaligned_be16(reg, &st->tx_buf[0]);
+
+ if (num_bytes == 1)
+ st->tx_buf[2] = (u8)val;
+ else if (num_bytes == 2)
+ put_unaligned_be16(val, &st->tx_buf[2]);
+ else
+ return -EINVAL;
+
+ return spi_sync_transfer(st->spi, &xfer, 1);
+}
+
+static int ad5706r_regmap_read(void *context, const void *reg_buf,
+ size_t reg_size, void *val_buf, size_t val_size)
+{
+ struct ad5706r_state *st = context;
+ unsigned int num_bytes;
+ u16 reg, cmd, val;
+ int ret;
+
+ if (reg_size != 2 || val_size != 2)
+ return -EINVAL;
+
+ reg = get_unaligned_be16(reg_buf);
+ num_bytes = ad5706r_reg_len(reg);
+
+ /* Full duplex, device responds immediately after command */
+ struct spi_transfer xfer = {
+ .tx_buf = st->tx_buf,
+ .rx_buf = st->rx_buf,
+ .len = 2 + num_bytes,
+ };
+
+ cmd = AD5706R_RD_MASK | (reg & AD5706R_ADDR_MASK);
+ put_unaligned_be16(cmd, &st->tx_buf[0]);
+ put_unaligned_be16(0, &st->tx_buf[2]);
+
+ ret = spi_sync_transfer(st->spi, &xfer, 1);
+ if (ret)
+ return ret;
+
+ /* Extract value from response (skip 2-byte command echo) */
+ if (num_bytes == 1)
+ val = st->rx_buf[2];
+ else if (num_bytes == 2)
+ val = get_unaligned_be16(&st->rx_buf[2]);
+ else
+ return -EINVAL;
+
+ put_unaligned_be16(val, val_buf);
+
+ return 0;
+}
+
+static int ad5706r_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct ad5706r_state *st = iio_priv(indio_dev);
+ unsigned int reg, reg_val;
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ reg = AD5706R_REG_DAC_DATA_READBACK_CH(chan->channel);
+ ret = regmap_read(st->regmap, reg, ®_val);
+ if (ret)
+ return ret;
+
+ *val = reg_val;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ *val = 50;
+ *val2 = AD5706R_DAC_RESOLUTION;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int ad5706r_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ struct ad5706r_state *st = iio_priv(indio_dev);
+ unsigned int reg;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ if (val < 0 || val > AD5706R_DAC_MAX_CODE)
+ return -EINVAL;
+
+ reg = AD5706R_REG_DAC_INPUT_A_CH(chan->channel);
+ return regmap_write(st->regmap, reg, val);
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct regmap_bus ad5706r_regmap_bus = {
+ .write = ad5706r_regmap_write,
+ .read = ad5706r_regmap_read,
+ .reg_format_endian_default = REGMAP_ENDIAN_BIG,
+ .val_format_endian_default = REGMAP_ENDIAN_BIG,
+};
+
+static const struct regmap_config ad5706r_regmap_config = {
+ .reg_bits = 16,
+ .val_bits = 16,
+ .max_register = AD5706R_MAX_REG,
+};
+
+static const struct iio_info ad5706r_info = {
+ .read_raw = ad5706r_read_raw,
+ .write_raw = ad5706r_write_raw,
+};
+
+#define AD5706R_CHAN(_channel) { \
+ .type = IIO_CURRENT, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+ BIT(IIO_CHAN_INFO_SCALE), \
+ .output = 1, \
+ .indexed = 1, \
+ .channel = _channel, \
+}
+
+static const struct iio_chan_spec ad5706r_channels[] = {
+ AD5706R_CHAN(0),
+ AD5706R_CHAN(1),
+ AD5706R_CHAN(2),
+ AD5706R_CHAN(3),
+};
+
+static int ad5706r_probe(struct spi_device *spi)
+{
+ struct device *dev = &spi->dev;
+ struct iio_dev *indio_dev;
+ struct ad5706r_state *st;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ st = iio_priv(indio_dev);
+ st->spi = spi;
+
+ st->regmap = devm_regmap_init(dev, &ad5706r_regmap_bus,
+ st, &ad5706r_regmap_config);
+ if (IS_ERR(st->regmap))
+ return dev_err_probe(dev, PTR_ERR(st->regmap),
+ "Failed to init regmap\n");
+
+ indio_dev->name = "ad5706r";
+ indio_dev->info = &ad5706r_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = ad5706r_channels;
+ indio_dev->num_channels = ARRAY_SIZE(ad5706r_channels);
+
+ return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct of_device_id ad5706r_of_match[] = {
+ { .compatible = "adi,ad5706r" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, ad5706r_of_match);
+
+static const struct spi_device_id ad5706r_id[] = {
+ { "ad5706r" },
+ { }
+};
+MODULE_DEVICE_TABLE(spi, ad5706r_id);
+
+static struct spi_driver ad5706r_driver = {
+ .driver = {
+ .name = "ad5706r",
+ .of_match_table = ad5706r_of_match,
+ },
+ .probe = ad5706r_probe,
+ .id_table = ad5706r_id,
+};
+module_spi_driver(ad5706r_driver);
+
+MODULE_AUTHOR("Alexis Czezar Torreno <alexisczezar.torreno@analog.com>");
+MODULE_DESCRIPTION("AD5706R 16-bit Current Output DAC driver");
+MODULE_LICENSE("GPL");
projects / thirdparty / kernel / linux.git / commitdiff
