@@ -1216,6 +1216,7 @@ L: linux-iio@vger.kernel.org
S: Supported
W: https://ez.analog.com/linux-software-drivers
F: Documentation/devicetree/bindings/iio/adc/adi,ad4695.yaml
+F: drivers/iio/adc/ad4695.c
F: include/dt-bindings/iio/adi,ad4695.h
ANALOG DEVICES INC AD7091R DRIVER
@@ -36,6 +36,17 @@ config AD4130
To compile this driver as a module, choose M here: the module will be
called ad4130.
+config AD4695
+ tristate "Analog Device AD4695 ADC Driver"
+ depends on SPI
+ select REGMAP_SPI
+ help
+ Say yes here to build support for Analog Devices AD4695 and similar
+ analog to digital converters (ADC).
+
+ To compile this driver as a module, choose M here: the module will be
+ called ad4695.
+
config AD7091R
tristate
@@ -7,6 +7,7 @@
obj-$(CONFIG_AB8500_GPADC) += ab8500-gpadc.o
obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o
obj-$(CONFIG_AD4130) += ad4130.o
+obj-$(CONFIG_AD4695) += ad4695.o
obj-$(CONFIG_AD7091R) += ad7091r-base.o
obj-$(CONFIG_AD7091R5) += ad7091r5.o
obj-$(CONFIG_AD7091R8) += ad7091r8.o
new file mode 100644
@@ -0,0 +1,730 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * SPI ADC driver for Analog Devices Inc. AD4695 and similar chips
+ *
+ * https://www.analog.com/en/products/ad4695.html
+ * https://www.analog.com/en/products/ad4696.html
+ * https://www.analog.com/en/products/ad4697.html
+ * https://www.analog.com/en/products/ad4698.html
+ *
+ * Copyright 2024 Analog Devices Inc.
+ * Copyright 2024 BayLibre, SAS
+ */
+
+#include <dt-bindings/iio/adi,ad4695.h>
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/compiler.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/iio/iio.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+#include <linux/units.h>
+
+/* AD4695 registers */
+#define AD4695_REG_SPI_CONFIG_A 0x0000
+#define AD4695_REG_SPI_CONFIG_A_SW_RST (BIT(7) | BIT(0))
+#define AD4695_REG_SPI_CONFIG_B 0x0001
+#define AD4695_REG_SPI_CONFIG_B_INST_MODE BIT(7)
+#define AD4695_REG_DEVICE_TYPE 0x0003
+#define AD4695_REG_SCRATCH_PAD 0x000A
+#define AD4695_REG_VENDOR_L 0x000C
+#define AD4695_REG_VENDOR_H 0x000D
+#define AD4695_REG_LOOP_MODE 0x000E
+#define AD4695_REG_SPI_CONFIG_C 0x0010
+#define AD4695_REG_SPI_CONFIG_C_MB_STRICT BIT(7)
+#define AD4695_REG_SPI_STATUS 0x0011
+#define AD4695_REG_STATUS 0x0014
+#define AD4695_REG_ALERT_STATUS1 0x0015
+#define AD4695_REG_ALERT_STATUS2 0x0016
+#define AD4695_REG_CLAMP_STATUS 0x001A
+#define AD4695_REG_SETUP 0x0020
+#define AD4695_REG_SETUP_LDO_EN BIT(4)
+#define AD4695_REG_SETUP_SPI_MODE BIT(2)
+#define AD4695_REG_SETUP_SPI_CYC_CTRL BIT(1)
+#define AD4695_REG_REF_CTRL 0x0021
+#define AD4695_REG_REF_CTRL_OV_MODE BIT(7)
+#define AD4695_REG_REF_CTRL_VREF_SET GENMASK(4, 2)
+#define AD4695_REG_REF_CTRL_REFHIZ_EN BIT(1)
+#define AD4695_REG_REF_CTRL_REFBUF_EN BIT(0)
+#define AD4695_REG_SEQ_CTRL 0x0022
+#define AD4695_REG_SEQ_CTRL_STD_SEQ_EN BIT(7)
+#define AD4695_REG_SEQ_CTRL_NUM_SLOTS_AS GENMASK(6, 0)
+#define AD4695_REG_AC_CTRL 0x0023
+#define AD4695_REG_STD_SEQ_CONFIG 0x0024
+#define AD4695_REG_GPIO_CTRL 0x0026
+#define AD4695_REG_GP_MODE 0x0027
+#define AD4695_REG_TEMP_CTRL 0x0029
+#define AD4695_REG_CONFIG_IN(n) (0x0030 | (n))
+#define AD4695_REG_CONFIG_IN_MODE BIT(6)
+#define AD4695_REG_CONFIG_IN_PAIR GENMASK(5, 4)
+#define AD4695_REG_CONFIG_IN_AINHIGHZ_EN BIT(3)
+#define AD4695_REG_UPPER_IN(n) (0x0040 | (2 * (n)))
+#define AD4695_REG_LOWER_IN(n) (0x0060 | (2 * (n)))
+#define AD4695_REG_HYST_IN(n) (0x0080 | (2 * (n)))
+#define AD4695_REG_OFFSET_IN(n) (0x00A0 | (2 * (n)))
+#define AD4695_REG_GAIN_IN(n) (0x00C0 | (2 * (n)))
+#define AD4695_REG_AS_SLOT(n) (0x0100 | (n))
+#define AD4695_REG_AS_SLOT_INX GENMASK(3, 0)
+#define AD4695_MAX_REG 0x017F
+
+/* Conversion mode commands */
+#define AD4695_CMD_EXIT_CNV_MODE 0x0A
+#define AD4695_CMD_TEMP_CHAN 0x0F
+#define AD4695_CMD_VOLTAGE_CHAN(n) (0x10 | (n))
+
+/* timing specs */
+#define AD4695_T_CONVERT_NS 415
+#define AD4695_T_WAKEUP_HW_MS 3
+#define AD4695_T_WAKEUP_SW_MS 3
+#define AD4695_T_REFBUF_MS 100
+#define AD4695_REG_ACCESS_SCLK_HZ (10 * MEGA)
+
+#define AD4695_MAX_CHANNELS 16
+
+enum ad4695_in_pair {
+ AD4695_IN_PAIR_REFGND,
+ AD4695_IN_PAIR_COM,
+ AD4695_IN_PAIR_EVEN_ODD,
+};
+
+struct ad4695_chip_info {
+ const char *name;
+ int max_sample_rate;
+ u8 num_voltage_inputs;
+};
+
+struct ad4695_channel_config {
+ unsigned int channel;
+ bool highz_en;
+ bool bipolar;
+ enum ad4695_in_pair pin_pairing;
+ unsigned int common_mode_mv;
+};
+
+struct ad4695_state {
+ struct spi_device *spi;
+ struct regmap *regmap;
+ struct gpio_desc *reset_gpio;
+ struct iio_chan_spec iio_chan[AD4695_MAX_CHANNELS + 1];
+ struct ad4695_channel_config channels_cfg[AD4695_MAX_CHANNELS];
+ const struct ad4695_chip_info *chip_info;
+ /* Reference voltage. */
+ unsigned int vref_mv;
+ /* Common mode input pin voltage. */
+ unsigned int com_mv;
+ /* raw data conversion data received */
+ u16 raw_data __aligned(IIO_DMA_MINALIGN);
+ /* Commands to send for single conversion */
+ u16 cnv_cmd;
+ u8 cnv_cmd2;
+};
+
+static const struct regmap_range ad4695_regmap_rd_ranges[] = {
+ regmap_reg_range(AD4695_REG_SPI_CONFIG_A, AD4695_REG_SPI_CONFIG_B),
+ regmap_reg_range(AD4695_REG_DEVICE_TYPE, AD4695_REG_DEVICE_TYPE),
+ regmap_reg_range(AD4695_REG_SCRATCH_PAD, AD4695_REG_SCRATCH_PAD),
+ regmap_reg_range(AD4695_REG_VENDOR_L, AD4695_REG_LOOP_MODE),
+ regmap_reg_range(AD4695_REG_SPI_CONFIG_C, AD4695_REG_SPI_STATUS),
+ regmap_reg_range(AD4695_REG_STATUS, AD4695_REG_ALERT_STATUS2),
+ regmap_reg_range(AD4695_REG_CLAMP_STATUS, AD4695_REG_CLAMP_STATUS),
+ regmap_reg_range(AD4695_REG_SETUP, AD4695_REG_TEMP_CTRL),
+ regmap_reg_range(AD4695_REG_CONFIG_IN(0), AD4695_MAX_REG),
+};
+
+static const struct regmap_access_table ad4695_regmap_rd_table = {
+ .yes_ranges = ad4695_regmap_rd_ranges,
+ .n_yes_ranges = ARRAY_SIZE(ad4695_regmap_rd_ranges),
+};
+
+static const struct regmap_range ad4695_regmap_wr_ranges[] = {
+ regmap_reg_range(AD4695_REG_SPI_CONFIG_A, AD4695_REG_SPI_CONFIG_B),
+ regmap_reg_range(AD4695_REG_SCRATCH_PAD, AD4695_REG_SCRATCH_PAD),
+ regmap_reg_range(AD4695_REG_LOOP_MODE, AD4695_REG_LOOP_MODE),
+ regmap_reg_range(AD4695_REG_SPI_CONFIG_C, AD4695_REG_SPI_STATUS),
+ regmap_reg_range(AD4695_REG_SETUP, AD4695_REG_TEMP_CTRL),
+ regmap_reg_range(AD4695_REG_CONFIG_IN(0), AD4695_MAX_REG),
+};
+
+static const struct regmap_access_table ad4695_regmap_wr_table = {
+ .yes_ranges = ad4695_regmap_wr_ranges,
+ .n_yes_ranges = ARRAY_SIZE(ad4695_regmap_wr_ranges),
+};
+
+static const struct regmap_config ad4695_regmap_config = {
+ .name = "ad4695",
+ .reg_bits = 16,
+ .val_bits = 8,
+ .max_register = AD4695_MAX_REG,
+ .rd_table = &ad4695_regmap_rd_table,
+ .wr_table = &ad4695_regmap_wr_table,
+ .can_multi_write = true,
+};
+
+static const struct iio_chan_spec ad4695_channel_template = {
+ .type = IIO_VOLTAGE,
+ .indexed = 1,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE) |
+ BIT(IIO_CHAN_INFO_OFFSET),
+ .scan_type = {
+ .sign = 'u',
+ .realbits = 16,
+ .storagebits = 16,
+ },
+};
+
+static const struct iio_chan_spec ad4695_temp_channel_template = {
+ .address = AD4695_CMD_TEMP_CHAN,
+ .type = IIO_TEMP,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE) |
+ BIT(IIO_CHAN_INFO_OFFSET),
+ .scan_type = {
+ .sign = 's',
+ .realbits = 16,
+ .storagebits = 16,
+ },
+};
+
+static const char * const ad4695_power_supplies[] = {
+ "avdd", "vio"
+};
+
+static const struct ad4695_chip_info ad4695_chip_info = {
+ .name = "ad4695",
+ .max_sample_rate = 500 * KILO,
+ .num_voltage_inputs = 16,
+};
+
+static const struct ad4695_chip_info ad4696_chip_info = {
+ .name = "ad4696",
+ .max_sample_rate = 1 * MEGA,
+ .num_voltage_inputs = 16,
+};
+
+static const struct ad4695_chip_info ad4697_chip_info = {
+ .name = "ad4697",
+ .max_sample_rate = 500 * KILO,
+ .num_voltage_inputs = 8,
+};
+
+static const struct ad4695_chip_info ad4698_chip_info = {
+ .name = "ad4698",
+ .max_sample_rate = 1 * MEGA,
+ .num_voltage_inputs = 8,
+};
+
+/**
+ * ad4695_set_single_cycle_mode - Set the device in single cycle mode
+ * @st: The AD4695 state
+ * @channel: The first channel to read
+ *
+ * As per the datasheet, to enable single cycle mode, we need to set
+ * STD_SEQ_EN=0, NUM_SLOTS_AS=0 and CYC_CTRL=1 (Table 15). Setting SPI_MODE=1
+ * triggers the first conversion using the channel in AS_SLOT0.
+ *
+ * Context: can sleep, must be called with iio_device_claim_direct held
+ * Return: 0 on success, a negative error code on failure
+ */
+static int ad4695_set_single_cycle_mode(struct ad4695_state *st,
+ unsigned int channel)
+{
+ int ret;
+
+ ret = regmap_clear_bits(st->regmap, AD4695_REG_SEQ_CTRL,
+ AD4695_REG_SEQ_CTRL_STD_SEQ_EN |
+ AD4695_REG_SEQ_CTRL_NUM_SLOTS_AS);
+ if (ret)
+ return ret;
+
+ ret = regmap_write(st->regmap, AD4695_REG_AS_SLOT(0),
+ FIELD_PREP(AD4695_REG_AS_SLOT_INX, channel));
+ if (ret)
+ return ret;
+
+ return regmap_set_bits(st->regmap, AD4695_REG_SETUP,
+ AD4695_REG_SETUP_SPI_MODE |
+ AD4695_REG_SETUP_SPI_CYC_CTRL);
+}
+
+static int ad4695_set_ref_voltage(struct ad4695_state *st, int vref_mv)
+{
+ u8 val;
+
+ if (vref_mv >= 2400 && vref_mv <= 2750)
+ val = 0;
+ else if (vref_mv > 2750 && vref_mv <= 3250)
+ val = 1;
+ else if (vref_mv > 3250 && vref_mv <= 3750)
+ val = 2;
+ else if (vref_mv > 3750 && vref_mv <= 4500)
+ val = 3;
+ else if (vref_mv > 4500 && vref_mv <= 5100)
+ val = 4;
+ else
+ return -EINVAL;
+
+ return regmap_update_bits(st->regmap, AD4695_REG_REF_CTRL,
+ AD4695_REG_REF_CTRL_VREF_SET,
+ FIELD_PREP(AD4695_REG_REF_CTRL_VREF_SET, val));
+}
+
+static int ad4695_write_chn_cfg(struct ad4695_state *st,
+ struct ad4695_channel_config *cfg)
+{
+ u32 mask = 0, val = 0;
+
+ mask |= AD4695_REG_CONFIG_IN_MODE;
+ val |= FIELD_PREP(AD4695_REG_CONFIG_IN_MODE, cfg->bipolar ? 1 : 0);
+
+ mask |= AD4695_REG_CONFIG_IN_PAIR;
+ val |= FIELD_PREP(AD4695_REG_CONFIG_IN_PAIR, cfg->pin_pairing);
+
+ mask |= AD4695_REG_CONFIG_IN_AINHIGHZ_EN;
+ val |= FIELD_PREP(AD4695_REG_CONFIG_IN_AINHIGHZ_EN, cfg->highz_en ? 1 : 0);
+
+ return regmap_update_bits(st->regmap, AD4695_REG_CONFIG_IN(cfg->channel),
+ mask, val);
+}
+
+/**
+ * ad4695_read_one_sample - Read a single sample using single-cycle mode
+ * @st: The AD4695 state
+ * @address: The address of the channel to read
+ *
+ * Upon return, the sample will be stored in the raw_data field of @st.
+ *
+ * Context: can sleep, must be called with iio_device_claim_direct held
+ * Return: 0 on success, a negative error code on failure
+ */
+static int ad4695_read_one_sample(struct ad4695_state *st, unsigned int address)
+{
+ struct spi_transfer xfer[2] = { };
+ int ret;
+
+ ret = ad4695_set_single_cycle_mode(st, address);
+ if (ret)
+ return ret;
+
+ /*
+ * Setting the first channel to the temperature channel isn't supported
+ * in single-cycle mode, so we have to do an extra xfer to read the
+ * temperature.
+ */
+ if (address == AD4695_CMD_TEMP_CHAN) {
+ /* We aren't reading, so we can make this a short xfer. */
+ st->cnv_cmd2 = AD4695_CMD_TEMP_CHAN << 3;
+ xfer[0].bits_per_word = 8;
+ xfer[0].tx_buf = &st->cnv_cmd2;
+ xfer[0].len = 1;
+ xfer[0].cs_change = 1;
+ xfer[0].cs_change_delay.value = AD4695_T_CONVERT_NS;
+ xfer[0].cs_change_delay.unit = SPI_DELAY_UNIT_NSECS;
+
+ /* Then read the result and exit conversion mode. */
+ st->cnv_cmd = AD4695_CMD_EXIT_CNV_MODE << 11;
+ xfer[1].bits_per_word = 16;
+ xfer[1].tx_buf = &st->cnv_cmd;
+ xfer[1].rx_buf = &st->raw_data;
+ xfer[1].len = 2;
+
+ return spi_sync_transfer(st->spi, xfer, 2);
+ }
+
+ /*
+ * The conversion has already been done and we just have to read the
+ * result and exit conversion mode.
+ */
+ st->cnv_cmd = AD4695_CMD_EXIT_CNV_MODE << 11;
+ xfer[0].bits_per_word = 16;
+ xfer[0].tx_buf = &st->cnv_cmd;
+ xfer[0].rx_buf = &st->raw_data;
+ xfer[0].len = 2;
+
+ return spi_sync_transfer(st->spi, xfer, 1);
+}
+
+static int ad4695_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct ad4695_state *st = iio_priv(indio_dev);
+ struct ad4695_channel_config *cfg = &st->channels_cfg[chan->scan_index];
+ u8 realbits = chan->scan_type.realbits;
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ iio_device_claim_direct_scoped(return -EBUSY, indio_dev) {
+ ret = ad4695_read_one_sample(st, chan->address);
+ if (ret)
+ return ret;
+
+ if (chan->scan_type.sign == 's')
+ *val = sign_extend32(st->raw_data, realbits - 1);
+ else
+ *val = st->raw_data;
+
+ return IIO_VAL_INT;
+ }
+ unreachable();
+ case IIO_CHAN_INFO_SCALE:
+ switch (chan->type) {
+ case IIO_VOLTAGE:
+ *val = st->vref_mv;
+ *val2 = chan->scan_type.realbits;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ case IIO_TEMP:
+ /* T_scale (°C) = raw * V_REF (mV) / (-1.8 mV/°C * 2^16) */
+ *val = st->vref_mv * -556;
+ *val2 = 16;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ default:
+ return -EINVAL;
+ }
+ case IIO_CHAN_INFO_OFFSET:
+ switch (chan->type) {
+ case IIO_VOLTAGE:
+ if (cfg->pin_pairing == AD4695_IN_PAIR_COM)
+ *val = st->com_mv * (1 << realbits) / st->vref_mv;
+ else if (cfg->pin_pairing == AD4695_IN_PAIR_EVEN_ODD)
+ *val = cfg->common_mode_mv * (1 << realbits) / st->vref_mv;
+ else
+ *val = 0;
+
+ return IIO_VAL_INT;
+ case IIO_TEMP:
+ /* T_offset (°C) = -725 mV / (-1.8 mV/°C) */
+ /* T_offset (raw) = T_offset (°C) * (-1.8 mV/°C) * 2^16 / V_REF (mV) */
+ *val = -47513600;
+ *val2 = st->vref_mv;
+ return IIO_VAL_FRACTIONAL;
+ default:
+ return -EINVAL;
+ }
+ default:
+ return -EINVAL;
+ }
+}
+
+static int ad4695_debugfs_reg_access(struct iio_dev *indio_dev, unsigned int reg,
+ unsigned int writeval, unsigned int *readval)
+{
+ struct ad4695_state *st = iio_priv(indio_dev);
+
+ iio_device_claim_direct_scoped(return -EBUSY, indio_dev) {
+ if (readval)
+ return regmap_read(st->regmap, reg, readval);
+
+ return regmap_write(st->regmap, reg, writeval);
+ }
+
+ unreachable();
+}
+
+static const struct iio_info ad4695_info = {
+ .read_raw = &ad4695_read_raw,
+ .debugfs_reg_access = &ad4695_debugfs_reg_access,
+};
+
+static int ad4695_parse_channel_cfg(struct iio_dev *indio_dev)
+{
+ struct device *dev = indio_dev->dev.parent;
+ struct ad4695_state *st = iio_priv(indio_dev);
+ struct ad4695_channel_config *chan_cfg;
+ struct iio_chan_spec *iio_chan;
+ int ret, i;
+
+ /* populate defaults */
+ for (i = 0; i < st->chip_info->num_voltage_inputs; i++) {
+ chan_cfg = &st->channels_cfg[i];
+ iio_chan = &st->iio_chan[i];
+
+ chan_cfg->highz_en = true;
+ chan_cfg->channel = i;
+
+ *iio_chan = ad4695_channel_template;
+ iio_chan->channel = i;
+ iio_chan->scan_index = i;
+ iio_chan->address = AD4695_CMD_VOLTAGE_CHAN(i);
+ }
+
+ /* modify based on firmware description */
+ device_for_each_child_node_scoped(dev, child) {
+ u32 reg, val;
+
+ ret = fwnode_property_read_u32(child, "reg", ®);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "failed to read reg property (%s)\n",
+ fwnode_get_name(child));
+
+ if (reg >= st->chip_info->num_voltage_inputs)
+ return dev_err_probe(dev, -EINVAL,
+ "reg out of range (%s)\n",
+ fwnode_get_name(child));
+
+ iio_chan = &st->iio_chan[reg];
+ chan_cfg = &st->channels_cfg[reg];
+
+ chan_cfg->highz_en = !fwnode_property_read_bool(child, "adi,no-high-z");
+ chan_cfg->bipolar = fwnode_property_read_bool(child, "bipolar");
+
+ ret = fwnode_property_read_u32(child, "common-mode-channel", &val);
+ if (ret && ret != -EINVAL)
+ return dev_err_probe(dev, ret,
+ "failed to read common-mode-channel (%s)\n",
+ fwnode_get_name(child));
+
+ if (ret == -EINVAL || val == AD4695_COMMON_MODE_REFGND)
+ chan_cfg->pin_pairing = AD4695_IN_PAIR_REFGND;
+ else if (val == AD4695_COMMON_MODE_COM)
+ chan_cfg->pin_pairing = AD4695_IN_PAIR_COM;
+ else
+ chan_cfg->pin_pairing = AD4695_IN_PAIR_EVEN_ODD;
+
+ if (chan_cfg->pin_pairing == AD4695_IN_PAIR_EVEN_ODD &&
+ val % 2 == 0)
+ return dev_err_probe(dev, -EINVAL,
+ "common-mode-channel must be odd number (%s)\n",
+ fwnode_get_name(child));
+
+ if (chan_cfg->pin_pairing == AD4695_IN_PAIR_EVEN_ODD &&
+ val != reg + 1)
+ return dev_err_probe(dev, -EINVAL,
+ "common-mode-channel must be next consecutive channel (%s)\n",
+ fwnode_get_name(child));
+
+ if (chan_cfg->pin_pairing == AD4695_IN_PAIR_EVEN_ODD) {
+ char name[5];
+
+ snprintf(name, sizeof(name), "in%d", reg + 1);
+
+ ret = devm_regulator_get_enable_read_voltage(dev, name);
+ if (ret < 0)
+ return dev_err_probe(dev, ret,
+ "failed to get %s voltage (%s)\n",
+ name, fwnode_get_name(child));
+
+ chan_cfg->common_mode_mv = ret / 1000;
+ }
+
+ if (chan_cfg->bipolar && chan_cfg->pin_pairing == AD4695_IN_PAIR_REFGND)
+ return dev_err_probe(dev, -EINVAL,
+ "bipolar mode is not available for inputs paired with REFGND (%s).\n",
+ fwnode_get_name(child));
+
+ if (chan_cfg->bipolar)
+ iio_chan->scan_type.sign = 's';
+
+ ret = ad4695_write_chn_cfg(st, chan_cfg);
+ if (ret)
+ return ret;
+ }
+
+ /* Temperature channel must be next scan index after voltage channels. */
+ st->iio_chan[i] = ad4695_temp_channel_template;
+ st->iio_chan[i].scan_index = i;
+
+ return 0;
+}
+
+static int ad4695_probe(struct spi_device *spi)
+{
+ struct device *dev = &spi->dev;
+ struct ad4695_state *st;
+ struct iio_dev *indio_dev;
+ struct gpio_desc *cnv_gpio;
+ bool use_internal_ldo_supply;
+ bool use_internal_ref_buffer;
+ int ret;
+
+ cnv_gpio = devm_gpiod_get_optional(dev, "cnv", GPIOD_OUT_LOW);
+ if (IS_ERR(cnv_gpio))
+ return dev_err_probe(dev, PTR_ERR(cnv_gpio), "Failed to get CNV GPIO\n");
+
+ /* Driver currently requires CNV pin to be connected to SPI CS */
+ if (cnv_gpio)
+ return dev_err_probe(dev, -ENODEV, "CNV GPIO is not supported\n");
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ st = iio_priv(indio_dev);
+ st->spi = spi;
+
+ st->chip_info = spi_get_device_match_data(spi);
+ if (!st->chip_info)
+ return -EINVAL;
+
+ /* Registers cannot be read at the max allowable speed */
+ spi->max_speed_hz = AD4695_REG_ACCESS_SCLK_HZ;
+
+ st->regmap = devm_regmap_init_spi(spi, &ad4695_regmap_config);
+ if (IS_ERR(st->regmap))
+ return dev_err_probe(dev, PTR_ERR(st->regmap), "Failed to initialize regmap\n");
+
+ ret = devm_regulator_bulk_get_enable(dev, ARRAY_SIZE(ad4695_power_supplies),
+ ad4695_power_supplies);
+ if (ret)
+ return dev_err_probe(dev, ret, "Failed to enable power supplies\n");
+
+ /* If LDO_IN supply is present, then we are using internal LDO. */
+ ret = devm_regulator_get_enable_optional(dev, "ldo-in");
+ if (ret < 0 && ret != -ENODEV)
+ return dev_err_probe(dev, ret, "Failed to enable LDO_IN supply\n");
+
+ use_internal_ldo_supply = ret == 0;
+
+ if (!use_internal_ldo_supply) {
+ /* Otherwise we need an external VDD supply. */
+ ret = devm_regulator_get_enable(dev, "vdd");
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "Failed to enable VDD supply\n");
+ }
+
+ /* If REFIN supply is given, then we are using internal buffer */
+ 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) {
+ st->vref_mv = ret / 1000;
+ use_internal_ref_buffer = true;
+ } else {
+ /* Otherwise, we need an external reference. */
+ ret = devm_regulator_get_enable_read_voltage(dev, "ref");
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "Failed to get REF voltage\n");
+
+ st->vref_mv = ret / 1000;
+ use_internal_ref_buffer = false;
+ }
+
+ ret = devm_regulator_get_enable_read_voltage(dev, "com");
+ if (ret < 0 && ret != -ENODEV)
+ return dev_err_probe(dev, ret, "Failed to get COM voltage\n");
+
+ st->com_mv = ret == -ENODEV ? 0 : ret / 1000;
+
+ /*
+ * Reset the device using hardware reset if available or fall back to
+ * software reset.
+ */
+
+ st->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+ if (IS_ERR(st->reset_gpio))
+ return PTR_ERR(st->reset_gpio);
+
+ if (st->reset_gpio) {
+ gpiod_set_value(st->reset_gpio, 0);
+ msleep(AD4695_T_WAKEUP_HW_MS);
+ } else {
+ ret = regmap_write(st->regmap, AD4695_REG_SPI_CONFIG_A,
+ AD4695_REG_SPI_CONFIG_A_SW_RST);
+ if (ret)
+ return ret;
+
+ msleep(AD4695_T_WAKEUP_SW_MS);
+ }
+
+ /* Needed for debugfs since it only access registers 1 byte at a time. */
+ ret = regmap_set_bits(st->regmap, AD4695_REG_SPI_CONFIG_C,
+ AD4695_REG_SPI_CONFIG_C_MB_STRICT);
+ if (ret)
+ return ret;
+
+ /* Disable internal LDO if it isn't needed. */
+ ret = regmap_update_bits(st->regmap, AD4695_REG_SETUP,
+ AD4695_REG_SETUP_LDO_EN,
+ FIELD_PREP(AD4695_REG_SETUP_LDO_EN,
+ use_internal_ldo_supply ? 1 : 0));
+ if (ret)
+ return ret;
+
+ /* configure reference supply */
+
+ if (device_property_present(dev, "adi,no-ref-current-limit")) {
+ ret = regmap_set_bits(st->regmap, AD4695_REG_REF_CTRL,
+ AD4695_REG_REF_CTRL_OV_MODE);
+ if (ret)
+ return ret;
+ }
+
+ if (device_property_present(dev, "adi,no-ref-high-z")) {
+ if (use_internal_ref_buffer)
+ return dev_err_probe(dev, -EINVAL,
+ "Cannot disable high-Z mode for internal reference buffer\n");
+
+ ret = regmap_clear_bits(st->regmap, AD4695_REG_REF_CTRL,
+ AD4695_REG_REF_CTRL_REFHIZ_EN);
+ if (ret)
+ return ret;
+ }
+
+ ret = ad4695_set_ref_voltage(st, st->vref_mv);
+ if (ret)
+ return ret;
+
+ if (use_internal_ref_buffer) {
+ ret = regmap_set_bits(st->regmap, AD4695_REG_REF_CTRL,
+ AD4695_REG_REF_CTRL_REFBUF_EN);
+ if (ret)
+ return ret;
+
+ /* Give the capacitor some time to charge up. */
+ msleep(AD4695_T_REFBUF_MS);
+ }
+
+ ret = ad4695_parse_channel_cfg(indio_dev);
+ if (ret)
+ return ret;
+
+ indio_dev->name = st->chip_info->name;
+ indio_dev->info = &ad4695_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = st->iio_chan;
+ indio_dev->num_channels = st->chip_info->num_voltage_inputs + 1;
+
+ return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct spi_device_id ad4695_spi_id_table[] = {
+ { .name = "ad4695", .driver_data = (kernel_ulong_t)&ad4695_chip_info },
+ { .name = "ad4696", .driver_data = (kernel_ulong_t)&ad4696_chip_info },
+ { .name = "ad4697", .driver_data = (kernel_ulong_t)&ad4697_chip_info },
+ { .name = "ad4698", .driver_data = (kernel_ulong_t)&ad4698_chip_info },
+ { }
+};
+MODULE_DEVICE_TABLE(spi, ad4695_spi_id_table);
+
+static const struct of_device_id ad4695_of_match_table[] = {
+ { .compatible = "adi,ad4695", .data = &ad4695_chip_info, },
+ { .compatible = "adi,ad4696", .data = &ad4696_chip_info, },
+ { .compatible = "adi,ad4697", .data = &ad4697_chip_info, },
+ { .compatible = "adi,ad4698", .data = &ad4698_chip_info, },
+ { }
+};
+MODULE_DEVICE_TABLE(of, ad4695_of_match_table);
+
+static struct spi_driver ad4695_driver = {
+ .driver = {
+ .name = "ad4695",
+ .of_match_table = ad4695_of_match_table,
+ },
+ .probe = ad4695_probe,
+ .id_table = ad4695_spi_id_table,
+};
+module_spi_driver(ad4695_driver);
+
+MODULE_AUTHOR("Ramona Gradinariu <ramona.gradinariu@analog.com>");
+MODULE_AUTHOR("David Lechner <dlechner@baylibre.com>");
+MODULE_DESCRIPTION("Analog Devices AD4695 ADC driver");
+MODULE_LICENSE("GPL");