[PATCH 2/3] iio: adc: add driver support for AD5940

From: Song Qiang
Date: Fri Nov 08 2019 - 08:10:05 EST

The AD5940 is a high precision, low power analog front end (AFE)
designed for portable applications that require high precision,
electrochemical-based measurement techniques, such as amper-
ometric, voltammetric, or impedance measurements.

Datasheet:
Link: https://www.analog.com/media/en/technical-documentation/data-sheets/AD5940.pdf

Signed-off-by: Song Qiang <songqiang1304521@xxxxxxxxx>
---
.../ABI/testing/sysfs-bus-iio-adc-ad5940 | 7 +
drivers/iio/adc/Kconfig | 10 +
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/ad5940.c | 679 ++++++++++++++++++
4 files changed, 697 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-adc-ad5940
create mode 100644 drivers/iio/adc/ad5940.c

diff --git a/Documentation/ABI/testing/sysfs-bus-iio-adc-ad5940 b/Documentation/ABI/testing/sysfs-bus-iio-adc-ad5940
new file mode 100644
index 000000000000..839644ffbd9b
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-iio-adc-ad5940
@@ -0,0 +1,7 @@
+What: /sys/bus/iio/devices/iio:deviceX/events/in_voltageY-voltageZ_name
+Date: June 2019
+KernelVersion: 4.14.5
+Contact: songqiang1304521@xxxxxxxxx
+Description:
+ Channel name assigned in devicetree, used to tell userspace
+ users which channel this is.
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index f0af3a42f53c..345f934d3444 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -11,6 +11,16 @@ config AD_SIGMA_DELTA
select IIO_BUFFER
select IIO_TRIGGERED_BUFFER

+config AD5940
+ tristate "Analog Devices AD5940 ADC Driver"
+ depends on SPI
+ help
+ Say yes here to build support for the ADC part of Analog Devices
+ analog front end AD5940.
+
+ To compile this driver as a module, choose M here: the
+ module will be called ad5940.
+
config AD7124
tristate "Analog Devices AD7124 and similar sigma-delta ADCs driver"
depends on SPI_MASTER
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index ef9cc485fb67..ac52d1b6f3fb 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -5,6 +5,7 @@

# When adding new entries keep the list in alphabetical order
obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o
+obj-$(CONFIG_AD5940) += ad5940.o
obj-$(CONFIG_AD7124) += ad7124.o
obj-$(CONFIG_AD7266) += ad7266.o
obj-$(CONFIG_AD7291) += ad7291.o
diff --git a/drivers/iio/adc/ad5940.c b/drivers/iio/adc/ad5940.c
new file mode 100644
index 000000000000..57f737edca36
--- /dev/null
+++ b/drivers/iio/adc/ad5940.c
@@ -0,0 +1,679 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AD5940 SPI ADC driver
+ *
+ * Copyright (C) 2019 Song Qiang <songqiang1304521@xxxxxxxxx>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bsearch.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of_irq.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+
+#include <linux/iio/iio.h>
+
+#define AD5940_CHANNEL_AINP_MSK GENMASK(5, 0)
+#define AD5940_CHANNEL_AINP(x) FIELD_PREP(AD5940_CHANNEL_AINP_MSK, x)
+#define AD5940_CHANNEL_AINN_MSK GENMASK(12, 8)
+#define AD5940_CHANNEL_AINN(x) FIELD_PREP(AD5940_CHANNEL_AINN_MSK, x)
+
+#define AD5940_CHANNEL_NAME 0
+
+#define AD5940_SPICMD_SETADDR 0x20
+#define AD5940_SPICMD_READREG 0x6d
+#define AD5940_SPICMD_WRITEREG 0x2d
+#define AD5940_SPICMD_READFIFO 0x5f
+
+#define AD5940_REG_AFECON 0x00002000
+#define AD5940_AFECON_ADCCONV_MSK BIT(8)
+#define AD5940_AFECON_ADCCONV_EN FIELD_PREP(AD5940_AFECON_ADCCONV_MSK, 1)
+#define AD5940_AFECON_ADCCONV_DIS FIELD_PREP(AD5940_AFECON_ADCCONV_MSK, 0)
+#define AD5940_AFECON_ADCEN_MSK BIT(7)
+#define AD5940_AFECON_ADCEN FIELD_PREP(AD5940_AFECON_ADCEN_MSK, 1)
+
+#define AD5940_REG_ADCDAT 0x00002074
+#define AD5940_REG_DFTREAL 0x00002078
+#define AD5940_REG_DFTIMAG 0x0000207C
+#define AD5940_REG_SINC2DAT 0x00002080
+#define AD5940_REG_TEMPSENSDAT 0x00002084
+#define AD5940_REG_STATSMEAN 0x000021C8
+#define AD5940_REG_STATSVAR 0x000021C0
+
+#define AD5940_REG_INTCPOL 0x00003000 /* Interrupt Polarity. */
+#define AD5940_INTCPOL_MSK BIT(0)
+#define AD5940_INTCPOL_POS FIELD_PREP(AD5940_INTCPOL_MSK, 1)
+#define AD5940_INTCPOL_NEG FIELD_PREP(AD5940_INTCPOL_MSK, 0)
+#define AD5940_REG_INTCLR 0x00003004
+
+#define AD5940_REG_PMBW 0x000022F0
+#define AD5940_PMBW_SYSHS_MSK BIT(0)
+#define AD5940_PMBW_HP FIELD_PREP(AD5940_PMBW_SYSHS_MSK, 1)
+#define AD5940_PMBW_LP FIELD_PREP(AD5940_PMBW_SYSHS_MSK, 0)
+#define AD5940_PMBW_SYSBW_MSK GENMASK(3, 2)
+#define AD5940_PMBW_BWNA FIELD_PREP(AD5940_PMBW_SYSBW_MSK, 0)
+#define AD5940_PMBW_BW50 FIELD_PREP(AD5940_PMBW_SYSBW_MSK, 1)
+#define AD5940_PMBW_BW100 FIELD_PREP(AD5940_PMBW_SYSBW_MSK, 2)
+#define AD5940_PMBW_BW250 FIELD_PREP(AD5940_PMBW_SYSBW_MSK, 3)
+
+#define AD5940_REG_ADCCON 0x000021A8
+#define AD5940_ADCCON_PGA_MSK GENMASK(18, 16)
+#define AD5940_ADCCON_PGA_1 FIELD_PREP(AD5940_ADCCON_PGA_MSK, 0)
+#define AD5940_ADCCON_PGA_1P5 FIELD_PREP(AD5940_ADCCON_PGA_MSK, 1)
+#define AD5940_ADCCON_PGA_2 FIELD_PREP(AD5940_ADCCON_PGA_MSK, 2)
+#define AD5940_ADCCON_PGA_4 FIELD_PREP(AD5940_ADCCON_PGA_MSK, 3)
+#define AD5940_ADCCON_PGA_9 FIELD_PREP(AD5940_ADCCON_PGA_MSK, 4)
+#define AD5940_ADCCON_MUX_MSK (GENMASK(12, 8) | GENMASK(5, 0))
+
+#define AD5940_REG_INTCLR 0x00003004
+#define AD5940_REG_INTCSEL0 0x00003008
+#define AD5940_INTC_BRK BIT(31)
+#define AD5940_INTC_OUTLIER BIT(29)
+#define AD5940_INTC_FIFO_UNDERFLOW BIT(27)
+#define AD5940_INTC_FIFO_OVERFLOW BIT(26)
+#define AD5940_INTC_FIFO_THRESHOLD BIT(25)
+#define AD5940_INTC_FIFO_EMPTY BIT(24)
+#define AD5940_INTC_FIFO_FULL BIT(23)
+#define AD5940_INTC_SEQ_TO_ERR BIT(17)
+#define AD5940_INTC_SEQ_TO_FINISH BIT(16)
+#define AD5940_INTC_SEQ_END BIT(15)
+#define AD5940_INTC_BL_DONE BIT(13)
+#define AD5940_INTC_IRQ_3 BIT(12)
+#define AD5940_INTC_IRQ_2 BIT(11)
+#define AD5940_INTC_IRQ_1 BIT(10)
+#define AD5940_INTC_IRQ_0 BIT(9)
+#define AD5940_INTC_VAR BIT(8)
+#define AD5940_INTC_MEAN BIT(7)
+#define AD5940_INTC_ADC_DELTA_FAIL BIT(6)
+#define AD5940_INTC_ADC_MAX_FAIL BIT(5)
+#define AD5940_INTC_ADC_MIN_FAIL BIT(4)
+#define AD5940_INTC_TEMP BIT(3)
+#define AD5940_INTC_SINC2 BIT(2)
+#define AD5940_INTC_DFT BIT(1)
+#define AD5940_INTC_ADC BIT(0)
+
+#define AD5940_REG_GP0CON 0x00000000
+#define AD5940_GP0CON_3_MSK GENMASK(7, 6)
+#define AD5940_GP0CON_3_INT FIELD_PREP(AD5940_GP0CON_3_MSK, 3)
+#define AD5940_GP0CON_6_MSK GENMASK(13, 12)
+#define AD5940_GP0CON_6_INT FIELD_PREP(AD5940_GP0CON_6_MSK, 3)
+
+#define AD5940_REG_GP0OEN 0x00000004
+
+#define AD5940_AFECON_CHIPID 0x00000404
+#define AD5940_CHIPID 0x5502
+
+struct ad5940_channel_config {
+ u32 ain;
+ const char *channel_name;
+};
+
+struct ad5940_state {
+ struct spi_device *spi;
+ /* This mutex is for protecting the SPI command sequences. */
+ struct mutex lock;
+
+ struct completion complete;
+ u32 conversion_time;
+
+ u8 n_input;
+ u8 p_input;
+
+ struct regulator *vref;
+ int vref_mv;
+
+ int num_channels;
+ struct ad5940_channel_config *channel_config;
+ union {
+ __be32 d32;
+ u8 d8[5];
+ } data ____cacheline_aligned;
+};
+
+static int ad5940_set_addr(struct ad5940_state *st, u16 addr)
+{
+ st->data.d8[0] = AD5940_SPICMD_SETADDR;
+ st->data.d8[1] = (addr >> 8) & 0xff;
+ st->data.d8[2] = addr & 0xff;
+
+ return spi_write(st->spi, st->data.d8, 3);
+}
+
+static int ad5940_read_reg(struct ad5940_state *st, u16 addr, u32 *data)
+{
+ int rx_len;
+ u8 shift;
+ int ret;
+
+ ret = ad5940_set_addr(st, addr);
+ if (ret < 0)
+ return ret;
+
+ if ((addr >= 0x1000) && (addr <= 0x3014))
+ rx_len = 4;
+ else
+ rx_len = 2;
+
+ st->data.d8[0] = AD5940_SPICMD_READREG;
+ st->data.d8[1] = 0;
+ shift = 32 - (8 * rx_len);
+
+ ret = spi_write_then_read(st->spi, st->data.d8, 2, &st->data.d32,
+ rx_len);
+ if (ret < 0)
+ return ret;
+
+ *data = be32_to_cpu(st->data.d32) >> shift;
+
+ return 0;
+}
+
+static int ad5940_write_reg(struct ad5940_state *st, u16 addr, u32 data)
+{
+ int tx_len;
+ int ret;
+
+ ret = ad5940_set_addr(st, addr);
+ if (ret < 0)
+ return ret;
+
+ st->data.d8[0] = AD5940_SPICMD_WRITEREG;
+ if ((addr >= 0x1000) && (addr <= 0x3014)) {
+ st->data.d8[1] = (data >> 24) & 0xff;
+ st->data.d8[2] = (data >> 16) & 0xff;
+ st->data.d8[3] = (data >> 8) & 0xff;
+ st->data.d8[4] = data & 0xff;
+ tx_len = 5;
+ } else {
+ st->data.d8[1] = (data >> 8) & 0xff;
+ st->data.d8[2] = data & 0xff;
+ tx_len = 3;
+ }
+
+ return spi_write(st->spi, st->data.d8, tx_len);
+}
+
+static int ad5940_write_reg_mask(struct ad5940_state *st, u16 addr,
+ u32 mask, u32 data)
+{
+ u32 temp;
+ int ret;
+
+ ret = ad5940_read_reg(st, addr, &temp);
+ if (ret < 0)
+ return ret;
+
+ temp &= ~mask;
+ temp |= data;
+
+ return ad5940_write_reg(st, addr, temp);
+}
+
+static ssize_t ad5940_read_info(struct iio_dev *indio_dev,
+ uintptr_t private,
+ const struct iio_chan_spec *chan,
+ char *buf)
+{
+ struct ad5940_state *st = iio_priv(indio_dev);
+
+ switch ((u32)private) {
+ case AD5940_CHANNEL_NAME:
+ return sprintf(buf, "%s\n",
+ st->channel_config[chan->address].channel_name);
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_chan_spec_ext_info ad4590_ext_info[] = {
+ {
+ .name = "name",
+ .read = ad5940_read_info,
+ .private = AD5940_CHANNEL_NAME,
+ .shared = IIO_SEPARATE,
+ },
+ { },
+};
+
+static const struct iio_chan_spec ad5940_channel_template = {
+ .type = IIO_VOLTAGE,
+ .differential = 1,
+ .indexed = 1,
+ .ext_info = ad4590_ext_info,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+};
+
+static int ad5940_clear_ready(struct ad5940_state *st)
+{
+ int ret;
+
+ ret = ad5940_write_reg_mask(st, AD5940_REG_AFECON,
+ AD5940_AFECON_ADCCONV_MSK,
+ AD5940_AFECON_ADCCONV_DIS);
+ if (ret < 0)
+ return ret;
+
+ return ad5940_write_reg(st, AD5940_REG_INTCLR, AD5940_INTC_ADC);
+}
+
+static irqreturn_t ad5940_irq_handler(int irq, void *private)
+{
+ struct ad5940_state *st = private;
+ int ret;
+
+ ret = ad5940_clear_ready(st);
+ if (ret < 0)
+ return ret;
+
+ complete(&st->complete);
+
+ return IRQ_HANDLED;
+}
+
+static int ad5940_scan_direct(struct ad5940_state *st, u32 mux, int *val)
+{
+ int ret;
+ u32 result;
+
+ mutex_lock(&st->lock);
+ ret = ad5940_write_reg_mask(st, AD5940_REG_ADCCON,
+ AD5940_ADCCON_MUX_MSK, mux);
+ if (ret < 0)
+ goto unlock_return;
+
+ reinit_completion(&st->complete);
+ ret = ad5940_write_reg_mask(st, AD5940_REG_AFECON,
+ AD5940_AFECON_ADCCONV_MSK,
+ AD5940_AFECON_ADCCONV_EN);
+ if (ret < 0)
+ goto unlock_return;
+
+ ret = wait_for_completion_timeout(&st->complete,
+ msecs_to_jiffies(1000));
+ if (!ret) {
+ ad5940_clear_ready(st);
+ ret = -ETIMEDOUT;
+ goto unlock_return;
+ }
+
+ ret = ad5940_read_reg(st, AD5940_REG_ADCDAT, &result);
+ mutex_unlock(&st->lock);
+ if (ret < 0)
+ return ret;
+ *val = result & 0xffff;
+
+ return 0;
+
+unlock_return:
+ mutex_unlock(&st->lock);
+ return ret;
+}
+
+static int ad5940_read_raw(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan, int *val, int *val2, long info)
+{
+ struct ad5940_state *st = iio_priv(indio_dev);
+ int ret;
+
+ switch (info) {
+ case IIO_CHAN_INFO_RAW:
+ ret = ad5940_scan_direct(st,
+ st->channel_config[chan->address].ain,
+ val);
+ if (ret < 0)
+ return ret;
+ else
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ *val = st->vref_mv;
+ *val2 = 16;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_info ad5940_info = {
+ .read_raw = &ad5940_read_raw,
+};
+
+int cmp_u8(const void *a, const void *b)
+{
+ return (*(u8 *)a - *(u8 *)b);
+}
+
+static int ad5940_check_channel_indexes(struct device *dev, u32 *ain)
+{
+ const u8 channel_p[] = {
+ 0, 1, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 18, 19,
+ 20, 22, 23, 24, 25, 26, 31, 33, 35, 36
+ };
+ const u8 channel_n[] = {
+ 0, 1, 2, 4, 5, 6, 7, 10, 11, 12, 14, 16, 17, 20
+ };
+ u8 *index;
+
+ index = (u8 *) bsearch(&ain[0], channel_p, ARRAY_SIZE(channel_p),
+ sizeof(u8), cmp_u8);
+ if (!index) {
+ dev_err(dev, "Positive input index not found.\n");
+ return -EINVAL;
+ }
+
+ index = (u8 *) bsearch(&ain[1], channel_n, ARRAY_SIZE(channel_n),
+ sizeof(u8), cmp_u8);
+ if (!index) {
+ dev_err(dev, "negtive input index not found.\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int ad5940_of_parse_channel_config(struct iio_dev *indio_dev,
+ struct device_node *np)
+{
+ struct ad5940_state *st = iio_priv(indio_dev);
+ struct iio_chan_spec *chan;
+ struct device_node *child;
+ u32 channel, ain[2];
+ int ret;
+
+ st->num_channels = of_get_available_child_count(np);
+ if (!st->num_channels) {
+ dev_err(indio_dev->dev.parent, "no channel children\n");
+ return -ENODEV;
+ }
+
+ chan = devm_kcalloc(indio_dev->dev.parent, st->num_channels,
+ sizeof(*chan), GFP_KERNEL);
+ if (!chan)
+ return -ENOMEM;
+
+ st->channel_config = devm_kcalloc(indio_dev->dev.parent,
+ st->num_channels,
+ sizeof(*st->channel_config),
+ GFP_KERNEL);
+ if (!st->channel_config)
+ return -ENOMEM;
+
+ indio_dev->channels = chan;
+ indio_dev->num_channels = st->num_channels;
+
+ for_each_available_child_of_node(np, child) {
+ ret = of_property_read_u32(child, "reg", &channel);
+ if (ret)
+ goto err;
+
+ ret = of_property_read_u32_array(child, "diff-channels",
+ ain, 2);
+ if (ret)
+ goto err;
+
+ ret = of_property_read_string(child, "channel-name",
+ &st->channel_config[channel].channel_name);
+ if (ret)
+ st->channel_config[channel].channel_name = "none-name";
+
+ ret = ad5940_check_channel_indexes(indio_dev->dev.parent, ain);
+ if (ret) {
+ dev_err(indio_dev->dev.parent,
+ "some input channel index does not exist: %d, %d, %d",
+ channel, ain[0], ain[1]);
+ goto err;
+ }
+
+ st->channel_config[channel].ain = AD5940_CHANNEL_AINP(ain[0]) |
+ AD5940_CHANNEL_AINN(ain[1]);
+
+ *chan = ad5940_channel_template;
+ chan->address = channel;
+ chan->scan_index = channel;
+ chan->channel = ain[0];
+ chan->channel2 = ain[1];
+
+ chan++;
+ }
+
+ return 0;
+err:
+ of_node_put(child);
+
+ return ret;
+}
+
+static int ad5940_config_polarity(struct ad5940_state *st, u32 polarity)
+{
+ u32 val;
+
+ if (polarity == IRQF_TRIGGER_RISING)
+ val = AD5940_INTCPOL_POS;
+ else
+ val = AD5940_INTCPOL_NEG;
+
+ return ad5940_write_reg_mask(st, AD5940_REG_INTCPOL,
+ AD5940_INTCPOL_MSK, val);
+}
+
+static int ad5940_config_int_io(struct ad5940_state *st, u8 int_io)
+{
+ int ret = 0;
+
+ if (int_io == 3)
+ ret = ad5940_write_reg_mask(st, AD5940_REG_GP0CON,
+ AD5940_GP0CON_3_MSK,
+ AD5940_GP0CON_3_INT);
+ else if (int_io == 6)
+ ret = ad5940_write_reg_mask(st, AD5940_REG_GP0CON,
+ AD5940_GP0CON_6_MSK,
+ AD5940_GP0CON_6_INT);
+ if (ret < 0)
+ return ret;
+
+ return ad5940_write_reg(st, AD5940_REG_GP0OEN, BIT(int_io));
+}
+
+static const u32 ad5940_powerup_setting[][2] = {
+ { 0x0908, 0x02c9 },
+ { 0x0c08, 0x206c },
+ { 0x21f0, 0x0010 },
+ { 0x0410, 0x02c9 },
+ { 0x0a28, 0x0009 },
+ { 0x238c, 0x0104 },
+ { 0x0a04, 0x4859 },
+ { 0x0a04, 0xf27b },
+ { 0x0a00, 0x8009 },
+ { 0x22f0, 0x0000 },
+ { 0x2230, 0xde87a5af },
+ { 0x2250, 0x103f },
+ { 0x22b0, 0x203c },
+ { 0x2230, 0xde87a5a0 },
+};
+
+static int ad5940_setup(struct ad5940_state *st, u8 int_io)
+{
+ u32 chip_id;
+ int ret;
+ u8 i;
+
+ for (i = 0; i < ARRAY_SIZE(ad5940_powerup_setting); i++) {
+ ret = ad5940_write_reg(st, ad5940_powerup_setting[i][0],
+ ad5940_powerup_setting[i][1]);
+ if (ret < 0)
+ return ret;
+ }
+
+ ret = ad5940_read_reg(st, AD5940_AFECON_CHIPID, &chip_id);
+ if (ret < 0)
+ return ret;
+ if (chip_id != AD5940_CHIPID) {
+ dev_err(&st->spi->dev, "Wrong chip ID with 0x%x.", chip_id);
+ return -ENXIO;
+ }
+ dev_info(&st->spi->dev, "Found ad5940");
+
+ ret = ad5940_write_reg(st, AD5940_REG_PMBW,
+ AD5940_PMBW_LP | AD5940_PMBW_BW250);
+ if (ret < 0)
+ return ret;
+
+ ret = ad5940_config_int_io(st, int_io);
+ if (ret < 0)
+ return ret;
+
+ ret = ad5940_clear_ready(st);
+ if (ret < 0)
+ return ret;
+
+ ret = ad5940_write_reg(st, AD5940_REG_INTCSEL0, AD5940_INTC_ADC);
+ if (ret < 0)
+ return ret;
+
+ ret = ad5940_write_reg_mask(st, AD5940_REG_ADCCON,
+ AD5940_ADCCON_PGA_MSK,
+ AD5940_ADCCON_PGA_1);
+ if (ret < 0)
+ return ret;
+
+ return ad5940_write_reg_mask(st, AD5940_REG_AFECON,
+ AD5940_AFECON_ADCEN_MSK,
+ AD5940_AFECON_ADCEN);
+}
+
+static void ad5940_regulator_disable(void *data)
+{
+ struct ad5940_state *st = data;
+
+ regulator_disable(st->vref);
+}
+
+static inline int ad5940_check_int_io(u32 io, struct device *dev)
+{
+ static const u8 int_io[3] = {0, 3, 6};
+ u8 *p;
+
+ p = bsearch(&io, int_io, 3, sizeof(u8), cmp_u8);
+ if (!p) {
+ dev_err(dev, "interrupt output pin not valid,");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int ad5940_probe(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev;
+ struct ad5940_state *st;
+ u32 trig_type;
+ int vref_uv = 0;
+ u32 int_io;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ st = iio_priv(indio_dev);
+
+ ret = device_property_read_u32(&spi->dev, "adi,interrupt-io", &int_io);
+ if (ret) {
+ dev_err(&spi->dev,
+ "reading dt property 'adi,interrupt-io' failed.");
+ return -EINVAL;
+ }
+
+ st->spi = spi;
+
+ trig_type = irq_get_trigger_type(spi->irq);
+ if (trig_type != IRQF_TRIGGER_RISING &&
+ trig_type != IRQF_TRIGGER_FALLING) {
+ dev_err(&spi->dev, "trigger type must be rising or falling.");
+ return -EINVAL;
+ }
+ ret = ad5940_config_polarity(st, trig_type);
+ if (ret < 0) {
+ dev_err(&spi->dev, "config polarity failed.");
+ return ret;
+ }
+
+ ret = ad5940_check_int_io(int_io, &spi->dev);
+ if (ret < 0)
+ return ret;
+
+ st->vref = devm_regulator_get_optional(&spi->dev, "vref");
+ if (!IS_ERR(st->vref)) {
+ ret = regulator_enable(st->vref);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to enbale specified vref supply.\n");
+ return ret;
+ }
+
+ ret = devm_add_action_or_reset(&spi->dev,
+ ad5940_regulator_disable, st);
+ if (ret) {
+ regulator_disable(st->vref);
+ return ret;
+ }
+
+ ret = regulator_get_voltage(st->vref);
+ if (ret < 0)
+ return ret;
+
+ vref_uv = ret;
+ }
+
+ if (vref_uv)
+ st->vref_mv = vref_uv / 1000;
+ else
+ st->vref_mv = 1820;
+
+ indio_dev->dev.parent = &spi->dev;
+ indio_dev->dev.of_node = spi->dev.of_node;
+ indio_dev->name = spi->dev.of_node->name;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->info = &ad5940_info;
+
+ ret = ad5940_of_parse_channel_config(indio_dev, spi->dev.of_node);
+ if (ret < 0)
+ return ret;
+
+ init_completion(&st->complete);
+
+ ret = ad5940_setup(st, int_io);
+ if (ret)
+ return ret;
+
+ ret = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
+ ad5940_irq_handler,
+ trig_type | IRQF_ONESHOT,
+ dev_name(&spi->dev), st);
+ if (ret < 0)
+ return ret;
+
+ return devm_iio_device_register(&spi->dev, indio_dev);
+}
+
+static const struct of_device_id ad5940_dt_match[] = {
+ { .compatible = "adi,ad5940" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, ad5940_spi_ids);
+
+static struct spi_driver ad5940_driver = {
+ .driver = {
+ .name = "ad5940",
+ .of_match_table = ad5940_dt_match,
+ },
+ .probe = ad5940_probe,
+};
+module_spi_driver(ad5940_driver);
+
+MODULE_AUTHOR("Song Qiang <songqiang1304521@xxxxxxxxx>");
+MODULE_DESCRIPTION("Analog Device AD5940 ADC driver");
+MODULE_LICENSE("GPL");
--
2.17.1