Initial import

1 files changed, 865 insertions, 0 deletions

diff --git a/drivers/iio/adc/ad7793.c b/drivers/iio/adc/ad7793.c
new file mode 100644
index 000000000..b84922a4b
--- /dev/null
+++ b/drivers/iio/adc/ad7793.c
@@ -0,0 +1,865 @@
+/*
+ * AD7785/AD7792/AD7793/AD7794/AD7795 SPI ADC driver
+ *
+ * Copyright 2011-2012 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/spi/spi.h>
+#include <linux/regulator/consumer.h>
+#include <linux/err.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/adc/ad_sigma_delta.h>
+#include <linux/platform_data/ad7793.h>
+
+/* Registers */
+#define AD7793_REG_COMM		0 /* Communications Register (WO, 8-bit) */
+#define AD7793_REG_STAT		0 /* Status Register	     (RO, 8-bit) */
+#define AD7793_REG_MODE		1 /* Mode Register	     (RW, 16-bit */
+#define AD7793_REG_CONF		2 /* Configuration Register  (RW, 16-bit) */
+#define AD7793_REG_DATA		3 /* Data Register	     (RO, 16-/24-bit) */
+#define AD7793_REG_ID		4 /* ID Register	     (RO, 8-bit) */
+#define AD7793_REG_IO		5 /* IO Register	     (RO, 8-bit) */
+#define AD7793_REG_OFFSET	6 /* Offset Register	     (RW, 16-bit
+				   * (AD7792)/24-bit (AD7793)) */
+#define AD7793_REG_FULLSALE	7 /* Full-Scale Register
+				   * (RW, 16-bit (AD7792)/24-bit (AD7793)) */
+
+/* Communications Register Bit Designations (AD7793_REG_COMM) */
+#define AD7793_COMM_WEN		(1 << 7) /* Write Enable */
+#define AD7793_COMM_WRITE	(0 << 6) /* Write Operation */
+#define AD7793_COMM_READ	(1 << 6) /* Read Operation */
+#define AD7793_COMM_ADDR(x)	(((x) & 0x7) << 3) /* Register Address */
+#define AD7793_COMM_CREAD	(1 << 2) /* Continuous Read of Data Register */
+
+/* Status Register Bit Designations (AD7793_REG_STAT) */
+#define AD7793_STAT_RDY		(1 << 7) /* Ready */
+#define AD7793_STAT_ERR		(1 << 6) /* Error (Overrange, Underrange) */
+#define AD7793_STAT_CH3		(1 << 2) /* Channel 3 */
+#define AD7793_STAT_CH2		(1 << 1) /* Channel 2 */
+#define AD7793_STAT_CH1		(1 << 0) /* Channel 1 */
+
+/* Mode Register Bit Designations (AD7793_REG_MODE) */
+#define AD7793_MODE_SEL(x)	(((x) & 0x7) << 13) /* Operation Mode Select */
+#define AD7793_MODE_SEL_MASK	(0x7 << 13) /* Operation Mode Select mask */
+#define AD7793_MODE_CLKSRC(x)	(((x) & 0x3) << 6) /* ADC Clock Source Select */
+#define AD7793_MODE_RATE(x)	((x) & 0xF) /* Filter Update Rate Select */
+
+#define AD7793_MODE_CONT		0 /* Continuous Conversion Mode */
+#define AD7793_MODE_SINGLE		1 /* Single Conversion Mode */
+#define AD7793_MODE_IDLE		2 /* Idle Mode */
+#define AD7793_MODE_PWRDN		3 /* Power-Down Mode */
+#define AD7793_MODE_CAL_INT_ZERO	4 /* Internal Zero-Scale Calibration */
+#define AD7793_MODE_CAL_INT_FULL	5 /* Internal Full-Scale Calibration */
+#define AD7793_MODE_CAL_SYS_ZERO	6 /* System Zero-Scale Calibration */
+#define AD7793_MODE_CAL_SYS_FULL	7 /* System Full-Scale Calibration */
+
+#define AD7793_CLK_INT		0 /* Internal 64 kHz Clock not
+				   * available at the CLK pin */
+#define AD7793_CLK_INT_CO	1 /* Internal 64 kHz Clock available
+				   * at the CLK pin */
+#define AD7793_CLK_EXT		2 /* External 64 kHz Clock */
+#define AD7793_CLK_EXT_DIV2	3 /* External Clock divided by 2 */
+
+/* Configuration Register Bit Designations (AD7793_REG_CONF) */
+#define AD7793_CONF_VBIAS(x)	(((x) & 0x3) << 14) /* Bias Voltage
+						     * Generator Enable */
+#define AD7793_CONF_BO_EN	(1 << 13) /* Burnout Current Enable */
+#define AD7793_CONF_UNIPOLAR	(1 << 12) /* Unipolar/Bipolar Enable */
+#define AD7793_CONF_BOOST	(1 << 11) /* Boost Enable */
+#define AD7793_CONF_GAIN(x)	(((x) & 0x7) << 8) /* Gain Select */
+#define AD7793_CONF_REFSEL(x)	((x) << 6) /* INT/EXT Reference Select */
+#define AD7793_CONF_BUF		(1 << 4) /* Buffered Mode Enable */
+#define AD7793_CONF_CHAN(x)	((x) & 0xf) /* Channel select */
+#define AD7793_CONF_CHAN_MASK	0xf /* Channel select mask */
+
+#define AD7793_CH_AIN1P_AIN1M	0 /* AIN1(+) - AIN1(-) */
+#define AD7793_CH_AIN2P_AIN2M	1 /* AIN2(+) - AIN2(-) */
+#define AD7793_CH_AIN3P_AIN3M	2 /* AIN3(+) - AIN3(-) */
+#define AD7793_CH_AIN1M_AIN1M	3 /* AIN1(-) - AIN1(-) */
+#define AD7793_CH_TEMP		6 /* Temp Sensor */
+#define AD7793_CH_AVDD_MONITOR	7 /* AVDD Monitor */
+
+#define AD7795_CH_AIN4P_AIN4M	4 /* AIN4(+) - AIN4(-) */
+#define AD7795_CH_AIN5P_AIN5M	5 /* AIN5(+) - AIN5(-) */
+#define AD7795_CH_AIN6P_AIN6M	6 /* AIN6(+) - AIN6(-) */
+#define AD7795_CH_AIN1M_AIN1M	8 /* AIN1(-) - AIN1(-) */
+
+/* ID Register Bit Designations (AD7793_REG_ID) */
+#define AD7785_ID		0xB
+#define AD7792_ID		0xA
+#define AD7793_ID		0xB
+#define AD7794_ID		0xF
+#define AD7795_ID		0xF
+#define AD7796_ID		0xA
+#define AD7797_ID		0xB
+#define AD7798_ID		0x8
+#define AD7799_ID		0x9
+#define AD7793_ID_MASK		0xF
+
+/* IO (Excitation Current Sources) Register Bit Designations (AD7793_REG_IO) */
+#define AD7793_IO_IEXC1_IOUT1_IEXC2_IOUT2	0 /* IEXC1 connect to IOUT1,
+						   * IEXC2 connect to IOUT2 */
+#define AD7793_IO_IEXC1_IOUT2_IEXC2_IOUT1	1 /* IEXC1 connect to IOUT2,
+						   * IEXC2 connect to IOUT1 */
+#define AD7793_IO_IEXC1_IEXC2_IOUT1		2 /* Both current sources
+						   * IEXC1,2 connect to IOUT1 */
+#define AD7793_IO_IEXC1_IEXC2_IOUT2		3 /* Both current sources
+						   * IEXC1,2 connect to IOUT2 */
+
+#define AD7793_IO_IXCEN_10uA	(1 << 0) /* Excitation Current 10uA */
+#define AD7793_IO_IXCEN_210uA	(2 << 0) /* Excitation Current 210uA */
+#define AD7793_IO_IXCEN_1mA	(3 << 0) /* Excitation Current 1mA */
+
+/* NOTE:
+ * The AD7792/AD7793 features a dual use data out ready DOUT/RDY output.
+ * In order to avoid contentions on the SPI bus, it's therefore necessary
+ * to use spi bus locking.
+ *
+ * The DOUT/RDY output must also be wired to an interrupt capable GPIO.
+ */
+
+#define AD7793_FLAG_HAS_CLKSEL		BIT(0)
+#define AD7793_FLAG_HAS_REFSEL		BIT(1)
+#define AD7793_FLAG_HAS_VBIAS		BIT(2)
+#define AD7793_HAS_EXITATION_CURRENT	BIT(3)
+#define AD7793_FLAG_HAS_GAIN		BIT(4)
+#define AD7793_FLAG_HAS_BUFFER		BIT(5)
+
+struct ad7793_chip_info {
+	unsigned int id;
+	const struct iio_chan_spec *channels;
+	unsigned int num_channels;
+	unsigned int flags;
+
+	const struct iio_info *iio_info;
+	const u16 *sample_freq_avail;
+};
+
+struct ad7793_state {
+	const struct ad7793_chip_info	*chip_info;
+	struct regulator		*reg;
+	u16				int_vref_mv;
+	u16				mode;
+	u16				conf;
+	u32				scale_avail[8][2];
+
+	struct ad_sigma_delta		sd;
+
+};
+
+enum ad7793_supported_device_ids {
+	ID_AD7785,
+	ID_AD7792,
+	ID_AD7793,
+	ID_AD7794,
+	ID_AD7795,
+	ID_AD7796,
+	ID_AD7797,
+	ID_AD7798,
+	ID_AD7799,
+};
+
+static struct ad7793_state *ad_sigma_delta_to_ad7793(struct ad_sigma_delta *sd)
+{
+	return container_of(sd, struct ad7793_state, sd);
+}
+
+static int ad7793_set_channel(struct ad_sigma_delta *sd, unsigned int channel)
+{
+	struct ad7793_state *st = ad_sigma_delta_to_ad7793(sd);
+
+	st->conf &= ~AD7793_CONF_CHAN_MASK;
+	st->conf |= AD7793_CONF_CHAN(channel);
+
+	return ad_sd_write_reg(&st->sd, AD7793_REG_CONF, 2, st->conf);
+}
+
+static int ad7793_set_mode(struct ad_sigma_delta *sd,
+			   enum ad_sigma_delta_mode mode)
+{
+	struct ad7793_state *st = ad_sigma_delta_to_ad7793(sd);
+
+	st->mode &= ~AD7793_MODE_SEL_MASK;
+	st->mode |= AD7793_MODE_SEL(mode);
+
+	return ad_sd_write_reg(&st->sd, AD7793_REG_MODE, 2, st->mode);
+}
+
+static const struct ad_sigma_delta_info ad7793_sigma_delta_info = {
+	.set_channel = ad7793_set_channel,
+	.set_mode = ad7793_set_mode,
+	.has_registers = true,
+	.addr_shift = 3,
+	.read_mask = BIT(6),
+};
+
+static const struct ad_sd_calib_data ad7793_calib_arr[6] = {
+	{AD7793_MODE_CAL_INT_ZERO, AD7793_CH_AIN1P_AIN1M},
+	{AD7793_MODE_CAL_INT_FULL, AD7793_CH_AIN1P_AIN1M},
+	{AD7793_MODE_CAL_INT_ZERO, AD7793_CH_AIN2P_AIN2M},
+	{AD7793_MODE_CAL_INT_FULL, AD7793_CH_AIN2P_AIN2M},
+	{AD7793_MODE_CAL_INT_ZERO, AD7793_CH_AIN3P_AIN3M},
+	{AD7793_MODE_CAL_INT_FULL, AD7793_CH_AIN3P_AIN3M}
+};
+
+static int ad7793_calibrate_all(struct ad7793_state *st)
+{
+	return ad_sd_calibrate_all(&st->sd, ad7793_calib_arr,
+				   ARRAY_SIZE(ad7793_calib_arr));
+}
+
+static int ad7793_check_platform_data(struct ad7793_state *st,
+	const struct ad7793_platform_data *pdata)
+{
+	if ((pdata->current_source_direction == AD7793_IEXEC1_IEXEC2_IOUT1 ||
+		pdata->current_source_direction == AD7793_IEXEC1_IEXEC2_IOUT2) &&
+		((pdata->exitation_current != AD7793_IX_10uA) &&
+		(pdata->exitation_current != AD7793_IX_210uA)))
+		return -EINVAL;
+
+	if (!(st->chip_info->flags & AD7793_FLAG_HAS_CLKSEL) &&
+		pdata->clock_src != AD7793_CLK_SRC_INT)
+		return -EINVAL;
+
+	if (!(st->chip_info->flags & AD7793_FLAG_HAS_REFSEL) &&
+		pdata->refsel != AD7793_REFSEL_REFIN1)
+		return -EINVAL;
+
+	if (!(st->chip_info->flags & AD7793_FLAG_HAS_VBIAS) &&
+		pdata->bias_voltage != AD7793_BIAS_VOLTAGE_DISABLED)
+		return -EINVAL;
+
+	if (!(st->chip_info->flags & AD7793_HAS_EXITATION_CURRENT) &&
+		pdata->exitation_current != AD7793_IX_DISABLED)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int ad7793_setup(struct iio_dev *indio_dev,
+	const struct ad7793_platform_data *pdata,
+	unsigned int vref_mv)
+{
+	struct ad7793_state *st = iio_priv(indio_dev);
+	int i, ret = -1;
+	unsigned long long scale_uv;
+	u32 id;
+
+	ret = ad7793_check_platform_data(st, pdata);
+	if (ret)
+		return ret;
+
+	/* reset the serial interface */
+	ret = spi_write(st->sd.spi, (u8 *)&ret, sizeof(ret));
+	if (ret < 0)
+		goto out;
+	usleep_range(500, 2000); /* Wait for at least 500us */
+
+	/* write/read test for device presence */
+	ret = ad_sd_read_reg(&st->sd, AD7793_REG_ID, 1, &id);
+	if (ret)
+		goto out;
+
+	id &= AD7793_ID_MASK;
+
+	if (id != st->chip_info->id) {
+		dev_err(&st->sd.spi->dev, "device ID query failed\n");
+		goto out;
+	}
+
+	st->mode = AD7793_MODE_RATE(1);
+	st->conf = 0;
+
+	if (st->chip_info->flags & AD7793_FLAG_HAS_CLKSEL)
+		st->mode |= AD7793_MODE_CLKSRC(pdata->clock_src);
+	if (st->chip_info->flags & AD7793_FLAG_HAS_REFSEL)
+		st->conf |= AD7793_CONF_REFSEL(pdata->refsel);
+	if (st->chip_info->flags & AD7793_FLAG_HAS_VBIAS)
+		st->conf |= AD7793_CONF_VBIAS(pdata->bias_voltage);
+	if (pdata->buffered || !(st->chip_info->flags & AD7793_FLAG_HAS_BUFFER))
+		st->conf |= AD7793_CONF_BUF;
+	if (pdata->boost_enable &&
+		(st->chip_info->flags & AD7793_FLAG_HAS_VBIAS))
+		st->conf |= AD7793_CONF_BOOST;
+	if (pdata->burnout_current)
+		st->conf |= AD7793_CONF_BO_EN;
+	if (pdata->unipolar)
+		st->conf |= AD7793_CONF_UNIPOLAR;
+
+	if (!(st->chip_info->flags & AD7793_FLAG_HAS_GAIN))
+		st->conf |= AD7793_CONF_GAIN(7);
+
+	ret = ad7793_set_mode(&st->sd, AD_SD_MODE_IDLE);
+	if (ret)
+		goto out;
+
+	ret = ad7793_set_channel(&st->sd, 0);
+	if (ret)
+		goto out;
+
+	if (st->chip_info->flags & AD7793_HAS_EXITATION_CURRENT) {
+		ret = ad_sd_write_reg(&st->sd, AD7793_REG_IO, 1,
+				pdata->exitation_current |
+				(pdata->current_source_direction << 2));
+		if (ret)
+			goto out;
+	}
+
+	ret = ad7793_calibrate_all(st);
+	if (ret)
+		goto out;
+
+	/* Populate available ADC input ranges */
+	for (i = 0; i < ARRAY_SIZE(st->scale_avail); i++) {
+		scale_uv = ((u64)vref_mv * 100000000)
+			>> (st->chip_info->channels[0].scan_type.realbits -
+			(!!(st->conf & AD7793_CONF_UNIPOLAR) ? 0 : 1));
+		scale_uv >>= i;
+
+		st->scale_avail[i][1] = do_div(scale_uv, 100000000) * 10;
+		st->scale_avail[i][0] = scale_uv;
+	}
+
+	return 0;
+out:
+	dev_err(&st->sd.spi->dev, "setup failed\n");
+	return ret;
+}
+
+static const u16 ad7793_sample_freq_avail[16] = {0, 470, 242, 123, 62, 50, 39,
+					33, 19, 17, 16, 12, 10, 8, 6, 4};
+
+static const u16 ad7797_sample_freq_avail[16] = {0, 0, 0, 123, 62, 50, 0,
+					33, 0, 17, 16, 12, 10, 8, 6, 4};
+
+static ssize_t ad7793_read_frequency(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct ad7793_state *st = iio_priv(indio_dev);
+
+	return sprintf(buf, "%d\n",
+	       st->chip_info->sample_freq_avail[AD7793_MODE_RATE(st->mode)]);
+}
+
+static ssize_t ad7793_write_frequency(struct device *dev,
+		struct device_attribute *attr,
+		const char *buf,
+		size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct ad7793_state *st = iio_priv(indio_dev);
+	long lval;
+	int i, ret;
+
+	mutex_lock(&indio_dev->mlock);
+	if (iio_buffer_enabled(indio_dev)) {
+		mutex_unlock(&indio_dev->mlock);
+		return -EBUSY;
+	}
+	mutex_unlock(&indio_dev->mlock);
+
+	ret = kstrtol(buf, 10, &lval);
+	if (ret)
+		return ret;
+
+	if (lval == 0)
+		return -EINVAL;
+
+	ret = -EINVAL;
+
+	for (i = 0; i < 16; i++)
+		if (lval == st->chip_info->sample_freq_avail[i]) {
+			mutex_lock(&indio_dev->mlock);
+			st->mode &= ~AD7793_MODE_RATE(-1);
+			st->mode |= AD7793_MODE_RATE(i);
+			ad_sd_write_reg(&st->sd, AD7793_REG_MODE,
+					 sizeof(st->mode), st->mode);
+			mutex_unlock(&indio_dev->mlock);
+			ret = 0;
+		}
+
+	return ret ? ret : len;
+}
+
+static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
+		ad7793_read_frequency,
+		ad7793_write_frequency);
+
+static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(
+	"470 242 123 62 50 39 33 19 17 16 12 10 8 6 4");
+
+static IIO_CONST_ATTR_NAMED(sampling_frequency_available_ad7797,
+	sampling_frequency_available, "123 62 50 33 17 16 12 10 8 6 4");
+
+static ssize_t ad7793_show_scale_available(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct ad7793_state *st = iio_priv(indio_dev);
+	int i, len = 0;
+
+	for (i = 0; i < ARRAY_SIZE(st->scale_avail); i++)
+		len += sprintf(buf + len, "%d.%09u ", st->scale_avail[i][0],
+			       st->scale_avail[i][1]);
+
+	len += sprintf(buf + len, "\n");
+
+	return len;
+}
+
+static IIO_DEVICE_ATTR_NAMED(in_m_in_scale_available,
+		in_voltage-voltage_scale_available, S_IRUGO,
+		ad7793_show_scale_available, NULL, 0);
+
+static struct attribute *ad7793_attributes[] = {
+	&iio_dev_attr_sampling_frequency.dev_attr.attr,
+	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
+	&iio_dev_attr_in_m_in_scale_available.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group ad7793_attribute_group = {
+	.attrs = ad7793_attributes,
+};
+
+static struct attribute *ad7797_attributes[] = {
+	&iio_dev_attr_sampling_frequency.dev_attr.attr,
+	&iio_const_attr_sampling_frequency_available_ad7797.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group ad7797_attribute_group = {
+	.attrs = ad7797_attributes,
+};
+
+static int ad7793_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val,
+			   int *val2,
+			   long m)
+{
+	struct ad7793_state *st = iio_priv(indio_dev);
+	int ret;
+	unsigned long long scale_uv;
+	bool unipolar = !!(st->conf & AD7793_CONF_UNIPOLAR);
+
+	switch (m) {
+	case IIO_CHAN_INFO_RAW:
+		ret = ad_sigma_delta_single_conversion(indio_dev, chan, val);
+		if (ret < 0)
+			return ret;
+
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->type) {
+		case IIO_VOLTAGE:
+			if (chan->differential) {
+				*val = st->
+					scale_avail[(st->conf >> 8) & 0x7][0];
+				*val2 = st->
+					scale_avail[(st->conf >> 8) & 0x7][1];
+				return IIO_VAL_INT_PLUS_NANO;
+			} else {
+				/* 1170mV / 2^23 * 6 */
+				scale_uv = (1170ULL * 1000000000ULL * 6ULL);
+			}
+			break;
+		case IIO_TEMP:
+				/* 1170mV / 0.81 mV/C / 2^23 */
+				scale_uv = 1444444444444444ULL;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		scale_uv >>= (chan->scan_type.realbits - (unipolar ? 0 : 1));
+		*val = 0;
+		*val2 = scale_uv;
+		return IIO_VAL_INT_PLUS_NANO;
+	case IIO_CHAN_INFO_OFFSET:
+		if (!unipolar)
+			*val = -(1 << (chan->scan_type.realbits - 1));
+		else
+			*val = 0;
+
+		/* Kelvin to Celsius */
+		if (chan->type == IIO_TEMP) {
+			unsigned long long offset;
+			unsigned int shift;
+
+			shift = chan->scan_type.realbits - (unipolar ? 0 : 1);
+			offset = 273ULL << shift;
+			do_div(offset, 1444);
+			*val -= offset;
+		}
+		return IIO_VAL_INT;
+	}
+	return -EINVAL;
+}
+
+static int ad7793_write_raw(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       int val,
+			       int val2,
+			       long mask)
+{
+	struct ad7793_state *st = iio_priv(indio_dev);
+	int ret, i;
+	unsigned int tmp;
+
+	mutex_lock(&indio_dev->mlock);
+	if (iio_buffer_enabled(indio_dev)) {
+		mutex_unlock(&indio_dev->mlock);
+		return -EBUSY;
+	}
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SCALE:
+		ret = -EINVAL;
+		for (i = 0; i < ARRAY_SIZE(st->scale_avail); i++)
+			if (val2 == st->scale_avail[i][1]) {
+				ret = 0;
+				tmp = st->conf;
+				st->conf &= ~AD7793_CONF_GAIN(-1);
+				st->conf |= AD7793_CONF_GAIN(i);
+
+				if (tmp == st->conf)
+					break;
+
+				ad_sd_write_reg(&st->sd, AD7793_REG_CONF,
+						sizeof(st->conf), st->conf);
+				ad7793_calibrate_all(st);
+				break;
+			}
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	mutex_unlock(&indio_dev->mlock);
+	return ret;
+}
+
+static int ad7793_write_raw_get_fmt(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       long mask)
+{
+	return IIO_VAL_INT_PLUS_NANO;
+}
+
+static const struct iio_info ad7793_info = {
+	.read_raw = &ad7793_read_raw,
+	.write_raw = &ad7793_write_raw,
+	.write_raw_get_fmt = &ad7793_write_raw_get_fmt,
+	.attrs = &ad7793_attribute_group,
+	.validate_trigger = ad_sd_validate_trigger,
+	.driver_module = THIS_MODULE,
+};
+
+static const struct iio_info ad7797_info = {
+	.read_raw = &ad7793_read_raw,
+	.write_raw = &ad7793_write_raw,
+	.write_raw_get_fmt = &ad7793_write_raw_get_fmt,
+	.attrs = &ad7793_attribute_group,
+	.validate_trigger = ad_sd_validate_trigger,
+	.driver_module = THIS_MODULE,
+};
+
+#define DECLARE_AD7793_CHANNELS(_name, _b, _sb, _s) \
+const struct iio_chan_spec _name##_channels[] = { \
+	AD_SD_DIFF_CHANNEL(0, 0, 0, AD7793_CH_AIN1P_AIN1M, (_b), (_sb), (_s)), \
+	AD_SD_DIFF_CHANNEL(1, 1, 1, AD7793_CH_AIN2P_AIN2M, (_b), (_sb), (_s)), \
+	AD_SD_DIFF_CHANNEL(2, 2, 2, AD7793_CH_AIN3P_AIN3M, (_b), (_sb), (_s)), \
+	AD_SD_SHORTED_CHANNEL(3, 0, AD7793_CH_AIN1M_AIN1M, (_b), (_sb), (_s)), \
+	AD_SD_TEMP_CHANNEL(4, AD7793_CH_TEMP, (_b), (_sb), (_s)), \
+	AD_SD_SUPPLY_CHANNEL(5, 3, AD7793_CH_AVDD_MONITOR, (_b), (_sb), (_s)), \
+	IIO_CHAN_SOFT_TIMESTAMP(6), \
+}
+
+#define DECLARE_AD7795_CHANNELS(_name, _b, _sb) \
+const struct iio_chan_spec _name##_channels[] = { \
+	AD_SD_DIFF_CHANNEL(0, 0, 0, AD7793_CH_AIN1P_AIN1M, (_b), (_sb), 0), \
+	AD_SD_DIFF_CHANNEL(1, 1, 1, AD7793_CH_AIN2P_AIN2M, (_b), (_sb), 0), \
+	AD_SD_DIFF_CHANNEL(2, 2, 2, AD7793_CH_AIN3P_AIN3M, (_b), (_sb), 0), \
+	AD_SD_DIFF_CHANNEL(3, 3, 3, AD7795_CH_AIN4P_AIN4M, (_b), (_sb), 0), \
+	AD_SD_DIFF_CHANNEL(4, 4, 4, AD7795_CH_AIN5P_AIN5M, (_b), (_sb), 0), \
+	AD_SD_DIFF_CHANNEL(5, 5, 5, AD7795_CH_AIN6P_AIN6M, (_b), (_sb), 0), \
+	AD_SD_SHORTED_CHANNEL(6, 0, AD7795_CH_AIN1M_AIN1M, (_b), (_sb), 0), \
+	AD_SD_TEMP_CHANNEL(7, AD7793_CH_TEMP, (_b), (_sb), 0), \
+	AD_SD_SUPPLY_CHANNEL(8, 3, AD7793_CH_AVDD_MONITOR, (_b), (_sb), 0), \
+	IIO_CHAN_SOFT_TIMESTAMP(9), \
+}
+
+#define DECLARE_AD7797_CHANNELS(_name, _b, _sb) \
+const struct iio_chan_spec _name##_channels[] = { \
+	AD_SD_DIFF_CHANNEL(0, 0, 0, AD7793_CH_AIN1P_AIN1M, (_b), (_sb), 0), \
+	AD_SD_SHORTED_CHANNEL(1, 0, AD7793_CH_AIN1M_AIN1M, (_b), (_sb), 0), \
+	AD_SD_TEMP_CHANNEL(2, AD7793_CH_TEMP, (_b), (_sb), 0), \
+	AD_SD_SUPPLY_CHANNEL(3, 3, AD7793_CH_AVDD_MONITOR, (_b), (_sb), 0), \
+	IIO_CHAN_SOFT_TIMESTAMP(4), \
+}
+
+#define DECLARE_AD7799_CHANNELS(_name, _b, _sb) \
+const struct iio_chan_spec _name##_channels[] = { \
+	AD_SD_DIFF_CHANNEL(0, 0, 0, AD7793_CH_AIN1P_AIN1M, (_b), (_sb), 0), \
+	AD_SD_DIFF_CHANNEL(1, 1, 1, AD7793_CH_AIN2P_AIN2M, (_b), (_sb), 0), \
+	AD_SD_DIFF_CHANNEL(2, 2, 2, AD7793_CH_AIN3P_AIN3M, (_b), (_sb), 0), \
+	AD_SD_SHORTED_CHANNEL(3, 0, AD7793_CH_AIN1M_AIN1M, (_b), (_sb), 0), \
+	AD_SD_SUPPLY_CHANNEL(4, 3, AD7793_CH_AVDD_MONITOR, (_b), (_sb), 0), \
+	IIO_CHAN_SOFT_TIMESTAMP(5), \
+}
+
+static DECLARE_AD7793_CHANNELS(ad7785, 20, 32, 4);
+static DECLARE_AD7793_CHANNELS(ad7792, 16, 32, 0);
+static DECLARE_AD7793_CHANNELS(ad7793, 24, 32, 0);
+static DECLARE_AD7795_CHANNELS(ad7794, 16, 32);
+static DECLARE_AD7795_CHANNELS(ad7795, 24, 32);
+static DECLARE_AD7797_CHANNELS(ad7796, 16, 16);
+static DECLARE_AD7797_CHANNELS(ad7797, 24, 32);
+static DECLARE_AD7799_CHANNELS(ad7798, 16, 16);
+static DECLARE_AD7799_CHANNELS(ad7799, 24, 32);
+
+static const struct ad7793_chip_info ad7793_chip_info_tbl[] = {
+	[ID_AD7785] = {
+		.id = AD7785_ID,
+		.channels = ad7785_channels,
+		.num_channels = ARRAY_SIZE(ad7785_channels),
+		.iio_info = &ad7793_info,
+		.sample_freq_avail = ad7793_sample_freq_avail,
+		.flags = AD7793_FLAG_HAS_CLKSEL |
+			AD7793_FLAG_HAS_REFSEL |
+			AD7793_FLAG_HAS_VBIAS |
+			AD7793_HAS_EXITATION_CURRENT |
+			AD7793_FLAG_HAS_GAIN |
+			AD7793_FLAG_HAS_BUFFER,
+	},
+	[ID_AD7792] = {
+		.id = AD7792_ID,
+		.channels = ad7792_channels,
+		.num_channels = ARRAY_SIZE(ad7792_channels),
+		.iio_info = &ad7793_info,
+		.sample_freq_avail = ad7793_sample_freq_avail,
+		.flags = AD7793_FLAG_HAS_CLKSEL |
+			AD7793_FLAG_HAS_REFSEL |
+			AD7793_FLAG_HAS_VBIAS |
+			AD7793_HAS_EXITATION_CURRENT |
+			AD7793_FLAG_HAS_GAIN |
+			AD7793_FLAG_HAS_BUFFER,
+	},
+	[ID_AD7793] = {
+		.id = AD7793_ID,
+		.channels = ad7793_channels,
+		.num_channels = ARRAY_SIZE(ad7793_channels),
+		.iio_info = &ad7793_info,
+		.sample_freq_avail = ad7793_sample_freq_avail,
+		.flags = AD7793_FLAG_HAS_CLKSEL |
+			AD7793_FLAG_HAS_REFSEL |
+			AD7793_FLAG_HAS_VBIAS |
+			AD7793_HAS_EXITATION_CURRENT |
+			AD7793_FLAG_HAS_GAIN |
+			AD7793_FLAG_HAS_BUFFER,
+	},
+	[ID_AD7794] = {
+		.id = AD7794_ID,
+		.channels = ad7794_channels,
+		.num_channels = ARRAY_SIZE(ad7794_channels),
+		.iio_info = &ad7793_info,
+		.sample_freq_avail = ad7793_sample_freq_avail,
+		.flags = AD7793_FLAG_HAS_CLKSEL |
+			AD7793_FLAG_HAS_REFSEL |
+			AD7793_FLAG_HAS_VBIAS |
+			AD7793_HAS_EXITATION_CURRENT |
+			AD7793_FLAG_HAS_GAIN |
+			AD7793_FLAG_HAS_BUFFER,
+	},
+	[ID_AD7795] = {
+		.id = AD7795_ID,
+		.channels = ad7795_channels,
+		.num_channels = ARRAY_SIZE(ad7795_channels),
+		.iio_info = &ad7793_info,
+		.sample_freq_avail = ad7793_sample_freq_avail,
+		.flags = AD7793_FLAG_HAS_CLKSEL |
+			AD7793_FLAG_HAS_REFSEL |
+			AD7793_FLAG_HAS_VBIAS |
+			AD7793_HAS_EXITATION_CURRENT |
+			AD7793_FLAG_HAS_GAIN |
+			AD7793_FLAG_HAS_BUFFER,
+	},
+	[ID_AD7796] = {
+		.id = AD7796_ID,
+		.channels = ad7796_channels,
+		.num_channels = ARRAY_SIZE(ad7796_channels),
+		.iio_info = &ad7797_info,
+		.sample_freq_avail = ad7797_sample_freq_avail,
+		.flags = AD7793_FLAG_HAS_CLKSEL,
+	},
+	[ID_AD7797] = {
+		.id = AD7797_ID,
+		.channels = ad7797_channels,
+		.num_channels = ARRAY_SIZE(ad7797_channels),
+		.iio_info = &ad7797_info,
+		.sample_freq_avail = ad7797_sample_freq_avail,
+		.flags = AD7793_FLAG_HAS_CLKSEL,
+	},
+	[ID_AD7798] = {
+		.id = AD7798_ID,
+		.channels = ad7798_channels,
+		.num_channels = ARRAY_SIZE(ad7798_channels),
+		.iio_info = &ad7793_info,
+		.sample_freq_avail = ad7793_sample_freq_avail,
+		.flags = AD7793_FLAG_HAS_GAIN |
+			AD7793_FLAG_HAS_BUFFER,
+	},
+	[ID_AD7799] = {
+		.id = AD7799_ID,
+		.channels = ad7799_channels,
+		.num_channels = ARRAY_SIZE(ad7799_channels),
+		.iio_info = &ad7793_info,
+		.sample_freq_avail = ad7793_sample_freq_avail,
+		.flags = AD7793_FLAG_HAS_GAIN |
+			AD7793_FLAG_HAS_BUFFER,
+	},
+};
+
+static int ad7793_probe(struct spi_device *spi)
+{
+	const struct ad7793_platform_data *pdata = spi->dev.platform_data;
+	struct ad7793_state *st;
+	struct iio_dev *indio_dev;
+	int ret, vref_mv = 0;
+
+	if (!pdata) {
+		dev_err(&spi->dev, "no platform data?\n");
+		return -ENODEV;
+	}
+
+	if (!spi->irq) {
+		dev_err(&spi->dev, "no IRQ?\n");
+		return -ENODEV;
+	}
+
+	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+	if (indio_dev == NULL)
+		return -ENOMEM;
+
+	st = iio_priv(indio_dev);
+
+	ad_sd_init(&st->sd, indio_dev, spi, &ad7793_sigma_delta_info);
+
+	if (pdata->refsel != AD7793_REFSEL_INTERNAL) {
+		st->reg = devm_regulator_get(&spi->dev, "refin");
+		if (IS_ERR(st->reg))
+			return PTR_ERR(st->reg);
+
+		ret = regulator_enable(st->reg);
+		if (ret)
+			return ret;
+
+		vref_mv = regulator_get_voltage(st->reg);
+		if (vref_mv < 0) {
+			ret = vref_mv;
+			goto error_disable_reg;
+		}
+
+		vref_mv /= 1000;
+	} else {
+		vref_mv = 1170; /* Build-in ref */
+	}
+
+	st->chip_info =
+		&ad7793_chip_info_tbl[spi_get_device_id(spi)->driver_data];
+
+	spi_set_drvdata(spi, indio_dev);
+
+	indio_dev->dev.parent = &spi->dev;
+	indio_dev->name = spi_get_device_id(spi)->name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = st->chip_info->channels;
+	indio_dev->num_channels = st->chip_info->num_channels;
+	indio_dev->info = st->chip_info->iio_info;
+
+	ret = ad_sd_setup_buffer_and_trigger(indio_dev);
+	if (ret)
+		goto error_disable_reg;
+
+	ret = ad7793_setup(indio_dev, pdata, vref_mv);
+	if (ret)
+		goto error_remove_trigger;
+
+	ret = iio_device_register(indio_dev);
+	if (ret)
+		goto error_remove_trigger;
+
+	return 0;
+
+error_remove_trigger:
+	ad_sd_cleanup_buffer_and_trigger(indio_dev);
+error_disable_reg:
+	if (pdata->refsel != AD7793_REFSEL_INTERNAL)
+		regulator_disable(st->reg);
+
+	return ret;
+}
+
+static int ad7793_remove(struct spi_device *spi)
+{
+	const struct ad7793_platform_data *pdata = spi->dev.platform_data;
+	struct iio_dev *indio_dev = spi_get_drvdata(spi);
+	struct ad7793_state *st = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+	ad_sd_cleanup_buffer_and_trigger(indio_dev);
+
+	if (pdata->refsel != AD7793_REFSEL_INTERNAL)
+		regulator_disable(st->reg);
+
+	return 0;
+}
+
+static const struct spi_device_id ad7793_id[] = {
+	{"ad7785", ID_AD7785},
+	{"ad7792", ID_AD7792},
+	{"ad7793", ID_AD7793},
+	{"ad7794", ID_AD7794},
+	{"ad7795", ID_AD7795},
+	{"ad7796", ID_AD7796},
+	{"ad7797", ID_AD7797},
+	{"ad7798", ID_AD7798},
+	{"ad7799", ID_AD7799},
+	{}
+};
+MODULE_DEVICE_TABLE(spi, ad7793_id);
+
+static struct spi_driver ad7793_driver = {
+	.driver = {
+		.name	= "ad7793",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= ad7793_probe,
+	.remove		= ad7793_remove,
+	.id_table	= ad7793_id,
+};
+module_spi_driver(ad7793_driver);
+
+MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
+MODULE_DESCRIPTION("Analog Devices AD7793 and similar ADCs");
+MODULE_LICENSE("GPL v2");