Merge tag 'iio-for-4.9b' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-next

Jonathan writes:

Second set of iio new device support, features and cleanups for the 4.9 cycle.

New device support
* ad8801 dac
  - new driver supporting ad8801 and ad8803 DACs.
* adc12138
  - new driver supporting TI adc12130/adc12132 and adc12138 ADCs.
* ltc2485 adc
  - new driver
* mxc6255
  - add support for the mxc6225 part name and fixup the ID check so it works.
* vz89x VOC sensor
  - add support for the vz89te part which drops the voc_short channel and adds
    CRCs compared to other supported parts.

New features
* core
  - immutable triggers.  These effectively grant exclusive control over a
    trigger. The typical usecase is a device representing an analog part
    (perhaps a MUX) that needs to control the sampling of a downstream
    ADC.
  - resource managed trigger registration and triggered_buffer_init.
  - iio_push_event now protected against case of the event interface
    registration not having yet occured.  Only matters if an interrupt
    can occur during this window - might happen on shared interrupt lines.
  - helper to let a driver query if the trigger it is using is provided by
    itself (using the convention of both device and trigger having the same
    parent).
* tools
  - iio-utils. Used channel modifier scaling in preference to generic scaling
    when both exist.
* at91-adc
  - Add support for touchscreen switches closure time needed by some newer
    parts.
* stx104
  - support the ADC channels on this ADC/DAC board. As these are the primary
    feature of the board also move the driver to the iio/adc directory.
* sx9500
  - device tree bindings.

Cleanups / Fixes
* ad5755
  - fix an off-by-one on devnr limit check (introduced earlier this cycle)
* ad7266
  - drop NULL check on devm_regulator_get_optional as it can't return NULL.
* ak8974
  - avoid an unused functional warning due to rework in PM core code.
  - remove .owner field setting as done by i2c_core.
* ina2xx
  - clear out a left over debug field from chip global data.
* hid-sensors
  - avoid an unused functional warning due to rework in PM core code.
* maxim-thermocouple
  - fix non static symbol warnings.
* ms5611
  - fetch and enable regulators unconditionally when they aren't optional.
* sca3000
  - whitespace cleanup.
* st_sensors
  - fetch and enable regulators unconditionally rather than having them
    supported as optional regulators (missunderstanding on my part amongst
    others a while back)
  - followup to previous patch fixes error checking on the regulators.
  - mark symbols static where possible.
  - use the 'is it my trigger' help function.  This prevents the odd case
    of another device triggering from the st-sensors trigger whilst the
    st-sensors trigger is itself not using it but rather using say an hrtimer.
* ti-ads1015
  - add missing of_node_put.
* vz89x
  - rework to all support of new devices.
  - prevent reading of a corrupted buffer.
  - fixup a return value of 0/1 in a bool returning function.

Address updates
- Vlad Dogaru email address change.

28 files changed, 1497 insertions, 133 deletions

diff --git a/drivers/iio/accel/mxc6255.c b/drivers/iio/accel/mxc6255.c
index 97ccde722e7b..0abad6948201 100644
--- a/drivers/iio/accel/mxc6255.c
+++ b/drivers/iio/accel/mxc6255.c
@@ -154,7 +154,7 @@ static int mxc6255_probe(struct i2c_client *client,
 		return ret;
 	}
 
-	if (chip_id != MXC6255_CHIP_ID) {
+	if ((chip_id & 0x1f) != MXC6255_CHIP_ID) {
 		dev_err(&client->dev, "Invalid chip id %x\n", chip_id);
 		return -ENODEV;
 	}
@@ -171,12 +171,14 @@ static int mxc6255_probe(struct i2c_client *client,
 }
 
 static const struct acpi_device_id mxc6255_acpi_match[] = {
+	{"MXC6225",	0},
 	{"MXC6255",	0},
 	{ }
 };
 MODULE_DEVICE_TABLE(acpi, mxc6255_acpi_match);
 
 static const struct i2c_device_id mxc6255_id[] = {
+	{"mxc6225",	0},
 	{"mxc6255",	0},
 	{ }
 };
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 586830ec8800..7edcf3238620 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -264,6 +264,15 @@ config LPC18XX_ADC
 	  To compile this driver as a module, choose M here: the module will be
 	  called lpc18xx_adc.
 
+config LTC2485
+	tristate "Linear Technology LTC2485 ADC driver"
+	depends on I2C
+	help
+	  Say yes here to build support for Linear Technology LTC2485 ADC.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called ltc2485.
+
 config MAX1027
 	tristate "Maxim max1027 ADC driver"
 	depends on SPI
@@ -410,6 +419,21 @@ config ROCKCHIP_SARADC
 	  To compile this driver as a module, choose M here: the
 	  module will be called rockchip_saradc.
 
+config STX104
+	tristate "Apex Embedded Systems STX104 driver"
+	depends on X86 && ISA_BUS_API
+	select GPIOLIB
+	help
+	  Say yes here to build support for the Apex Embedded Systems STX104
+	  integrated analog PC/104 card.
+
+	  This driver supports the 16 channels of single-ended (8 channels of
+	  differential) analog inputs, 2 channels of analog output, 4 digital
+	  inputs, and 4 digital outputs provided by the STX104.
+
+	  The base port addresses for the devices may be configured via the base
+	  array module parameter.
+
 config TI_ADC081C
 	tristate "Texas Instruments ADC081C/ADC101C/ADC121C family"
 	depends on I2C
@@ -430,6 +454,18 @@ config TI_ADC0832
 	  This driver can also be built as a module. If so, the module will be
 	  called ti-adc0832.
 
+config TI_ADC12138
+	tristate "Texas Instruments ADC12130/ADC12132/ADC12138"
+	depends on SPI
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	help
+	  If you say yes here you get support for Texas Instruments ADC12130,
+	  ADC12132 and ADC12138 chips.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called ti-adc12138.
+
 config TI_ADC128S052
 	tristate "Texas Instruments ADC128S052/ADC122S021/ADC124S021"
 	depends on SPI
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 33254eb96bec..7a40c04c311f 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_IMX7D_ADC) += imx7d_adc.o
 obj-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o
 obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
 obj-$(CONFIG_LPC18XX_ADC) += lpc18xx_adc.o
+obj-$(CONFIG_LTC2485) += ltc2485.o
 obj-$(CONFIG_MAX1027) += max1027.o
 obj-$(CONFIG_MAX1363) += max1363.o
 obj-$(CONFIG_MCP320X) += mcp320x.o
@@ -39,8 +40,10 @@ obj-$(CONFIG_PALMAS_GPADC) += palmas_gpadc.o
 obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.o
 obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
 obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
+obj-$(CONFIG_STX104) += stx104.o
 obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
 obj-$(CONFIG_TI_ADC0832) += ti-adc0832.o
+obj-$(CONFIG_TI_ADC12138) += ti-adc12138.o
 obj-$(CONFIG_TI_ADC128S052) += ti-adc128s052.o
 obj-$(CONFIG_TI_ADC161S626) += ti-adc161s626.o
 obj-$(CONFIG_TI_ADS1015) += ti-ads1015.o
diff --git a/drivers/iio/adc/ad7266.c b/drivers/iio/adc/ad7266.c
index c0f6a98fd9bd..b8d5cfd57ec4 100644
--- a/drivers/iio/adc/ad7266.c
+++ b/drivers/iio/adc/ad7266.c
@@ -481,7 +481,7 @@ error_free_gpios:
 	if (!st->fixed_addr)
 		gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));
 error_disable_reg:
-	if (!IS_ERR_OR_NULL(st->reg))
+	if (!IS_ERR(st->reg))
 		regulator_disable(st->reg);
 
 	return ret;
@@ -496,7 +496,7 @@ static int ad7266_remove(struct spi_device *spi)
 	iio_triggered_buffer_cleanup(indio_dev);
 	if (!st->fixed_addr)
 		gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));
-	if (!IS_ERR_OR_NULL(st->reg))
+	if (!IS_ERR(st->reg))
 		regulator_disable(st->reg);
 
 	return 0;
diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
index 0438c68015e8..bbdac07f4aaa 100644
--- a/drivers/iio/adc/at91_adc.c
+++ b/drivers/iio/adc/at91_adc.c
@@ -113,6 +113,7 @@
 #define		AT91_ADC_TSMR_TSAV	(3 << 4)	/* Averages samples */
 #define			AT91_ADC_TSMR_TSAV_(x)		((x) << 4)
 #define		AT91_ADC_TSMR_SCTIM	(0x0f << 16)	/* Switch closure time */
+#define			AT91_ADC_TSMR_SCTIM_(x)		((x) << 16)
 #define		AT91_ADC_TSMR_PENDBC	(0x0f << 28)	/* Pen Debounce time */
 #define			AT91_ADC_TSMR_PENDBC_(x)	((x) << 28)
 #define		AT91_ADC_TSMR_NOTSDMA	(1 << 22)	/* No Touchscreen DMA */
@@ -150,6 +151,7 @@
 #define MAX_RLPOS_BITS         10
 #define TOUCH_SAMPLE_PERIOD_US_RL      10000   /* 10ms, the SoC can't keep up with 2ms */
 #define TOUCH_SHTIM                    0xa
+#define TOUCH_SCTIM_US		10		/* 10us for the Touchscreen Switches Closure Time */
 
 /**
  * struct at91_adc_reg_desc - Various informations relative to registers
@@ -1001,7 +1003,9 @@ static void atmel_ts_close(struct input_dev *dev)
 
 static int at91_ts_hw_init(struct at91_adc_state *st, u32 adc_clk_khz)
 {
+	struct iio_dev *idev = iio_priv_to_dev(st);
 	u32 reg = 0;
+	u32 tssctim = 0;
 	int i = 0;
 
 	/* a Pen Detect Debounce Time is necessary for the ADC Touch to avoid
@@ -1034,11 +1038,20 @@ static int at91_ts_hw_init(struct at91_adc_state *st, u32 adc_clk_khz)
 		return 0;
 	}
 
+	/* Touchscreen Switches Closure time needed for allowing the value to
+	 * stabilize.
+	 * Switch Closure Time = (TSSCTIM * 4) ADCClock periods
+	 */
+	tssctim = DIV_ROUND_UP(TOUCH_SCTIM_US * adc_clk_khz / 1000, 4);
+	dev_dbg(&idev->dev, "adc_clk at: %d KHz, tssctim at: %d\n",
+		adc_clk_khz, tssctim);
+
 	if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
 		reg = AT91_ADC_TSMR_TSMODE_4WIRE_PRESS;
 	else
 		reg = AT91_ADC_TSMR_TSMODE_5WIRE;
 
+	reg |= AT91_ADC_TSMR_SCTIM_(tssctim) & AT91_ADC_TSMR_SCTIM;
 	reg |= AT91_ADC_TSMR_TSAV_(st->caps->ts_filter_average)
 	       & AT91_ADC_TSMR_TSAV;
 	reg |= AT91_ADC_TSMR_PENDBC_(st->ts_pendbc) & AT91_ADC_TSMR_PENDBC;
diff --git a/drivers/iio/adc/ina2xx-adc.c b/drivers/iio/adc/ina2xx-adc.c
index 955f3fdaf519..59b7d76e1ad2 100644
--- a/drivers/iio/adc/ina2xx-adc.c
+++ b/drivers/iio/adc/ina2xx-adc.c
@@ -114,7 +114,6 @@ struct ina2xx_chip_info {
 	struct mutex state_lock;
 	unsigned int shunt_resistor;
 	int avg;
-	s64 prev_ns; /* track buffer capture time, check for underruns */
 	int int_time_vbus; /* Bus voltage integration time uS */
 	int int_time_vshunt; /* Shunt voltage integration time uS */
 	bool allow_async_readout;
@@ -509,8 +508,6 @@ static int ina2xx_work_buffer(struct iio_dev *indio_dev)
 	iio_push_to_buffers_with_timestamp(indio_dev,
 					   (unsigned int *)data, time_a);
 
-	chip->prev_ns = time_a;
-
 	return (unsigned long)(time_b - time_a) / 1000;
 };
 
@@ -554,8 +551,6 @@ static int ina2xx_buffer_enable(struct iio_dev *indio_dev)
 	dev_dbg(&indio_dev->dev, "Async readout mode: %d\n",
 		chip->allow_async_readout);
 
-	chip->prev_ns = iio_get_time_ns(indio_dev);
-
 	chip->task = kthread_run(ina2xx_capture_thread, (void *)indio_dev,
 				 "%s:%d-%uus", indio_dev->name, indio_dev->id,
 				 sampling_us);
diff --git a/drivers/iio/adc/ltc2485.c b/drivers/iio/adc/ltc2485.c
new file mode 100644
index 000000000000..eab91f12454a
--- /dev/null
+++ b/drivers/iio/adc/ltc2485.c
@@ -0,0 +1,148 @@
+/*
+ * ltc2485.c - Driver for Linear Technology LTC2485 ADC
+ *
+ * Copyright (C) 2016 Alison Schofield <amsfield22@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Datasheet: http://cds.linear.com/docs/en/datasheet/2485fd.pdf
+ */
+
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+/* Power-on configuration: rejects both 50/60Hz, operates at 1x speed */
+#define LTC2485_CONFIG_DEFAULT		0
+
+struct ltc2485_data {
+	struct i2c_client	*client;
+	ktime_t			time_prev;	/* last conversion */
+};
+
+static void ltc2485_wait_conv(struct ltc2485_data *data)
+{
+	const unsigned int conv_time = 147;	/* conversion time ms */
+	unsigned int time_elapsed;
+
+	/* delay if conversion time not passed since last read or write */
+	time_elapsed = ktime_ms_delta(ktime_get(), data->time_prev);
+
+	if (time_elapsed < conv_time)
+		msleep(conv_time - time_elapsed);
+}
+
+static int ltc2485_read(struct ltc2485_data *data, int *val)
+{
+	struct i2c_client *client = data->client;
+	__be32 buf = 0;
+	int ret;
+
+	ltc2485_wait_conv(data);
+
+	ret = i2c_master_recv(client, (char *)&buf, 4);
+	if (ret < 0)  {
+		dev_err(&client->dev, "i2c_master_recv failed\n");
+		return ret;
+	}
+	data->time_prev = ktime_get();
+	*val = sign_extend32(be32_to_cpu(buf) >> 6, 24);
+
+	return ret;
+}
+
+static int ltc2485_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int *val, int *val2, long mask)
+{
+	struct ltc2485_data *data = iio_priv(indio_dev);
+	int ret;
+
+	if (mask == IIO_CHAN_INFO_RAW) {
+		ret = ltc2485_read(data, val);
+		if (ret < 0)
+			return ret;
+
+		return IIO_VAL_INT;
+
+	} else if (mask == IIO_CHAN_INFO_SCALE) {
+		*val = 5000;			/* on board vref millivolts */
+		*val2 = 25;			/* 25 (24 + sign) data bits */
+		return IIO_VAL_FRACTIONAL_LOG2;
+
+	} else {
+		return -EINVAL;
+	}
+}
+
+static const struct iio_chan_spec ltc2485_channel[] = {
+	{
+		.type = IIO_VOLTAGE,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)
+	},
+};
+
+static const struct iio_info ltc2485_info = {
+	.read_raw = ltc2485_read_raw,
+	.driver_module = THIS_MODULE,
+};
+
+static int ltc2485_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct iio_dev *indio_dev;
+	struct ltc2485_data *data;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
+				     I2C_FUNC_SMBUS_WRITE_BYTE))
+		return -EOPNOTSUPP;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	i2c_set_clientdata(client, indio_dev);
+	data->client = client;
+
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->name = id->name;
+	indio_dev->info = &ltc2485_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = ltc2485_channel;
+	indio_dev->num_channels = ARRAY_SIZE(ltc2485_channel);
+
+	ret = i2c_smbus_write_byte(data->client, LTC2485_CONFIG_DEFAULT);
+	if (ret < 0)
+		return ret;
+
+	data->time_prev = ktime_get();
+
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id ltc2485_id[] = {
+	{ "ltc2485", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ltc2485_id);
+
+static struct i2c_driver ltc2485_driver = {
+	.driver = {
+		.name = "ltc2485",
+	},
+	.probe = ltc2485_probe,
+	.id_table = ltc2485_id,
+};
+module_i2c_driver(ltc2485_driver);
+
+MODULE_AUTHOR("Alison Schofield <amsfield22@gmail.com>");
+MODULE_DESCRIPTION("Linear Technology LTC2485 ADC driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/iio/dac/stx104.c b/drivers/iio/adc/stx104.c
index bebbd00304ce..7e3645749eaf 100644
--- a/drivers/iio/dac/stx104.c
+++ b/drivers/iio/adc/stx104.c
@@ -1,5 +1,5 @@
 /*
- * DAC driver for the Apex Embedded Systems STX104
+ * IIO driver for the Apex Embedded Systems STX104
  * Copyright (C) 2016 William Breathitt Gray
  *
  * This program is free software; you can redistribute it and/or modify
@@ -20,19 +20,30 @@
 #include <linux/io.h>
 #include <linux/ioport.h>
 #include <linux/isa.h>
+#include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/spinlock.h>
 
-#define STX104_NUM_CHAN 2
-
-#define STX104_CHAN(chan) {				\
+#define STX104_OUT_CHAN(chan) {				\
 	.type = IIO_VOLTAGE,				\
 	.channel = chan,				\
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
 	.indexed = 1,					\
 	.output = 1					\
 }
+#define STX104_IN_CHAN(chan, diff) {					\
+	.type = IIO_VOLTAGE,						\
+	.channel = chan,						\
+	.channel2 = chan,						\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_HARDWAREGAIN) |	\
+		BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE),	\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),			\
+	.indexed = 1,							\
+	.differential = diff						\
+}
+
+#define STX104_NUM_OUT_CHAN 2
 
 #define STX104_EXTENT 16
 
@@ -47,8 +58,8 @@ MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses");
  * @base:		base port address of the IIO device
  */
 struct stx104_iio {
-	unsigned chan_out_states[STX104_NUM_CHAN];
-	unsigned base;
+	unsigned int chan_out_states[STX104_NUM_OUT_CHAN];
+	unsigned int base;
 };
 
 /**
@@ -79,28 +90,95 @@ static int stx104_read_raw(struct iio_dev *indio_dev,
 	struct iio_chan_spec const *chan, int *val, int *val2, long mask)
 {
 	struct stx104_iio *const priv = iio_priv(indio_dev);
+	unsigned int adc_config;
+	int adbu;
+	int gain;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_HARDWAREGAIN:
+		/* get gain configuration */
+		adc_config = inb(priv->base + 11);
+		gain = adc_config & 0x3;
+
+		*val = 1 << gain;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_RAW:
+		if (chan->output) {
+			*val = priv->chan_out_states[chan->channel];
+			return IIO_VAL_INT;
+		}
+
+		/* select ADC channel */
+		outb(chan->channel | (chan->channel << 4), priv->base + 2);
+
+		/* trigger ADC sample capture and wait for completion */
+		outb(0, priv->base);
+		while (inb(priv->base + 8) & BIT(7));
+
+		*val = inw(priv->base);
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_OFFSET:
+		/* get ADC bipolar/unipolar configuration */
+		adc_config = inb(priv->base + 11);
+		adbu = !(adc_config & BIT(2));
+
+		*val = -32768 * adbu;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		/* get ADC bipolar/unipolar and gain configuration */
+		adc_config = inb(priv->base + 11);
+		adbu = !(adc_config & BIT(2));
+		gain = adc_config & 0x3;
+
+		*val = 5;
+		*val2 = 15 - adbu + gain;
+		return IIO_VAL_FRACTIONAL_LOG2;
+	}
 
-	if (mask != IIO_CHAN_INFO_RAW)
-		return -EINVAL;
-
-	*val = priv->chan_out_states[chan->channel];
-
-	return IIO_VAL_INT;
+	return -EINVAL;
 }
 
 static int stx104_write_raw(struct iio_dev *indio_dev,
 	struct iio_chan_spec const *chan, int val, int val2, long mask)
 {
 	struct stx104_iio *const priv = iio_priv(indio_dev);
-	const unsigned chan_addr_offset = 2 * chan->channel;
 
-	if (mask != IIO_CHAN_INFO_RAW)
+	switch (mask) {
+	case IIO_CHAN_INFO_HARDWAREGAIN:
+		/* Only four gain states (x1, x2, x4, x8) */
+		switch (val) {
+		case 1:
+			outb(0, priv->base + 11);
+			break;
+		case 2:
+			outb(1, priv->base + 11);
+			break;
+		case 4:
+			outb(2, priv->base + 11);
+			break;
+		case 8:
+			outb(3, priv->base + 11);
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		return 0;
+	case IIO_CHAN_INFO_RAW:
+		if (chan->output) {
+			/* DAC can only accept up to a 16-bit value */
+			if ((unsigned int)val > 65535)
+				return -EINVAL;
+
+			priv->chan_out_states[chan->channel] = val;
+			outw(val, priv->base + 4 + 2 * chan->channel);
+
+			return 0;
+		}
 		return -EINVAL;
+	}
 
-	priv->chan_out_states[chan->channel] = val;
-	outw(val, priv->base + 4 + chan_addr_offset);
-
-	return 0;
+	return -EINVAL;
 }
 
 static const struct iio_info stx104_info = {
@@ -109,9 +187,22 @@ static const struct iio_info stx104_info = {
 	.write_raw = stx104_write_raw
 };
 
-static const struct iio_chan_spec stx104_channels[STX104_NUM_CHAN] = {
-	STX104_CHAN(0),
-	STX104_CHAN(1)
+/* single-ended input channels configuration */
+static const struct iio_chan_spec stx104_channels_sing[] = {
+	STX104_OUT_CHAN(0), STX104_OUT_CHAN(1),
+	STX104_IN_CHAN(0, 0), STX104_IN_CHAN(1, 0), STX104_IN_CHAN(2, 0),
+	STX104_IN_CHAN(3, 0), STX104_IN_CHAN(4, 0), STX104_IN_CHAN(5, 0),
+	STX104_IN_CHAN(6, 0), STX104_IN_CHAN(7, 0), STX104_IN_CHAN(8, 0),
+	STX104_IN_CHAN(9, 0), STX104_IN_CHAN(10, 0), STX104_IN_CHAN(11, 0),
+	STX104_IN_CHAN(12, 0), STX104_IN_CHAN(13, 0), STX104_IN_CHAN(14, 0),
+	STX104_IN_CHAN(15, 0)
+};
+/* differential input channels configuration */
+static const struct iio_chan_spec stx104_channels_diff[] = {
+	STX104_OUT_CHAN(0), STX104_OUT_CHAN(1),
+	STX104_IN_CHAN(0, 1), STX104_IN_CHAN(1, 1), STX104_IN_CHAN(2, 1),
+	STX104_IN_CHAN(3, 1), STX104_IN_CHAN(4, 1), STX104_IN_CHAN(5, 1),
+	STX104_IN_CHAN(6, 1), STX104_IN_CHAN(7, 1)
 };
 
 static int stx104_gpio_get_direction(struct gpio_chip *chip,
@@ -204,13 +295,27 @@ static int stx104_probe(struct device *dev, unsigned int id)
 
 	indio_dev->info = &stx104_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
-	indio_dev->channels = stx104_channels;
-	indio_dev->num_channels = STX104_NUM_CHAN;
+
+	/* determine if differential inputs */
+	if (inb(base[id] + 8) & BIT(5)) {
+		indio_dev->num_channels = ARRAY_SIZE(stx104_channels_diff);
+		indio_dev->channels = stx104_channels_diff;
+	} else {
+		indio_dev->num_channels = ARRAY_SIZE(stx104_channels_sing);
+		indio_dev->channels = stx104_channels_sing;
+	}
+
 	indio_dev->name = dev_name(dev);
 
 	priv = iio_priv(indio_dev);
 	priv->base = base[id];
 
+	/* configure device for software trigger operation */
+	outb(0, base[id] + 9);
+
+	/* initialize gain setting to x1 */
+	outb(0, base[id] + 11);
+
 	/* initialize DAC output to 0V */
 	outw(0, base[id] + 4);
 	outw(0, base[id] + 6);
@@ -271,5 +376,5 @@ static struct isa_driver stx104_driver = {
 module_isa_driver(stx104_driver, num_stx104);
 
 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
-MODULE_DESCRIPTION("Apex Embedded Systems STX104 DAC driver");
+MODULE_DESCRIPTION("Apex Embedded Systems STX104 IIO driver");
 MODULE_LICENSE("GPL v2");
diff --git a/drivers/iio/adc/ti-adc12138.c b/drivers/iio/adc/ti-adc12138.c
new file mode 100644
index 000000000000..072f03bfe6a0
--- /dev/null
+++ b/drivers/iio/adc/ti-adc12138.c
@@ -0,0 +1,552 @@
+/*
+ * ADC12130/ADC12132/ADC12138 12-bit plus sign ADC driver
+ *
+ * Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com>
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License.  See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * Datasheet: http://www.ti.com/lit/ds/symlink/adc12138.pdf
+ */
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/completion.h>
+#include <linux/clk.h>
+#include <linux/spi/spi.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/regulator/consumer.h>
+
+#define ADC12138_MODE_AUTO_CAL			0x08
+#define ADC12138_MODE_READ_STATUS		0x0c
+#define ADC12138_MODE_ACQUISITION_TIME_6	0x0e
+#define ADC12138_MODE_ACQUISITION_TIME_10	0x4e
+#define ADC12138_MODE_ACQUISITION_TIME_18	0x8e
+#define ADC12138_MODE_ACQUISITION_TIME_34	0xce
+
+#define ADC12138_STATUS_CAL			BIT(6)
+
+enum {
+	adc12130,
+	adc12132,
+	adc12138,
+};
+
+struct adc12138 {
+	struct spi_device *spi;
+	unsigned int id;
+	/* conversion clock */
+	struct clk *cclk;
+	/* positive analog voltage reference */
+	struct regulator *vref_p;
+	/* negative analog voltage reference */
+	struct regulator *vref_n;
+	struct mutex lock;
+	struct completion complete;
+	/* The number of cclk periods for the S/H's acquisition time */
+	unsigned int acquisition_time;
+
+	u8 tx_buf[2] ____cacheline_aligned;
+	u8 rx_buf[2];
+};
+
+#define ADC12138_VOLTAGE_CHANNEL(chan)					\
+	{								\
+		.type = IIO_VOLTAGE,					\
+		.indexed = 1,						\
+		.channel = chan,					\
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)	\
+					| BIT(IIO_CHAN_INFO_OFFSET),	\
+		.scan_index = chan,					\
+		.scan_type = {						\
+			.sign = 's',					\
+			.realbits = 13,					\
+			.storagebits = 16,				\
+			.shift = 3,					\
+			.endianness = IIO_BE,				\
+		},							\
+	}
+
+#define ADC12138_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si)			\
+	{								\
+		.type = IIO_VOLTAGE,					\
+		.indexed = 1,						\
+		.channel = (chan1),					\
+		.channel2 = (chan2),					\
+		.differential = 1,					\
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)	\
+					| BIT(IIO_CHAN_INFO_OFFSET),	\
+		.scan_index = si,					\
+		.scan_type = {						\
+			.sign = 's',					\
+			.realbits = 13,					\
+			.storagebits = 16,				\
+			.shift = 3,					\
+			.endianness = IIO_BE,				\
+		},							\
+	}
+
+static const struct iio_chan_spec adc12132_channels[] = {
+	ADC12138_VOLTAGE_CHANNEL(0),
+	ADC12138_VOLTAGE_CHANNEL(1),
+	ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 2),
+	ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 3),
+	IIO_CHAN_SOFT_TIMESTAMP(4),
+};
+
+static const struct iio_chan_spec adc12138_channels[] = {
+	ADC12138_VOLTAGE_CHANNEL(0),
+	ADC12138_VOLTAGE_CHANNEL(1),
+	ADC12138_VOLTAGE_CHANNEL(2),
+	ADC12138_VOLTAGE_CHANNEL(3),
+	ADC12138_VOLTAGE_CHANNEL(4),
+	ADC12138_VOLTAGE_CHANNEL(5),
+	ADC12138_VOLTAGE_CHANNEL(6),
+	ADC12138_VOLTAGE_CHANNEL(7),
+	ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 8),
+	ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 9),
+	ADC12138_VOLTAGE_CHANNEL_DIFF(2, 3, 10),
+	ADC12138_VOLTAGE_CHANNEL_DIFF(3, 2, 11),
+	ADC12138_VOLTAGE_CHANNEL_DIFF(4, 5, 12),
+	ADC12138_VOLTAGE_CHANNEL_DIFF(5, 4, 13),
+	ADC12138_VOLTAGE_CHANNEL_DIFF(6, 7, 14),
+	ADC12138_VOLTAGE_CHANNEL_DIFF(7, 6, 15),
+	IIO_CHAN_SOFT_TIMESTAMP(16),
+};
+
+static int adc12138_mode_programming(struct adc12138 *adc, u8 mode,
+				     void *rx_buf, int len)
+{
+	struct spi_transfer xfer = {
+		.tx_buf = adc->tx_buf,
+		.rx_buf = adc->rx_buf,
+		.len = len,
+	};
+	int ret;
+
+	/* Skip unused bits for ADC12130 and ADC12132 */
+	if (adc->id != adc12138)
+		mode = (mode & 0xc0) | ((mode & 0x0f) << 2);
+
+	adc->tx_buf[0] = mode;
+
+	ret = spi_sync_transfer(adc->spi, &xfer, 1);
+	if (ret)
+		return ret;
+
+	memcpy(rx_buf, adc->rx_buf, len);
+
+	return 0;
+}
+
+static int adc12138_read_status(struct adc12138 *adc)
+{
+	u8 rx_buf[2];
+	int ret;
+
+	ret = adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS,
+					rx_buf, 2);
+	if (ret)
+		return ret;
+
+	return (rx_buf[0] << 1) | (rx_buf[1] >> 7);
+}
+
+static int __adc12138_start_conv(struct adc12138 *adc,
+				 struct iio_chan_spec const *channel,
+				 void *data, int len)
+
+{
+	const u8 ch_to_mux[] = { 0, 4, 1, 5, 2, 6, 3, 7 };
+	u8 mode = (ch_to_mux[channel->channel] << 4) |
+		  (channel->differential ? 0 : 0x80);
+
+	return adc12138_mode_programming(adc, mode, data, len);
+}
+
+static int adc12138_start_conv(struct adc12138 *adc,
+			       struct iio_chan_spec const *channel)
+{
+	u8 trash;
+
+	return __adc12138_start_conv(adc, channel, &trash, 1);
+}
+
+static int adc12138_start_and_read_conv(struct adc12138 *adc,
+					struct iio_chan_spec const *channel,
+					__be16 *data)
+{
+	return __adc12138_start_conv(adc, channel, data, 2);
+}
+
+static int adc12138_read_conv_data(struct adc12138 *adc, __be16 *value)
+{
+	/* Issue a read status instruction and read previous conversion data */
+	return adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS,
+					 value, sizeof(*value));
+}
+
+static int adc12138_wait_eoc(struct adc12138 *adc, unsigned long timeout)
+{
+	if (!wait_for_completion_timeout(&adc->complete, timeout))
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+static int adc12138_adc_conversion(struct adc12138 *adc,
+				   struct iio_chan_spec const *channel,
+				   __be16 *value)
+{
+	int ret;
+
+	reinit_completion(&adc->complete);
+
+	ret = adc12138_start_conv(adc, channel);
+	if (ret)
+		return ret;
+
+	ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100));
+	if (ret)
+		return ret;
+
+	return adc12138_read_conv_data(adc, value);
+}
+
+static int adc12138_read_raw(struct iio_dev *iio,
+			     struct iio_chan_spec const *channel, int *value,
+			     int