Merge tag 'iio-for-3.17b' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-next

Jonathan writes:

Second round of new drivers and cleanups for IIO in the 3.17 cycle.

New drivers
* mcp4902, mcp4912 and mcp4922 SPI DAC driver.
* max1027, max1029 and max1031 SPI ADC driver.

Cleanups
* cm32181 - use devm APIs to simplify error paths.
* ak8975 - use devm APIs to simplify error paths.
* ad9850 - drop some unused defines and an unnecessary goto.
* hmc5843 - add missing devices to the device id table and the documentation.
* ad9832 - small formatting cleanups.
* sca3000 - hide direct use of the stufftoread element by adding a
    data_available function.  This is a precursor for the addition of buffer
    watermarks to the subsystem but stands as a good cleanup on its own.

9 files changed, 774 insertions, 58 deletions

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index a80d23628f14..20a7073f1dd6 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -131,6 +131,15 @@ config LP8788_ADC
 	help
 	  Say yes here to build support for TI LP8788 ADC.
 
+config MAX1027
+	tristate "Maxim max1027 ADC driver"
+	depends on SPI
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	help
+	  Say yes here to build support for Maxim SPI ADC models
+	  max1027, max1029 and max1031.
+
 config MAX1363
 	tristate "Maxim max1363 ADC driver"
 	depends on I2C
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 9d60f2deaaaf..38cf5c3f5631 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_AD799X) += ad799x.o
 obj-$(CONFIG_AT91_ADC) += at91_adc.o
 obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
 obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
+obj-$(CONFIG_MAX1027) += max1027.o
 obj-$(CONFIG_MAX1363) += max1363.o
 obj-$(CONFIG_MCP320X) += mcp320x.o
 obj-$(CONFIG_MCP3422) += mcp3422.o
diff --git a/drivers/iio/adc/max1027.c b/drivers/iio/adc/max1027.c
new file mode 100644
index 000000000000..87ee1c7d0b54
--- /dev/null
+++ b/drivers/iio/adc/max1027.c
@@ -0,0 +1,521 @@
+ /*
+  * iio/adc/max1027.c
+  * Copyright (C) 2014 Philippe Reynes
+  *
+  * based on linux/drivers/iio/ad7923.c
+  * Copyright 2011 Analog Devices Inc (from AD7923 Driver)
+  * Copyright 2012 CS Systemes d'Information
+  *
+  * 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.
+  *
+  * max1027.c
+  *
+  * Partial support for max1027 and similar chips.
+  */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+#include <linux/delay.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+#define MAX1027_CONV_REG  BIT(7)
+#define MAX1027_SETUP_REG BIT(6)
+#define MAX1027_AVG_REG   BIT(5)
+#define MAX1027_RST_REG   BIT(4)
+
+/* conversion register */
+#define MAX1027_TEMP      BIT(0)
+#define MAX1027_SCAN_0_N  (0x00 << 1)
+#define MAX1027_SCAN_N_M  (0x01 << 1)
+#define MAX1027_SCAN_N    (0x02 << 1)
+#define MAX1027_NOSCAN    (0x03 << 1)
+#define MAX1027_CHAN(n)   ((n) << 3)
+
+/* setup register */
+#define MAX1027_UNIPOLAR  0x02
+#define MAX1027_BIPOLAR   0x03
+#define MAX1027_REF_MODE0 (0x00 << 2)
+#define MAX1027_REF_MODE1 (0x01 << 2)
+#define MAX1027_REF_MODE2 (0x02 << 2)
+#define MAX1027_REF_MODE3 (0x03 << 2)
+#define MAX1027_CKS_MODE0 (0x00 << 4)
+#define MAX1027_CKS_MODE1 (0x01 << 4)
+#define MAX1027_CKS_MODE2 (0x02 << 4)
+#define MAX1027_CKS_MODE3 (0x03 << 4)
+
+/* averaging register */
+#define MAX1027_NSCAN_4   0x00
+#define MAX1027_NSCAN_8   0x01
+#define MAX1027_NSCAN_12  0x02
+#define MAX1027_NSCAN_16  0x03
+#define MAX1027_NAVG_4    (0x00 << 2)
+#define MAX1027_NAVG_8    (0x01 << 2)
+#define MAX1027_NAVG_16   (0x02 << 2)
+#define MAX1027_NAVG_32   (0x03 << 2)
+#define MAX1027_AVG_EN    BIT(4)
+
+enum max1027_id {
+	max1027,
+	max1029,
+	max1031,
+};
+
+static const struct spi_device_id max1027_id[] = {
+	{"max1027", max1027},
+	{"max1029", max1029},
+	{"max1031", max1031},
+	{}
+};
+MODULE_DEVICE_TABLE(spi, max1027_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id max1027_adc_dt_ids[] = {
+	{ .compatible = "maxim,max1027" },
+	{ .compatible = "maxim,max1029" },
+	{ .compatible = "maxim,max1031" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, max1027_adc_dt_ids);
+#endif
+
+#define MAX1027_V_CHAN(index)						\
+	{								\
+		.type = IIO_VOLTAGE,					\
+		.indexed = 1,						\
+		.channel = index,					\
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+		.scan_index = index + 1,				\
+		.scan_type = {						\
+			.sign = 'u',					\
+			.realbits = 10,					\
+			.storagebits = 16,				\
+			.shift = 2,					\
+			.endianness = IIO_BE,				\
+		},							\
+	}
+
+#define MAX1027_T_CHAN							\
+	{								\
+		.type = IIO_TEMP,					\
+		.channel = 0,						\
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+		.scan_index = 0,					\
+		.scan_type = {						\
+			.sign = 'u',					\
+			.realbits = 12,					\
+			.storagebits = 16,				\
+			.endianness = IIO_BE,				\
+		},							\
+	}
+
+static const struct iio_chan_spec max1027_channels[] = {
+	MAX1027_T_CHAN,
+	MAX1027_V_CHAN(0),
+	MAX1027_V_CHAN(1),
+	MAX1027_V_CHAN(2),
+	MAX1027_V_CHAN(3),
+	MAX1027_V_CHAN(4),
+	MAX1027_V_CHAN(5),
+	MAX1027_V_CHAN(6),
+	MAX1027_V_CHAN(7)
+};
+
+static const struct iio_chan_spec max1029_channels[] = {
+	MAX1027_T_CHAN,
+	MAX1027_V_CHAN(0),
+	MAX1027_V_CHAN(1),
+	MAX1027_V_CHAN(2),
+	MAX1027_V_CHAN(3),
+	MAX1027_V_CHAN(4),
+	MAX1027_V_CHAN(5),
+	MAX1027_V_CHAN(6),
+	MAX1027_V_CHAN(7),
+	MAX1027_V_CHAN(8),
+	MAX1027_V_CHAN(9),
+	MAX1027_V_CHAN(10),
+	MAX1027_V_CHAN(11)
+};
+
+static const struct iio_chan_spec max1031_channels[] = {
+	MAX1027_T_CHAN,
+	MAX1027_V_CHAN(0),
+	MAX1027_V_CHAN(1),
+	MAX1027_V_CHAN(2),
+	MAX1027_V_CHAN(3),
+	MAX1027_V_CHAN(4),
+	MAX1027_V_CHAN(5),
+	MAX1027_V_CHAN(6),
+	MAX1027_V_CHAN(7),
+	MAX1027_V_CHAN(8),
+	MAX1027_V_CHAN(9),
+	MAX1027_V_CHAN(10),
+	MAX1027_V_CHAN(11),
+	MAX1027_V_CHAN(12),
+	MAX1027_V_CHAN(13),
+	MAX1027_V_CHAN(14),
+	MAX1027_V_CHAN(15)
+};
+
+static const unsigned long max1027_available_scan_masks[] = {
+	0x000001ff,
+	0x00000000,
+};
+
+static const unsigned long max1029_available_scan_masks[] = {
+	0x00001fff,
+	0x00000000,
+};
+
+static const unsigned long max1031_available_scan_masks[] = {
+	0x0001ffff,
+	0x00000000,
+};
+
+struct max1027_chip_info {
+	const struct iio_chan_spec *channels;
+	unsigned int num_channels;
+	const unsigned long *available_scan_masks;
+};
+
+static const struct max1027_chip_info max1027_chip_info_tbl[] = {
+	[max1027] = {
+		.channels = max1027_channels,
+		.num_channels = ARRAY_SIZE(max1027_channels),
+		.available_scan_masks = max1027_available_scan_masks,
+	},
+	[max1029] = {
+		.channels = max1029_channels,
+		.num_channels = ARRAY_SIZE(max1029_channels),
+		.available_scan_masks = max1029_available_scan_masks,
+	},
+	[max1031] = {
+		.channels = max1031_channels,
+		.num_channels = ARRAY_SIZE(max1031_channels),
+		.available_scan_masks = max1031_available_scan_masks,
+	},
+};
+
+struct max1027_state {
+	const struct max1027_chip_info	*info;
+	struct spi_device		*spi;
+	struct iio_trigger		*trig;
+	__be16				*buffer;
+	struct mutex			lock;
+
+	u8				reg ____cacheline_aligned;
+};
+
+static int max1027_read_single_value(struct iio_dev *indio_dev,
+				     struct iio_chan_spec const *chan,
+				     int *val)
+{
+	int ret;
+	struct max1027_state *st = iio_priv(indio_dev);
+
+	if (iio_buffer_enabled(indio_dev)) {
+		dev_warn(&indio_dev->dev, "trigger mode already enabled");
+		return -EBUSY;
+	}
+
+	/* Start acquisition on conversion register write */
+	st->reg = MAX1027_SETUP_REG | MAX1027_REF_MODE2 | MAX1027_CKS_MODE2;
+	ret = spi_write(st->spi, &st->reg, 1);
+	if (ret < 0) {
+		dev_err(&indio_dev->dev,
+			"Failed to configure setup register\n");
+		return ret;
+	}
+
+	/* Configure conversion register with the requested chan */
+	st->reg = MAX1027_CONV_REG | MAX1027_CHAN(chan->channel) |
+		  MAX1027_NOSCAN | !!(chan->type == IIO_TEMP);
+	ret = spi_write(st->spi, &st->reg, 1);
+	if (ret < 0) {
+		dev_err(&indio_dev->dev,
+			"Failed to configure conversion register\n");
+		return ret;
+	}
+
+	/*
+	 * For an unknown reason, when we use the mode "10" (write
+	 * conversion register), the interrupt doesn't occur every time.
+	 * So we just wait 1 ms.
+	 */
+	mdelay(1);
+
+	/* Read result */
+	ret = spi_read(st->spi, st->buffer, (chan->type == IIO_TEMP) ? 4 : 2);
+	if (ret < 0)
+		return ret;
+
+	*val = be16_to_cpu(st->buffer[0]);
+
+	return IIO_VAL_INT;
+}
+
+static int max1027_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int *val, int *val2, long mask)
+{
+	int ret = 0;
+	struct max1027_state *st = iio_priv(indio_dev);
+
+	mutex_lock(&st->lock);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = max1027_read_single_value(indio_dev, chan, val);
+		break;
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->type) {
+		case IIO_TEMP:
+			*val = 1;
+			*val2 = 8;
+			ret = IIO_VAL_FRACTIONAL;
+			break;
+		case IIO_VOLTAGE:
+			*val = 2500;
+			*val2 = 10;
+			ret = IIO_VAL_FRACTIONAL_LOG2;
+			break;
+		default:
+			ret = -EINVAL;
+			break;
+		}
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	mutex_unlock(&st->lock);
+
+	return ret;
+}
+
+static int max1027_debugfs_reg_access(struct iio_dev *indio_dev,
+				      unsigned reg, unsigned writeval,
+				      unsigned *readval)
+{
+	struct max1027_state *st = iio_priv(indio_dev);
+	u8 *val = (u8 *)st->buffer;
+
+	if (readval != NULL)
+		return -EINVAL;
+
+	*val = (u8)writeval;
+	return spi_write(st->spi, val, 1);
+}
+
+static int max1027_validate_trigger(struct iio_dev *indio_dev,
+				    struct iio_trigger *trig)
+{
+	struct max1027_state *st = iio_priv(indio_dev);
+
+	if (st->trig != trig)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int max1027_set_trigger_state(struct iio_trigger *trig, bool state)
+{
+	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+	struct max1027_state *st = iio_priv(indio_dev);
+	int ret;
+
+	if (state) {
+		/* Start acquisition on cnvst */
+		st->reg = MAX1027_SETUP_REG | MAX1027_CKS_MODE0 |
+			  MAX1027_REF_MODE2;
+		ret = spi_write(st->spi, &st->reg, 1);
+		if (ret < 0)
+			return ret;
+
+		/* Scan from 0 to max */
+		st->reg = MAX1027_CONV_REG | MAX1027_CHAN(0) |
+			  MAX1027_SCAN_N_M | MAX1027_TEMP;
+		ret = spi_write(st->spi, &st->reg, 1);
+		if (ret < 0)
+			return ret;
+	} else {
+		/* Start acquisition on conversion register write */
+		st->reg = MAX1027_SETUP_REG | MAX1027_CKS_MODE2	|
+			  MAX1027_REF_MODE2;
+		ret = spi_write(st->spi, &st->reg, 1);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int max1027_validate_device(struct iio_trigger *trig,
+				   struct iio_dev *indio_dev)
+{
+	struct iio_dev *indio = iio_trigger_get_drvdata(trig);
+
+	if (indio != indio_dev)
+		return -EINVAL;
+
+	return 0;
+}
+
+static irqreturn_t max1027_trigger_handler(int irq, void *private)
+{
+	struct iio_poll_func *pf = (struct iio_poll_func *)private;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct max1027_state *st = iio_priv(indio_dev);
+
+	pr_debug("%s(irq=%d, private=0x%p)\n", __func__, irq, private);
+
+	/* fill buffer with all channel */
+	spi_read(st->spi, st->buffer, indio_dev->masklength * 2);
+
+	iio_push_to_buffers(indio_dev, st->buffer);
+
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static const struct iio_trigger_ops max1027_trigger_ops = {
+	.owner = THIS_MODULE,
+	.validate_device = &max1027_validate_device,
+	.set_trigger_state = &max1027_set_trigger_state,
+};
+
+static const struct iio_info max1027_info = {
+	.driver_module = THIS_MODULE,
+	.read_raw = &max1027_read_raw,
+	.validate_trigger = &max1027_validate_trigger,
+	.debugfs_reg_access = &max1027_debugfs_reg_access,
+};
+
+static int max1027_probe(struct spi_device *spi)
+{
+	int ret;
+	struct iio_dev *indio_dev;
+	struct max1027_state *st;
+
+	pr_debug("%s: probe(spi = 0x%p)\n", __func__, spi);
+
+	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+	if (indio_dev == NULL) {
+		pr_err("Can't allocate iio device\n");
+		return -ENOMEM;
+	}
+
+	spi_set_drvdata(spi, indio_dev);
+
+	st = iio_priv(indio_dev);
+	st->spi = spi;
+	st->info = &max1027_chip_info_tbl[spi_get_device_id(spi)->driver_data];
+
+	mutex_init(&st->lock);
+
+	indio_dev->name = spi_get_device_id(spi)->name;
+	indio_dev->dev.parent = &spi->dev;
+	indio_dev->info = &max1027_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = st->info->channels;
+	indio_dev->num_channels = st->info->num_channels;
+	indio_dev->available_scan_masks = st->info->available_scan_masks;
+
+	st->buffer = devm_kmalloc(&indio_dev->dev,
+				  indio_dev->num_channels * 2,
+				  GFP_KERNEL);
+	if (st->buffer == NULL) {
+		dev_err(&indio_dev->dev, "Can't allocate bufffer\n");
+		return -ENOMEM;
+	}
+
+	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
+					 &max1027_trigger_handler, NULL);
+	if (ret < 0) {
+		dev_err(&indio_dev->dev, "Failed to setup buffer\n");
+		return ret;
+	}
+
+	st->trig = devm_iio_trigger_alloc(&spi->dev, "%s-trigger",
+							indio_dev->name);
+	if (st->trig == NULL) {
+		ret = -ENOMEM;
+		dev_err(&indio_dev->dev, "Failed to allocate iio trigger\n");
+		goto fail_trigger_alloc;
+	}
+
+	st->trig->ops = &max1027_trigger_ops;
+	st->trig->dev.parent = &spi->dev;
+	iio_trigger_set_drvdata(st->trig, indio_dev);
+	iio_trigger_register(st->trig);
+
+	ret = devm_request_threaded_irq(&spi->dev, spi->irq,
+					iio_trigger_generic_data_rdy_poll,
+					NULL,
+					IRQF_TRIGGER_FALLING,
+					spi->dev.driver->name, st->trig);
+	if (ret < 0) {
+		dev_err(&indio_dev->dev, "Failed to allocate IRQ.\n");
+		goto fail_dev_register;
+	}
+
+	/* Disable averaging */
+	st->reg = MAX1027_AVG_REG;
+	ret = spi_write(st->spi, &st->reg, 1);
+	if (ret < 0) {
+		dev_err(&indio_dev->dev, "Failed to configure averaging register\n");
+		goto fail_dev_register;
+	}
+
+	ret = iio_device_register(indio_dev);
+	if (ret < 0) {
+		dev_err(&indio_dev->dev, "Failed to register iio device\n");
+		goto fail_dev_register;
+	}
+
+	return 0;
+
+fail_dev_register:
+fail_trigger_alloc:
+	iio_triggered_buffer_cleanup(indio_dev);
+
+	return ret;
+}
+
+static int max1027_remove(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev = spi_get_drvdata(spi);
+
+	pr_debug("%s: remove(spi = 0x%p)\n", __func__, spi);
+
+	iio_device_unregister(indio_dev);
+	iio_triggered_buffer_cleanup(indio_dev);
+
+	return 0;
+}
+
+static struct spi_driver max1027_driver = {
+	.driver = {
+		.name	= "max1027",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= max1027_probe,
+	.remove		= max1027_remove,
+	.id_table	= max1027_id,
+};
+module_spi_driver(max1027_driver);
+
+MODULE_AUTHOR("Philippe Reynes <tremyfr@yahoo.fr>");
+MODULE_DESCRIPTION("MAX1027/MAX1029/MAX1031 ADC");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
index f378ca8033db..f278eff42a4c 100644
--- a/drivers/iio/dac/Kconfig
+++ b/drivers/iio/dac/Kconfig
@@ -163,4 +163,14 @@ config MCP4725
 	  To compile this driver as a module, choose M here: the module
 	  will be called mcp4725.
 
+config MCP4922
+	tristate "MCP4902, MCP4912, MCP4922 DAC driver"
+	depends on SPI
+	help
+	  Say yes here to build the driver for the Microchip MCP4902
+	  MCP4912, and MCP4922 DAC devices.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called mcp4922.
+
 endmenu
diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
index bb84ad64463f..10107640bb46 100644
--- a/drivers/iio/dac/Makefile
+++ b/drivers/iio/dac/Makefile
@@ -18,3 +18,4 @@ obj-$(CONFIG_AD5686) += ad5686.o
 obj-$(CONFIG_AD7303) += ad7303.o
 obj-$(CONFIG_MAX517) += max517.o
 obj-$(CONFIG_MCP4725) += mcp4725.o
+obj-$(CONFIG_MCP4922) += mcp4922.o
diff --git a/drivers/iio/dac/mcp4922.c b/drivers/iio/dac/mcp4922.c
new file mode 100644
index 000000000000..92cf4ca6981d
--- /dev/null
+++ b/drivers/iio/dac/mcp4922.c
@@ -0,0 +1,216 @@
+/*
+ * mcp4922.c
+ *
+ * Driver for Microchip Digital to Analog Converters.
+ * Supports MCP4902, MCP4912, and MCP4922.
+ *
+ * Copyright (c) 2014 EMAC Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/spi/spi.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/regulator/consumer.h>
+#include <linux/bitops.h>
+
+#define MCP4922_NUM_CHANNELS	2
+
+enum mcp4922_supported_device_ids {
+	ID_MCP4902,
+	ID_MCP4912,
+	ID_MCP4922,
+};
+
+struct mcp4922_state {
+	struct spi_device *spi;
+	unsigned int value[MCP4922_NUM_CHANNELS];
+	unsigned int vref_mv;
+	struct regulator *vref_reg;
+	u8 mosi[2] ____cacheline_aligned;
+};
+
+#define MCP4922_CHAN(chan, bits) {			\
+	.type = IIO_VOLTAGE,				\
+	.output = 1,					\
+	.indexed = 1,					\
+	.channel = chan,				\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+	.scan_type = {					\
+		.sign = 'u',				\
+		.realbits = (bits),			\
+		.storagebits = 16,			\
+		.shift = 12 - (bits),			\
+	},						\
+}
+
+static int mcp4922_spi_write(struct mcp4922_state *state, u8 addr, u32 val)
+{
+	state->mosi[1] = val & 0xff;
+	state->mosi[0] = (addr == 0) ? 0x00 : 0x80;
+	state->mosi[0] |= 0x30 | ((val >> 8) & 0x0f);
+
+	return spi_write(state->spi, state->mosi, 2);
+}
+
+static int mcp4922_read_raw(struct iio_dev *indio_dev,
+		struct iio_chan_spec const *chan,
+		int *val,
+		int *val2,
+		long mask)
+{
+	struct mcp4922_state *state = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		*val = state->value[chan->channel];
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = state->vref_mv;
+		*val2 = chan->scan_type.realbits;
+		return IIO_VAL_FRACTIONAL_LOG2;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int mcp4922_write_raw(struct iio_dev *indio_dev,
+		struct iio_chan_spec const *chan,
+		int val,
+		int val2,
+		long mask)
+{
+	struct mcp4922_state *state = iio_priv(indio_dev);
+
+	if (val2 != 0)
+		return -EINVAL;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (val > GENMASK(chan->scan_type.realbits-1, 0))
+			return -EINVAL;
+		val <<= chan->scan_type.shift;
+		state->value[chan->channel] = val;
+		return mcp4922_spi_write(state, chan->channel, val);
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_chan_spec mcp4922_channels[3][MCP4922_NUM_CHANNELS] = {
+	[ID_MCP4902] = { MCP4922_CHAN(0, 8),	MCP4922_CHAN(1, 8) },
+	[ID_MCP4912] = { MCP4922_CHAN(0, 10),	MCP4922_CHAN(1, 10) },
+	[ID_MCP4922] = { MCP4922_CHAN(0, 12),	MCP4922_CHAN(1, 12) },
+};
+
+static const struct iio_info mcp4922_info = {
+	.read_raw = &mcp4922_read_raw,
+	.write_raw = &mcp4922_write_raw,
+	.driver_module = THIS_MODULE,
+};
+
+static int mcp4922_probe(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev;
+	struct mcp4922_state *state;
+	const struct spi_device_id *id;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state));
+	if (indio_dev == NULL)
+		return -ENOMEM;
+
+	state = iio_priv(indio_dev);
+	state->spi = spi;
+	state->vref_reg = devm_regulator_get(&spi->dev, "vref");
+	if (IS_ERR(state->vref_reg)) {
+		dev_err(&spi->dev, "Vref regulator not specified\n");
+		return PTR_ERR(state->vref_reg);
+	}
+
+	ret = regulator_enable(state->vref_reg);
+	if (ret) {
+		dev_err(&spi->dev, "Failed to enable vref regulator: %d\n",
+				ret);
+		return ret;
+	}
+
+	ret = regulator_get_voltage(state->vref_reg);
+	if (ret < 0) {
+		dev_err(&spi->dev, "Failed to read vref regulator: %d\n",
+				ret);
+		goto error_disable_reg;
+	}
+	state->vref_mv = ret / 1000;
+
+	spi_set_drvdata(spi, indio_dev);
+	id = spi_get_device_id(spi);
+	indio_dev->dev.parent = &spi->dev;
+	indio_dev->info = &mcp4922_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = mcp4922_channels[id->driver_data];
+	indio_dev->num_channels = MCP4922_NUM_CHANNELS;
+	indio_dev->name = id->name;
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(&spi->dev, "Failed to register iio device: %d\n",
+				ret);
+		goto error_disable_reg;
+	}
+
+	return 0;
+
+error_disable_reg:
+	regulator_disable(state->vref_reg);
+
+	return ret;
+}
+
+static int mcp4922_remove(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev = spi_get_drvdata(spi);
+	struct mcp4922_state *state;
+
+	iio_device_unregister(indio_dev);
+	state = iio_priv(indio_dev);
+	regulator_disable(state->vref_reg);
+
+	return 0;
+}
+
+static const struct spi_device_id mcp4922_id[] = {
+	{"mcp4902", ID_MCP4902},
+	{"mcp4912", ID_MCP4912},
+	{"mcp4922", ID_MCP4922},
+	{}
+};
+MODULE_DEVICE_TABLE(spi, mcp4922_id);
+
+static struct spi_driver mcp4922_driver = {
+	.driver = {
+		   .name = "mcp4922",
+		   .owner = THIS_MODULE,
+		   },
+	.probe = mcp4922_probe,
+	.remove = mcp4922_remove,
+	.id_table = mcp4922_id,
+};
+module_spi_driver(mcp4922_driver);
+
+MODULE_AUTHOR("Michael Welling <mwelling@ieee.org>");
+MODULE_DESCRIPTION("Microchip MCP4902, MCP4912, MCP4922 DAC");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 36b1ae92e239..2952ee038477 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -39,10 +39,7 @@ static bool iio_buffer_is_active(struct iio_buffer *buf)
 
 static bool iio_buffer_data_available(struct iio_buffer *buf)
 {
-	if (buf->access->data_available)
-		return buf->access->data_available(buf);
-
-	return buf->stufftoread;
+	return buf->access->data_available(buf);
 }
 
 /**
diff --git a/drivers/iio/light/cm32181.c b/drivers/iio/light/cm32181.c
index d976e6ce60db..ad36b294e4d5 100644
--- a/drivers/iio/light/cm32181.c
+++ b/drivers/iio/light/cm32181.c
@@ -331,7 +331,7 @@ static int cm32181_probe(struct i2c_client *client,
 		return ret;
 	}
 
-	ret = iio_device_register(indio_dev);
+	ret = devm_iio_device_register(&client->dev, indio_dev);
 	if (ret) {
 		dev_err(&client->dev,
 			"%s: regist device failed\n",
@@ -342,14 +342,6 @@ static int cm32181_probe(struct i2c_client *client,
 	return 0;
 }
 
-static int cm32181_remove(struct i2c_client *client)
-{
-	struct iio_dev *indio_dev = i2c_get_clientdata(client);
-
-	iio_device_unregister(indio_dev);
-	return 0;
-}
-
 static const struct i2c_device_id cm32181_id[] = {
 	{ "cm32181", 0 },
 	{ }
@@ -370,7 +362,6 @@ static struct i2c_driver cm32181_driver = {
 	},
 	.id_table       = cm32181_id,
 	.probe		= cm32181_probe,
-	.remove		= cm32181_remove,
 };
 
 module_i2c_driver(cm32181_driver);
diff --git a/drivers/iio/magnetometer/ak8975.c b/drivers/iio/magnetometer/ak8975.c
index ea08313af0d2..a2357921d761 100644
--- a/drivers/iio/magnetometer/ak8975.c
+++ b/drivers/iio/magnetometer/ak8975.c
@@ -165,7 +165,7 @@ static int ak8975_setup_irq(struct ak8975_data *data)
 	else
 		irq = gpio_to_irq(data->eoc_gpio);
 
-	rc = request_irq(irq, ak8975_irq_handler,
+	rc = devm_request_irq(&client->dev, irq, ak8975_irq_handler,
 			 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
 			 dev_name(&client->dev), data);
 	if (rc < 0) {
@@ -513,21 +513,21 @@ static int ak8975_probe(struct i2c_client *client,
 	/* We may not have a GPIO based IRQ to scan, that is fine, we will
 	   poll if so */
 	if (gpio_is_valid(eoc_gpio)) {
-		err = gpio_request_one(eoc_gpio, GPIOF_IN, "ak_8975");
+		err = devm_gpio_request_one(&client->dev, eoc_gpio,
+							GPIOF_IN, "ak_8975");
 		if (err < 0) {
 			dev_err(&client->dev,
 				"failed to request GPIO %d, error %d\n",
 							eoc_gpio, err);
-			goto exit;
+			return err;
 		}
 	}
 
 	/* Register with IIO */
-	indio_dev = iio_device_alloc(sizeof(*data));
-	if (indio_dev == NULL) {
-		err = -ENOMEM;
-		goto exit_gpio;
-	}
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (indio_dev == NULL)
+		return -ENOMEM;
+
 	data = iio_priv(indio_dev);
 	i2c_set_clientdata(client, indio_dev);
 
@@ -542,17 +542,16 @@ static int ak8975_probe(struct i2c_client *client,
 		name = (char *) id->name;
 	} else if (ACPI_HANDLE(&client->dev))
 		name = ak8975_match_acpi_device(&client->dev, &data->chipset);
-	else {
-		err = -ENOSYS;
-		goto exit_free_iio;
-	}
+	else
+		return -ENOSYS;
+
 	dev_dbg(&client->dev, "Asahi compass chip %s\n", name);
 
 	/* Perform some basic start-of-day setup of the device. */
 	err = ak8975_setup(client);
 	if (err < 0) {
 		dev_err(&client->dev, "AK8975 initialization fails\n");
-		goto exit_free_iio;
+		return err;
 	}
 
 	data->client = client;
@@ -564,37 +563,9 @@ static int ak8975_probe(struct i2c_client *client,
 	indio_dev->info = &ak8975_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->name = name;
-	err = iio_device_register(indio_dev);
+	err = devm_iio_device_register(&client->dev, indio_dev);
 	if (err < 0)
-		goto exit_free_iio;
-
-	return 0;
-
-exit_free_iio:
-	iio_device_free(indio_dev);
-	if (data->eoc_irq)
-		free_irq(data->eoc_irq, data);
-exit_gpio:
-	if (gpio_is_valid(eoc_gpio))
-		gpio_free(eoc_gpio);
-exit:
-	return err;
-}
-
-static int ak8975_remove(struct i2c_client *client)
-{
-	struct iio_dev *indio_dev = i2c_get_clientdata(client);
-	struct ak8975_data *data = iio_priv(indio_dev);
-
-	iio_device_unregister(indio_dev);
-
-	if (data->eoc_irq)
-		free_irq(data->eoc_irq, data);
-
-	if (gpio_is_valid(data->eoc_gpio))
-		gpio_free(data->eoc_gpio);
-
-	iio_device_free(indio_dev);
+		return err;
 
 	return 0;
 }
@@ -621,7 +592,6 @@ static struct i2c_driver ak8975_driver = {
 		.acpi_match_table = ACPI_PTR(ak_acpi_match),
 	},
 	.probe		= ak8975_probe,
-	.remove		= ak8975_remove,
 	.id_table	= ak8975_id,
 };
 module_i2c_driver(ak8975_driver);