staging: iio: adc: Enable driver support for ad7887 AD converter (2b4756aa) · Commits · e / devices / android_kernel_teracube_2e

drivers/staging/iio/adc/Kconfig

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Original line number	Diff line number	Diff line
		@@ -97,6 +97,20 @@ config AD7476
		To compile this driver as a module, choose M here: the
		module will be called ad7476.

		config AD7887
		tristate "Analog Devices AD7887 ADC driver"
		depends on SPI
		select IIO_RING_BUFFER
		select IIO_SW_RING
		select IIO_TRIGGER
		help
		Say yes here to build support for Analog Devices
		AD7887 SPI analog to digital convertor (ADC).
		If unsure, say N (but it's safe to say "Y").

		To compile this driver as a module, choose M here: the
		module will be called ad7887.

		config AD7745
		tristate "Analog Devices AD7745, AD7746 AD7747 capacitive sensor driver"
		depends on I2C

drivers/staging/iio/adc/Makefile

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Original line number	Diff line number	Diff line
		@@ -15,6 +15,10 @@ ad7476-y := ad7476_core.o
		ad7476-$(CONFIG_IIO_RING_BUFFER) += ad7476_ring.o
		obj-$(CONFIG_AD7476) += ad7476.o

		ad7887-y := ad7887_core.o
		ad7887-$(CONFIG_IIO_RING_BUFFER) += ad7887_ring.o
		obj-$(CONFIG_AD7887) += ad7887.o

		obj-$(CONFIG_AD7150) += ad7150.o
		obj-$(CONFIG_AD7152) += ad7152.o
		obj-$(CONFIG_AD7291) += ad7291.o

drivers/staging/iio/adc/ad7887.h

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		/*
		* AD7887 SPI ADC driver
		*
		* Copyright 2010 Analog Devices Inc.
		*
		* Licensed under the GPL-2 or later.
		*/
		#ifndef IIO_ADC_AD7887_H_
		#define IIO_ADC_AD7887_H_

		#define AD7887_REF_DIS (1 << 5) /* on-chip reference disable */
		#define AD7887_DUAL (1 << 4) /* dual-channel mode */
		#define AD7887_CH_AIN1 (1 << 3) /* convert on channel 1, DUAL=1 */
		#define AD7887_CH_AIN0 (0 << 3) /* convert on channel 0, DUAL=0,1 */
		#define AD7887_PM_MODE1 (0) /* CS based shutdown */
		#define AD7887_PM_MODE2 (1) /* full on */
		#define AD7887_PM_MODE3 (2) /* auto shutdown after conversion */
		#define AD7887_PM_MODE4 (3) /* standby mode */

		enum ad7887_channels {
		AD7887_CH0,
		AD7887_CH0_CH1,
		AD7887_CH1,
		};

		#define RES_MASK(bits) ((1 << (bits)) - 1) /* TODO: move this into a common header */

		/*
		* TODO: struct ad7887_platform_data needs to go into include/linux/iio
		*/

		struct ad7887_platform_data {
		/* External Vref voltage applied */
		u16 vref_mv;
		/*
		* AD7887:
		* In single channel mode en_dual = flase, AIN1/Vref pins assumes its
		* Vref function. In dual channel mode en_dual = true, AIN1 becomes the
		* second input channel, and Vref is internally connected to Vdd.
		*/
		bool en_dual;
		/*
		* AD7887:
		* use_onchip_ref = true, the Vref is internally connected to the 2.500V
		* Voltage reference. If use_onchip_ref = false, the reference voltage
		* is supplied by AIN1/Vref
		*/
		bool use_onchip_ref;
		};

		struct ad7887_chip_info {
		u8 bits; /* number of ADC bits */
		u8 storagebits; /* number of bits read from the ADC */
		u8 left_shift; /* number of bits the sample must be shifted */
		char sign; /* [s]igned or [u]nsigned */
		u16 int_vref_mv; /* internal reference voltage */
		};

		struct ad7887_state {
		struct iio_dev *indio_dev;
		struct spi_device *spi;
		const struct ad7887_chip_info *chip_info;
		struct regulator *reg;
		struct work_struct poll_work;
		atomic_t protect_ring;
		u16 int_vref_mv;
		bool en_dual;
		struct spi_transfer xfer[4];
		struct spi_message msg[3];
		struct spi_message *ring_msg;
		unsigned char tx_cmd_buf[8];

		/*
		* DMA (thus cache coherency maintenance) requires the
		* transfer buffers to live in their own cache lines.
		*/

		unsigned char data[4] ____cacheline_aligned;
		};

		enum ad7887_supported_device_ids {
		ID_AD7887
		};

		#ifdef CONFIG_IIO_RING_BUFFER
		int ad7887_scan_from_ring(struct ad7887_state *st, long mask);
		int ad7887_register_ring_funcs_and_init(struct iio_dev *indio_dev);
		void ad7887_ring_cleanup(struct iio_dev *indio_dev);
		#else /* CONFIG_IIO_RING_BUFFER */
		static inline int ad7887_scan_from_ring(struct ad7887_state *st, long mask)
		{
		return 0;
		}

		static inline int
		ad7887_register_ring_funcs_and_init(struct iio_dev *indio_dev)
		{
		return 0;
		}

		static inline void ad7887_ring_cleanup(struct iio_dev *indio_dev)
		{
		}
		#endif /* CONFIG_IIO_RING_BUFFER */
		#endif /* IIO_ADC_AD7887_H_ */

drivers/staging/iio/adc/ad7887_core.c

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Original line number	Diff line number	Diff line
		/*
		* AD7887 SPI ADC driver
		*
		* Copyright 2010 Analog Devices Inc.
		*
		* Licensed under the GPL-2 or later.
		*/

		#include <linux/interrupt.h>
		#include <linux/workqueue.h>
		#include <linux/device.h>
		#include <linux/kernel.h>
		#include <linux/slab.h>
		#include <linux/sysfs.h>
		#include <linux/list.h>
		#include <linux/spi/spi.h>
		#include <linux/regulator/consumer.h>
		#include <linux/err.h>

		#include "../iio.h"
		#include "../sysfs.h"
		#include "../ring_generic.h"
		#include "adc.h"

		#include "ad7887.h"

		static int ad7887_scan_direct(struct ad7887_state *st, unsigned ch)
		{
		int ret = spi_sync(st->spi, &st->msg[ch]);
		if (ret)
		return ret;

		return (st->data[(ch * 2)] << 8) \| st->data[(ch * 2) + 1];
		}

		static ssize_t ad7887_scan(struct device *dev,
		struct device_attribute *attr,
		char *buf)
		{
		struct iio_dev *dev_info = dev_get_drvdata(dev);
		struct ad7887_state *st = dev_info->dev_data;
		struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
		int ret;

		mutex_lock(&dev_info->mlock);
		if (iio_ring_enabled(dev_info))
		ret = ad7887_scan_from_ring(st, 1 << this_attr->address);
		else
		ret = ad7887_scan_direct(st, this_attr->address);
		mutex_unlock(&dev_info->mlock);

		if (ret < 0)
		return ret;

		return sprintf(buf, "%d\n", (ret >> st->chip_info->left_shift) &
		RES_MASK(st->chip_info->bits));
		}
		static IIO_DEV_ATTR_IN_RAW(0, ad7887_scan, 0);
		static IIO_DEV_ATTR_IN_RAW(1, ad7887_scan, 1);

		static ssize_t ad7887_show_scale(struct device *dev,
		struct device_attribute *attr,
		char *buf)
		{
		/* Driver currently only support internal vref */
		struct iio_dev *dev_info = dev_get_drvdata(dev);
		struct ad7887_state *st = iio_dev_get_devdata(dev_info);
		/* Corresponds to Vref / 2^(bits) */
		unsigned int scale_uv = (st->int_vref_mv * 1000) >> st->chip_info->bits;

		return sprintf(buf, "%d.%d\n", scale_uv / 1000, scale_uv % 1000);
		}
		static IIO_DEVICE_ATTR(in_scale, S_IRUGO, ad7887_show_scale, NULL, 0);

		static ssize_t ad7887_show_name(struct device *dev,
		struct device_attribute *attr,
		char *buf)
		{
		struct iio_dev *dev_info = dev_get_drvdata(dev);
		struct ad7887_state *st = iio_dev_get_devdata(dev_info);

		return sprintf(buf, "%s\n", spi_get_device_id(st->spi)->name);
		}
		static IIO_DEVICE_ATTR(name, S_IRUGO, ad7887_show_name, NULL, 0);

		static struct attribute *ad7887_attributes[] = {
		&iio_dev_attr_in0_raw.dev_attr.attr,
		&iio_dev_attr_in1_raw.dev_attr.attr,
		&iio_dev_attr_in_scale.dev_attr.attr,
		&iio_dev_attr_name.dev_attr.attr,
		NULL,
		};

		static mode_t ad7887_attr_is_visible(struct kobject *kobj,
		struct attribute *attr, int n)
		{
		struct device *dev = container_of(kobj, struct device, kobj);
		struct iio_dev *dev_info = dev_get_drvdata(dev);
		struct ad7887_state *st = iio_dev_get_devdata(dev_info);

		mode_t mode = attr->mode;

		if ((attr == &iio_dev_attr_in1_raw.dev_attr.attr) && !st->en_dual)
		mode = 0;

		return mode;
		}

		static const struct attribute_group ad7887_attribute_group = {
		.attrs = ad7887_attributes,
		.is_visible = ad7887_attr_is_visible,
		};

		static const struct ad7887_chip_info ad7887_chip_info_tbl[] = {
		/*
		* More devices added in future
		*/
		[ID_AD7887] = {
		.bits = 12,
		.storagebits = 16,
		.left_shift = 0,
		.sign = IIO_SCAN_EL_TYPE_UNSIGNED,
		.int_vref_mv = 2500,
		},
		};

		static int __devinit ad7887_probe(struct spi_device *spi)
		{
		struct ad7887_platform_data *pdata = spi->dev.platform_data;
		struct ad7887_state *st;
		int ret, voltage_uv = 0;

		st = kzalloc(sizeof(*st), GFP_KERNEL);
		if (st == NULL) {
		ret = -ENOMEM;
		goto error_ret;
		}

		st->reg = regulator_get(&spi->dev, "vcc");
		if (!IS_ERR(st->reg)) {
		ret = regulator_enable(st->reg);
		if (ret)
		goto error_put_reg;

		voltage_uv = regulator_get_voltage(st->reg);
		}

		st->chip_info =
		&ad7887_chip_info_tbl[spi_get_device_id(spi)->driver_data];

		spi_set_drvdata(spi, st);

		atomic_set(&st->protect_ring, 0);
		st->spi = spi;

		st->indio_dev = iio_allocate_device();
		if (st->indio_dev == NULL) {
		ret = -ENOMEM;
		goto error_disable_reg;
		}

		/* Estabilish that the iio_dev is a child of the spi device */
		st->indio_dev->dev.parent = &spi->dev;
		st->indio_dev->attrs = &ad7887_attribute_group;
		st->indio_dev->dev_data = (void *)(st);
		st->indio_dev->driver_module = THIS_MODULE;
		st->indio_dev->modes = INDIO_DIRECT_MODE;

		/* Setup default message */

		st->tx_cmd_buf[0] = AD7887_CH_AIN0 \| AD7887_PM_MODE4 \|
		((pdata && pdata->use_onchip_ref) ?
		0 : AD7887_REF_DIS);

		st->xfer[0].rx_buf = &st->data[0];
		st->xfer[0].tx_buf = &st->tx_cmd_buf[0];
		st->xfer[0].len = 2;

		spi_message_init(&st->msg[AD7887_CH0]);
		spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]);

		if (pdata && pdata->en_dual) {
		st->tx_cmd_buf[0] \|= AD7887_DUAL \| AD7887_REF_DIS;

		st->tx_cmd_buf[2] = AD7887_CH_AIN1 \| AD7887_DUAL \|
		AD7887_REF_DIS \| AD7887_PM_MODE4;
		st->tx_cmd_buf[4] = AD7887_CH_AIN0 \| AD7887_DUAL \|
		AD7887_REF_DIS \| AD7887_PM_MODE4;
		st->tx_cmd_buf[6] = AD7887_CH_AIN1 \| AD7887_DUAL \|
		AD7887_REF_DIS \| AD7887_PM_MODE4;

		st->xfer[1].rx_buf = &st->data[0];
		st->xfer[1].tx_buf = &st->tx_cmd_buf[2];
		st->xfer[1].len = 2;

		st->xfer[2].rx_buf = &st->data[2];
		st->xfer[2].tx_buf = &st->tx_cmd_buf[4];
		st->xfer[2].len = 2;

		spi_message_init(&st->msg[AD7887_CH0_CH1]);
		spi_message_add_tail(&st->xfer[1], &st->msg[AD7887_CH0_CH1]);
		spi_message_add_tail(&st->xfer[2], &st->msg[AD7887_CH0_CH1]);

		st->xfer[3].rx_buf = &st->data[0];
		st->xfer[3].tx_buf = &st->tx_cmd_buf[6];
		st->xfer[3].len = 2;

		spi_message_init(&st->msg[AD7887_CH1]);
		spi_message_add_tail(&st->xfer[3], &st->msg[AD7887_CH1]);

		st->en_dual = true;

		if (pdata && pdata->vref_mv)
		st->int_vref_mv = pdata->vref_mv;
		else if (voltage_uv)
		st->int_vref_mv = voltage_uv / 1000;
		else
		dev_warn(&spi->dev, "reference voltage unspecified\n");

		} else {
		if (pdata && pdata->vref_mv)
		st->int_vref_mv = pdata->vref_mv;
		else if (pdata && pdata->use_onchip_ref)
		st->int_vref_mv = st->chip_info->int_vref_mv;
		else
		dev_warn(&spi->dev, "reference voltage unspecified\n");
		}


		ret = ad7887_register_ring_funcs_and_init(st->indio_dev);
		if (ret)
		goto error_free_device;

		ret = iio_device_register(st->indio_dev);
		if (ret)
		goto error_free_device;

		ret = iio_ring_buffer_register(st->indio_dev->ring, 0);
		if (ret)
		goto error_cleanup_ring;
		return 0;

		error_cleanup_ring:
		ad7887_ring_cleanup(st->indio_dev);
		iio_device_unregister(st->indio_dev);
		error_free_device:
		iio_free_device(st->indio_dev);
		error_disable_reg:
		if (!IS_ERR(st->reg))
		regulator_disable(st->reg);
		error_put_reg:
		if (!IS_ERR(st->reg))
		regulator_put(st->reg);
		kfree(st);
		error_ret:
		return ret;
		}

		static int ad7887_remove(struct spi_device *spi)
		{
		struct ad7887_state *st = spi_get_drvdata(spi);
		struct iio_dev *indio_dev = st->indio_dev;
		iio_ring_buffer_unregister(indio_dev->ring);
		ad7887_ring_cleanup(indio_dev);
		iio_device_unregister(indio_dev);
		if (!IS_ERR(st->reg)) {
		regulator_disable(st->reg);
		regulator_put(st->reg);
		}
		kfree(st);
		return 0;
		}

		static const struct spi_device_id ad7887_id[] = {
		{"ad7887", ID_AD7887},
		{}
		};

		static struct spi_driver ad7887_driver = {
		.driver = {
		.name = "ad7887",
		.bus = &spi_bus_type,
		.owner = THIS_MODULE,
		},
		.probe = ad7887_probe,
		.remove = __devexit_p(ad7887_remove),
		.id_table = ad7887_id,
		};

		static int __init ad7887_init(void)
		{
		return spi_register_driver(&ad7887_driver);
		}
		module_init(ad7887_init);

		static void __exit ad7887_exit(void)
		{
		spi_unregister_driver(&ad7887_driver);
		}
		module_exit(ad7887_exit);

		MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
		MODULE_DESCRIPTION("Analog Devices AD7887 ADC");
		MODULE_LICENSE("GPL v2");
		MODULE_ALIAS("spi:ad7887");

drivers/staging/iio/adc/ad7887_ring.c

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Original line number	Diff line number	Diff line
		/*
		* Copyright 2010 Analog Devices Inc.
		* Copyright (C) 2008 Jonathan Cameron
		*
		* Licensed under the GPL-2 or later.
		*
		* ad7887_ring.c
		*/

		#include <linux/interrupt.h>
		#include <linux/gpio.h>
		#include <linux/workqueue.h>
		#include <linux/device.h>
		#include <linux/kernel.h>
		#include <linux/slab.h>
		#include <linux/sysfs.h>
		#include <linux/list.h>
		#include <linux/spi/spi.h>

		#include "../iio.h"
		#include "../ring_generic.h"
		#include "../ring_sw.h"
		#include "../trigger.h"
		#include "../sysfs.h"

		#include "ad7887.h"

		static IIO_SCAN_EL_C(in0, 0, 0, NULL);
		static IIO_SCAN_EL_C(in1, 1, 0, NULL);

		static ssize_t ad7887_show_type(struct device *dev,
		struct device_attribute *attr,
		char *buf)
		{
		struct iio_ring_buffer *ring = dev_get_drvdata(dev);
		struct iio_dev *indio_dev = ring->indio_dev;
		struct ad7887_state *st = indio_dev->dev_data;

		return sprintf(buf, "%c%d/%d>>%d\n", st->chip_info->sign,
		st->chip_info->bits, st->chip_info->storagebits,
		st->chip_info->left_shift);
		}
		static IIO_DEVICE_ATTR(in_type, S_IRUGO, ad7887_show_type, NULL, 0);

		static struct attribute *ad7887_scan_el_attrs[] = {
		&iio_scan_el_in0.dev_attr.attr,
		&iio_const_attr_in0_index.dev_attr.attr,
		&iio_scan_el_in1.dev_attr.attr,
		&iio_const_attr_in1_index.dev_attr.attr,
		&iio_dev_attr_in_type.dev_attr.attr,
		NULL,
		};

		static mode_t ad7887_scan_el_attr_is_visible(struct kobject *kobj,
		struct attribute *attr, int n)
		{
		struct device *dev = container_of(kobj, struct device, kobj);
		struct iio_ring_buffer *ring = dev_get_drvdata(dev);
		struct iio_dev *indio_dev = ring->indio_dev;
		struct ad7887_state *st = indio_dev->dev_data;

		mode_t mode = attr->mode;

		if ((attr == &iio_scan_el_in1.dev_attr.attr) \|\|
		(attr == &iio_const_attr_in1_index.dev_attr.attr))
		if (!st->en_dual)
		mode = 0;

		return mode;
		}

		static struct attribute_group ad7887_scan_el_group = {
		.name = "scan_elements",
		.attrs = ad7887_scan_el_attrs,
		.is_visible = ad7887_scan_el_attr_is_visible,
		};

		int ad7887_scan_from_ring(struct ad7887_state *st, long mask)
		{
		struct iio_ring_buffer *ring = st->indio_dev->ring;
		int count = 0, ret;
		u16 *ring_data;

		if (!(ring->scan_mask & mask)) {
		ret = -EBUSY;
		goto error_ret;
		}

		ring_data = kmalloc(ring->access.get_bytes_per_datum(ring), GFP_KERNEL);
		if (ring_data == NULL) {
		ret = -ENOMEM;
		goto error_ret;
		}
		ret = ring->access.read_last(ring, (u8 *) ring_data);
		if (ret)
		goto error_free_ring_data;

		/* for single channel scan the result is stored with zero offset */
		if ((ring->scan_mask == ((1 << 1) \| (1 << 0))) && (mask == (1 << 1)))
		count = 1;

		ret = be16_to_cpu(ring_data[count]);

		error_free_ring_data:
		kfree(ring_data);
		error_ret:
		return ret;
		}

		/**
		* ad7887_ring_preenable() setup the parameters of the ring before enabling
		*
		* The complex nature of the setting of the nuber of bytes per datum is due
		* to this driver currently ensuring that the timestamp is stored at an 8
		* byte boundary.
		**/
		static int ad7887_ring_preenable(struct iio_dev *indio_dev)
		{
		struct ad7887_state *st = indio_dev->dev_data;
		struct iio_ring_buffer *ring = indio_dev->ring;
		size_t d_size;

		if (indio_dev->ring->access.set_bytes_per_datum) {
		d_size = st->chip_info->storagebits / 8 + sizeof(s64);
		if (d_size % 8)
		d_size += 8 - (d_size % 8);
		indio_dev->ring->access.set_bytes_per_datum(indio_dev->ring,
		d_size);
		}

		switch (ring->scan_mask) {
		case (1 << 0):
		st->ring_msg = &st->msg[AD7887_CH0];
		break;
		case (1 << 1):
		st->ring_msg = &st->msg[AD7887_CH1];
		/* Dummy read: push CH1 setting down to hardware */
		spi_sync(st->spi, st->ring_msg);
		break;
		case ((1 << 1) \| (1 << 0)):
		st->ring_msg = &st->msg[AD7887_CH0_CH1];
		break;
		}

		return 0;
		}

		static int ad7887_ring_postdisable(struct iio_dev *indio_dev)
		{
		struct ad7887_state *st = indio_dev->dev_data;

		/* dummy read: restore default CH0 settin */
		return spi_sync(st->spi, &st->msg[AD7887_CH0]);
		}

		/**
		* ad7887_poll_func_th() th of trigger launched polling to ring buffer
		*
		* As sampling only occurs on spi comms occuring, leave timestamping until
		* then. Some triggers will generate their own time stamp. Currently
		* there is no way of notifying them when no one cares.
		**/
		static void ad7887_poll_func_th(struct iio_dev *indio_dev, s64 time)
		{
		struct ad7887_state *st = indio_dev->dev_data;

		schedule_work(&st->poll_work);
		return;
		}
		/**
		* ad7887_poll_bh_to_ring() bh of trigger launched polling to ring buffer
		* @work_s: the work struct through which this was scheduled
		*
		* Currently there is no option in this driver to disable the saving of
		* timestamps within the ring.
		* I think the one copy of this at a time was to avoid problems if the
		* trigger was set far too high and the reads then locked up the computer.
		**/
		static void ad7887_poll_bh_to_ring(struct work_struct *work_s)
		{
		struct ad7887_state *st = container_of(work_s, struct ad7887_state,
		poll_work);
		struct iio_dev *indio_dev = st->indio_dev;
		struct iio_sw_ring_buffer *sw_ring = iio_to_sw_ring(indio_dev->ring);
		struct iio_ring_buffer *ring = indio_dev->ring;
		s64 time_ns;
		__u8 *buf;
		int b_sent;
		size_t d_size;

		unsigned int bytes = ring->scan_count * st->chip_info->storagebits / 8;

		/* Ensure the timestamp is 8 byte aligned */
		d_size = bytes + sizeof(s64);
		if (d_size % sizeof(s64))
		d_size += sizeof(s64) - (d_size % sizeof(s64));

		/* Ensure only one copy of this function running at a time */
		if (atomic_inc_return(&st->protect_ring) > 1)
		return;

		buf = kzalloc(d_size, GFP_KERNEL);
		if (buf == NULL)
		return;

		b_sent = spi_sync(st->spi, st->ring_msg);
		if (b_sent)
		goto done;

		time_ns = iio_get_time_ns();

		memcpy(buf, st->data, bytes);
		memcpy(buf + d_size - sizeof(s64), &time_ns, sizeof(time_ns));

		indio_dev->ring->access.store_to(&sw_ring->buf, buf, time_ns);
		done:
		kfree(buf);
		atomic_dec(&st->protect_ring);
		}

		int ad7887_register_ring_funcs_and_init(struct iio_dev *indio_dev)
		{
		struct ad7887_state *st = indio_dev->dev_data;
		int ret;

		indio_dev->ring = iio_sw_rb_allocate(indio_dev);
		if (!indio_dev->ring) {
		ret = -ENOMEM;
		goto error_ret;
		}
		/* Effectively select the ring buffer implementation */
		iio_ring_sw_register_funcs(&indio_dev->ring->access);
		ret = iio_alloc_pollfunc(indio_dev, NULL, &ad7887_poll_func_th);
		if (ret)
		goto error_deallocate_sw_rb;

		/* Ring buffer functions - here trigger setup related */

		indio_dev->ring->preenable = &ad7887_ring_preenable;
		indio_dev->ring->postenable = &iio_triggered_ring_postenable;
		indio_dev->ring->predisable = &iio_triggered_ring_predisable;
		indio_dev->ring->postdisable = &ad7887_ring_postdisable;
		indio_dev->ring->scan_el_attrs = &ad7887_scan_el_group;

		INIT_WORK(&st->poll_work, &ad7887_poll_bh_to_ring);

		/* Flag that polled ring buffering is possible */
		indio_dev->modes \|= INDIO_RING_TRIGGERED;
		return 0;
		error_deallocate_sw_rb:
		iio_sw_rb_free(indio_dev->ring);
		error_ret:
		return ret;
		}

		void ad7887_ring_cleanup(struct iio_dev *indio_dev)
		{
		/* ensure that the trigger has been detached */
		if (indio_dev->trig) {
		iio_put_trigger(indio_dev->trig);
		iio_trigger_dettach_poll_func(indio_dev->trig,
		indio_dev->pollfunc);
		}
		kfree(indio_dev->pollfunc);
		iio_sw_rb_free(indio_dev->ring);
		}