[deliverable/linux.git] / drivers / staging / iio / accel / sca3000_ring.c

/*
 * sca3000_ring.c -- support VTI sca3000 series accelerometers via SPI
 *
 * 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.
 *
 * Copyright (c) 2009 Jonathan Cameron <jic23@cam.ac.uk>
 *
 */

#include <linux/interrupt.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/spi/spi.h>
#include <linux/sysfs.h>
#include <linux/sched.h>
#include <linux/poll.h>

#include "../iio.h"
#include "../sysfs.h"
#include "../ring_generic.h"
#include "../ring_hw.h"
#include "sca3000.h"

/* RFC / future work
 *
 * The internal ring buffer doesn't actually change what it holds depending
 * on which signals are enabled etc, merely whether you can read them.
 * As such the scan mode selection is somewhat different than for a software
 * ring buffer and changing it actually covers any data already in the buffer.
 * Currently scan elements aren't configured so it doesn't matter.
 */

static int sca3000_read_data(struct sca3000_state *st,
			    uint8_t reg_address_high,
			    u8 **rx_p,
			    int len)
{
	int ret;
	struct spi_message msg;
	struct spi_transfer xfer[2] = {
		{
			.len = 1,
			.tx_buf = st->tx,
		}, {
			.len = len,
		}
	};
	*rx_p = kmalloc(len, GFP_KERNEL);
	if (*rx_p == NULL) {
		ret = -ENOMEM;
		goto error_ret;
	}
	xfer[1].rx_buf = *rx_p;
	st->tx[0] = SCA3000_READ_REG(reg_address_high);
	spi_message_init(&msg);
	spi_message_add_tail(&xfer[0], &msg);
	spi_message_add_tail(&xfer[1], &msg);
	ret = spi_sync(st->us, &msg);
	if (ret) {
		dev_err(get_device(&st->us->dev), "problem reading register");
		goto error_free_rx;
	}

	return 0;
error_free_rx:
	kfree(*rx_p);
error_ret:
	return ret;
}

/**
 * sca3000_read_first_n_hw_rb() - main ring access, pulls data from ring
 * @r:			the ring
 * @count:		number of samples to try and pull
 * @data:		output the actual samples pulled from the hw ring
 *
 * Currently does not provide timestamps.  As the hardware doesn't add them they
 * can only be inferred approximately from ring buffer events such as 50% full
 * and knowledge of when buffer was last emptied.  This is left to userspace.
 **/
static int sca3000_read_first_n_hw_rb(struct iio_ring_buffer *r,
				      size_t count, char __user *buf)
{
	struct iio_hw_ring_buffer *hw_ring = iio_to_hw_ring_buf(r);
	struct iio_dev *indio_dev = hw_ring->private;
	struct sca3000_state *st = iio_priv(indio_dev);
	u8 *rx;
	int ret, i, num_available, num_read = 0;
	int bytes_per_sample = 1;

	if (st->bpse == 11)
		bytes_per_sample = 2;

	mutex_lock(&st->lock);
	if (count % bytes_per_sample) {
		ret = -EINVAL;
		goto error_ret;
	}

	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_BUF_COUNT, 1);
	if (ret)
		goto error_ret;
	else
		num_available = st->rx[0];
	/*
	 * num_available is the total number of samples available
	 * i.e. number of time points * number of channels.
	 */
	if (count > num_available * bytes_per_sample)
		num_read = num_available*bytes_per_sample;
	else
		num_read = count;

	ret = sca3000_read_data(st,
				SCA3000_REG_ADDR_RING_OUT,
				&rx, num_read);
	if (ret)
		goto error_ret;

	for (i = 0; i < num_read; i++)
		*(((u16 *)rx) + i) = be16_to_cpup((u16 *)rx + i);

	if (copy_to_user(buf, rx, num_read))
		ret = -EFAULT;
	kfree(rx);
	r->stufftoread = 0;
error_ret:
	mutex_unlock(&st->lock);

	return ret ? ret : num_read;
}

/* This is only valid with all 3 elements enabled */
static int sca3000_ring_get_length(struct iio_ring_buffer *r)
{
	return 64;
}

/* only valid if resolution is kept at 11bits */
static int sca3000_ring_get_bytes_per_datum(struct iio_ring_buffer *r)
{
	return 6;
}

static IIO_RING_ENABLE_ATTR;
static IIO_RING_BYTES_PER_DATUM_ATTR;
static IIO_RING_LENGTH_ATTR;

/**
 * sca3000_query_ring_int() is the hardware ring status interrupt enabled
 **/
static ssize_t sca3000_query_ring_int(struct device *dev,
				      struct device_attribute *attr,
				      char *buf)
{
	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	int ret, val;
	struct iio_ring_buffer *ring = dev_get_drvdata(dev);
	struct iio_dev *indio_dev = ring->indio_dev;
	struct sca3000_state *st = iio_priv(indio_dev);

	mutex_lock(&st->lock);
	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_INT_MASK, 1);
	val = st->rx[0];
	mutex_unlock(&st->lock);
	if (ret)
		return ret;

	return sprintf(buf, "%d\n", !!(val & this_attr->address));
}

/**
 * sca3000_set_ring_int() set state of ring status interrupt
 **/
static ssize_t sca3000_set_ring_int(struct device *dev,
				      struct device_attribute *attr,
				      const char *buf,
				      size_t len)
{
	struct iio_ring_buffer *ring = dev_get_drvdata(dev);
	struct iio_dev *indio_dev = ring->indio_dev;
	struct sca3000_state *st = iio_priv(indio_dev);
	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	long val;
	int ret;

	mutex_lock(&st->lock);
	ret = strict_strtol(buf, 10, &val);
	if (ret)
		goto error_ret;
	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_INT_MASK, 1);
	if (ret)
		goto error_ret;
	if (val)
		ret = sca3000_write_reg(st,
					SCA3000_REG_ADDR_INT_MASK,
					st->rx[0] | this_attr->address);
	else
		ret = sca3000_write_reg(st,
					SCA3000_REG_ADDR_INT_MASK,
					st->rx[0] & ~this_attr->address);
error_ret:
	mutex_unlock(&st->lock);

	return ret ? ret : len;
}

static IIO_DEVICE_ATTR(50_percent, S_IRUGO | S_IWUSR,
		       sca3000_query_ring_int,
		       sca3000_set_ring_int,
		       SCA3000_INT_MASK_RING_HALF);

static IIO_DEVICE_ATTR(75_percent, S_IRUGO | S_IWUSR,
		       sca3000_query_ring_int,
		       sca3000_set_ring_int,
		       SCA3000_INT_MASK_RING_THREE_QUARTER);

static ssize_t sca3000_show_buffer_scale(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 sca3000_state *st = iio_priv(indio_dev);

	return sprintf(buf, "0.%06d\n", 4*st->info->scale);
}

static IIO_DEVICE_ATTR(accel_scale,
		       S_IRUGO,
		       sca3000_show_buffer_scale,
		       NULL,
		       0);

/*
 * Ring buffer attributes
 * This device is a bit unusual in that the sampling frequency and bpse
 * only apply to the ring buffer.  At all times full rate and accuracy
 * is available via direct reading from registers.
 */
static struct attribute *sca3000_ring_attributes[] = {
	&dev_attr_length.attr,
	&dev_attr_bytes_per_datum.attr,
	&dev_attr_enable.attr,
	&iio_dev_attr_50_percent.dev_attr.attr,
	&iio_dev_attr_75_percent.dev_attr.attr,
	&iio_dev_attr_accel_scale.dev_attr.attr,
	NULL,
};

static struct attribute_group sca3000_ring_attr = {
	.attrs = sca3000_ring_attributes,
	.name = "buffer",
};

static struct iio_ring_buffer *sca3000_rb_allocate(struct iio_dev *indio_dev)
{
	struct iio_ring_buffer *buf;
	struct iio_hw_ring_buffer *ring;

	ring = kzalloc(sizeof *ring, GFP_KERNEL);
	if (!ring)
		return NULL;

	ring->private = indio_dev;
	buf = &ring->buf;
	buf->stufftoread = 0;
	buf->attrs = &sca3000_ring_attr;
	iio_ring_buffer_init(buf, indio_dev);

	return buf;
}

static inline void sca3000_rb_free(struct iio_ring_buffer *r)
{
	kfree(iio_to_hw_ring_buf(r));
}

static const struct iio_ring_access_funcs sca3000_ring_access_funcs = {
	.read_first_n = &sca3000_read_first_n_hw_rb,
	.get_length = &sca3000_ring_get_length,
	.get_bytes_per_datum = &sca3000_ring_get_bytes_per_datum,
};

int sca3000_configure_ring(struct iio_dev *indio_dev)
{
	indio_dev->ring = sca3000_rb_allocate(indio_dev);
	if (indio_dev->ring == NULL)
		return -ENOMEM;
	indio_dev->modes |= INDIO_RING_HARDWARE_BUFFER;

	indio_dev->ring->access = &sca3000_ring_access_funcs;

	iio_scan_mask_set(indio_dev->ring, 0);
	iio_scan_mask_set(indio_dev->ring, 1);
	iio_scan_mask_set(indio_dev->ring, 2);

	return 0;
}

void sca3000_unconfigure_ring(struct iio_dev *indio_dev)
{
	sca3000_rb_free(indio_dev->ring);
}

static inline
int __sca3000_hw_ring_state_set(struct iio_dev *indio_dev, bool state)
{
	struct sca3000_state *st = iio_priv(indio_dev);
	int ret;

	mutex_lock(&st->lock);
	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
	if (ret)
		goto error_ret;
	if (state) {
		printk(KERN_INFO "supposedly enabling ring buffer\n");
		ret = sca3000_write_reg(st,
					SCA3000_REG_ADDR_MODE,
					(st->rx[0] | SCA3000_RING_BUF_ENABLE));
	} else
		ret = sca3000_write_reg(st,
					SCA3000_REG_ADDR_MODE,
					(st->rx[0] & ~SCA3000_RING_BUF_ENABLE));
error_ret:
	mutex_unlock(&st->lock);

	return ret;
}
/**
 * sca3000_hw_ring_preenable() hw ring buffer preenable function
 *
 * Very simple enable function as the chip will allows normal reads
 * during ring buffer operation so as long as it is indeed running
 * before we notify the core, the precise ordering does not matter.
 **/
static int sca3000_hw_ring_preenable(struct iio_dev *indio_dev)
{
	return __sca3000_hw_ring_state_set(indio_dev, 1);
}

static int sca3000_hw_ring_postdisable(struct iio_dev *indio_dev)
{
	return __sca3000_hw_ring_state_set(indio_dev, 0);
}

static const struct iio_ring_setup_ops sca3000_ring_setup_ops = {
	.preenable = &sca3000_hw_ring_preenable,
	.postdisable = &sca3000_hw_ring_postdisable,
};

void sca3000_register_ring_funcs(struct iio_dev *indio_dev)
{
	indio_dev->ring->setup_ops = &sca3000_ring_setup_ops;
}

/**
 * sca3000_ring_int_process() ring specific interrupt handling.
 *
 * This is only split from the main interrupt handler so as to
 * reduce the amount of code if the ring buffer is not enabled.
 **/
void sca3000_ring_int_process(u8 val, struct iio_ring_buffer *ring)
{
	if (val & (SCA3000_INT_STATUS_THREE_QUARTERS |
		   SCA3000_INT_STATUS_HALF)) {
		ring->stufftoread = true;
		wake_up_interruptible(&ring->pollq);
	}
}
Commit	Line	Data
574fb258 JC	1	/*
	2	* sca3000_ring.c -- support VTI sca3000 series accelerometers via SPI
	3	*
	4	* This program is free software; you can redistribute it and/or modify it
	5	* under the terms of the GNU General Public License version 2 as published by
	6	* the Free Software Foundation.
	7	*
	8	* Copyright (c) 2009 Jonathan Cameron <jic23@cam.ac.uk>
	9	*
	10	*/
	11
	12	#include <linux/interrupt.h>
574fb258	13	#include <linux/fs.h>
5a0e3ad6	14	#include <linux/slab.h>
574fb258 JC	15	#include <linux/kernel.h>
	16	#include <linux/spi/spi.h>
	17	#include <linux/sysfs.h>
25888dc5 JC	18	#include <linux/sched.h>
25888dc5 JC	19	#include <linux/poll.h>
574fb258 JC	20
	21	#include "../iio.h"
	22	#include "../sysfs.h"
	23	#include "../ring_generic.h"
	24	#include "../ring_hw.h"
574fb258 JC	25	#include "sca3000.h"
	26
	27	/* RFC / future work
	28	*
	29	* The internal ring buffer doesn't actually change what it holds depending
	30	* on which signals are enabled etc, merely whether you can read them.
	31	* As such the scan mode selection is somewhat different than for a software
	32	* ring buffer and changing it actually covers any data already in the buffer.
	33	* Currently scan elements aren't configured so it doesn't matter.
	34	*/
	35
25888dc5 JC	36	static int sca3000_read_data(struct sca3000_state *st,
	37	uint8_t reg_address_high,
	38	u8 **rx_p,
	39	int len)
	40	{
	41	int ret;
	42	struct spi_message msg;
	43	struct spi_transfer xfer[2] = {
	44	{
	45	.len = 1,
	46	.tx_buf = st->tx,
	47	}, {
	48	.len = len,
	49	}
	50	};
	51	*rx_p = kmalloc(len, GFP_KERNEL);
	52	if (*rx_p == NULL) {
	53	ret = -ENOMEM;
	54	goto error_ret;
	55	}
	56	xfer[1].rx_buf = *rx_p;
	57	st->tx[0] = SCA3000_READ_REG(reg_address_high);
	58	spi_message_init(&msg);
	59	spi_message_add_tail(&xfer[0], &msg);
	60	spi_message_add_tail(&xfer[1], &msg);
	61	ret = spi_sync(st->us, &msg);
	62	if (ret) {
	63	dev_err(get_device(&st->us->dev), "problem reading register");
	64	goto error_free_rx;
	65	}
	66
	67	return 0;
	68	error_free_rx:
	69	kfree(*rx_p);
	70	error_ret:
	71	return ret;
	72	}
	73
574fb258	74	/**
b4281733	75	* sca3000_read_first_n_hw_rb() - main ring access, pulls data from ring
574fb258 JC	76	* @r: the ring
	77	* @count: number of samples to try and pull
	78	* @data: output the actual samples pulled from the hw ring
574fb258 JC	79	*
574fb258 JC	80	* Currently does not provide timestamps. As the hardware doesn't add them they
25985edc	81	* can only be inferred approximately from ring buffer events such as 50% full
574fb258 JC	82	* and knowledge of when buffer was last emptied. This is left to userspace.
574fb258 JC	83	**/
b4281733	84	static int sca3000_read_first_n_hw_rb(struct iio_ring_buffer *r,
b26a2188	85	size_t count, char __user *buf)
574fb258 JC	86	{
	87	struct iio_hw_ring_buffer *hw_ring = iio_to_hw_ring_buf(r);
	88	struct iio_dev *indio_dev = hw_ring->private;
83f0422d	89	struct sca3000_state *st = iio_priv(indio_dev);
574fb258	90	u8 *rx;
6267ea65	91	int ret, i, num_available, num_read = 0;
574fb258 JC	92	int bytes_per_sample = 1;
	93
	94	if (st->bpse == 11)
	95	bytes_per_sample = 2;
	96
	97	mutex_lock(&st->lock);
25888dc5 JC	98	if (count % bytes_per_sample) {
	99	ret = -EINVAL;
	100	goto error_ret;
	101	}
	102
	103	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_BUF_COUNT, 1);
574fb258 JC	104	if (ret)
	105	goto error_ret;
	106	else
25888dc5 JC	107	num_available = st->rx[0];
	108	/*
	109	* num_available is the total number of samples available
574fb258 JC	110	* i.e. number of time points * number of channels.
574fb258 JC	111	*/
574fb258 JC	112	if (count > num_available * bytes_per_sample)
	113	num_read = num_available*bytes_per_sample;
	114	else
25888dc5	115	num_read = count;
574fb258	116
574fb258 JC	117	ret = sca3000_read_data(st,
574fb258 JC	118	SCA3000_REG_ADDR_RING_OUT,
25888dc5 JC	119	&rx, num_read);
	120	if (ret)
	121	goto error_ret;
	122
	123	for (i = 0; i < num_read; i++)
	124	(((u16 )rx) + i) = be16_to_cpup((u16 *)rx + i);
6267ea65	125
25888dc5 JC	126	if (copy_to_user(buf, rx, num_read))
	127	ret = -EFAULT;
	128	kfree(rx);
	129	r->stufftoread = 0;
574fb258 JC	130	error_ret:
	131	mutex_unlock(&st->lock);
	132
	133	return ret ? ret : num_read;
	134	}
	135
	136	/* This is only valid with all 3 elements enabled */
	137	static int sca3000_ring_get_length(struct iio_ring_buffer *r)
	138	{
	139	return 64;
	140	}
	141
	142	/* only valid if resolution is kept at 11bits */
ffcab07a	143	static int sca3000_ring_get_bytes_per_datum(struct iio_ring_buffer *r)
574fb258 JC	144	{
	145	return 6;
	146	}
574fb258 JC	147
574fb258 JC	148	static IIO_RING_ENABLE_ATTR;
ffcab07a	149	static IIO_RING_BYTES_PER_DATUM_ATTR;
574fb258 JC	150	static IIO_RING_LENGTH_ATTR;
574fb258 JC	151
25888dc5 JC	152	/**
	153	* sca3000_query_ring_int() is the hardware ring status interrupt enabled
	154	**/
	155	static ssize_t sca3000_query_ring_int(struct device *dev,
	156	struct device_attribute *attr,
	157	char *buf)
	158	{
	159	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	160	int ret, val;
	161	struct iio_ring_buffer *ring = dev_get_drvdata(dev);
	162	struct iio_dev *indio_dev = ring->indio_dev;
83f0422d	163	struct sca3000_state *st = iio_priv(indio_dev);
25888dc5 JC	164
	165	mutex_lock(&st->lock);
	166	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_INT_MASK, 1);
	167	val = st->rx[0];
	168	mutex_unlock(&st->lock);
	169	if (ret)
	170	return ret;
	171
	172	return sprintf(buf, "%d\n", !!(val & this_attr->address));
	173	}
	174
	175	/**
	176	* sca3000_set_ring_int() set state of ring status interrupt
	177	**/
	178	static ssize_t sca3000_set_ring_int(struct device *dev,
	179	struct device_attribute *attr,
	180	const char *buf,
	181	size_t len)
	182	{
	183	struct iio_ring_buffer *ring = dev_get_drvdata(dev);
	184	struct iio_dev *indio_dev = ring->indio_dev;
83f0422d	185	struct sca3000_state *st = iio_priv(indio_dev);
25888dc5 JC	186	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	187	long val;
	188	int ret;
	189
	190	mutex_lock(&st->lock);
	191	ret = strict_strtol(buf, 10, &val);
	192	if (ret)
	193	goto error_ret;
	194	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_INT_MASK, 1);
	195	if (ret)
	196	goto error_ret;
	197	if (val)
	198	ret = sca3000_write_reg(st,
	199	SCA3000_REG_ADDR_INT_MASK,
	200	st->rx[0] \| this_attr->address);
	201	else
	202	ret = sca3000_write_reg(st,
	203	SCA3000_REG_ADDR_INT_MASK,
	204	st->rx[0] & ~this_attr->address);
	205	error_ret:
	206	mutex_unlock(&st->lock);
	207
	208	return ret ? ret : len;
	209	}
	210
	211	static IIO_DEVICE_ATTR(50_percent, S_IRUGO \| S_IWUSR,
	212	sca3000_query_ring_int,
	213	sca3000_set_ring_int,
	214	SCA3000_INT_MASK_RING_HALF);
	215
	216	static IIO_DEVICE_ATTR(75_percent, S_IRUGO \| S_IWUSR,
	217	sca3000_query_ring_int,
	218	sca3000_set_ring_int,
	219	SCA3000_INT_MASK_RING_THREE_QUARTER);
	220
25888dc5 JC	221	static ssize_t sca3000_show_buffer_scale(struct device *dev,
	222	struct device_attribute *attr,
	223	char *buf)
	224	{
	225	struct iio_ring_buffer *ring = dev_get_drvdata(dev);
	226	struct iio_dev *indio_dev = ring->indio_dev;
83f0422d	227	struct sca3000_state *st = iio_priv(indio_dev);
574fb258	228
25888dc5 JC	229	return sprintf(buf, "0.%06d\n", 4*st->info->scale);
25888dc5 JC	230	}
f3fb0011	231
25888dc5 JC	232	static IIO_DEVICE_ATTR(accel_scale,
	233	S_IRUGO,
	234	sca3000_show_buffer_scale,
	235	NULL,
	236	0);
574fb258 JC	237
	238	/*
	239	* Ring buffer attributes
	240	* This device is a bit unusual in that the sampling frequency and bpse
	241	* only apply to the ring buffer. At all times full rate and accuracy
	242	* is available via direct reading from registers.
	243	*/
f3fb0011	244	static struct attribute *sca3000_ring_attributes[] = {
574fb258	245	&dev_attr_length.attr,
ffcab07a MS	246	&dev_attr_bytes_per_datum.attr,
ffcab07a MS	247	&dev_attr_enable.attr,
25888dc5 JC	248	&iio_dev_attr_50_percent.dev_attr.attr,
	249	&iio_dev_attr_75_percent.dev_attr.attr,
	250	&iio_dev_attr_accel_scale.dev_attr.attr,
574fb258 JC	251	NULL,
	252	};
	253
	254	static struct attribute_group sca3000_ring_attr = {
f3fb0011	255	.attrs = sca3000_ring_attributes,
1aa04278	256	.name = "buffer",
574fb258 JC	257	};
	258
	259	static struct iio_ring_buffer sca3000_rb_allocate(struct iio_dev indio_dev)
	260	{
	261	struct iio_ring_buffer *buf;
	262	struct iio_hw_ring_buffer *ring;
	263
	264	ring = kzalloc(sizeof *ring, GFP_KERNEL);
	265	if (!ring)
7cfce527	266	return NULL;
25888dc5	267
574fb258 JC	268	ring->private = indio_dev;
574fb258 JC	269	buf = &ring->buf;
25888dc5	270	buf->stufftoread = 0;
1aa04278	271	buf->attrs = &sca3000_ring_attr;
574fb258	272	iio_ring_buffer_init(buf, indio_dev);
574fb258 JC	273
	274	return buf;
	275	}
	276
	277	static inline void sca3000_rb_free(struct iio_ring_buffer *r)
	278	{
1aa04278	279	kfree(iio_to_hw_ring_buf(r));
574fb258 JC	280	}
574fb258 JC	281
5565a450 JC	282	static const struct iio_ring_access_funcs sca3000_ring_access_funcs = {
	283	.read_first_n = &sca3000_read_first_n_hw_rb,
	284	.get_length = &sca3000_ring_get_length,
	285	.get_bytes_per_datum = &sca3000_ring_get_bytes_per_datum,
	286	};
	287
574fb258 JC	288	int sca3000_configure_ring(struct iio_dev *indio_dev)
	289	{
	290	indio_dev->ring = sca3000_rb_allocate(indio_dev);
	291	if (indio_dev->ring == NULL)
	292	return -ENOMEM;
	293	indio_dev->modes \|= INDIO_RING_HARDWARE_BUFFER;
	294
5565a450	295	indio_dev->ring->access = &sca3000_ring_access_funcs;
25888dc5 JC	296
	297	iio_scan_mask_set(indio_dev->ring, 0);
	298	iio_scan_mask_set(indio_dev->ring, 1);
	299	iio_scan_mask_set(indio_dev->ring, 2);
574fb258 JC	300
	301	return 0;
	302	}
	303
	304	void sca3000_unconfigure_ring(struct iio_dev *indio_dev)
	305	{
	306	sca3000_rb_free(indio_dev->ring);
	307	}
	308
	309	static inline
	310	int __sca3000_hw_ring_state_set(struct iio_dev *indio_dev, bool state)
	311	{
83f0422d	312	struct sca3000_state *st = iio_priv(indio_dev);
574fb258	313	int ret;
574fb258 JC	314
574fb258 JC	315	mutex_lock(&st->lock);
25888dc5	316	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
574fb258 JC	317	if (ret)
	318	goto error_ret;
	319	if (state) {
	320	printk(KERN_INFO "supposedly enabling ring buffer\n");
	321	ret = sca3000_write_reg(st,
	322	SCA3000_REG_ADDR_MODE,
25888dc5	323	(st->rx[0] \| SCA3000_RING_BUF_ENABLE));
574fb258 JC	324	} else
	325	ret = sca3000_write_reg(st,
	326	SCA3000_REG_ADDR_MODE,
25888dc5	327	(st->rx[0] & ~SCA3000_RING_BUF_ENABLE));
574fb258 JC	328	error_ret:
	329	mutex_unlock(&st->lock);
	330
	331	return ret;
	332	}
	333	/**
	334	* sca3000_hw_ring_preenable() hw ring buffer preenable function
	335	*
	336	* Very simple enable function as the chip will allows normal reads
	337	* during ring buffer operation so as long as it is indeed running
	338	* before we notify the core, the precise ordering does not matter.
	339	**/
	340	static int sca3000_hw_ring_preenable(struct iio_dev *indio_dev)
	341	{
	342	return __sca3000_hw_ring_state_set(indio_dev, 1);
	343	}
	344
	345	static int sca3000_hw_ring_postdisable(struct iio_dev *indio_dev)
	346	{
	347	return __sca3000_hw_ring_state_set(indio_dev, 0);
	348	}
	349
5565a450 JC	350	static const struct iio_ring_setup_ops sca3000_ring_setup_ops = {
	351	.preenable = &sca3000_hw_ring_preenable,
	352	.postdisable = &sca3000_hw_ring_postdisable,
	353	};
	354
574fb258 JC	355	void sca3000_register_ring_funcs(struct iio_dev *indio_dev)
574fb258 JC	356	{
5565a450	357	indio_dev->ring->setup_ops = &sca3000_ring_setup_ops;
574fb258 JC	358	}
	359
	360	/**
	361	* sca3000_ring_int_process() ring specific interrupt handling.
	362	*
	363	* This is only split from the main interrupt handler so as to
	364	* reduce the amount of code if the ring buffer is not enabled.
	365	**/
	366	void sca3000_ring_int_process(u8 val, struct iio_ring_buffer *ring)
	367	{
25888dc5 JC	368	if (val & (SCA3000_INT_STATUS_THREE_QUARTERS \|
	369	SCA3000_INT_STATUS_HALF)) {
	370	ring->stufftoread = true;
	371	wake_up_interruptible(&ring->pollq);
	372	}
574fb258	373	}