[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@kernel.org>
 *
 */

#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 <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.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_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);
	ret = spi_sync_transfer(st->us, xfer, ARRAY_SIZE(xfer));
	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_buffer *r,
				      size_t count, char __user *buf)
{
	struct iio_hw_buffer *hw_ring = iio_to_hw_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_buffer *r)
{
	return 64;
}

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

static bool sca3000_ring_buf_data_available(struct iio_buffer *r)
{
	return r->stufftoread;
}

static IIO_BUFFER_ENABLE_ATTR;
static IIO_BUFFER_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_dev *indio_dev = dev_to_iio_dev(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_dev *indio_dev = dev_to_iio_dev(dev);
	struct sca3000_state *st = iio_priv(indio_dev);
	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	u8 val;
	int ret;

	mutex_lock(&st->lock);
	ret = kstrtou8(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_dev *indio_dev = dev_to_iio_dev(dev);
	struct sca3000_state *st = iio_priv(indio_dev);

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

static IIO_DEVICE_ATTR(in_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_enable.attr,
	&iio_dev_attr_50_percent.dev_attr.attr,
	&iio_dev_attr_75_percent.dev_attr.attr,
	&iio_dev_attr_in_accel_scale.dev_attr.attr,
	NULL,
};

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

static struct iio_buffer *sca3000_rb_allocate(struct iio_dev *indio_dev)
{
	struct iio_buffer *buf;
	struct iio_hw_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_buffer_init(buf);

	return buf;
}

static void sca3000_ring_release(struct iio_buffer *r)
{
	kfree(iio_to_hw_buf(r));
}

static const struct iio_buffer_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,
	.data_available = sca3000_ring_buf_data_available,
	.release = sca3000_ring_release,
};

int sca3000_configure_ring(struct iio_dev *indio_dev)
{
	struct iio_buffer *buffer;

	buffer = sca3000_rb_allocate(indio_dev);
	if (buffer == NULL)
		return -ENOMEM;
	indio_dev->modes |= INDIO_BUFFER_HARDWARE;

	indio_dev->buffer->access = &sca3000_ring_access_funcs;

	iio_device_attach_buffer(indio_dev, buffer);

	return 0;
}

void sca3000_unconfigure_ring(struct iio_dev *indio_dev)
{
	iio_buffer_put(indio_dev->buffer);
}

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) {
		dev_info(&indio_dev->dev, "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_buffer_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->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_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	*
0f8c9620	8	* Copyright (c) 2009 Jonathan Cameron <jic23@kernel.org>
574fb258 JC	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	20
06458e27 JC	21	#include <linux/iio/iio.h>
	22	#include <linux/iio/sysfs.h>
	23	#include <linux/iio/buffer.h>
574fb258	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;
25888dc5 JC	42	struct spi_transfer xfer[2] = {
	43	{
	44	.len = 1,
	45	.tx_buf = st->tx,
	46	}, {
	47	.len = len,
	48	}
	49	};
	50	*rx_p = kmalloc(len, GFP_KERNEL);
	51	if (*rx_p == NULL) {
	52	ret = -ENOMEM;
	53	goto error_ret;
	54	}
	55	xfer[1].rx_buf = *rx_p;
	56	st->tx[0] = SCA3000_READ_REG(reg_address_high);
ad6c46b0	57	ret = spi_sync_transfer(st->us, xfer, ARRAY_SIZE(xfer));
25888dc5 JC	58	if (ret) {
	59	dev_err(get_device(&st->us->dev), "problem reading register");
	60	goto error_free_rx;
	61	}
	62
	63	return 0;
	64	error_free_rx:
	65	kfree(*rx_p);
	66	error_ret:
	67	return ret;
	68	}
	69
574fb258	70	/**
b4281733	71	* sca3000_read_first_n_hw_rb() - main ring access, pulls data from ring
574fb258 JC	72	* @r: the ring
	73	* @count: number of samples to try and pull
	74	* @data: output the actual samples pulled from the hw ring
574fb258 JC	75	*
574fb258 JC	76	* Currently does not provide timestamps. As the hardware doesn't add them they
25985edc	77	* can only be inferred approximately from ring buffer events such as 50% full
574fb258 JC	78	* and knowledge of when buffer was last emptied. This is left to userspace.
574fb258 JC	79	**/
14555b14	80	static int sca3000_read_first_n_hw_rb(struct iio_buffer *r,
b26a2188	81	size_t count, char __user *buf)
574fb258	82	{
14555b14	83	struct iio_hw_buffer *hw_ring = iio_to_hw_buf(r);
574fb258	84	struct iio_dev *indio_dev = hw_ring->private;
83f0422d	85	struct sca3000_state *st = iio_priv(indio_dev);
574fb258	86	u8 *rx;
6267ea65	87	int ret, i, num_available, num_read = 0;
574fb258 JC	88	int bytes_per_sample = 1;
	89
	90	if (st->bpse == 11)
	91	bytes_per_sample = 2;
	92
	93	mutex_lock(&st->lock);
25888dc5 JC	94	if (count % bytes_per_sample) {
	95	ret = -EINVAL;
	96	goto error_ret;
	97	}
	98
	99	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_BUF_COUNT, 1);
574fb258 JC	100	if (ret)
	101	goto error_ret;
	102	else
25888dc5 JC	103	num_available = st->rx[0];
	104	/*
	105	* num_available is the total number of samples available
574fb258 JC	106	* i.e. number of time points * number of channels.
574fb258 JC	107	*/
574fb258 JC	108	if (count > num_available * bytes_per_sample)
	109	num_read = num_available*bytes_per_sample;
	110	else
25888dc5	111	num_read = count;
574fb258	112
574fb258 JC	113	ret = sca3000_read_data(st,
574fb258 JC	114	SCA3000_REG_ADDR_RING_OUT,
25888dc5 JC	115	&rx, num_read);
	116	if (ret)
	117	goto error_ret;
	118
	119	for (i = 0; i < num_read; i++)
	120	(((u16 )rx) + i) = be16_to_cpup((u16 *)rx + i);
6267ea65	121
25888dc5 JC	122	if (copy_to_user(buf, rx, num_read))
	123	ret = -EFAULT;
	124	kfree(rx);
	125	r->stufftoread = 0;
574fb258 JC	126	error_ret:
	127	mutex_unlock(&st->lock);
	128
	129	return ret ? ret : num_read;
	130	}
	131
	132	/* This is only valid with all 3 elements enabled */
14555b14	133	static int sca3000_ring_get_length(struct iio_buffer *r)
574fb258 JC	134	{
	135	return 64;
	136	}
	137
	138	/* only valid if resolution is kept at 11bits */
14555b14	139	static int sca3000_ring_get_bytes_per_datum(struct iio_buffer *r)
574fb258 JC	140	{
	141	return 6;
	142	}
574fb258	143
9dd4694d JC	144	static bool sca3000_ring_buf_data_available(struct iio_buffer *r)
	145	{
	146	return r->stufftoread;
	147	}
	148
14555b14	149	static IIO_BUFFER_ENABLE_ATTR;
14555b14	150	static IIO_BUFFER_LENGTH_ATTR;
574fb258	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;
4b522ce7	161	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
83f0422d	162	struct sca3000_state *st = iio_priv(indio_dev);
25888dc5 JC	163
	164	mutex_lock(&st->lock);
	165	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_INT_MASK, 1);
	166	val = st->rx[0];
	167	mutex_unlock(&st->lock);
	168	if (ret)
	169	return ret;
	170
	171	return sprintf(buf, "%d\n", !!(val & this_attr->address));
	172	}
	173
	174	/**
	175	* sca3000_set_ring_int() set state of ring status interrupt
	176	**/
	177	static ssize_t sca3000_set_ring_int(struct device *dev,
	178	struct device_attribute *attr,
	179	const char *buf,
	180	size_t len)
	181	{
4b522ce7	182	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
83f0422d	183	struct sca3000_state *st = iio_priv(indio_dev);
25888dc5	184	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
e5e26dd5	185	u8 val;
25888dc5 JC	186	int ret;
	187
	188	mutex_lock(&st->lock);
e5e26dd5	189	ret = kstrtou8(buf, 10, &val);
25888dc5 JC	190	if (ret)
	191	goto error_ret;
	192	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_INT_MASK, 1);
	193	if (ret)
	194	goto error_ret;
	195	if (val)
	196	ret = sca3000_write_reg(st,
	197	SCA3000_REG_ADDR_INT_MASK,
	198	st->rx[0] \| this_attr->address);
	199	else
	200	ret = sca3000_write_reg(st,
	201	SCA3000_REG_ADDR_INT_MASK,
	202	st->rx[0] & ~this_attr->address);
	203	error_ret:
	204	mutex_unlock(&st->lock);
	205
	206	return ret ? ret : len;
	207	}
	208
	209	static IIO_DEVICE_ATTR(50_percent, S_IRUGO \| S_IWUSR,
	210	sca3000_query_ring_int,
	211	sca3000_set_ring_int,
	212	SCA3000_INT_MASK_RING_HALF);
	213
	214	static IIO_DEVICE_ATTR(75_percent, S_IRUGO \| S_IWUSR,
	215	sca3000_query_ring_int,
	216	sca3000_set_ring_int,
	217	SCA3000_INT_MASK_RING_THREE_QUARTER);
	218
25888dc5 JC	219	static ssize_t sca3000_show_buffer_scale(struct device *dev,
	220	struct device_attribute *attr,
	221	char *buf)
	222	{
4b522ce7	223	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
83f0422d	224	struct sca3000_state *st = iio_priv(indio_dev);
574fb258	225
25888dc5 JC	226	return sprintf(buf, "0.%06d\n", 4*st->info->scale);
25888dc5 JC	227	}
f3fb0011	228
322c9563	229	static IIO_DEVICE_ATTR(in_accel_scale,
25888dc5 JC	230	S_IRUGO,
	231	sca3000_show_buffer_scale,
	232	NULL,
	233	0);
574fb258 JC	234
	235	/*
	236	* Ring buffer attributes
	237	* This device is a bit unusual in that the sampling frequency and bpse
	238	* only apply to the ring buffer. At all times full rate and accuracy
	239	* is available via direct reading from registers.
	240	*/
f3fb0011	241	static struct attribute *sca3000_ring_attributes[] = {
574fb258	242	&dev_attr_length.attr,
ffcab07a	243	&dev_attr_enable.attr,
25888dc5 JC	244	&iio_dev_attr_50_percent.dev_attr.attr,
25888dc5 JC	245	&iio_dev_attr_75_percent.dev_attr.attr,
322c9563	246	&iio_dev_attr_in_accel_scale.dev_attr.attr,
574fb258 JC	247	NULL,
	248	};
	249
	250	static struct attribute_group sca3000_ring_attr = {
f3fb0011	251	.attrs = sca3000_ring_attributes,
1aa04278	252	.name = "buffer",
574fb258 JC	253	};
574fb258 JC	254
14555b14	255	static struct iio_buffer sca3000_rb_allocate(struct iio_dev indio_dev)
574fb258	256	{
14555b14 JC	257	struct iio_buffer *buf;
14555b14 JC	258	struct iio_hw_buffer *ring;
574fb258	259
c92cb53d	260	ring = kzalloc(sizeof(*ring), GFP_KERNEL);
574fb258	261	if (!ring)
7cfce527	262	return NULL;
25888dc5	263
574fb258 JC	264	ring->private = indio_dev;
574fb258 JC	265	buf = &ring->buf;
25888dc5	266	buf->stufftoread = 0;
1aa04278	267	buf->attrs = &sca3000_ring_attr;
f79a9098	268	iio_buffer_init(buf);
574fb258 JC	269
	270	return buf;
	271	}
	272
9e69c935	273	static void sca3000_ring_release(struct iio_buffer *r)
574fb258	274	{
14555b14	275	kfree(iio_to_hw_buf(r));
574fb258 JC	276	}
574fb258 JC	277
14555b14	278	static const struct iio_buffer_access_funcs sca3000_ring_access_funcs = {
5565a450 JC	279	.read_first_n = &sca3000_read_first_n_hw_rb,
	280	.get_length = &sca3000_ring_get_length,
	281	.get_bytes_per_datum = &sca3000_ring_get_bytes_per_datum,
9dd4694d	282	.data_available = sca3000_ring_buf_data_available,
9e69c935	283	.release = sca3000_ring_release,
5565a450 JC	284	};
5565a450 JC	285
574fb258 JC	286	int sca3000_configure_ring(struct iio_dev *indio_dev)
574fb258 JC	287	{
9e69c935 LPC	288	struct iio_buffer *buffer;
	289
	290	buffer = sca3000_rb_allocate(indio_dev);
	291	if (buffer == NULL)
574fb258	292	return -ENOMEM;
ec3afa40	293	indio_dev->modes \|= INDIO_BUFFER_HARDWARE;
574fb258	294
14555b14	295	indio_dev->buffer->access = &sca3000_ring_access_funcs;
25888dc5	296
9e69c935 LPC	297	iio_device_attach_buffer(indio_dev, buffer);
9e69c935 LPC	298
574fb258 JC	299	return 0;
	300	}
	301
	302	void sca3000_unconfigure_ring(struct iio_dev *indio_dev)
	303	{
9e69c935	304	iio_buffer_put(indio_dev->buffer);
574fb258 JC	305	}
	306
	307	static inline
	308	int __sca3000_hw_ring_state_set(struct iio_dev *indio_dev, bool state)
	309	{
83f0422d	310	struct sca3000_state *st = iio_priv(indio_dev);
574fb258	311	int ret;
574fb258 JC	312
574fb258 JC	313	mutex_lock(&st->lock);
25888dc5	314	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
574fb258 JC	315	if (ret)
	316	goto error_ret;
	317	if (state) {
941060b4	318	dev_info(&indio_dev->dev, "supposedly enabling ring buffer\n");
574fb258 JC	319	ret = sca3000_write_reg(st,
574fb258 JC	320	SCA3000_REG_ADDR_MODE,
25888dc5	321	(st->rx[0] \| SCA3000_RING_BUF_ENABLE));
574fb258 JC	322	} else
	323	ret = sca3000_write_reg(st,
	324	SCA3000_REG_ADDR_MODE,
25888dc5	325	(st->rx[0] & ~SCA3000_RING_BUF_ENABLE));
574fb258 JC	326	error_ret:
	327	mutex_unlock(&st->lock);
	328
	329	return ret;
	330	}
	331	/**
	332	* sca3000_hw_ring_preenable() hw ring buffer preenable function
	333	*
	334	* Very simple enable function as the chip will allows normal reads
	335	* during ring buffer operation so as long as it is indeed running
	336	* before we notify the core, the precise ordering does not matter.
	337	**/
	338	static int sca3000_hw_ring_preenable(struct iio_dev *indio_dev)
	339	{
	340	return __sca3000_hw_ring_state_set(indio_dev, 1);
	341	}
	342
	343	static int sca3000_hw_ring_postdisable(struct iio_dev *indio_dev)
	344	{
	345	return __sca3000_hw_ring_state_set(indio_dev, 0);
	346	}
	347
14555b14	348	static const struct iio_buffer_setup_ops sca3000_ring_setup_ops = {
5565a450 JC	349	.preenable = &sca3000_hw_ring_preenable,
	350	.postdisable = &sca3000_hw_ring_postdisable,
	351	};
	352
574fb258 JC	353	void sca3000_register_ring_funcs(struct iio_dev *indio_dev)
574fb258 JC	354	{
1612244f	355	indio_dev->setup_ops = &sca3000_ring_setup_ops;
574fb258 JC	356	}
	357
	358	/**
	359	* sca3000_ring_int_process() ring specific interrupt handling.
	360	*
	361	* This is only split from the main interrupt handler so as to
	362	* reduce the amount of code if the ring buffer is not enabled.
	363	**/
14555b14	364	void sca3000_ring_int_process(u8 val, struct iio_buffer *ring)
574fb258	365	{
25888dc5 JC	366	if (val & (SCA3000_INT_STATUS_THREE_QUARTERS \|
	367	SCA3000_INT_STATUS_HALF)) {
	368	ring->stufftoread = true;
	369	wake_up_interruptible(&ring->pollq);
	370	}
574fb258	371	}