[deliverable/linux.git] / drivers / staging / iio / Documentation / generic_buffer.c

/* Industrialio buffer test code.
 *
 * Copyright (c) 2008 Jonathan Cameron
 *
 * 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.
 *
 * This program is primarily intended as an example application.
 * Reads the current buffer setup from sysfs and starts a short capture
 * from the specified device, pretty printing the result after appropriate
 * conversion.
 *
 * Command line parameters
 * generic_buffer -n <device_name> -t <trigger_name>
 * If trigger name is not specified the program assumes you want a dataready
 * trigger associated with the device and goes looking for it.
 *
 */

#define _GNU_SOURCE

#include <unistd.h>
#include <dirent.h>
#include <fcntl.h>
#include <stdio.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/dir.h>
#include <linux/types.h>
#include <string.h>
#include <poll.h>
#include <endian.h>
#include <getopt.h>
#include <inttypes.h>
#include "iio_utils.h"

/**
 * size_from_channelarray() - calculate the storage size of a scan
 * @channels:		the channel info array
 * @num_channels:	number of channels
 *
 * Has the side effect of filling the channels[i].location values used
 * in processing the buffer output.
 **/
int size_from_channelarray(struct iio_channel_info *channels, int num_channels)
{
	int bytes = 0;
	int i = 0;
	while (i < num_channels) {
		if (bytes % channels[i].bytes == 0)
			channels[i].location = bytes;
		else
			channels[i].location = bytes - bytes%channels[i].bytes
				+ channels[i].bytes;
		bytes = channels[i].location + channels[i].bytes;
		i++;
	}
	return bytes;
}

void print2byte(int input, struct iio_channel_info *info)
{
	/* First swap if incorrect endian */
	if (info->be)
		input = be16toh((uint16_t)input);
	else
		input = le16toh((uint16_t)input);

	/*
	 * Shift before conversion to avoid sign extension
	 * of left aligned data
	 */
	input = input >> info->shift;
	if (info->is_signed) {
		int16_t val = input;
		val &= (1 << info->bits_used) - 1;
		val = (int16_t)(val << (16 - info->bits_used)) >>
			(16 - info->bits_used);
		printf("%05f ", ((float)val + info->offset)*info->scale);
	} else {
		uint16_t val = input;
		val &= (1 << info->bits_used) - 1;
		printf("%05f ", ((float)val + info->offset)*info->scale);
	}
}
/**
 * process_scan() - print out the values in SI units
 * @data:		pointer to the start of the scan
 * @channels:		information about the channels. Note
 *  size_from_channelarray must have been called first to fill the
 *  location offsets.
 * @num_channels:	number of channels
 **/
void process_scan(char *data,
		  struct iio_channel_info *channels,
		  int num_channels)
{
	int k;
	for (k = 0; k < num_channels; k++)
		switch (channels[k].bytes) {
			/* only a few cases implemented so far */
		case 2:
			print2byte(*(uint16_t *)(data + channels[k].location),
				   &channels[k]);
			break;
		case 8:
			if (channels[k].is_signed) {
				int64_t val = *(int64_t *)
					(data +
					 channels[k].location);
				if ((val >> channels[k].bits_used) & 1)
					val = (val & channels[k].mask) |
						~channels[k].mask;
				/* special case for timestamp */
				if (channels[k].scale == 1.0f &&
				    channels[k].offset == 0.0f)
					printf("%" PRId64 " ", val);
				else
					printf("%05f ", ((float)val +
							 channels[k].offset)*
					       channels[k].scale);
			}
			break;
		default:
			break;
		}
	printf("\n");
}

int main(int argc, char **argv)
{
	unsigned long num_loops = 2;
	unsigned long timedelay = 1000000;
	unsigned long buf_len = 128;

	int ret, c, i, j, toread;
	int fp;

	int num_channels;
	char *trigger_name = NULL, *device_name = NULL;
	char *dev_dir_name, *buf_dir_name;

	int datardytrigger = 1;
	char *data;
	ssize_t read_size;
	int dev_num, trig_num;
	char *buffer_access;
	int scan_size;
	int noevents = 0;
	char *dummy;

	struct iio_channel_info *channels;

	while ((c = getopt(argc, argv, "l:w:c:et:n:")) != -1) {
		switch (c) {
		case 'n':
			device_name = optarg;
			break;
		case 't':
			trigger_name = optarg;
			datardytrigger = 0;
			break;
		case 'e':
			noevents = 1;
			break;
		case 'c':
			num_loops = strtoul(optarg, &dummy, 10);
			break;
		case 'w':
			timedelay = strtoul(optarg, &dummy, 10);
			break;
		case 'l':
			buf_len = strtoul(optarg, &dummy, 10);
			break;
		case '?':
			return -1;
		}
	}

	if (device_name == NULL)
		return -1;

	/* Find the device requested */
	dev_num = find_type_by_name(device_name, "iio:device");
	if (dev_num < 0) {
		printf("Failed to find the %s\n", device_name);
		ret = -ENODEV;
		goto error_ret;
	}
	printf("iio device number being used is %d\n", dev_num);

	asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
	if (trigger_name == NULL) {
		/*
		 * Build the trigger name. If it is device associated its
		 * name is <device_name>_dev[n] where n matches the device
		 * number found above
		 */
		ret = asprintf(&trigger_name,
			       "%s-dev%d", device_name, dev_num);
		if (ret < 0) {
			ret = -ENOMEM;
			goto error_ret;
		}
	}

	/* Verify the trigger exists */
	trig_num = find_type_by_name(trigger_name, "trigger");
	if (trig_num < 0) {
		printf("Failed to find the trigger %s\n", trigger_name);
		ret = -ENODEV;
		goto error_free_triggername;
	}
	printf("iio trigger number being used is %d\n", trig_num);

	/*
	 * Parse the files in scan_elements to identify what channels are
	 * present
	 */
	ret = build_channel_array(dev_dir_name, &channels, &num_channels);
	if (ret) {
		printf("Problem reading scan element information\n");
		printf("diag %s\n", dev_dir_name);
		goto error_free_triggername;
	}

	/*
	 * Construct the directory name for the associated buffer.
	 * As we know that the lis3l02dq has only one buffer this may
	 * be built rather than found.
	 */
	ret = asprintf(&buf_dir_name,
		       "%siio:device%d/buffer", iio_dir, dev_num);
	if (ret < 0) {
		ret = -ENOMEM;
		goto error_free_triggername;
	}
	printf("%s %s\n", dev_dir_name, trigger_name);
	/* Set the device trigger to be the data ready trigger found above */
	ret = write_sysfs_string_and_verify("trigger/current_trigger",
					dev_dir_name,
					trigger_name);
	if (ret < 0) {
		printf("Failed to write current_trigger file\n");
		goto error_free_buf_dir_name;
	}

	/* Setup ring buffer parameters */
	ret = write_sysfs_int("length", buf_dir_name, buf_len);
	if (ret < 0)
		goto error_free_buf_dir_name;

	/* Enable the buffer */
	ret = write_sysfs_int("enable", buf_dir_name, 1);
	if (ret < 0)
		goto error_free_buf_dir_name;
	scan_size = size_from_channelarray(channels, num_channels);
	data = malloc(scan_size*buf_len);
	if (!data) {
		ret = -ENOMEM;
		goto error_free_buf_dir_name;
	}

	ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
	if (ret < 0) {
		ret = -ENOMEM;
		goto error_free_data;
	}

	/* Attempt to open non blocking the access dev */
	fp = open(buffer_access, O_RDONLY | O_NONBLOCK);
	if (fp == -1) { /* If it isn't there make the node */
		printf("Failed to open %s\n", buffer_access);
		ret = -errno;
		goto error_free_buffer_access;
	}

	/* Wait for events 10 times */
	for (j = 0; j < num_loops; j++) {
		if (!noevents) {
			struct pollfd pfd = {
				.fd = fp,
				.events = POLLIN,
			};

			poll(&pfd, 1, -1);
			toread = buf_len;

		} else {
			usleep(timedelay);
			toread = 64;
		}

		read_size = read(fp,
				 data,
				 toread*scan_size);
		if (read_size == -EAGAIN) {
			printf("nothing available\n");
			continue;
		}
		for (i = 0; i < read_size/scan_size; i++)
			process_scan(data + scan_size*i,
				     channels,
				     num_channels);
	}

	/* Stop the buffer */
	ret = write_sysfs_int("enable", buf_dir_name, 0);
	if (ret < 0)
		goto error_close_buffer_access;

	/* Disconnect the trigger - just write a dummy name. */
	write_sysfs_string("trigger/current_trigger",
			dev_dir_name, "NULL");

error_close_buffer_access:
	close(fp);
error_free_data:
	free(data);
error_free_buffer_access:
	free(buffer_access);
error_free_buf_dir_name:
	free(buf_dir_name);
error_free_triggername:
	if (datardytrigger)
		free(trigger_name);
error_ret:
	return ret;
}
Commit	Line	Data
e58537cc JC	1	/* Industrialio buffer test code.
	2	*
	3	* Copyright (c) 2008 Jonathan Cameron
	4	*
	5	* This program is free software; you can redistribute it and/or modify it
	6	* under the terms of the GNU General Public License version 2 as published by
	7	* the Free Software Foundation.
	8	*
	9	* This program is primarily intended as an example application.
	10	* Reads the current buffer setup from sysfs and starts a short capture
	11	* from the specified device, pretty printing the result after appropriate
	12	* conversion.
	13	*
	14	* Command line parameters
	15	* generic_buffer -n <device_name> -t <trigger_name>
	16	* If trigger name is not specified the program assumes you want a dataready
	17	* trigger associated with the device and goes looking for it.
	18	*
	19	*/
	20
bb23378c PM	21	#define _GNU_SOURCE
bb23378c PM	22
e58537cc JC	23	#include <unistd.h>
	24	#include <dirent.h>
	25	#include <fcntl.h>
	26	#include <stdio.h>
	27	#include <errno.h>
	28	#include <sys/stat.h>
	29	#include <sys/dir.h>
	30	#include <linux/types.h>
30268a3d	31	#include <string.h>
52615d47	32	#include <poll.h>
117cf8b7	33	#include <endian.h>
bb23378c	34	#include <getopt.h>
1bcdfbcf	35	#include <inttypes.h>
e58537cc JC	36	#include "iio_utils.h"
e58537cc JC	37
e58537cc JC	38	/**
e58537cc JC	39	* size_from_channelarray() - calculate the storage size of a scan
d8da0eee PM	40	* @channels: the channel info array
d8da0eee PM	41	* @num_channels: number of channels
e58537cc JC	42	*
	43	* Has the side effect of filling the channels[i].location values used
	44	* in processing the buffer output.
	45	**/
	46	int size_from_channelarray(struct iio_channel_info *channels, int num_channels)
	47	{
	48	int bytes = 0;
	49	int i = 0;
	50	while (i < num_channels) {
	51	if (bytes % channels[i].bytes == 0)
	52	channels[i].location = bytes;
	53	else
	54	channels[i].location = bytes - bytes%channels[i].bytes
	55	+ channels[i].bytes;
	56	bytes = channels[i].location + channels[i].bytes;
	57	i++;
	58	}
	59	return bytes;
	60	}
	61
52615d47 JC	62	void print2byte(int input, struct iio_channel_info *info)
52615d47 JC	63	{
117cf8b7	64	/* First swap if incorrect endian */
117cf8b7	65	if (info->be)
09f78be7	66	input = be16toh((uint16_t)input);
117cf8b7	67	else
09f78be7	68	input = le16toh((uint16_t)input);
117cf8b7	69
d8da0eee PM	70	/*
	71	* Shift before conversion to avoid sign extension
	72	* of left aligned data
	73	*/
52615d47 JC	74	input = input >> info->shift;
	75	if (info->is_signed) {
	76	int16_t val = input;
	77	val &= (1 << info->bits_used) - 1;
	78	val = (int16_t)(val << (16 - info->bits_used)) >>
	79	(16 - info->bits_used);
1d633fd1	80	printf("%05f ", ((float)val + info->offset)*info->scale);
52615d47 JC	81	} else {
	82	uint16_t val = input;
	83	val &= (1 << info->bits_used) - 1;
	84	printf("%05f ", ((float)val + info->offset)*info->scale);
	85	}
	86	}
e58537cc JC	87	/**
	88	* process_scan() - print out the values in SI units
	89	* @data: pointer to the start of the scan
d8da0eee	90	* @channels: information about the channels. Note
e58537cc JC	91	* size_from_channelarray must have been called first to fill the
e58537cc JC	92	* location offsets.
d8da0eee	93	* @num_channels: number of channels
e58537cc JC	94	**/
e58537cc JC	95	void process_scan(char *data,
d8da0eee	96	struct iio_channel_info *channels,
e58537cc JC	97	int num_channels)
	98	{
	99	int k;
	100	for (k = 0; k < num_channels; k++)
d8da0eee	101	switch (channels[k].bytes) {
e58537cc JC	102	/* only a few cases implemented so far */
e58537cc JC	103	case 2:
d8da0eee PM	104	print2byte((uint16_t )(data + channels[k].location),
d8da0eee PM	105	&channels[k]);
e58537cc JC	106	break;
e58537cc JC	107	case 8:
d8da0eee	108	if (channels[k].is_signed) {
e58537cc JC	109	int64_t val = (int64_t )
e58537cc JC	110	(data +
d8da0eee PM	111	channels[k].location);
	112	if ((val >> channels[k].bits_used) & 1)
	113	val = (val & channels[k].mask) \|
	114	~channels[k].mask;
e58537cc	115	/* special case for timestamp */
d8da0eee PM	116	if (channels[k].scale == 1.0f &&
d8da0eee PM	117	channels[k].offset == 0.0f)
1bcdfbcf	118	printf("%" PRId64 " ", val);
e58537cc JC	119	else
e58537cc JC	120	printf("%05f ", ((float)val +
d8da0eee PM	121	channels[k].offset)*
d8da0eee PM	122	channels[k].scale);
e58537cc JC	123	}
	124	break;
	125	default:
	126	break;
	127	}
	128	printf("\n");
	129	}
	130
	131	int main(int argc, char **argv)
	132	{
96df9799 JC	133	unsigned long num_loops = 2;
	134	unsigned long timedelay = 1000000;
	135	unsigned long buf_len = 128;
	136
e58537cc	137	int ret, c, i, j, toread;
e58537cc JC	138	int fp;
	139
	140	int num_channels;
	141	char trigger_name = NULL, device_name = NULL;
	142	char dev_dir_name, buf_dir_name;
	143
	144	int datardytrigger = 1;
	145	char *data;
c77b3810	146	ssize_t read_size;
e58537cc	147	int dev_num, trig_num;
52615d47	148	char *buffer_access;
e58537cc	149	int scan_size;
30268a3d	150	int noevents = 0;
96df9799	151	char *dummy;
e58537cc	152
d8da0eee	153	struct iio_channel_info *channels;
e58537cc	154
96df9799	155	while ((c = getopt(argc, argv, "l:w:c:et:n:")) != -1) {
e58537cc JC	156	switch (c) {
	157	case 'n':
	158	device_name = optarg;
	159	break;
	160	case 't':
	161	trigger_name = optarg;
	162	datardytrigger = 0;
	163	break;
30268a3d JC	164	case 'e':
	165	noevents = 1;
	166	break;
96df9799 JC	167	case 'c':
	168	num_loops = strtoul(optarg, &dummy, 10);
	169	break;
	170	case 'w':
	171	timedelay = strtoul(optarg, &dummy, 10);
	172	break;
	173	case 'l':
	174	buf_len = strtoul(optarg, &dummy, 10);
	175	break;
e58537cc JC	176	case '?':
	177	return -1;
	178	}
	179	}
	180
065896e9 MH	181	if (device_name == NULL)
	182	return -1;
	183
e58537cc	184	/* Find the device requested */
1aa04278	185	dev_num = find_type_by_name(device_name, "iio:device");
e58537cc JC	186	if (dev_num < 0) {
	187	printf("Failed to find the %s\n", device_name);
	188	ret = -ENODEV;
	189	goto error_ret;
	190	}
	191	printf("iio device number being used is %d\n", dev_num);
	192
1aa04278	193	asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
e58537cc JC	194	if (trigger_name == NULL) {
e58537cc JC	195	/*
d8da0eee	196	* Build the trigger name. If it is device associated its
e58537cc JC	197	* name is <device_name>_dev[n] where n matches the device
	198	* number found above
	199	*/
	200	ret = asprintf(&trigger_name,
	201	"%s-dev%d", device_name, dev_num);
	202	if (ret < 0) {
	203	ret = -ENOMEM;
	204	goto error_ret;
	205	}
	206	}
	207
	208	/* Verify the trigger exists */
	209	trig_num = find_type_by_name(trigger_name, "trigger");
	210	if (trig_num < 0) {
	211	printf("Failed to find the trigger %s\n", trigger_name);
	212	ret = -ENODEV;
	213	goto error_free_triggername;
	214	}
	215	printf("iio trigger number being used is %d\n", trig_num);
	216
	217	/*
	218	* Parse the files in scan_elements to identify what channels are
	219	* present
	220	*/
d8da0eee	221	ret = build_channel_array(dev_dir_name, &channels, &num_channels);
e58537cc	222	if (ret) {
52615d47	223	printf("Problem reading scan element information\n");
1aa04278	224	printf("diag %s\n", dev_dir_name);
e58537cc JC	225	goto error_free_triggername;
	226	}
	227
	228	/*
	229	* Construct the directory name for the associated buffer.
	230	* As we know that the lis3l02dq has only one buffer this may
	231	* be built rather than found.
	232	*/
1aa04278 JC	233	ret = asprintf(&buf_dir_name,
1aa04278 JC	234	"%siio:device%d/buffer", iio_dir, dev_num);
e58537cc JC	235	if (ret < 0) {
	236	ret = -ENOMEM;
	237	goto error_free_triggername;
	238	}
	239	printf("%s %s\n", dev_dir_name, trigger_name);
d8da0eee	240	/* Set the device trigger to be the data ready trigger found above */
e58537cc JC	241	ret = write_sysfs_string_and_verify("trigger/current_trigger",
	242	dev_dir_name,
	243	trigger_name);
	244	if (ret < 0) {
	245	printf("Failed to write current_trigger file\n");
	246	goto error_free_buf_dir_name;
	247	}
	248
	249	/* Setup ring buffer parameters */
	250	ret = write_sysfs_int("length", buf_dir_name, buf_len);
	251	if (ret < 0)
	252	goto error_free_buf_dir_name;
	253
	254	/* Enable the buffer */
	255	ret = write_sysfs_int("enable", buf_dir_name, 1);
	256	if (ret < 0)
	257	goto error_free_buf_dir_name;
d8da0eee	258	scan_size = size_from_channelarray(channels, num_channels);
e58537cc JC	259	data = malloc(scan_size*buf_len);
	260	if (!data) {
	261	ret = -ENOMEM;
	262	goto error_free_buf_dir_name;
	263	}
	264
1aa04278	265	ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
e58537cc JC	266	if (ret < 0) {
	267	ret = -ENOMEM;
	268	goto error_free_data;
	269	}
	270
e58537cc JC	271	/* Attempt to open non blocking the access dev */
e58537cc JC	272	fp = open(buffer_access, O_RDONLY \| O_NONBLOCK);
d8da0eee	273	if (fp == -1) { /* If it isn't there make the node */
e58537cc JC	274	printf("Failed to open %s\n", buffer_access);
e58537cc JC	275	ret = -errno;
52615d47	276	goto error_free_buffer_access;
e58537cc JC	277	}
	278
	279	/* Wait for events 10 times */
	280	for (j = 0; j < num_loops; j++) {
30268a3d	281	if (!noevents) {
52615d47 JC	282	struct pollfd pfd = {
	283	.fd = fp,
	284	.events = POLLIN,
	285	};
	286
	287	poll(&pfd, 1, -1);
	288	toread = buf_len;
	289
30268a3d	290	} else {
96df9799	291	usleep(timedelay);
30268a3d	292	toread = 64;
e58537cc	293	}
30268a3d	294
e58537cc JC	295	read_size = read(fp,
	296	data,
	297	toread*scan_size);
	298	if (read_size == -EAGAIN) {
	299	printf("nothing available\n");
	300	continue;
	301	}
	302	for (i = 0; i < read_size/scan_size; i++)
	303	process_scan(data + scan_size*i,
d8da0eee	304	channels,
e58537cc JC	305	num_channels);
	306	}
	307
d8da0eee	308	/* Stop the buffer */
e58537cc JC	309	ret = write_sysfs_int("enable", buf_dir_name, 0);
e58537cc JC	310	if (ret < 0)
52615d47	311	goto error_close_buffer_access;
e58537cc	312
d8da0eee	313	/* Disconnect the trigger - just write a dummy name. */
e58537cc JC	314	write_sysfs_string("trigger/current_trigger",
	315	dev_dir_name, "NULL");
	316
e58537cc JC	317	error_close_buffer_access:
	318	close(fp);
	319	error_free_data:
	320	free(data);
	321	error_free_buffer_access:
	322	free(buffer_access);
e58537cc JC	323	error_free_buf_dir_name:
	324	free(buf_dir_name);
	325	error_free_triggername:
	326	if (datardytrigger)
	327	free(trigger_name);
	328	error_ret:
	329	return ret;
	330	}