/* 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. * */ #include <unistd.h>#include <stdlib.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 >>= 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 4:			if (!channels[k].is_signed) {				uint32_t val = *(uint32_t *)					(data + channels[k].location);				printf("%05f ", ((float)val +						 channels[k].offset)*				       channels[k].scale); 			}			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;	int notrigger = 0;	char *dummy; 	struct iio_channel_info *channels; 	while ((c = getopt(argc, argv, "l:w:c:et:n:g")) != -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 'g':			notrigger = 1;			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 (!notrigger) {		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);	} else		printf("trigger-less mode selected\n"); 	/*	 * 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;	} 	if (!notrigger) {		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 < 0) {			if (errno == -EAGAIN) {				printf("nothing available\n");				continue;			} else				break;		}		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; 	if (!notrigger)		/* 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;}