diff options
Diffstat (limited to 'drivers/staging/iio/Documentation/generic_buffer.c')
| -rw-r--r-- | drivers/staging/iio/Documentation/generic_buffer.c | 318 |
1 files changed, 318 insertions, 0 deletions
diff --git a/drivers/staging/iio/Documentation/generic_buffer.c b/drivers/staging/iio/Documentation/generic_buffer.c new file mode 100644 index 0000000..df23aeb --- /dev/null +++ b/drivers/staging/iio/Documentation/generic_buffer.c @@ -0,0 +1,318 @@ +/* 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 <dirent.h> +#include <fcntl.h> +#include <stdio.h> +#include <errno.h> +#include <sys/stat.h> +#include <sys/dir.h> +#include <linux/types.h> +#include "iio_utils.h" + +const int buf_len = 128; +const int num_loops = 2; + +/** + * size_from_channelarray() - calculate the storage size of a scan + * @channels: the channel info array + * @num_channels: size of the channel info array + * + * 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; +} + +/** + * process_scan() - print out the values in SI units + * @data: pointer to the start of the scan + * @infoarray: information about the channels. Note + * size_from_channelarray must have been called first to fill the + * location offsets. + * @num_channels: the number of active channels + **/ +void process_scan(char *data, + struct iio_channel_info *infoarray, + int num_channels) +{ + int k; + for (k = 0; k < num_channels; k++) + switch (infoarray[k].bytes) { + /* only a few cases implemented so far */ + case 2: + if (infoarray[k].is_signed) { + int16_t val = *(int16_t *) + (data + + infoarray[k].location); + if ((val >> infoarray[k].bits_used) & 1) + val = (val & infoarray[k].mask) | + ~infoarray[k].mask; + printf("%05f ", ((float)val + + infoarray[k].offset)* + infoarray[k].scale); + } else { + uint16_t val = *(uint16_t *) + (data + + infoarray[k].location); + val = (val & infoarray[k].mask); + printf("%05f ", ((float)val + + infoarray[k].offset)* + infoarray[k].scale); + } + break; + case 8: + if (infoarray[k].is_signed) { + int64_t val = *(int64_t *) + (data + + infoarray[k].location); + if ((val >> infoarray[k].bits_used) & 1) + val = (val & infoarray[k].mask) | + ~infoarray[k].mask; + /* special case for timestamp */ + if (infoarray[k].scale == 1.0f && + infoarray[k].offset == 0.0f) + printf(" %lld", val); + else + printf("%05f ", ((float)val + + infoarray[k].offset)* + infoarray[k].scale); + } + break; + default: + break; + } + printf("\n"); +} + +int main(int argc, char **argv) +{ + int ret, c, i, j, toread; + + FILE *fp_ev; + int fp; + + int num_channels; + char *trigger_name = NULL, *device_name = NULL; + char *dev_dir_name, *buf_dir_name; + + int datardytrigger = 1; + char *data; + size_t read_size; + struct iio_event_data dat; + int dev_num, trig_num; + char *buffer_access, *buffer_event; + int scan_size; + + struct iio_channel_info *infoarray; + + while ((c = getopt(argc, argv, "t:n:")) != -1) { + switch (c) { + case 'n': + device_name = optarg; + break; + case 't': + trigger_name = optarg; + datardytrigger = 0; + break; + case '?': + return -1; + } + } + + /* Find the device requested */ + dev_num = find_type_by_name(device_name, "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, "%sdevice%d", iio_dir, dev_num); + if (trigger_name == NULL) { + /* + * Build the trigger name. If it is device associated it's + * 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, &infoarray, &num_channels); + if (ret) { + printf("Problem reading scan element information \n"); + 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, "%sdevice%d:buffer0", 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 rdy 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(infoarray, num_channels); + data = malloc(scan_size*buf_len); + if (!data) { + ret = -ENOMEM; + goto error_free_buf_dir_name; + } + + ret = asprintf(&buffer_access, + "/dev/device%d:buffer0:access0", + dev_num); + if (ret < 0) { + ret = -ENOMEM; + goto error_free_data; + } + + ret = asprintf(&buffer_event, "/dev/device%d:buffer0:event0", dev_num); + if (ret < 0) { + ret = -ENOMEM; + goto error_free_buffer_access; + } + /* 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_event; + } + /* Attempt to open the event access dev (blocking this time) */ + fp_ev = fopen(buffer_event, "rb"); + if (fp_ev == NULL) { + printf("Failed to open %s\n", buffer_event); + ret = -errno; + goto error_close_buffer_access; + } + + /* Wait for events 10 times */ + for (j = 0; j < num_loops; j++) { + read_size = fread(&dat, 1, sizeof(struct iio_event_data), + fp_ev); + switch (dat.id) { + case IIO_EVENT_CODE_RING_100_FULL: + toread = buf_len; + break; + case IIO_EVENT_CODE_RING_75_FULL: + toread = buf_len*3/4; + break; + case IIO_EVENT_CODE_RING_50_FULL: + toread = buf_len/2; + break; + default: + printf("Unexpecteded event code\n"); + continue; + } + 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, + infoarray, + num_channels); + } + + /* Stop the ring buffer */ + ret = write_sysfs_int("enable", buf_dir_name, 0); + if (ret < 0) + goto error_close_buffer_event; + + /* Disconnect from the trigger - just write a dummy name.*/ + write_sysfs_string("trigger/current_trigger", + dev_dir_name, "NULL"); + +error_close_buffer_event: + fclose(fp_ev); +error_close_buffer_access: + close(fp); +error_free_data: + free(data); +error_free_buffer_access: + free(buffer_access); +error_free_buffer_event: + free(buffer_event); +error_free_buf_dir_name: + free(buf_dir_name); +error_free_triggername: + if (datardytrigger) + free(trigger_name); +error_ret: + return ret; +} |
