staging: iio: update example application.

The application is now considerably more generic and should cope
with all devices in tree.  The process function will need to be
extended to handle other type values as needed.

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

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 000000000000..df23aeb9d529
--- /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;
+}