Remove workaround when checking for a trigger of a device

The bug where libiio would return error EIO in case the iio device
supports a trigger but none is assigned, no longer exists in latest
versions of libiio. Probably was fixed long time ago.
However I found that on serial backend the EIO is being returned by
iio_device_get_trigger() even though the intention was to report that
iio device doesn't support/need a trigger. The expected behaviour is
that 0 is returned and trigger argument is set to NULL. But this unhappy
coincidence was forcing users to provide a trigger for an iio device
that does not need one. It happened that no trigger was available making
the users unable to ask for samples from the device.
Note: this doesn't happend to all scenarios where serial backend is
used. I have seen the issue only on 2 projects. And I have seen it
working properly on other projects.

Signed-off-by: Dan Nechita <[email protected]>

osc.c

@@ -1420,7 +1420,7 @@ static double read_sampling_frequency(const struct iio_device *dev)
  buf, sizeof(buf));
  if (ret < 0) {
  const struct iio_device *trigger;
- ret = osc_iio_device_get_trigger(dev, &trigger);
+ ret = iio_device_get_trigger(dev, &trigger);
  if (ret == 0 && trigger) {
  attr = iio_device_find_attr(trigger, "sampling_frequency");
  if (!attr)
@@ -1430,6 +1430,10 @@ static double read_sampling_frequency(const struct iio_device *dev)
  sizeof(buf));
  else
  ret = -ENOENT;
+ } else {
+ fprintf(stderr, "Failed to check if device: %s has trigger. Error:"
+ "%s\n", iio_device_get_name(dev) ?: iio_device_get_id(dev),
+ strerror(-ret));
  }
  }
 

osc.h

@@ -174,26 +174,6 @@ extern void do_init(struct iio_context *new_ctx);
 extern void create_default_plot(void);
 extern GtkWidget * new_plot_cb(GtkMenuItem *item, gpointer user_data);
 extern bool check_inifile(const char *filepath);
-
-/*
- * There is a bug in libiio that lets it return -EIO if no trigger is
- * assigned. Assume that EIO means there is a trigger, but none
- * assigned. Drop since once libiio has been fixed for a while.
- */
-static inline int osc_iio_device_get_trigger(const struct iio_device *dev,
- const struct iio_device **trigger)
-{
- int ret;
-
- ret = iio_device_get_trigger(dev, trigger);
- if (ret == -EIO) {
- ret = 0;
- *trigger = NULL;
- }
-
- return ret;
-}
-
 extern int osc_load_glade_file(GtkBuilder *builder, const char *fname);
 extern int osc_load_objects_from_glade_file(GtkBuilder *builder, const char *fname, gchar **object_ids);
 

oscplot.c

@@ -2195,12 +2195,16 @@ static gboolean check_valid_setup_of_device(OscPlot *plot, const char *name)
  const struct iio_device *trigger;
  int ret;
 
- ret = osc_iio_device_get_trigger(dev, &trigger);
+ ret = iio_device_get_trigger(dev, &trigger);
  if (ret == 0 && trigger == NULL && num_enabled > 0) {
  snprintf(warning_text, sizeof(warning_text),
  "Device %s needs an impulse generator", name);
  gtk_widget_set_tooltip_text(priv->capture_button, warning_text);
  return false;
+ } else {
+ fprintf(stderr, "Failed to check if device: %s has trigger. Error:"
+ "%s\n", iio_device_get_name(dev) ?: iio_device_get_id(dev),
+ strerror(-ret));
  }
 
  /* Additional validation rules provided by the plugin of the device */
@@ -6767,11 +6771,15 @@ static gboolean right_click_menu_show(OscPlot *plot, GdkEvent *event)
  bool has_trigger;
  int ret;
 
- ret = osc_iio_device_get_trigger(dev, &trigger);
- if (ret == 0)
+ ret = iio_device_get_trigger(dev, &trigger);
+ has_trigger = false;
+ if (ret == 0 && trigger) {
  has_trigger = true;
- else
- has_trigger = false;
+ } else {
+ fprintf(stderr, "Failed to check if device: %s has trigger. Error:"
+ "%s\n", iio_device_get_name(dev) ?: iio_device_get_id(dev),
+ strerror(-ret));
+ }
 
  gtk_widget_set_sensitive(priv->device_trigger_menuitem,
  has_trigger);

trigger_dialog.c

@@ -92,7 +92,7 @@ static void trigger_load_settings(GtkBuilder *builder, const char *device)
  if (!dev)
  return;
 
- ret = osc_iio_device_get_trigger(dev, &trigger);
+ ret = iio_device_get_trigger(dev, &trigger);
  if (ret < 0)
  trigger = NULL;