STPK-1429 Make the sensor enable/disable code path more robust

Tests on the number of enabled sensors can be replaced by a
check on the iio device fd status (having any sensor active
on a iio device implies that the associated device was open).

This simplifies the enable path somewhat. On the disable path
we still need to check whether a regular or poll-mode sensor
associated to the device remains in operation before actually
closing the fd and setting it back to -1.

Issue: STPK-1429

Change-Id: Ib3084d0075630d48ffb97bcdd01b880271b3192c
Signed-off-by: Patrick Porlan <patrick.porlan@intel.com>

diff --git a/control.c b/control.c
index 7edd8db..4155432 100644 (file)
--- a/control.c
+++ b/control.c
@@ -325,10 +325,9 @@ int sensor_activate(int s, int enabled)
         */
        dev_fd = device_fd[dev_num];
 
-       switch (poll_sensors_per_dev[dev_num] + trig_sensors_per_dev[dev_num]) {
-
-               case 0:
-                       if (dev_fd != -1) {
+       if (!enabled) {
+               if (dev_fd != -1 && !poll_sensors_per_dev[dev_num] &&
+                       !trig_sensors_per_dev[dev_num]) {
                                /*
                                 * Stop watching this fd. This should be a no-op
                                 * in case this fd was not in the poll set.
@@ -338,44 +337,41 @@ int sensor_activate(int s, int enabled)
                                close(dev_fd);
                                device_fd[dev_num] = -1;
                        }
-                       return 0;
+               return 0;
+       }
 
-               case 1:
-                       /* First enabled sensor on this iio device */
-                       sprintf(device_name, DEV_FILE_PATH, dev_num);
-                       dev_fd = open(device_name, O_RDONLY | O_NONBLOCK);
+       if (dev_fd == -1) {
+               /* First enabled sensor on this iio device */
+               sprintf(device_name, DEV_FILE_PATH, dev_num);
+               dev_fd = open(device_name, O_RDONLY | O_NONBLOCK);
 
-                       device_fd[dev_num] = dev_fd;
+               device_fd[dev_num] = dev_fd;
 
-                       if (dev_fd == -1) {
-                               ALOGE("Could not open fd on %s (%s)\n",
-                                     device_name, strerror(errno));
-                               adjust_counters(s, 0);
-                               return -1;
-                       }
+               if (dev_fd == -1) {
+                       ALOGE("Could not open fd on %s (%s)\n",
+                             device_name, strerror(errno));
+                       adjust_counters(s, 0);
+                       return -1;
+               }
 
-                       ALOGV("Opened %s: fd=%d\n", device_name, dev_fd);
-                       break;
+               ALOGV("Opened %s: fd=%d\n", device_name, dev_fd);
 
-               default:
-                       break;
-       }
+               if (!is_poll_sensor) {
 
-       if (!is_poll_sensor && trig_sensors_per_dev[dev_num] == 1) {
+                       /* Add this iio device fd to the set of watched fds */
+                       ev.events = EPOLLIN;
+                       ev.data.u32 = dev_num;
 
-               /* Add this iio device fd to the set of watched fds */
-               ev.events = EPOLLIN;
-               ev.data.u32 = dev_num;
+                       ret = epoll_ctl(poll_fd, EPOLL_CTL_ADD, dev_fd, &ev);
 
-               ret = epoll_ctl(poll_fd, EPOLL_CTL_ADD, dev_fd, &ev);
+                       if (ret == -1) {
+                               ALOGE(  "Failed adding %d to poll set (%s)\n",
+                                       dev_fd, strerror(errno));
+                               return -1;
+                       }
 
-               if (ret == -1) {
-                       ALOGE("Failed adding %d to poll set (%s)\n", dev_fd,
-                             strerror(errno));
-                       return -1;
+                       /* Note: poll-mode fds are not readable */
                }
-
-               /* Note: poll-mode fds are not readable */
        }
 
        return 0;