sr: sr_hw_has_hwcap(): More docs, error checks.

diff --git a/hwdriver.c b/hwdriver.c
index c68d6e0c2167347d68f30283b8f065066f741606..dc314823999089fd7842f645ea4468d024ae27ad 100644 (file)
--- a/hwdriver.c
+++ b/hwdriver.c
@@ -264,13 +264,24 @@ SR_PRIV void sr_serial_dev_inst_free(struct sr_serial_dev_inst *serial)
  * @param driver The hardware driver in which to search for the capability.
  * @param hwcap The capability to find in the list.
  *
- * @return TRUE if found, FALSE otherwise.
+ * @return TRUE if the specified capability exists in the specified driver,
+ *         FALSE otherwise. Also, if 'driver' is NULL or the respective driver
+ *         returns an invalid capability list, FALSE is returned.
  */
 SR_API gboolean sr_hw_has_hwcap(struct sr_dev_driver *driver, int hwcap)
 {
        int *hwcaps, i;
 
-       hwcaps = driver->hwcap_get_all();
+       if (!driver) {
+               sr_err("hwdriver: %s: driver was NULL", __func__);
+               return FALSE;
+       }
+
+       if (!(hwcaps = driver->hwcap_get_all())) {
+               sr_err("hwdriver: %s: hwcap_get_all() returned NULL", __func__);
+               return FALSE;
+       }
+
        for (i = 0; hwcaps[i]; i++) {
                if (hwcaps[i] == hwcap)
                        return TRUE;