Add QSPI standard pin names

Author: maciejbocianski

docs/reference/contributing/target/QuadSPI.md

@@ -29,6 +29,28 @@ To make sure your platform is ready for the upcoming changes, you need to implem
 
 The target needs to define the `qspi_s` structure - target specific QSPI object.
 
+The target needs to define the QSPI interface pin names:
+- `QSPI_FLASHn_XXX` for pins connected to onboard flash memory.
+- `QSPIn_XXX` for pins routed out to external connector.
+
+`n` - is interface index, typically `1` if single QSPI interface available
+
+```
+QSPIn_IO0
+QSPIn_IO1
+QSPIn_IO2
+QSPIn_IO3
+QSPIn_SCK
+QSPIn_CSN
+
+QSPI_FLASHn_IO0
+QSPI_FLASHn_IO1
+QSPI_FLASHn_IO2
+QSPI_FLASHn_IO3
+QSPI_FLASHn_SCK
+QSPI_FLASHn_CSN
+```
+
 Functions to implement:
 
 ```
@@ -53,4 +75,8 @@ To enable the QSPI HAL, define `QSPI` in the targets.json file inside `device_ha
 
 ### Testing
 
-To be implemented
+The Mbed OS HAL provides a set of conformance tests for the QSPI interface (**Note: QSPI HAL tests require onboard QSPI flash memory**). You can use these tests to validate the correctness of your implementation. To run the QSPI HAL tests, use the following command:
+
+```
+mbed test -t <toolchain> -m <target> -n tests-mbed_hal-qspi
+```