script: Add Py script to check for guideline rules & README.md

Added readme_check_guideline.md along with the check_guideline.py
to explain the usage of this and to show how it should be used.

Signed-off-by: Iulia Moldovan <iulia.moldovan@analog.com>

.github/scripts/readme_check_guideline.md

@@ -0,0 +1,107 @@
+# User guide for [check_guideline.py](https://github.com/analogdevicesinc/hdl/tree/master/.github/scripts/check_guideline.py)
+
+## Prerequisites
+
+* the script must be run while being in the root directory (/hdl)
+* clean the repository to remove the files generated by Vivado
+* it will be run only on Verilog and SystemVerilog files that do not contain "tb" in their path
+* uses Python 3.x
+
+## Rules that are checked
+
+These rules can be found in the [HDL coding guideline](https://github.com/analogdevicesinc/hdl/blob/master/docs/hdl_coding_guideline.md).
+
+### 1. License header
+
+It checks if the license header is up-to-date, containing the current year in
+the year range. Exceptions are the JESD files and the ones specified in the
+`avoid_list` string list.  
+If `-e` option is added, the script can update the year range.
+
+### 2. Two or more consecutive empty lines
+
+It checks in the whole file if there are two or more consecutive empty lines.  
+If `-e` option is added, the script can remove them and leave only one empty line.
+
+### 3. Trailing whitespace
+
+It checks if there are whitespace characters at the end of the lines.  
+If `-e` option is added, then they can be removed.
+
+### 4. Lines after `endmodule` tag
+
+It checks if there are  lines after it.  
+If `-e` option is added, the script can remove them.
+
+### 5. Parentheses around the module declaration
+
+It checks if the parentheses around the module declaration (meaning `) (` for
+the parameters' list) are on an empty line, right after the last parameter.  
+It also checks for the closing parenthesis at the module declaration (meaning `);`)
+to be on an empty line, at the beginning, right after the last I/O port line.  
+If `-e` option is added, the script can put them in their proper place.
+
+### 6. Indentation of code
+
+It checks if all lines (except for the ones that are commented) have an indentation 
+of two or multiple of two spaces.  
+Other exceptions to this are the `module` line, the `endmodule` line, the `) (` 
+and the `);` from the module declaration.
+
+### 7. Position of the module instances
+
+It checks if the parameters' list (if that's the case) is in proper position, 
+meaning that the position of `#` is checked, the parameters to be specified each 
+on its own line, the parentheses around the instance name and the closing parenthesis 
+of the module instance.
+
+_NOTE_: these rules are marked in the script with **GC** (stands for Guideline Check) 
+in the comments.
+
+## Changes done by the script to your files
+
+If one wants the script to make changes in files, they will be regarding:
+* license header, except for JESD files and the ones specified in `avoid_list`
+* two or more consecutive empty lines
+* trailing whitespaces
+* lines after `endmodule` tag
+* parentheses around the module declaration (meaning `) (` for the parameters'
+  list and `);` for when closing the declaration)
+
+## Ways to run the script
+
+1. With no arguments: `python3 check_guideline.py`  
+Checks all files with the properties specified above. 
+Does not modify the files.
+
+2. With arguments:
+  1. `-e` with no file specified  
+    Checks all files with the properties specified above. Additionally, 
+    it modifies the module definition parentheses according to the guideline.
+
+  2. `-m`
+    Checks files that are given as arguments (by their names including the
+    extension).
+
+  3. `-me`
+    Checks files that are given as arguments (by their names including the
+    extension) and modifies the files where the guideline is not respected.
+
+  4. `-p`
+    Checks files that are given as arguments (by their relative path) and
+    modifies the files where the guideline is not respected.
+
+  5. `-pe`
+    Checks files that are given as arguments (by their relative path) and
+    modifies the files where the guideline is not respected.
+
+## Examples of running
+
+```
+python3 check_guideline.py     >> warnings.txt
+python3 check_guideline.py -e  >> warnings.txt
+python3 check_guideline.py -m  axi_ad9783.v >> warnings.txt
+python3 check_guideline.py -me axi_ad9783.v axi_ad9783_if.v up_adc_common.v >> warnings.txt
+python3 check_guideline.py -p  ./library/axi_ad9783/axi_ad9783.v ./library/common/up_adc_common.v >> warnings.txt
+python3 check_guideline.py -pe ./library/axi_ad9783/axi_ad9783_if.v >> warnings.txt
+```