binman: Tidy up some docs and comments

Fix a few missing comments and tidy up some existing ones.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/binman/README b/tools/binman/README
index 32d8919..f3a979e 100644
--- a/tools/binman/README
+++ b/tools/binman/README
@@ -409,8 +409,8 @@
 as a single output file.
 
 This feature provides a way of creating hierarchical images. For example here
-is an example with two copies of U-Boot. One is read-only (ro), intended to be
-written only in the factory. Another is read-write (rw), so that it can be
+is an example image with two copies of U-Boot. One is read-only (ro), intended
+to be written only in the factory. Another is read-write (rw), so that it can be
 upgraded in the field. The sizes are fixed so that the ro/rw boundary is known
 and can be programmed:
 
@@ -597,7 +597,7 @@
 a reasonably simple and sound design but has expanded greatly over the
 years. In particular its handling of x86 images is convoluted.
 
-Quite a few lessons have been learned which are hopefully be applied here.
+Quite a few lessons have been learned which are hopefully applied here.
 
 
 Design notes
diff --git a/tools/binman/ftest.py b/tools/binman/ftest.py
index 06b8132..9e12df5 100644
--- a/tools/binman/ftest.py
+++ b/tools/binman/ftest.py
@@ -150,7 +150,8 @@
         """Run binman with a given test file
 
         Args:
-            fname: Device tree source filename to use (e.g. 05_simple.dts)
+            fname: Device-tree source filename to use (e.g. 05_simple.dts)
+            debug: True to enable debugging output
         """
         args = ['-p', '-I', self._indir, '-d', self.TestFile(fname)]
         if debug:
@@ -165,10 +166,10 @@
 
         Args:
             fname: Filename of .dts file to read
-            outfile: Output filename for compiled device tree binary
+            outfile: Output filename for compiled device-tree binary
 
         Returns:
-            Contents of device tree binary
+            Contents of device-tree binary
         """
         if not self._output_setup:
             tools.PrepareOutputDir(self._indir, True)
@@ -189,7 +190,7 @@
         Raises an assertion failure if binman returns a non-zero exit code.
 
         Args:
-            fname: Device tree source filename to use (e.g. 05_simple.dts)
+            fname: Device-tree source filename to use (e.g. 05_simple.dts)
             use_real_dtb: True to use the test file as the contents of
                 the u-boot-dtb entry. Normally this is not needed and the
                 test contents (the U_BOOT_DTB_DATA string) can be used.
@@ -221,7 +222,15 @@
                 TestFunctional._MakeInputFile('u-boot.dtb', U_BOOT_DTB_DATA)
 
     def _DoReadFile(self, fname, use_real_dtb=False):
-        """Helper function which discards the device-tree binary"""
+        """Helper function which discards the device-tree binary
+
+        Args:
+            fname: Device-tree source filename to use (e.g. 05_simple.dts)
+            use_real_dtb: True to use the test file as the contents of
+                the u-boot-dtb entry. Normally this is not needed and the
+                test contents (the U_BOOT_DTB_DATA string) can be used.
+                But in some test we need the real contents.
+        """
         return self._DoReadFileDtb(fname, use_real_dtb)[0]
 
     @classmethod
@@ -270,13 +279,13 @@
             pos += entry.size
 
     def GetFdtLen(self, dtb):
-        """Get the totalsize field from a device tree binary
+        """Get the totalsize field from a device-tree binary
 
         Args:
-            dtb: Device tree binary contents
+            dtb: Device-tree binary contents
 
         Returns:
-            Total size of device tree binary, from the header
+            Total size of device-tree binary, from the header
         """
         return struct.unpack('>L', dtb[4:8])[0]
 
@@ -326,7 +335,7 @@
                 str(e.exception))
 
     def testMissingDt(self):
-        """Test that an invalid device tree file generates an error"""
+        """Test that an invalid device-tree file generates an error"""
         with self.assertRaises(Exception) as e:
             self._RunBinman('-d', 'missing_file')
         # We get one error from libfdt, and a different one from fdtget.
@@ -334,7 +343,7 @@
                            'No such file or directory'], str(e.exception))
 
     def testBrokenDt(self):
-        """Test that an invalid device tree source file generates an error
+        """Test that an invalid device-tree source file generates an error
 
         Since this is a source file it should be compiled and the error
         will come from the device-tree compiler (dtc).
diff --git a/tools/binman/image.py b/tools/binman/image.py
index 1d23496..74bc46f 100644
--- a/tools/binman/image.py
+++ b/tools/binman/image.py
@@ -30,6 +30,11 @@
         _size: Image size in bytes, or None if not known yet
         _filename: Output filename for image
         _sections: Sections present in this image (may be one or more)
+
+    Args:
+        test: True if this is being called from a test of Images. This this case
+            there is no device tree defining the structure of the section, so
+            we create a section manually.
     """
     def __init__(self, name, node, test=False):
         self._node = node