dtoc: Tidy up more Python style in dtb_platdata

Update this file to reduce the number of pylint warnings. Also add a few
missing comments while we are here.

Signed-off-by: Simon Glass <sjg@chromium.org>

1 files changed, 46 insertions, 45 deletions

diff --git a/tools/dtoc/dtb_platdata.py b/tools/dtoc/dtb_platdata.py
index 6b10eabafb9..b0d3c27720c 100644
--- a/tools/dtoc/dtb_platdata.py
+++ b/tools/dtoc/dtb_platdata.py
@@ -114,8 +114,8 @@ def get_value(ftype, value):
     if ftype == fdt.Type.INT:
         return '%#x' % fdt_util.fdt32_to_cpu(value)
     elif ftype == fdt.Type.BYTE:
-        ch = value[0]
-        return '%#x' % (ord(ch) if isinstance(ch, str) else ch)
+        char = value[0]
+        return '%#x' % (ord(char) if isinstance(char, str) else char)
     elif ftype == fdt.Type.STRING:
         # Handle evil ACPI backslashes by adding another backslash before them.
         # So "\\_SB.GPO0" in the device tree effectively stays like that in C
@@ -163,7 +163,7 @@ class DtbPlatdata(object):
         _drivers_additional: List of additional drivers to use during scanning
     """
     def __init__(self, dtb_fname, include_disabled, warning_disabled,
-                 drivers_additional=[]):
+                 drivers_additional=None):
         self._fdt = None
         self._dtb_fname = dtb_fname
         self._valid_nodes = None
@@ -173,7 +173,7 @@ class DtbPlatdata(object):
         self._lines = []
         self._drivers = []
         self._driver_aliases = {}
-        self._drivers_additional = drivers_additional
+        self._drivers_additional = drivers_additional or []
 
     def get_normalized_compat_name(self, node):
         """Get a node's normalized compat name
@@ -312,20 +312,20 @@ class DtbPlatdata(object):
             return PhandleInfo(max_args, args)
         return None
 
-    def scan_driver(self, fn):
+    def scan_driver(self, fname):
         """Scan a driver file to build a list of driver names and aliases
 
         This procedure will populate self._drivers and self._driver_aliases
 
         Args
-            fn: Driver filename to scan
+            fname: Driver filename to scan
         """
-        with open(fn, encoding='utf-8') as fd:
+        with open(fname, encoding='utf-8') as inf:
             try:
-                buff = fd.read()
+                buff = inf.read()
             except UnicodeDecodeError:
                 # This seems to happen on older Python versions
-                print("Skipping file '%s' due to unicode error" % fn)
+                print("Skipping file '%s' due to unicode error" % fname)
                 return
 
             # The following re will search for driver names declared as
@@ -337,8 +337,9 @@ class DtbPlatdata(object):
 
             # The following re will search for driver aliases declared as
             # U_BOOT_DRIVER_ALIAS(alias, driver_name)
-            driver_aliases = re.findall('U_BOOT_DRIVER_ALIAS\(\s*(\w+)\s*,\s*(\w+)\s*\)',
-                                        buff)
+            driver_aliases = re.findall(
+                'U_BOOT_DRIVER_ALIAS\(\s*(\w+)\s*,\s*(\w+)\s*\)',
+                buff)
 
             for alias in driver_aliases: # pragma: no cover
                 if len(alias) != 2:
@@ -354,19 +355,19 @@ class DtbPlatdata(object):
         basedir = sys.argv[0].replace('tools/dtoc/dtoc', '')
         if basedir == '':
             basedir = './'
-        for (dirpath, dirnames, filenames) in os.walk(basedir):
-            for fn in filenames:
-                if not fn.endswith('.c'):
+        for (dirpath, _, filenames) in os.walk(basedir):
+            for fname in filenames:
+                if not fname.endswith('.c'):
                     continue
-                self.scan_driver(dirpath + '/' + fn)
+                self.scan_driver(dirpath + '/' + fname)
 
-        for fn in self._drivers_additional:
-            if not isinstance(fn, str) or len(fn) == 0:
+        for fname in self._drivers_additional:
+            if not isinstance(fname, str) or len(fname) == 0:
                 continue
-            if fn[0] == '/':
-                self.scan_driver(fn)
+            if fname[0] == '/':
+                self.scan_driver(fname)
             else:
-                self.scan_driver(basedir + '/' + fn)
+                self.scan_driver(basedir + '/' + fname)
 
     def scan_dtb(self):
         """Scan the device tree to obtain a tree of nodes and properties
@@ -422,15 +423,15 @@ class DtbPlatdata(object):
                 Number of size cells for this node
         """
         parent = node.parent
-        na, ns = 2, 2
+        num_addr, num_size = 2, 2
         if parent:
-            na_prop = parent.props.get('#address-cells')
-            ns_prop = parent.props.get('#size-cells')
-            if na_prop:
-                na = fdt_util.fdt32_to_cpu(na_prop.value)
-            if ns_prop:
-                ns = fdt_util.fdt32_to_cpu(ns_prop.value)
-        return na, ns
+            addr_prop = parent.props.get('#address-cells')
+            size_prop = parent.props.get('#size-cells')
+            if addr_prop:
+                num_addr = fdt_util.fdt32_to_cpu(addr_prop.value)
+            if size_prop:
+                num_size = fdt_util.fdt32_to_cpu(size_prop.value)
+        return num_addr, num_size
 
     def scan_reg_sizes(self):
         """Scan for 64-bit 'reg' properties and update the values
@@ -443,8 +444,8 @@ class DtbPlatdata(object):
             reg = node.props.get('reg')
             if not reg:
                 continue
-            na, ns = self.get_num_cells(node)
-            total = na + ns
+            num_addr, num_size = self.get_num_cells(node)
+            total = num_addr + num_size
 
             if reg.type != fdt.Type.INT:
                 raise ValueError("Node '%s' reg property is not an int" %
@@ -453,10 +454,10 @@ class DtbPlatdata(object):
                 raise ValueError(
                     "Node '%s' reg property has %d cells "
                     'which is not a multiple of na + ns = %d + %d)' %
-                    (node.name, len(reg.value), na, ns))
-            reg.na = na
-            reg.ns = ns
-            if na != 1 or ns != 1:
+                    (node.name, len(reg.value), num_addr, num_size))
+            reg.num_addr = num_addr
+            reg.num_size = num_size
+            if num_addr != 1 or num_size != 1:
                 reg.type = fdt.Type.INT64
                 i = 0
                 new_value = []
@@ -464,10 +465,10 @@ class DtbPlatdata(object):
                 if not isinstance(val, list):
                     val = [val]
                 while i < len(val):
-                    addr = fdt_util.fdt_cells_to_cpu(val[i:], reg.na)
-                    i += na
-                    size = fdt_util.fdt_cells_to_cpu(val[i:], reg.ns)
-                    i += ns
+                    addr = fdt_util.fdt_cells_to_cpu(val[i:], reg.num_addr)
+                    i += num_addr
+                    size = fdt_util.fdt_cells_to_cpu(val[i:], reg.num_size)
+                    i += num_size
                     new_value += [addr, size]
                 reg.value = new_value
 
@@ -513,14 +514,12 @@ class DtbPlatdata(object):
             else:
                 structs[node_name] = fields
 
-        upto = 0
         for node in self._valid_nodes:
             node_name, _ = self.get_normalized_compat_name(node)
             struct = structs[node_name]
             for name, prop in node.props.items():
                 if name not in PROP_IGNORE_LIST and name[0] != '#':
                     prop.Widen(struct[name])
-            upto += 1
 
         return structs
 
@@ -613,12 +612,10 @@ class DtbPlatdata(object):
             if info:
                 # Process the list as pairs of (phandle, id)
                 pos = 0
-                item = 0
                 for args in info.args:
                     phandle_cell = prop.value[pos]
                     phandle = fdt_util.fdt32_to_cpu(phandle_cell)
                     target_node = self._fdt.phandle_to_node[phandle]
-                    name = conv_name_to_c(target_node.name)
                     arg_values = []
                     for i in range(args):
                         arg_values.append(
@@ -626,7 +623,6 @@ class DtbPlatdata(object):
                     pos += 1 + args
                     vals.append('\t{%d, {%s}}' % (target_node.idx,
                                                   ', '.join(arg_values)))
-                    item += 1
                 for val in vals:
                     self.buf('\n\t\t%s,' % val)
             else:
@@ -714,7 +710,7 @@ class DtbPlatdata(object):
         self.out(''.join(self.get_buf()))
 
 def run_steps(args, dtb_file, include_disabled, output, warning_disabled=False,
-              drivers_additional=[]):
+              drivers_additional=None):
     """Run all the steps of the dtoc tool
 
     Args:
@@ -722,13 +718,18 @@ def run_steps(args, dtb_file, include_disabled, output, warning_disabled=False,
         dtb_file (str): Filename of dtb file to process
         include_disabled (bool): True to include disabled nodes
         output (str): Name of output file
+        warning_disabled (bool): True to avoid showing warnings about missing
+            drivers
+       _drivers_additional (list): List of additional drivers to use during
+            scanning
     Raises:
         ValueError: if args has no command, or an unknown command
     """
     if not args:
         raise ValueError('Please specify a command: struct, platdata')
 
-    plat = DtbPlatdata(dtb_file, include_disabled, warning_disabled, drivers_additional)
+    plat = DtbPlatdata(dtb_file, include_disabled, warning_disabled,
+                       drivers_additional)
     plat.scan_drivers()
     plat.scan_dtb()
     plat.scan_tree()