srd: add generic I2C filter PD

4 files changed, 138 insertions, 0 deletions

diff --git a/decoders/Makefile.am b/decoders/Makefile.am
index aee4e2b..7e40b2f 100644
--- a/decoders/Makefile.am
+++ b/decoders/Makefile.am
@@ -26,6 +26,7 @@ SUBDIRS = \
 	edid \
 	i2c \
 	i2cdemux \
+	i2cfilter \
 	mlx90614 \
 	mx25lxx05d \
 	nunchuk \
diff --git a/decoders/i2cfilter/Makefile.am b/decoders/i2cfilter/Makefile.am
new file mode 100644
index 0000000..5b90489
--- /dev/null
+++ b/decoders/i2cfilter/Makefile.am
@@ -0,0 +1,25 @@
+##
+## This file is part of the sigrok project.
+##
+## Copyright (C) 2012 Bert Vermeulen <bert@biot.com>
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, see <http://www.gnu.org/licenses/>.
+##
+
+pkgdatadir = $(DECODERS_DIR)/i2cfilter
+
+dist_pkgdata_DATA = __init__.py i2cfilter.py
+
+CLEANFILES = *.pyc
+
diff --git a/decoders/i2cfilter/__init__.py b/decoders/i2cfilter/__init__.py
new file mode 100644
index 0000000..6c5f1ec
--- /dev/null
+++ b/decoders/i2cfilter/__init__.py
@@ -0,0 +1,36 @@
+##
+## This file is part of the sigrok project.
+##
+## Copyright (C) 2012 Bert Vermeulen <bert@biot.com>
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, see <http://www.gnu.org/licenses/>.
+##
+
+'''
+Takes input from the I2C protocol decoder and filters out traffic from/to
+a single address on the I2C bus.
+
+It then outputs the filtered data one byte at a time as OUTPUT_PROTO up the
+protocol decoder stack. No annotations are output.
+
+The I2C address to filter out should be passed in as an option 'address', as
+an integer. A specific read or write operation can be selected with the
+'direction' option, which should be 'read' or 'write'.
+
+Both of these are optional; if no options are specified the entire payload
+of the I2C session will be output.
+'''
+
+from .i2cfilter import *
+
diff --git a/decoders/i2cfilter/i2cfilter.py b/decoders/i2cfilter/i2cfilter.py
new file mode 100644
index 0000000..4b88bef
--- /dev/null
+++ b/decoders/i2cfilter/i2cfilter.py
@@ -0,0 +1,76 @@
+##
+## This file is part of the sigrok project.
+##
+## Copyright (C) 2012 Bert Vermeulen <bert@biot.com>
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, see <http://www.gnu.org/licenses/>.
+##
+
+import sigrokdecode as srd
+
+
+class Decoder(srd.Decoder):
+    api_version = 1
+    id = 'i2cfilter'
+    name = 'I2C filter'
+    longname = 'I2C filter'
+    desc = 'Filter out specific addresses/directions in an I2C stream.'
+    license = 'gplv3+'
+    inputs = ['i2c']
+    outputs = []
+    options = {
+        'address': ['Address to filter out of the I2C stream', 0],
+        'direction': ['Direction to filter (read/write)', '']
+    }
+
+    def __init__(self, **kwargs):
+        self.state = None
+
+    def start(self, metadata):
+        self.out_proto = self.add(srd.OUTPUT_PROTO, 'i2cdata')
+        if self.options['direction'] not in ('', 'read', 'write'):
+            raise Exception("Invalid direction: expected 'read' or 'write'")
+
+    def decode(self, ss, es, data):
+        try:
+            cmd, data, ack_bit = data
+        except Exception as e:
+            raise Exception('Malformed I2C input: %s' % str(e)) from e
+
+        # Whichever state we're in, these always reset the state machine.
+        # This should make it easier to deal with corrupt data etc.
+        if cmd in ('START', 'START REPEAT'):
+            self.state = 'start'
+            return
+        if cmd == 'STOP':
+            self.state = None
+            return
+
+        if self.state == 'start':
+            # Start of a transfer, see if we want this one.
+            if cmd == 'ADDRESS READ' and self.options['direction'] == 'write':
+                return
+            elif cmd == 'ADDRESS WRITE' and self.options['direction'] == 'read':
+                return
+            elif cmd in ('ADDRESS READ', 'ADDRESS WRITE'):
+                if self.options['address'] in (0, data):
+                    # We want this tranfer.
+                    self.state = 'transfer'
+        elif self.state == 'transfer':
+            if cmd in ('DATA READ', 'DATA WRITE'):
+                self.put(ss, es, self.out_proto, data)
+        else:
+            raise Exception('Invalid state: %s' % self.state)
+
+