srd: Add ebr30a_i2c_demux PD (I2C in, 3 x I2C out).

2 files changed, 107 insertions, 0 deletions

diff --git a/decoders/Makefile.am b/decoders/Makefile.am
index 8b64f7f..c44424e 100644
--- a/decoders/Makefile.am
+++ b/decoders/Makefile.am
@@ -31,6 +31,7 @@ dist_pkgdata_DATA = \
 	spi.py \
 	srd_usb.py \
 	transitioncounter.py \
+	ebr30a_i2c_demux.py \
 	uart.py
 
 CLEANFILES = *.pyc
diff --git a/decoders/ebr30a_i2c_demux.py b/decoders/ebr30a_i2c_demux.py
new file mode 100644
index 0000000..85048b3
--- /dev/null
+++ b/decoders/ebr30a_i2c_demux.py
@@ -0,0 +1,106 @@
+##
+## This file is part of the sigrok project.
+##
+## Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de>
+##
+## 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 2 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, write to the Free Software
+## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+##
+
+#
+# TrekStor EBR30-a I2C demux protocol decoder
+#
+# Takes an I2C stream as input and outputs 3 different I2C streams, for the
+# 3 different I2C devices on the TrekStor EBR30-a eBook reader (which are all
+# physically connected to the same SCL/SDA lines).
+#
+# I2C slave addresses:
+#
+#  - AXP199 battery management chip: 0x69/0x68 (8bit R/W), 0x34 (7bit)
+#  - H8563S RTC chip: 0xa3/0xa2 (8bit R/W), 0x51 (7bit)
+#  - Unknown accelerometer chip: 0x2b/0x2a (8bit R/W), 0x15 (7bit)
+#
+
+import sigrokdecode as srd
+
+# I2C devices
+AXP199 = 0
+H8563S = 1
+ACCEL = 2
+
+class Decoder(srd.Decoder):
+    id = 'ebr30a_i2c_demux'
+    name = 'EBR30-a I2C demux'
+    longname = 'TrekStor EBR30-a I2C demux'
+    desc = 'TODO.'
+    longdesc = 'TODO.'
+    author = 'Uwe Hermann'
+    email = 'uwe@hermann-uwe.de'
+    license = 'gplv2+'
+    inputs = ['i2c']
+    outputs = ['i2c-axp199', 'i2c-h8563s', 'i2c-accel']
+    probes = []
+    options = {}
+    annotations = []
+
+    def __init__(self, **kwargs):
+        self.packets = []
+        self.stream = -1
+
+    def start(self, metadata):
+        self.out_proto = []
+        self.out_proto.append(self.add(srd.OUTPUT_PROTO, 'i2c-axp199'))
+        self.out_proto.append(self.add(srd.OUTPUT_PROTO, 'i2c-h8563s'))
+        self.out_proto.append(self.add(srd.OUTPUT_PROTO, 'i2c-accel'))
+        # TODO: Annotations?
+
+    def report(self):
+        pass
+
+    # Grab I2C packets into a local cache, until an I2C STOP condition
+    # packet comes along. At some point before that STOP condition, there
+    # will have been an ADDRESS READ or ADDRESS WRITE which contains the
+    # I2C address of the slave that the master wants to talk to.
+    # We use this slave address to figure out which output stream should
+    # get the whole chunk of packets (from START to STOP).
+    def decode(self, ss, es, data):
+
+        cmd, databyte, ack_bit = data
+
+        # Add the I2C packet to our local cache.
+        self.packets += [[ss, es, data]]
+
+        if cmd in ('ADDRESS READ', 'ADDRESS WRITE'):
+            # print(hex(databyte))
+            if databyte == 0x34:
+                self.stream = AXP199
+            elif databyte == 0x51:
+                self.stream = H8563S
+            elif databyte == 0x15:
+                self.stream = ACCEL
+            else:
+                pass # TODO: Error?
+            # TODO: Can there be two ADDRESS READ/WRITE with two different
+            #       slave addresses before any STOP occurs?
+        elif cmd == 'STOP':
+            if self.stream != -1:
+                # Send the whole chunk of I2C packets to the correct stream.
+                for p in self.packets:
+                    # print(self.out_proto[self.stream], p)
+                    self.put(p[0], p[1], self.out_proto[self.stream], p[2])
+            else:
+                print('Error: Could not determine correct stream!') # FIXME
+            self.packets = []
+            self.stream = -1
+