Add Avago ADNS-5020 optical mouse sensor decoder.

Decodes reads/writes of registers. Understands resetting on chip select if
provided. Does not understand burst mode.

Signed-off-by: Karl Palsson <karlp@tweak.net.au>

1 files changed, 113 insertions, 0 deletions

diff --git a/decoders/adns5020/pd.py b/decoders/adns5020/pd.py
new file mode 100644
index 0000000..ed92322
--- /dev/null
+++ b/decoders/adns5020/pd.py
@@ -0,0 +1,113 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2015 Karl Palsson <karlp@tweak.net.au>
+##
+## 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
+##
+
+import sigrokdecode as srd
+
+regs = {
+	0: 'Product_ID',
+	1: 'Revision_ID',
+	2: 'Motion',
+	3: 'Delta_X',
+	4: 'Delta_Y',
+	5: 'SQUAL',
+	6: 'Shutter_Upper',
+	7: 'Shutter_Lower',
+	8: 'Maximum_Pixel',
+	9: 'Pixel_Sum',
+	0xa: 'Minimum_Pixel',
+	0xb: 'Pixel_Grab',
+	0xd: 'Mouse_Control',
+	0x3a: 'Chip_Reset',
+	0x3f: 'Inv_Rev_ID',
+	0x63: 'Motion_Burst',
+}
+
+class Decoder(srd.Decoder):
+    api_version = 2
+    id = 'adns5020'
+    name = 'ADNS-5020'
+    longname = 'ADNS-5020 optical mouse sensor'
+    desc = 'Bidirectional command and data over an SPI-like protocol.'
+    license = 'gplv2'
+    inputs = ['spi']
+    outputs = ['adns5020']
+    annotations = (
+        ('read', 'Register read commands'),
+        ('write', 'Register write commands'),
+        ('warning', 'Warnings'),
+    )
+    annotation_rows = (
+        ('read', 'Read', (0,)),
+        ('write', 'Write', (1,)),
+        ('warnings', 'Warnings', (2,)),
+    )
+
+    def __init__(self, **kwargs):
+        self.ss_cmd, self.es_cmd = 0, 0
+        self.mosi_bytes = []
+
+    def start(self):
+        self.out_ann = self.register(srd.OUTPUT_ANN)
+
+    def putx(self, data):
+        self.put(self.ss_cmd, self.es_cmd, self.out_ann, data)
+
+    def put_warn(self, pos, msg):
+        self.put(pos[0], pos[1], self.out_ann, [2, [msg]])
+
+    def decode(self, ss, es, data):
+        ptype = data[0]
+        if ptype == 'CS-CHANGE':
+            # If we transition high mid-stream, toss out our data and restart.
+            cs_old, cs_new = data[1:]
+            if cs_old is not None and cs_old == 0 and cs_new == 1:
+                if len(self.mosi_bytes) not in [0, 2]:
+                    self.put_warn([self.ss_cmd, es], 'Misplaced CS#!')
+                    self.mosi_bytes = []
+            return
+
+        # Don't care about anything else.
+        if ptype != 'DATA':
+            return
+        mosi, miso = data[1:]
+
+        self.ss, self.es = ss, es
+
+        if len(self.mosi_bytes) == 0:
+            self.ss_cmd = ss
+        self.mosi_bytes.append(mosi)
+
+        # Writes/reads are mostly two transfers (burst mode is different).
+        if len(self.mosi_bytes) != 2:
+            return
+
+        self.es_cmd = es
+        cmd, arg = self.mosi_bytes
+        write = cmd & 0x80
+        reg = cmd & 0x7f
+        reg_desc = regs.get(reg, 'Reserved %#x' % reg)
+        if reg > 0x63:
+            reg_desc = 'Unknown'
+        if write:
+            self.putx([1, ['%s=>%#x' % (reg_desc, arg)]])
+        else:
+            self.putx([0, ['%s<=%d' % (reg_desc, arg)]])
+
+        self.mosi_bytes = []