From 3273668e2cf398d5ccceb9a3b864ad7ebfb1ec61 Mon Sep 17 00:00:00 2001
From: Nathaniel Wesley Filardo <nwfilardo@gmail.com>
Date: Sat, 24 Oct 2020 19:31:35 +0100
Subject: [PATCH] i2c: improve and use utility wrapper

---
 cap1188/cap1188.lua | 20 ++++++--------------
 ht16k33/ht16k33.lua | 22 +++-------------------
 util/i2cu.lua       | 35 +++++++++++++++++++++++++----------
 3 files changed, 34 insertions(+), 43 deletions(-)

diff --git a/cap1188/cap1188.lua b/cap1188/cap1188.lua
index 5893c63..1a33924 100644
--- a/cap1188/cap1188.lua
+++ b/cap1188/cap1188.lua
@@ -1,27 +1,19 @@
--- DEPENDS: i2c
+-- DEPENDS: i2c, i2cu
 -- cap1188 based heavily on adafruit's documentation and code as well as the
 -- device datasheet.  Unsurprising, really, esp. that it's their breakout.
 local self = {}
+self.bus = 0
 self.addr = 0x29
 
+local i2cu = require "i2cu"
+
 function self:rr(r)
-  i2c.start(0)
-  if not i2c.address(0, self.addr, i2c.TRANSMITTER) then i2c.stop(0) return nil end
-   i2c.write(0,r)
-  i2c.start(0)
-   i2c.address(0,0x29,i2c.RECEIVER)
-   local x = i2c.read(0,1)
-  i2c.stop(0)
+  local x = i2cu.wr(self.bus, self.addr, 1, r)
   return x:byte(1)
 end
 
 function self:wr(r,v)
-  i2c.start(0)
-  if not i2c.address(0, self.addr, i2c.TRANSMITTER) then i2c.stop(0) return nil end
-  i2c.write(0,r)
-  i2c.write(0,v)
-  i2c.stop(0)
-  return true
+  return i2cu.writen(self.bus, self.addr, r, v)
 end
 
 function self:mr(r,f) local n = f(self:rr(r)) ; self:wr(r,n); return n end
diff --git a/ht16k33/ht16k33.lua b/ht16k33/ht16k33.lua
index 3f5239f..92d5ba6 100644
--- a/ht16k33/ht16k33.lua
+++ b/ht16k33/ht16k33.lua
@@ -2,25 +2,9 @@
 
 local M = {}
 
-local function tx(self, ...)
-  local i2c, bus, addr = i2c, self.bus, self.addr
-  i2c.start(bus)
-  i2c.address(bus, addr, i2c.TRANSMITTER) 
-  i2c.write(bus, ...)
-  i2c.stop(bus)
-end
-
-local function txrx(self, w, rn)
-  local i2c, bus, addr = i2c, self.bus, self.addr
-  i2c.start(bus)
-  i2c.address(bus, addr, i2c.TRANSMITTER) 
-  i2c.write(bus, w)
-  i2c.start(bus)
-  i2c.address(bus, addr, i2c.TRANSMITTER) 
-  local ret = i2c.read(rn)
-  i2c.stop(bus)
-  return ret
-end
+local i2cu = require "i2cu"
+local function tx  (self, ...)   return i2cu.writen(self.bus, self.addr, ...  ) end
+local function txrx(self, w, rn) return i2cu.wr    (self.bus, self.addr, rn, w) end
 
 -- control the primary oscillator
 local function osc(self,on)
diff --git a/util/i2cu.lua b/util/i2cu.lua
index a7e3fd9..3a59f1d 100644
--- a/util/i2cu.lua
+++ b/util/i2cu.lua
@@ -1,19 +1,34 @@
 local self = {}
 
-function self.readn(addr, len)
-  i2c.start(0)
-  if not i2c.address(0, addr, i2c.RECEIVER) then i2c.stop(0) return nil end
-  local v = i2c.read(0, len)
-  i2c.stop(0)
+function self.readn(bus, addr, len)
+  local i2c = i2c
+  i2c.start(bus)
+  if not i2c.address(bus, addr, i2c.RECEIVER) then i2c.stop(bus) return nil end
+  local v = i2c.read(bus, len)
+  i2c.stop(bus)
   return v
 end
 
-function self.writen(addr, ...)
-  i2c.start(0)
-  if not i2c.address(0, addr, i2c.TRANSMITTER) then i2c.stop(0) return nil end
-  i2c.write(0, ...)
-  i2c.stop(0)
+function self.writen(bus, addr, ...)
+  local i2c = i2c
+  i2c.start(bus)
+  if not i2c.address(bus, addr, i2c.TRANSMITTER) then i2c.stop(bus) return nil end
+  i2c.write(bus, ...)
+  i2c.stop(bus)
   return true
 end
 
+-- write/read without a full stop/start
+function self.wr(bus, addr, len, ...)
+  local i2c = i2c
+  i2c.start(bus)
+  if not i2c.address(bus, addr, i2c.TRANSMITTER) then i2c.stop(bus) return nil end
+  i2c.write(bus, ...)
+  i2c.start(bus)
+  if not i2c.address(bus, addr, i2c.RECEIVER) then i2c.stop(bus) return nil end
+  local v = i2c.read(bus, len)
+  i2c.stop(bus)
+  return v
+end
+
 return self
-- 
2.50.1