From 3e47ed6b335bc84d6469cf4c84eb1ccf5a0353cc Mon Sep 17 00:00:00 2001
From: Megan Wachs <megan@sifive.com>
Date: Mon, 2 Oct 2017 11:13:33 -0700
Subject: [PATCH] PWM: Add the ability to invert the output directly in PWM
 (without GPIO pinmux)

---
 src/main/scala/devices/pwm/PWM.scala | 6 +++++-
 src/main/scala/util/Timer.scala      | 6 ++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/main/scala/devices/pwm/PWM.scala b/src/main/scala/devices/pwm/PWM.scala
index 6381004..7e7b30d 100644
--- a/src/main/scala/devices/pwm/PWM.scala
+++ b/src/main/scala/devices/pwm/PWM.scala
@@ -18,6 +18,7 @@ class PWM(val ncmp: Int = 4, val cmpWidth: Int = 16) extends GenericTimer {
   protected lazy val feed = count.carryOut(scale + UInt(cmpWidth))
   protected lazy val countEn = Wire(Bool())
   override protected lazy val oneShot = RegEnable(io.regs.cfg.write.bits(13) && !countReset, Bool(false), (io.regs.cfg.write.valid && unlocked) || countReset)
+  override protected lazy val extra  = RegEnable(io.regs.cfg.write.bits(20 + ncmp - 1, 20), init = 0.U, enable = io.regs.cfg.write.valid && unlocked)
   override protected lazy val center = RegEnable(io.regs.cfg.write.bits(16 + ncmp - 1, 16), io.regs.cfg.write.valid && unlocked)
   override protected lazy val gang = RegEnable(io.regs.cfg.write.bits(24 + ncmp - 1, 24), io.regs.cfg.write.valid && unlocked)
   override protected lazy val deglitch = RegEnable(io.regs.cfg.write.bits(10), io.regs.cfg.write.valid && unlocked)(0)
@@ -33,7 +34,10 @@ class PWM(val ncmp: Int = 4, val cmpWidth: Int = 16) extends GenericTimer {
   lazy val io = new GenericTimerIO {
     val gpio = Vec(ncmp, Bool()).asOutput
   }
-  io.gpio := io.gpio.fromBits(ip & ~(gang & Cat(ip(0), ip >> 1)))
+
+  val invert = extra
+
+  io.gpio := io.gpio.fromBits((ip & ~(gang & Cat(ip(0), ip >> 1))) ^ invert)
   countEn := countAlways || oneShot
 }
 
diff --git a/src/main/scala/util/Timer.scala b/src/main/scala/util/Timer.scala
index 52bbab2..c46d2be 100644
--- a/src/main/scala/util/Timer.scala
+++ b/src/main/scala/util/Timer.scala
@@ -38,6 +38,7 @@ abstract class GenericTimer extends Module {
   protected def sticky: Bool = Bool(false)
   protected def oneShot: Bool = Bool(false)
   protected def center: UInt = UInt(0)
+  protected def extra: UInt = UInt(0)
   protected def gang: UInt = UInt(0)
   protected val scaleWidth = 4
   protected val regWidth = 32
@@ -76,8 +77,9 @@ abstract class GenericTimer extends Module {
   protected val countReset = feed || (zerocmp && elapsed(0))
   when (countReset) { count := 0 }
 
-  io.regs.cfg.read := Cat(ip, gang | UInt(0, maxcmp), UInt(0, maxcmp), center | UInt(0, maxcmp),
-                          UInt(0, 2), countAwake || oneShot, countAlways, UInt(0, 1), deglitch, zerocmp, rsten || sticky, UInt(0, 8-scaleWidth), scale)
+  io.regs.cfg.read := Cat(ip, gang | UInt(0, maxcmp), extra | UInt(0, maxcmp), center | UInt(0, maxcmp),
+    UInt(0, 2), countAwake || oneShot, countAlways, UInt(0, 1), deglitch, zerocmp, rsten || sticky,
+    UInt(0, 8-scaleWidth),  scale)
   io.regs.countLo.read := count
   io.regs.countHi.read := count >> regWidth
   io.regs.s.read := s