From 15b3d932a4e8e068b824f1b3eabb6d1fcc0de104 Mon Sep 17 00:00:00 2001
From: Robert Szczepanski <rszczepanski@internships.antmicro.com>
Date: Tue, 9 Feb 2021 15:29:31 +0100
Subject: [PATCH] gpio: add support for interrupts on GPIOIn

---
 litex/soc/cores/gpio.py | 46 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 45 insertions(+), 1 deletion(-)

diff --git a/litex/soc/cores/gpio.py b/litex/soc/cores/gpio.py
index 3de711dd5..73e0d15c0 100644
--- a/litex/soc/cores/gpio.py
+++ b/litex/soc/cores/gpio.py
@@ -10,18 +10,62 @@ from migen.genlib.cdc import MultiReg
 
 from litex.soc.interconnect.csr import *
 
+from litex.soc.interconnect.csr_eventmanager import *
+
+from enum import Enum
+
 # Helpers ------------------------------------------------------------------------------------------
 
 def _to_signal(obj):
     return obj.raw_bits() if isinstance(obj, Record) else obj
 
+class IRQ_Type(Enum):
+    NO_IRQ = 0
+    RISING_EDGE = 1
+    FALLING_EDGE = 2
+
 # GPIO Input ---------------------------------------------------------------------------------------
 
 class GPIOIn(Module, AutoCSR):
-    def __init__(self, pads):
+    """GPIO Input
+
+    Parameters / Attributes
+    -----------------------
+    pads : Object
+        GPIO Input pads description.
+
+    irq : list of IRQ_Type (optional)
+        List containing IRQ types for each pad. It can take values supported by IRQ_Type Enum.
+
+        Example use:
+        irq = [IRQ_Type.NO_IRQ, IRQ_Type.NO_IRQ, IRQ_Type.FALLING_EDGE, IRQ_Type.RISING_EDGE] 
+        This adds interrupts on pins 2 (falling edge) and 3 (rising edge).
+    """
+    def __init__(self, pads, irq=None):
         pads = _to_signal(pads)
         self._in = CSRStatus(len(pads), description="GPIO Input(s) Status.")
         self.specials += MultiReg(pads, self._in.status)
+        
+        if irq:
+            assert(len(irq) <= len(pads))
+            self.submodules.ev = EventManager()
+
+            irq_no = []
+            for i, irq_type in enumerate(irq):
+                assert(irq_type, IRQ_Type)
+                name = "pin" + str(i)
+                if irq_type == IRQ_Type.RISING_EDGE:
+                    setattr(self.ev, name, EventSourcePulse())
+                    irq_no.append(i)
+                elif irq_type == IRQ_Type.FALLING_EDGE:
+                    setattr(self.ev, name, EventSourceProcess())
+                    irq_no.append(i)
+                
+            self.ev.finalize()
+
+            sources_u = [v for k, v in xdir(self.ev, True) if isinstance(v, (EventSourcePulse, EventSourceProcess))]
+            for i, source in enumerate(sources_u):
+                self.comb += source.trigger.eq(pads[irq_no[i]])
 
 # GPIO Output --------------------------------------------------------------------------------------