From 3d49afe6edbe408f75880c0ba4106dca41f3eaeb Mon Sep 17 00:00:00 2001
From: Saji <saji@saji.dev>
Date: Fri, 27 Sep 2024 01:04:17 -0500
Subject: [PATCH] rename bitslicer to hub75, rework hub75ctrl sig

---
 src/groovylight/common.py                  |  5 +++--
 src/groovylight/gamma.py                   | 22 ++++++++++++++++++++++
 src/groovylight/{bitslicer.py => hub75.py} |  3 +--
 src/groovylight/tests/test_hub75.py        |  7 ++++++-
 src/groovylight/tests/test_swapbuffer.py   |  7 +------
 tests/test_platform.py                     |  9 +++++++++
 6 files changed, 42 insertions(+), 11 deletions(-)
 rename src/groovylight/{bitslicer.py => hub75.py} (99%)

diff --git a/src/groovylight/common.py b/src/groovylight/common.py
index c8d07b8..675ca55 100644
--- a/src/groovylight/common.py
+++ b/src/groovylight/common.py
@@ -1,4 +1,4 @@
-from amaranth import unsigned
+from amaranth import Array, unsigned
 from amaranth.lib import wiring, data
 from amaranth.lib.wiring import Out
 
@@ -42,13 +42,14 @@ class Hub75Ctrl(wiring.Signature):
 
     """
 
-    def __init__(self):
+    def __init__(self, n_strings: int = 1):
         super().__init__(
             {
                 "latch": Out(1),
                 "oe": Out(1),
                 "addr": Out(5),
                 "display_clk": Out(1),
+                "data": Out(Hub75Data()).array(n_strings),
             }
         )
 
diff --git a/src/groovylight/gamma.py b/src/groovylight/gamma.py
index 362d9db..d358c89 100644
--- a/src/groovylight/gamma.py
+++ b/src/groovylight/gamma.py
@@ -24,8 +24,30 @@
 # This file contains code to generate these timing adjustments and
 # control/quantify them.
 
+
+# FIXME: This doesn't work. As much as I wish it did. Because the numbers are still
+# added linearly. values that are between the powers of two (which are fitted to the log
+# curve) are not even remotely close to matching.
+# thankfully a gamma LUT is only 64 elements. we will need 3 muxes per color (1 per channel).
+
 from math import pow
 
+from amaranth import Module, Cat, Mux, ShapeLike, Signal, Assert
+from amaranth.build import Platform
+from amaranth.lib import wiring, data
+from amaranth.lib.wiring import In, Out
+from amaranth.lib.memory import Memory, ReadPort, WritePort
+from amaranth.utils import ceil_log2
+
+
+class GammaLUT(wiring.Component):
+    def __init__(self, n_bits: int, gamma: float = 2.2):
+        self.gamma = gamma
+        self.n_bits = n_bits
+        self.lut = [pow(x, gamma) for x in range(2**n_bits)]
+
+        # TODO: we can combo it maybe with the variable timing method.
+        super().__init__(wiring.Signature({}))
 
 def _gammavec(vals: [float], g: float) -> [float]:
     return [pow(x, g) for x in vals]
diff --git a/src/groovylight/bitslicer.py b/src/groovylight/hub75.py
similarity index 99%
rename from src/groovylight/bitslicer.py
rename to src/groovylight/hub75.py
index b04474f..24773a4 100644
--- a/src/groovylight/bitslicer.py
+++ b/src/groovylight/hub75.py
@@ -163,8 +163,7 @@ class Hub75Coordinator(wiring.Component):
         self.n_strings = n_strings
         super().__init__(
             {
-                "ctrl": Out(Hub75Ctrl),
-                "data": data.ArrayLayout(Hub75Data, n_strings),
+                "hub75": Out(Hub75Ctrl(n_strings)),
                 # TODO: fetching routine? maybe it's passed through.
             }
         )
diff --git a/src/groovylight/tests/test_hub75.py b/src/groovylight/tests/test_hub75.py
index a0f8050..5b6a2c5 100644
--- a/src/groovylight/tests/test_hub75.py
+++ b/src/groovylight/tests/test_hub75.py
@@ -5,7 +5,7 @@ from amaranth.lib.wiring import In, Out
 from amaranth.lib.memory import Memory, WritePort
 from amaranth.sim import Simulator
 
-from ..bitslicer import Hub75StringDriver, Rgb666Layout
+from ..hub75 import Hub75Coordinator, Hub75StringDriver, Rgb666Layout
 
 
 def test_stringdriver():
@@ -36,3 +36,8 @@ def test_stringdriver():
 
     with sim.write_vcd("output.vcd"):
         sim.run_until(1e-6 * 1000)
+
+
+def test_hub75():
+    m = Module()
+    m.submodules.dut = dut = Hub75Coordinator(1)
diff --git a/src/groovylight/tests/test_swapbuffer.py b/src/groovylight/tests/test_swapbuffer.py
index e1498a9..e312ba9 100644
--- a/src/groovylight/tests/test_swapbuffer.py
+++ b/src/groovylight/tests/test_swapbuffer.py
@@ -1,11 +1,6 @@
-from amaranth import Array, Module, Cat, Signal, Assert, unsigned
-from amaranth.build import Platform
-from amaranth.lib import wiring, data
-from amaranth.lib.wiring import In, Out
-from amaranth.lib.memory import Memory, WritePort
 from amaranth.sim import Simulator
 
-from ..bitslicer import Hub75StringDriver, Rgb666Layout, SwapBuffer
+from ..hub75 import Hub75StringDriver, Rgb666Layout, SwapBuffer
 
 
 def test_swapbuffer():
diff --git a/tests/test_platform.py b/tests/test_platform.py
index 7194d5b..96acb01 100644
--- a/tests/test_platform.py
+++ b/tests/test_platform.py
@@ -5,6 +5,12 @@ from amaranth.lib.io import Buffer
 from groovylight.platforms.colorlight_5a75b_v8_2 import Colorlight_5A75B_R82Platform
 
 
+def progs_exist(programs) -> bool:
+    for p in programs:
+        if shutil.which(p) is None:
+            return False
+    return True
+
 class Blinky(Elaboratable):
     def elaborate(self, platform):
         m = Module()
@@ -24,5 +30,8 @@ class Blinky(Elaboratable):
 
 
 def test_platform():
+    if not progs_exist(["yosys", "nextpnr-ecp5", "openFPGALoader"]):
+        pytest.skip("missing toolchain programs")
     plat = Colorlight_5A75B_R82Platform()
+
     plat.build(Blinky())