From 2e48ab568bbc58ea459d21b70a395e1238aadf4b Mon Sep 17 00:00:00 2001
From: Florent Kermarrec <florent@enjoy-digital.fr>
Date: Fri, 27 Mar 2020 18:44:48 +0100
Subject: [PATCH] soc/cores/spi: make dynamic clk divider optional (can be
 enabled with add_clk_divider method) and only use it in add_spi_sdcard.

---
 litex/soc/cores/spi.py       | 6 ++++--
 litex/soc/integration/soc.py | 1 +
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/litex/soc/cores/spi.py b/litex/soc/cores/spi.py
index 58f3b6ca2..afa0b9506 100644
--- a/litex/soc/cores/spi.py
+++ b/litex/soc/cores/spi.py
@@ -137,7 +137,6 @@ class SPIMaster(Module, AutoCSR):
             CSRField("sel", len(self.cs), reset=1, description="Write ``1`` to corresponding bit to enable Xfer for chip.")
         ], description="SPI Chip Select.")
         self._loopback = CSRStorage(description="SPI loopback mode.\n\n Write ``1`` to enable MOSI to MISO internal loopback.")
-        self._clk_divider = CSRStorage(16, description="SPI Clk Divider.", reset=self.clk_divider.reset)
 
         self.comb += [
             self.start.eq(self._control.fields.start),
@@ -145,12 +144,15 @@ class SPIMaster(Module, AutoCSR):
             self.mosi.eq(self._mosi.storage),
             self.cs.eq(self._cs.storage),
             self.loopback.eq(self._loopback.storage),
-            self.clk_divider.eq(self._clk_divider.storage),
 
             self._status.fields.done.eq(self.done),
             self._miso.status.eq(self.miso),
         ]
 
+    def add_clk_divider(self):
+        self._clk_divider = CSRStorage(16, description="SPI Clk Divider.", reset=self.clk_divider.reset)
+        self.comb += self.clk_divider.eq(self._clk_divider.storage)
+
 # SPI Slave ----------------------------------------------------------------------------------------
 
 class SPISlave(Module):
diff --git a/litex/soc/integration/soc.py b/litex/soc/integration/soc.py
index fb2bfb74d..b06abdef7 100644
--- a/litex/soc/integration/soc.py
+++ b/litex/soc/integration/soc.py
@@ -1154,5 +1154,6 @@ class LiteXSoC(SoC):
         if hasattr(pads, "rst"):
             self.comb += pads.rst.eq(0)
         spisdcard = SPIMaster(pads, 8, self.sys_clk_freq, 400e3)
+        spisdcard.add_clk_divider()
         setattr(self.submodules, name, spisdcard)
         self.add_csr(name)