1 files changed, 61 insertions, 0 deletions
diff --git a/usrp2/firmware/lib/spi.c b/usrp2/firmware/lib/spi.c
new file mode 100644
index 000000000..937397df6
--- /dev/null
+++ b/usrp2/firmware/lib/spi.c
@@ -0,0 +1,61 @@
+/*
+ * Copyright 2007,2008 Free Software Foundation, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "spi.h"
+#include "memory_map.h"
+
+void
+spi_init(void) 
+{
+  /*
+   * f_sclk = f_wb / ((div + 1) * 2)
+   */
+  spi_regs->div = 1;  // 0 = Div by 2 (25 MHz); 1 = Div-by-4 (12.5 MHz)
+}
+
+void
+spi_wait(void) 
+{
+  while (spi_regs->ctrl & SPI_CTRL_GO_BSY)
+    ;
+}
+
+uint32_t
+spi_transact(bool readback, int slave, uint32_t data, int length, uint32_t flags) 
+{
+  flags &= (SPI_CTRL_TXNEG | SPI_CTRL_RXNEG);
+  int ctrl = SPI_CTRL_ASS | (SPI_CTRL_CHAR_LEN_MASK & length) | flags;
+
+  spi_wait();
+
+  // Tell it which SPI slave device to access
+  spi_regs->ss = slave & 0xff;
+
+  // Data we will send
+  spi_regs->txrx0 = data;
+
+  // Run it -- write once and rewrite with GO set
+  spi_regs->ctrl = ctrl;
+  spi_regs->ctrl = ctrl | SPI_CTRL_GO_BSY;
+
+  if(readback) {
+    spi_wait();
+    return spi_regs->txrx0;
+  }
+  else
+    return 0;
+}