ppc4xx: Initialize magnetic couplers in PLU405
This patch fixes an ugly behavior of the IL712 magnetic couplers
as used on PLU405. These parts will remember their last state
over a power cycle which might cause unwanted behavior.
Signed-off-by: Matthias Fuchs <matthias.fuchs@esd.eu>
Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/board/esd/plu405/plu405.c b/board/esd/plu405/plu405.c
index f14ef7a..c733587 100644
--- a/board/esd/plu405/plu405.c
+++ b/board/esd/plu405/plu405.c
@@ -26,6 +26,7 @@
#include <asm/io.h>
#include <command.h>
#include <malloc.h>
+#include <sja1000.h>
#undef FPGA_DEBUG
@@ -61,6 +62,34 @@
int N_AU_IMAGES = (sizeof(au_image) / sizeof(au_image[0]));
+/*
+ * generate a short spike on the CAN tx line
+ * to bring the couplers in sync
+ */
+void init_coupler(u32 addr)
+{
+ struct sja1000_basic_s *ctrl = (struct sja1000_basic_s *)addr;
+
+ /* reset */
+ out_8(&ctrl->cr, CR_RR);
+
+ /* dominant */
+ out_8(&ctrl->btr0, 0x00); /* btr setup is required */
+ out_8(&ctrl->btr1, 0x14); /* we use 1Mbit/s */
+ out_8(&ctrl->oc, OC_TP1 | OC_TN1 | OC_POL1 |
+ OC_TP0 | OC_TN0 | OC_POL0 | OC_MODE1);
+ out_8(&ctrl->cr, 0x00);
+
+ /* delay */
+ in_8(&ctrl->cr);
+ in_8(&ctrl->cr);
+ in_8(&ctrl->cr);
+ in_8(&ctrl->cr);
+
+ /* reset */
+ out_8(&ctrl->cr, CR_RR);
+}
+
/* Prototypes */
int gunzip(void *, int, unsigned char *, unsigned long *);
@@ -214,6 +243,13 @@
out_8((void *)DUART1_BA + 1, fctr); /* write FCTR */
out_8((void *)DUART1_BA + 3, 0); /* write LCR */
+ /*
+ * Init magnetic couplers
+ */
+ if (!getenv("noinitcoupler")) {
+ init_coupler(CAN0_BA);
+ init_coupler(CAN1_BA);
+ }
return 0;
}