[PATCH v4 10/31] net: can: mscan: add a comment on reg to idx mapping
From: Gerhard Sittig <hidden>
Date: 2013-08-06 20:43:50
Also in:
linuxppc-dev
Subsystem:
can network drivers, the rest · Maintainers:
Marc Kleine-Budde, Vincent Mailhol, Linus Torvalds
add a comment about the magic of deriving an MSCAN component index from the peripheral's physical address / register offset Signed-off-by: Gerhard Sittig <redacted> --- drivers/net/can/mscan/mpc5xxx_can.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/net/can/mscan/mpc5xxx_can.c b/drivers/net/can/mscan/mpc5xxx_can.c
index 5b0ee8e..bc422ba 100644
--- a/drivers/net/can/mscan/mpc5xxx_can.c
+++ b/drivers/net/can/mscan/mpc5xxx_can.c@@ -148,7 +148,10 @@ static u32 mpc512x_can_get_clock(struct platform_device *ofdev, goto exit_put; } - /* Determine the MSCAN device index from the physical address */ + /* Determine the MSCAN device index from the peripheral's + * physical address. Register address offsets against the + * IMMR base are: 0x1300, 0x1380, 0x2300, 0x2380 + */ pval = of_get_property(ofdev->dev.of_node, "reg", &plen); BUG_ON(!pval || plen < sizeof(*pval)); clockidx = (*pval & 0x80) ? 1 : 0;
--
1.7.10.4