usb: gadget: r8a66597-udc: Make BUSWAIT configurable through platform data
BUSWAIT is a 4-bit-wide value that controls the number of access waits
from the CPU to on-chip USB module. b'0000 inserts 0 wait (2 access
cycles) and b'1111 inserts 15 waits (17 access cycles, hardware
initial value), respectively.
BUSWAIT value depends on peripheral clock frequency supplied to on-chip
of each CPU, hence should be configurable through platform data.
Note that this patch assumes that b'0000 (0 wait, 2 access cycles) is
rerely used and considered as invalid. If valid 'buswait' data is not
provided by platform, initial b'1111 (15 waits, 17 access cycles) will
be applied as a safe default.
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/include/linux/usb/r8a66597.h b/include/linux/usb/r8a66597.h
index 26d2167..6e1bfae 100644
--- a/include/linux/usb/r8a66597.h
+++ b/include/linux/usb/r8a66597.h
@@ -31,6 +31,9 @@
/* This callback can control port power instead of DVSTCTR register. */
void (*port_power)(int port, int power);
+ /* This parameter is for BUSWAIT */
+ u16 buswait;
+
/* set one = on chip controller, set zero = external controller */
unsigned on_chip:1;