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usb: gadget: r8a66597-udc: Make BUSWAIT configurable through platform data

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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>
This commit is contained in:
Yoshihiro Shimoda 2011-07-08 14:51:27 +09:00 committed by Felipe Balbi
parent deafeb24e8
commit 5154e9f126
2 changed files with 8 additions and 1 deletions
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6
drivers/usb/gadget/r8a66597-udc.c
View file

@ -576,7 +576,11 @@ static void init_controller(struct r8a66597 *r8a66597)
u16 endian = r8a66597->pdata->endian ? BIGEND : 0;
if (r8a66597->pdata->on_chip) {
r8a66597_bset(r8a66597, 0x04, SYSCFG1);
if (r8a66597->pdata->buswait)
r8a66597_write(r8a66597, r8a66597->pdata->buswait,
SYSCFG1);
else
r8a66597_write(r8a66597, 0x0f, SYSCFG1);
r8a66597_bset(r8a66597, HSE, SYSCFG0);
r8a66597_bclr(r8a66597, USBE, SYSCFG0);

3
include/linux/usb/r8a66597.h
View file

@ -31,6 +31,9 @@ struct r8a66597_platdata {
/* 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;