[PATCH 2/2] USB: musb: omap2430: add mode change from A to B

[Wang Hui]

On omap2/3 series platforms, the musb can't raise id pin change
detection interrupt, so we must change otg mode through sysfs
interface manually. Currently when the musb is in B mode, if we
want musb to be changed to A mode, we should plug a mini-A cable
and then execute echo host > /sys/devices/platform/musb_hdrc/mode.
But if the musb is in A mode, we can't change it to B mode through
this method.
To solve this problem, add a process for sending end session request.
This process works like this, if the musb is in A mode, it will send
an end session request first, then it will follow original routine:
start a new session, during this session, it will identify whether
A or B is plugging in the socket,  then it will init controller to A
or B mode according to its identification.

Usage: change cable as you desired,
       change musb mode by #>echo host[peripheral] > /sys/devices/\
       platform/musb_hdrc/mode,
       then you will get required musb mode.

Signed-off-by: Wang Hui <Hui.Wang at windriver.com>
---
 drivers/usb/musb/omap2430.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/drivers/usb/musb/omap2430.c b/drivers/usb/musb/omap2430.c
index 3fe1686..b02897e 100644
--- a/drivers/usb/musb/omap2430.c
+++ b/drivers/usb/musb/omap2430.c
@@ -194,6 +194,11 @@ int musb_platform_set_mode(struct musb *musb, u8 musb_mode)
 {
 	u8	devctl = musb_readb(musb->mregs, MUSB_DEVCTL);
 
+	if ((devctl & MUSB_DEVCTL_BDEVICE) == 0x0) {
+		devctl &= ~MUSB_DEVCTL_SESSION;
+		musb_writeb(musb->mregs, MUSB_DEVCTL, devctl);
+	}
+
 	devctl |= MUSB_DEVCTL_SESSION;
 	musb_writeb(musb->mregs, MUSB_DEVCTL, devctl);
 
-- 
1.5.6.5