Re: Help needed to force USB host mode on AM335x CPU
Hi,
On Fri, Nov 22, 2013 at 02:28:50PM +, Mark Jackson wrote:
> We have a custom AM335x board where the USB0_ID pin has been left floating.
>
> By default, this puts the USB controller into peripheral mode, but we need
> to force it into host mode.
>
> This can be achieved in s/w by setting some bits in the relevant USB mode
> register (see TRM 16.5.2.35).
>
> This mode register's offset is already defined in musb_dsps.c
>
> static const struct dsps_musb_wrapper am33xx_driver_data = {
> ...
> .mode = 0xe8,
> ...
> };
>
> I can manually set this register to the correct value in musb_host.c and
> the USB all seems to work as expected.
>
> int musb_host_setup(struct musb *musb, int power_budget)
> {
> int ret;
> struct usb_hcd *hcd = musb->hcd;
>
> /* Force HOST mode */
> unsigned long __iomem *p;
> p = ioremap(0x474010e8, 4);
> *p = 0x80;/* IDDIG = 0, IDDIG_MUX = 1 */
>
> MUSB_HST_MODE(musb);
> ...
> };
>
> Ideally I'd like to add an entry in my dts file to flag for this "force mode"
> to be setup, such as:-
>
> usb@47401000 {
> status = "okay";
> dr_mode = "host";
> ti,force-host; /* force host mode */
> };
>
> Can anyone point me in the right direction as to where to put this extra code
> ?
>
> I see there's a musb_am335x.c file, but that just seems to be a wrapper.
>
> Any help would be greatly apperciated.
I just sent two patches to linux-usb and I suppose they can help. In
fact, I remember now that I have to fix commit log on one of them. I'll
do that now.
cheers
--
balbi
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Help needed to force USB host mode on AM335x CPU
We have a custom AM335x board where the USB0_ID pin has been left floating.
By default, this puts the USB controller into peripheral mode, but we need
to force it into host mode.
This can be achieved in s/w by setting some bits in the relevant USB mode
register (see TRM 16.5.2.35).
This mode register's offset is already defined in musb_dsps.c
static const struct dsps_musb_wrapper am33xx_driver_data = {
...
.mode = 0xe8,
...
};
I can manually set this register to the correct value in musb_host.c and
the USB all seems to work as expected.
int musb_host_setup(struct musb *musb, int power_budget)
{
int ret;
struct usb_hcd *hcd = musb->hcd;
/* Force HOST mode */
unsigned long __iomem *p;
p = ioremap(0x474010e8, 4);
*p = 0x80; /* IDDIG = 0, IDDIG_MUX = 1 */
MUSB_HST_MODE(musb);
...
};
Ideally I'd like to add an entry in my dts file to flag for this "force mode"
to be setup, such as:-
usb@47401000 {
status = "okay";
dr_mode = "host";
ti,force-host; /* force host mode */
};
Can anyone point me in the right direction as to where to put this extra code ?
I see there's a musb_am335x.c file, but that just seems to be a wrapper.
Any help would be greatly apperciated.
Regards
Mark J.
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