On Fri, Jun 26, 2015 at 03:47:04PM +0200, Mike Looijmans wrote:
> The datasheet for the USB343x PHY mentions a 50ms wait time before
> reading back the ID bit after enabling the internal pull-up or a
> reset:
> "To monitor the status of the ID pin, the Link activates the IdPullup
> bit in the OTG Control register, waits 50mS and then reads the status
> of the IdGnd bit in the USB Interrupt Status register."
> Implement this by adding a 50ms sleep at the only point in the code
> where the ID status is being read without IRQ trigger.
This 50mS delay is dedicated for this PHY, you may add it at the
PHY driver.
>
> When starting the board with a USB cable connected to a PC, the
> system would activate host mode, then in ~20ms get an ID IRQ and
> attempt to switch to gadget mode. This then failed because the
> VBUS will not drop to zero (because the host is supplying it).
>
> After this patch, the system starts up correctly and selects
> gadget mode immediately, and the USB link works. It also fixes
> the issue that the VBUS supply was being activated while already
> being supplied from the host PC.
>
> Signed-off-by: Mike Looijmans <mike.looijmans@xxxxxxxx>
> ---
> drivers/usb/chipidea/core.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
> index c865abe..4c6cf48 100644
> --- a/drivers/usb/chipidea/core.c
> +++ b/drivers/usb/chipidea/core.c
> @@ -801,6 +801,7 @@ static int ci_hdrc_probe(struct platform_device *pdev)
>
> if (ci->roles[CI_ROLE_HOST] && ci->roles[CI_ROLE_GADGET]) {
> if (ci->is_otg) {
> + msleep(50); /* Datasheet: Wait 50ms to read ID */
> ci->role = ci_otg_role(ci);
> /* Enable ID change irq */
> hw_write_otgsc(ci, OTGSC_IDIE, OTGSC_IDIE);
> --
> 1.9.1
>
--
Best Regards,
Peter Chen
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