On Thu, Nov 13, 2014 at 09:55:34PM -0600, Felipe Balbi wrote:
> Hi,
>
> On Fri, Nov 14, 2014 at 08:03:15AM +0800, Peter Chen wrote:
> > Add controller reset API, it may be used for host/otg driver in future.
>
> you need a better commit log here. How would it be used ? when ? And,
> more importantly, why ?
>
I will add more information
> Why would we need to reset the IP outside of ->probe() ?
>
> I don't oppose to the refactoring, but why would we ever need to reset
> this IP ?
Usually, we need to below reset controller at below situations:
- Role switch, host->device and device->host
- Return from hibernation, which the controller will lost its power,
and the content of the register are lost.
>
> > Signed-off-by: Peter Chen <peter.chen@xxxxxxxxxxxxx>
> > ---
> >
> > Changes for v2:
> > - Add return value check for controller reset at hw_device_reset
> >
> > drivers/usb/chipidea/core.c | 30 +++++++++++++++++++++++++++---
> > 1 file changed, 27 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
> > index bd74f27..dffd89b 100644
> > --- a/drivers/usb/chipidea/core.c
> > +++ b/drivers/usb/chipidea/core.c
> > @@ -385,6 +385,26 @@ static int ci_usb_phy_init(struct ci_hdrc *ci)
> > }
> >
> > /**
> > + * hw_controller_reset: do controller reset
> > + * @ci: the controller
> > + *
>
> minor nit: indentation
Will change
>
> > + * This function returns an error code
> > + */
> > +static int hw_controller_reset(struct ci_hdrc *ci)
> > +{
> > + int count = 0;
> > +
> > + hw_write(ci, OP_USBCMD, USBCMD_RST, USBCMD_RST);
> > + while (hw_read(ci, OP_USBCMD, USBCMD_RST)) {
> > + udelay(10);
> > + if (count++ > 1000)
> > + return -ETIMEDOUT;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +/**
> > * hw_device_reset: resets chip (execute without interruption)
> > * @ci: the controller
> > *
> > @@ -392,13 +412,17 @@ static int ci_usb_phy_init(struct ci_hdrc *ci)
> > */
> > int hw_device_reset(struct ci_hdrc *ci, u32 mode)
> > {
> > + int ret;
> > +
> > /* should flush & stop before reset */
> > hw_write(ci, OP_ENDPTFLUSH, ~0, ~0);
> > hw_write(ci, OP_USBCMD, USBCMD_RS, 0);
> >
> > - hw_write(ci, OP_USBCMD, USBCMD_RST, USBCMD_RST);
> > - while (hw_read(ci, OP_USBCMD, USBCMD_RST))
> > - udelay(10); /* not RTOS friendly */
> > + ret = hw_controller_reset(ci);
> > + if (ret) {
> > + dev_err(ci->dev, "error for reset, ret=%d\n", ret);
> > + return ret;
> > + }
> >
> > if (ci->platdata->notify_event)
> > ci->platdata->notify_event(ci,
> > --
> > 1.9.1
> >
> > --
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>
> --
> balbi
--
Best Regards,
Peter Chen
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