linux-kernel - Re: [PATCH] usb: cdns3: gadget: Don't manage pullups

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Date:   Fri, 25 Oct 2019 03:13:54 +0000
From:   Peter Chen <peter.chen@....com>
To:     Pawel Laszczak <pawell@...ence.com>
CC:     Roger Quadros <rogerq@...com>,
        "felipe.balbi@...ux.intel.com" <felipe.balbi@...ux.intel.com>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "nsekhar@...com" <nsekhar@...com>,
        Rahul Kumar <kurahul@...ence.com>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] usb: cdns3: gadget: Don't manage pullups

On 19-10-23 09:17:45, Pawel Laszczak wrote:
> Hi,
> 
> Reviewed-by: Pawel Laszczak <pawell@...ence.com>

Hi Roger & Pawel,

Assume gadget function has already enabled, if you switch host mode
to device mode, with your changes, where the device mode will be enabled
again?

Peter
> 
> Regards, 
> Pawel, 
> 
> >The USB gadget core is supposed to manage pullups
> >of the controller. Don't manage pullups from within
> >the controller driver. Otherwise, function drivers
> >are not able to keep the controller disconnected from
> >the bus till they are ready. (e.g. g_webcam)
> >
> >Signed-off-by: Roger Quadros <rogerq@...com>
> >---
> >Hi Greg/Felipe,
> >
> >This can be used for -rc as it is a bug fix.
> >
> >cheers,
> >-roger
> >
> > drivers/usb/cdns3/gadget.c | 4 ----
> > 1 file changed, 4 deletions(-)
> >
> >diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
> >index 2ca280f4c054..714382d96055 100644
> >--- a/drivers/usb/cdns3/gadget.c
> >+++ b/drivers/usb/cdns3/gadget.c
> >@@ -2324,8 +2324,6 @@ static void cdns3_gadget_config(struct cdns3_device *priv_dev)
> > 	writel(USB_CONF_CLK2OFFDS | USB_CONF_L1DS, &regs->usb_conf);
> >
> > 	cdns3_configure_dmult(priv_dev, NULL);
> >-
> >-	cdns3_gadget_pullup(&priv_dev->gadget, 1);
> > }
> >
> > /**
> >@@ -2708,8 +2706,6 @@ static int cdns3_gadget_suspend(struct cdns3 *cdns, bool do_wakeup)
> > 	/* disable interrupt for device */
> > 	writel(0, &priv_dev->regs->usb_ien);
> >
> >-	cdns3_gadget_pullup(&priv_dev->gadget, 0);
> >-
> > 	return 0;
> > }
> >
> >--
> >Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
> >Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
> 

-- 

Thanks,
Peter Chen