linux-kernel - Re: [PATCH v6 23/25] usb: chipidea: Pullup D+ in device mode via phy APIs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 3 Jan 2017 14:53:19 +0800
From:   Peter Chen <hzpeterchen@...il.com>
To:     Stephen Boyd <stephen.boyd@...aro.org>
Cc:     linux-usb@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        Andy Gross <andy.gross@...aro.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Neil Armstrong <narmstrong@...libre.com>,
        Arnd Bergmann <arnd@...db.de>, Felipe Balbi <balbi@...nel.org>,
        Peter Chen <peter.chen@....com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [PATCH v6 23/25] usb: chipidea: Pullup D+ in device mode via phy
 APIs

On Wed, Dec 28, 2016 at 02:57:09PM -0800, Stephen Boyd wrote:
> If the phy supports it, call phy_set_mode() to pull up D+ when
> required by setting the mode to PHY_MODE_USB_DEVICE. If we want
> to remove the pullup, set the mode to PHY_MODE_USB_HOST.
> 
> Cc: Peter Chen <peter.chen@....com>
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Signed-off-by: Stephen Boyd <stephen.boyd@...aro.org>
> ---
>  drivers/usb/chipidea/udc.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
> index 0d532a724d48..6d61fa0689b0 100644
> --- a/drivers/usb/chipidea/udc.c
> +++ b/drivers/usb/chipidea/udc.c
> @@ -18,6 +18,7 @@
>  #include <linux/kernel.h>
>  #include <linux/slab.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/phy/phy.h>
>  #include <linux/usb/ch9.h>
>  #include <linux/usb/gadget.h>
>  #include <linux/usb/otg-fsm.h>
> @@ -1609,10 +1610,15 @@ static int ci_udc_pullup(struct usb_gadget *_gadget, int is_on)
>  		return 0;
>  
>  	pm_runtime_get_sync(&ci->gadget.dev);
> -	if (is_on)
> +	if (is_on) {
> +		if (ci->phy)
> +			phy_set_mode(ci->phy, PHY_MODE_USB_DEVICE);
>  		hw_write(ci, OP_USBCMD, USBCMD_RS, USBCMD_RS);
> -	else
> +	} else {
>  		hw_write(ci, OP_USBCMD, USBCMD_RS, 0);
> +		if (ci->phy)
> +			phy_set_mode(ci->phy, PHY_MODE_USB_HOST);
> +	}
>  	pm_runtime_put_sync(&ci->gadget.dev);
>  
>  	return 0;
> -- 

Would you describe the use case for it? Why not adding it at
role switch routine?

-- 

Best Regards,
Peter Chen