--- On Mon, 8/23/10, Praveena Nadahally <praveen.nadahally@xxxxxxxxxxxxxx> wrote:
> From: Praveena Nadahally <praveen.nadahally@xxxxxxxxxxxxxx>
> Subject: [PATCH] USB Gadget: Verify VBUS current before setting the device self-powered bit
> To: linux-usb@xxxxxxxxxxxxxxx
> Cc: STEricsson_nomadik_linux@xxxxxxxxxxx, linus.walleij@xxxxxxxxxxxxxx, "Parirajan Muthalagu" <parirajan.muthalagu@xxxxxxxxxxxxxx>, "Praveena Nadahally" <praveen.nadahally@xxxxxxxxxxxxxx>
> Date: Monday, August 23, 2010, 1:25 AM
> From: Parirajan Muthalagu <parirajan.muthalagu@xxxxxxxxxxxxxx>
>
>
> Signed-off-by: Parirajan Muthalagu <parirajan.muthalagu@xxxxxxxxxxxxxx>
> Signed-off-by: Praveena Nadahally <praveen.nadahally@xxxxxxxxxxxxxx>
> Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxxxxxx>
Acked-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
... given the issues I note ar resolved first.
> ---
> drivers/usb/gadget/composite.c | 11
> ++++++++++-
> include/linux/usb/ch9.h |
> 9 +++++++++
> 2 files changed, 19 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/usb/gadget/composite.c
> b/drivers/usb/gadget/composite.c
> index e483f80..bfe0bd6 100644
> --- a/drivers/usb/gadget/composite.c
> +++ b/drivers/usb/gadget/composite.c
> @@ -1074,7 +1074,16 @@ static int composite_bind(struct
> usb_gadget *gadget)
> cdev->bufsiz = USB_BUFSIZ;
> cdev->driver = composite;
>
> - usb_gadget_set_selfpowered(gadget);
> + /*
> + * According to USB spec, a
> device that is actively drawing
> + * more than 100mA from USB
> must report itself as bus-powered in
> + * the GetStatus(DEVICE)
> call.
> + * There is no clear
> mentioning about the status when the device
> + * draws exactly 100mA. so,
Istoo. ...
> to be on the safer side, the device is
> + * self-powered only when
> VBUS is 'less' than 100mA.
> + */
> + if (CONFIG_USB_GADGET_VBUS_DRAW <
Annoyingly, I can't find where that CONFIG_ var is defined in KConfig.
References, yes. This seems to need fixing ...
> USB_SELF_POWER_VBUS_MAX_DRAW)
Make that "<= to match the USB-IF doc you reference.
A device that is actively drawing more than 100mA from USB must report itself as bus-powered in the GetStatus(DEVICE) call. Peripherals that return "Self-powered" in the GetStatus(DEVICE) call are prohibited from drawing more than 100mA at any time.
> usb_gadget_set_selfpowered(gadget);
>
> /* interface and string IDs start at
> zero via kzalloc.
> * we force endpoints to
> start unassigned; few controller
> diff --git a/include/linux/usb/ch9.h
> b/include/linux/usb/ch9.h
> index da2ed77..57cb2a6 100644
> --- a/include/linux/usb/ch9.h
> +++ b/include/linux/usb/ch9.h
> @@ -808,4 +808,13 @@ enum usb_device_state {
> */
> };
>
> +/*-------------------------------------------------------------------------*/
> +
> +/*
> + * USB compliance defines 'less' than 100mA is the
> maximum
> + * current a device can draw from Host, if it is
> self-powered.
> + * http://compliance.usb.org/index.asp?UpdateFile=Electrical&Format=Standard#34
> + */
> +#define USB_SELF_POWER_VBUS_MAX_DRAW
> 100
> +
> #endif /* __LINUX_USB_CH9_H */
> --
> 1.6.3.3
>
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