linux-kernel - Re: [PATCH]: fsl usb gadget driver pullup fix

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Date:	Sat, 25 Jul 2009 21:44:19 +0200 (CEST)
From:	Guennadi Liakhovetski <g.liakhovetski@....de>
To:	Stefani Seibold <stefani@...bold.net>
cc:	linux-kernel@...r.kernel.org, leoli@...escale.com,
	tanya.jiang@...escale.com
Subject: Re: [PATCH]: fsl usb gadget driver pullup fix

Hi Stefani

On Fri, 24 Jul 2009, Stefani Seibold wrote:

> Attached is a small fix for the fsl usb gadget driver. This fix the
> driver in a way that the usb device will be only "pulled up" on request,
> like other usb gadget drivers do. 
> 
> This is necessary, because the device information is not always
> available until an application is up and running which provides this
> datas.

I can confirm (as well as some others), that there indeed is a problem 
with the fsl_usb2_udc driver pullup control. If this patch fixes it - 
great! I cannot verify its correctness by just looking at it, but I might 
be able to test it on an i.MX31. On which hardware did you test it?

Thanks
Guennadi

> 
> Hope you like it.
> 
>  fsl_udc_core.c |   41 ++++++++++++++++++++---------------------
>  1 file changed, 20 insertions(+), 21 deletions(-)
> Signed-off-by: Stefani Seibold <stefani@...bold.net>
> 
> --- linux-2.6.31-rc4.orig/drivers/usb/gadget/fsl_udc_core.c	2009-07-24
> 20:35:29.000000000 +0200
> +++ linux-2.6.31-rc4/drivers/usb/gadget/fsl_udc_core.c	2009-07-24
> 21:44:10.000000000 +0200
> @@ -171,6 +171,21 @@
>  	}
>  }
>  
> +static int can_pullup(struct fsl_udc *udc)
> +{
> +	return udc->driver && udc->softconnect && udc->vbus_active;
> +}
> +
> +static void set_pullup(struct fsl_udc *udc)
> +{
> +	if (can_pullup(udc))
> +		fsl_writel((fsl_readl(&dr_regs->usbcmd) | USB_CMD_RUN_STOP),
> +				&dr_regs->usbcmd);
> +	else
> +		fsl_writel((fsl_readl(&dr_regs->usbcmd) & ~USB_CMD_RUN_STOP),
> +				&dr_regs->usbcmd);
> +}
> +
>  /*------------------------------------------------------------------
>  	Internal Hardware related function
>   ------------------------------------------------------------------*/
> @@ -283,10 +298,7 @@
>  	temp |= USB_MODE_CTRL_MODE_DEVICE;
>  	fsl_writel(temp, &dr_regs->usbmode);
>  
> -	/* Set controller to Run */
> -	temp = fsl_readl(&dr_regs->usbcmd);
> -	temp |= USB_CMD_RUN_STOP;
> -	fsl_writel(temp, &dr_regs->usbcmd);
> +	set_pullup(udc);
>  
>  	return;
>  }
> @@ -1059,11 +1071,6 @@
>  	return 0;
>  }
>  
> -static int can_pullup(struct fsl_udc *udc)
> -{
> -	return udc->driver && udc->softconnect && udc->vbus_active;
> -}
> -
>  /* Notify controller that VBUS is powered, Called by whatever
>     detects VBUS sessions */
>  static int fsl_vbus_session(struct usb_gadget *gadget, int is_active)
> @@ -1075,12 +1082,7 @@
>  	spin_lock_irqsave(&udc->lock, flags);
>  	VDBG("VBUS %s", is_active ? "on" : "off");
>  	udc->vbus_active = (is_active != 0);
> -	if (can_pullup(udc))
> -		fsl_writel((fsl_readl(&dr_regs->usbcmd) | USB_CMD_RUN_STOP),
> -				&dr_regs->usbcmd);
> -	else
> -		fsl_writel((fsl_readl(&dr_regs->usbcmd) & ~USB_CMD_RUN_STOP),
> -				&dr_regs->usbcmd);
> +	set_pullup(udc);
>  	spin_unlock_irqrestore(&udc->lock, flags);
>  	return 0;
>  }
> @@ -1111,12 +1113,7 @@
>  
>  	udc = container_of(gadget, struct fsl_udc, gadget);
>  	udc->softconnect = (is_on != 0);
> -	if (can_pullup(udc))
> -		fsl_writel((fsl_readl(&dr_regs->usbcmd) | USB_CMD_RUN_STOP),
> -				&dr_regs->usbcmd);
> -	else
> -		fsl_writel((fsl_readl(&dr_regs->usbcmd) & ~USB_CMD_RUN_STOP),
> -				&dr_regs->usbcmd);
> +	set_pullup(udc);
>  
>  	return 0;
>  }
> @@ -2194,6 +2191,8 @@
>  
>  	udc->resume_state = USB_STATE_NOTATTACHED;
>  	udc->usb_state = USB_STATE_POWERED;
> +	udc->vbus_active = 1;
> +	udc->softconnect = 1;
>  	udc->ep0_dir = 0;
>  	udc->remote_wakeup = 0;	/* default to 0 on reset */
>  
> 
> 
> --
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> 

---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
--
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