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From:   Felipe Balbi <felipe.balbi@linux.intel.com>
To:     Roger Quadros <rogerq@ti.com>, gregkh@linuxfoundation.org
Cc:     pawell@cadence.com, peter.chen@nxp.com, nsekhar@ti.com,
        kurahul@cadence.com, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org, Roger Quadros <rogerq@ti.com>
Subject: Re: [PATCH] usb: cdns3: gadget: Fix g_audio use case when connected to Super-Speed host
In-Reply-To: <20191029151514.28495-1-rogerq@ti.com>
References: <20191029151514.28495-1-rogerq@ti.com>
Date:   Wed, 30 Oct 2019 13:46:07 +0200
Message-ID: <87y2x2e9s0.fsf@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


Hi,

Roger Quadros <rogerq@ti.com> writes:

> Take into account gadget driver's speed limit when programming
> controller speed.
>
> Signed-off-by: Roger Quadros <rogerq@ti.com>
> ---
> Hi Greg,
>
> Please apply this for -rc.

if you want this in -rc, you should have a Fixes line there.

> Without this, g_audio is broken on cdns3 USB controller is
> connected to a Super-Speed host.
>
> cheers,
> -roger
>
>  drivers/usb/cdns3/gadget.c | 31 ++++++++++++++++++++++++++-----
>  1 file changed, 26 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
> index 40dad4e8d0dc..1c724c20d468 100644
> --- a/drivers/usb/cdns3/gadget.c
> +++ b/drivers/usb/cdns3/gadget.c
> @@ -2338,9 +2338,35 @@ static int cdns3_gadget_udc_start(struct usb_gadget *gadget,
>  {
>  	struct cdns3_device *priv_dev = gadget_to_cdns3_device(gadget);
>  	unsigned long flags;
> +	enum usb_device_speed max_speed = driver->max_speed;
>  
>  	spin_lock_irqsave(&priv_dev->lock, flags);
>  	priv_dev->gadget_driver = driver;
> +
> +	/* limit speed if necessary */
> +	max_speed = min(driver->max_speed, gadget->max_speed);
> +
> +	switch (max_speed) {
> +	case USB_SPEED_FULL:
> +		writel(USB_CONF_SFORCE_FS, &priv_dev->regs->usb_conf);
> +		writel(USB_CONF_USB3DIS, &priv_dev->regs->usb_conf);
> +		break;
> +	case USB_SPEED_HIGH:
> +		writel(USB_CONF_USB3DIS, &priv_dev->regs->usb_conf);
> +		break;

seems like this can be simplified a little:

	switch (max_speed) {
        case USB_SPEED_FULL:
        	writel(USB_CONF_SFORCE_FS, &priv_dev->regs->usb_conf);
                /* fallthrough */
        case USB_SPEED_HIGH:
		writel(USB_CONF_USB3DIS, &priv_dev->regs->usb_conf);
                /* fallthrough */
	case USB_SPEED_SUPER:
		break;

	[...]

		
-- 
balbi