[linux-sunxi] Re: [PATCH 2/2] musb: sunxi: Set state to A_WAIT_VRISE when enabling VBus

[Hans de Goede]

Hi,

On 13-05-16 20:35, Bin Liu wrote:
> Hi,
>
> On Thu, May 12, 2016 at 08:31:09PM +0200, Hans de Goede wrote:
>> When the board is powering attached usb devices via the otg port
>> sometimes / on some devices it takes slightly too long for the VBus
>> detection code in phy-sun4i-usb.c to signal that VBus is high after
>> enabling VBus and the musb hardware signals a MUSB_INTR_VBUSERROR
>> interrupt.
>>
>> This commit sets the otg state to A_WAIT_VRISE upon enabling Vbus
>> making musb_stage0_irq() ignore the first VBUSERR_RETRY_COUNT
>> VBUSERROR interrupts, fixing connection issues in these cases.
>>
>> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
>> ---
>>  drivers/usb/musb/sunxi.c | 8 +++++---
>>  1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/usb/musb/sunxi.c b/drivers/usb/musb/sunxi.c
>> index 2c33d9b..2ee48fb 100644
>> --- a/drivers/usb/musb/sunxi.c
>> +++ b/drivers/usb/musb/sunxi.c
>> @@ -112,7 +112,7 @@ static void sunxi_musb_work(struct work_struct *work)
>>  		if (test_bit(SUNXI_MUSB_FL_HOSTMODE, &glue->flags)) {
>>  			set_bit(SUNXI_MUSB_FL_VBUS_ON, &glue->flags);
>>  			musb->xceiv->otg->default_a = 1;
>> -			musb->xceiv->otg->state = OTG_STATE_A_IDLE;
>> +			musb->xceiv->otg->state = OTG_STATE_A_WAIT_VRISE;
>>  			MUSB_HST_MODE(musb);
>>  			devctl |= MUSB_DEVCTL_SESSION;
>>  		} else {
>> @@ -145,9 +145,10 @@ static void sunxi_musb_set_vbus(struct musb *musb, int is_on)
>>  {
>>  	struct sunxi_glue *glue = dev_get_drvdata(musb->controller->parent);
>>
>> -	if (is_on)
>> +	if (is_on) {
>>  		set_bit(SUNXI_MUSB_FL_VBUS_ON, &glue->flags);
>> -	else
>> +		musb->xceiv->otg->state = OTG_STATE_A_WAIT_VRISE;
>
> Why this has to be set in both sunxi_musb_work() and here? Only setting
> it in the work is not efficient?

Different code paths, sunxi_musb_work sets it when the id pin changes
(gets pulled low), this function gets called by musb_core in response
to a session-request interrupt.

Regards,

Hans


>
> Regards,
> -Bin.
>
>> +	} else
>>  		clear_bit(SUNXI_MUSB_FL_VBUS_ON, &glue->flags);
>>
>>  	schedule_work(&glue->work);
>> @@ -325,6 +326,7 @@ static int sunxi_set_mode(struct musb *musb, u8 mode)
>>  		set_bit(SUNXI_MUSB_FL_PHY_ON, &glue->flags);
>>  		/* Stop musb work from turning vbus off again */
>>  		set_bit(SUNXI_MUSB_FL_VBUS_ON, &glue->flags);
>> +		musb->xceiv->otg->state = OTG_STATE_A_WAIT_VRISE;
>>  	}
>>
>>  	return 0;
>> --
>> 2.7.4
>>