On 11/29/2016 05:16 PM, Bin Liu wrote:
> Hi,
>
> On Mon, Nov 28, 2016 at 05:26:20PM +0100, Alexandre Bailon wrote:
>> On da8xx, VBUS is not maintained during suspend when musb is in host mode.
>> On resume, all the connected devices will be disconnected and then will
>> be enumerated again.
>> This happens because MUSB_DEVCTL is cleared during suspend.
>> Add a quirk to preserve MUSB_DEVCTL during a suspend.
>
> Will preserving MUSB_DEVCTL prevent the device getting disconnected?
Yes. Preserving MUSB_DEVCTL keeps VBUS on though the PHY is off during
suspend.
Note that in device mode, the disconnect still happen but I think it's
the expected behavior.
> This doesn't happen on am335x. The PHY is off during suspend, during
> resume, PHY gets on, MUSB generates MUSB_CONNECT interrupt, then
> re-enumeration happens.
I haven't been able to try on the BBB. I don't know if my config is
incorrect or if some patches are missing but I was not able to
suspend it.
Regards,
Alexandre
>
> Regards,
> -Bin.
>
>>
>> Signed-off-by: Alexandre Bailon <abai...@baylibre.com>
>> ---
>> drivers/usb/musb/musb_core.c | 13 +++++++------
>> drivers/usb/musb/musb_core.h | 1 +
>> 2 files changed, 8 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
>> index 9e22646..7e2cd98 100644
>> --- a/drivers/usb/musb/musb_core.c
>> +++ b/drivers/usb/musb/musb_core.c
>> @@ -1040,14 +1040,15 @@ static void musb_enable_interrupts(struct musb *musb)
>>
>> }
>>
>> -static void musb_generic_disable(struct musb *musb)
>> +static void musb_generic_disable(struct musb *musb, bool suspend)
>> {
>> void __iomem *mbase = musb->mregs;
>>
>> musb_disable_interrupts(musb);
>>
>> /* off */
>> - musb_writeb(mbase, MUSB_DEVCTL, 0);
>> + if (!suspend || !(musb->io.quirks & MUSB_PRESERVE_DEVCTL))
>> + musb_writeb(mbase, MUSB_DEVCTL, 0);
>> }
>>
>> /*
>> @@ -1106,7 +1107,7 @@ void musb_stop(struct musb *musb)
>> {
>> /* stop IRQs, timers, ... */
>> musb_platform_disable(musb);
>> - musb_generic_disable(musb);
>> + musb_generic_disable(musb, false);
>> musb_dbg(musb, "HDRC disabled");
>>
>> /* FIXME
>> @@ -2310,7 +2311,7 @@ musb_init_controller(struct device *dev, int nIrq,
>> void __iomem *ctrl)
>>
>> /* be sure interrupts are disabled before connecting ISR */
>> musb_platform_disable(musb);
>> - musb_generic_disable(musb);
>> + musb_generic_disable(musb, false);
>>
>> /* Init IRQ workqueue before request_irq */
>> INIT_DELAYED_WORK(&musb->irq_work, musb_irq_work);
>> @@ -2486,7 +2487,7 @@ static int musb_remove(struct platform_device *pdev)
>> musb_gadget_cleanup(musb);
>> spin_lock_irqsave(&musb->lock, flags);
>> musb_platform_disable(musb);
>> - musb_generic_disable(musb);
>> + musb_generic_disable(musb, false);
>> spin_unlock_irqrestore(&musb->lock, flags);
>> musb_writeb(musb->mregs, MUSB_DEVCTL, 0);
>> pm_runtime_dont_use_autosuspend(musb->controller);
>> @@ -2663,7 +2664,7 @@ static int musb_suspend(struct device *dev)
>> unsigned long flags;
>>
>> musb_platform_disable(musb);
>> - musb_generic_disable(musb);
>> + musb_generic_disable(musb, true);
>> WARN_ON(!list_empty(&musb->pending_list));
>>
>> spin_lock_irqsave(&musb->lock, flags);
>> diff --git a/drivers/usb/musb/musb_core.h b/drivers/usb/musb/musb_core.h
>> index a611e2f..22961ef 100644
>> --- a/drivers/usb/musb/musb_core.h
>> +++ b/drivers/usb/musb/musb_core.h
>> @@ -172,6 +172,7 @@ struct musb_io;
>> */
>> struct musb_platform_ops {
>>
>> +#define MUSB_PRESERVE_DEVCTL BIT(7)
>> #define MUSB_DMA_UX500 BIT(6)
>> #define MUSB_DMA_CPPI41 BIT(5)
>> #define MUSB_DMA_CPPI BIT(4)
>> --
>> 2.7.3
>>
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