linux-kernel - Re: [PATCH 2/4] usb: dwc3: dwc3-omap: return -EPROBE

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Date:	Tue, 5 Mar 2013 20:48:24 +0530
From:	kishon <kishon@...com>
To:	<balbi@...com>
CC:	<grant.likely@...retlab.ca>, <rob.herring@...xeda.com>,
	<rob@...dley.net>, <gregkh@...uxfoundation.org>,
	<s-guiriec@...com>, <gg@...mlogic.co.uk>, <sameo@...ux.intel.com>,
	<broonie@...nsource.wolfsonmicro.com>, <ldewangan@...dia.com>,
	<devicetree-discuss@...ts.ozlabs.org>, <linux-doc@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <linux-usb@...r.kernel.org>,
	<linux-omap@...r.kernel.org>
Subject: Re: [PATCH 2/4] usb: dwc3: dwc3-omap: return -EPROBE_DEFER if probe
 has not yet executed

Hi,

On Tuesday 05 March 2013 08:36 PM, Felipe Balbi wrote:
> On Tue, Mar 05, 2013 at 08:31:58PM +0530, kishon wrote:
>> Hi,
>>
>> On Tuesday 05 March 2013 08:26 PM, Felipe Balbi wrote:
>>> On Tue, Mar 05, 2013 at 07:51:58PM +0530, Kishon Vijay Abraham I wrote:
>>>> return -EPROBE_DEFER from dwc3_omap_mailbox in dwc3-omap.c, if the probe of
>>>> dwc3-omap has not yet been executed or failed.
>>>>
>>>> Signed-off-by: Kishon Vijay Abraham I <kishon@...com>
>>>> ---
>>>>   drivers/usb/dwc3/dwc3-omap.c  |    7 +++++--
>>>>   include/linux/usb/dwc3-omap.h |    6 +++---
>>>>   2 files changed, 8 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/drivers/usb/dwc3/dwc3-omap.c b/drivers/usb/dwc3/dwc3-omap.c
>>>> index 19c6e72..9428f4e 100644
>>>> --- a/drivers/usb/dwc3/dwc3-omap.c
>>>> +++ b/drivers/usb/dwc3/dwc3-omap.c
>>>> @@ -138,11 +138,14 @@ static inline void dwc3_omap_writel(void __iomem *base, u32 offset, u32 value)
>>>>   	writel(value, base + offset);
>>>>   }
>>>>
>>>> -void dwc3_omap_mailbox(enum omap_dwc3_vbus_id_status status)
>>>> +int dwc3_omap_mailbox(enum omap_dwc3_vbus_id_status status)
>>>>   {
>>>>   	u32			val;
>>>>   	struct dwc3_omap	*omap = _omap;
>>>>
>>>> +	if (!omap)
>>>> +		return -EPROBE_DEFER;
>>>> +
>>>>   	switch (status) {
>>>>   	case OMAP_DWC3_ID_GROUND:
>>>>   		dev_dbg(omap->dev, "ID GND\n");
>>>> @@ -185,7 +188,7 @@ void dwc3_omap_mailbox(enum omap_dwc3_vbus_id_status status)
>>>>   		dev_dbg(omap->dev, "ID float\n");
>>>>   	}
>>>>
>>>> -	return;
>>>> +	return IRQ_HANDLED;
>>>
>>> IRQ_HANDLED ????
>>
>> Actually I did it that way since palmas_vbus_wakeup_irq can directly
>> return the return value from dwc3_omap_mailbox. If this seems hacky
>> to you, I'll change it.
>
> it does seem hacky :-) Try something like:
>
> ret = dwc3_omap_mailbox();
> if (ret)
> 	print_error();
>
> return IRQ_HANDLED;

hmm.. But there is one case where palmas_vbus_wakeup_irq should return 
EPROBE_DEFER. In the cold plug case, if palmas gets loaded before 
dwc3-omap, omap in dwc3_omap_mailbox will be NULL. So ideally palmas 
should be probed after dwc3-omap for this case. Returning IRQ_HANDLED or 
IRQ_NONE wont help here.

Thanks
Kishon




>

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