linux-kernel - Re: [PATCH v3] USB: PHY: Palmas USB Transceiver Driver

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Date:	Tue, 26 Mar 2013 15:04:59 +0530
From:	Laxman Dewangan <ldewangan@...dia.com>
To:	Graeme Gregory <gg@...mlogic.co.uk>
CC:	Kishon Vijay Abraham I <kishon@...com>,
	"balbi@...com" <balbi@...com>, Rajendra Nayak <rnayak@...com>,
	"grant.likely@...retlab.ca" <grant.likely@...retlab.ca>,
	"rob.herring@...xeda.com" <rob.herring@...xeda.com>,
	"rob@...dley.net" <rob@...dley.net>,
	"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
	"s-guiriec@...com" <s-guiriec@...com>,
	"sameo@...ux.intel.com" <sameo@...ux.intel.com>,
	"broonie@...nsource.wolfsonmicro.com" 
	<broonie@...nsource.wolfsonmicro.com>,
	"devicetree-discuss@...ts.ozlabs.org" 
	<devicetree-discuss@...ts.ozlabs.org>,
	"linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>
Subject: Re: [PATCH v3] USB: PHY: Palmas USB Transceiver Driver

On Tuesday 26 March 2013 02:57 PM, Graeme Gregory wrote:
> On 26/03/13 09:12, Laxman Dewangan wrote:
>> On Tuesday 26 March 2013 02:31 PM, Graeme Gregory wrote:
>>
>> But still you are using the PALMAS macro here and indirectly it is
>> tied up. It is not completely independent.
>> If need to be independent then regmap pointer with address need to be
>> passed as independt header and no where on code whould refer the PALMA.
>> I think as per current code, it is not possible although it is your
>> big plan what I understand from some time back in one of patch
>> discussion.
>>
> It is actually almost possible, but it is something I gave up looking
> at. You can get the regmap of your parent i2c device without having
> knowledge of the type of parent.

There is multiple regmap of parent and hence getting correct regmap is 
really issue.  May be RTC require regmap[0] and gpio require regmap[1].


>
>>>>>> +       palmas_usb->dev         = &pdev->dev;
>>>>>> +
>>>>>> +       palmas_usb->irq1 = regmap_irq_get_virq(palmas->irq_data,
>>>>>> +                                               PALMAS_ID_OTG_IRQ);
>>>>>> +       palmas_usb->irq2 = regmap_irq_get_virq(palmas->irq_data,
>>>>>> +                                               PALMAS_ID_IRQ);
>>>>>> +       palmas_usb->irq3 = regmap_irq_get_virq(palmas->irq_data,
>>>>>> +                                               PALMAS_VBUS_OTG_IRQ);
>>>>>> +       palmas_usb->irq4 = regmap_irq_get_virq(palmas->irq_data,
>>>>>> +                                               PALMAS_VBUS_IRQ);
>>>>> Should be come from platform_get_irq() through platform driver.
>>>> No. It can be obtained from regmap too.
>> Kishon,
>> I think it is very much possible. You can pass the interrupt throough
>> IRQ_RESOURCE and populate it from DT. If you provide proper interrupt
>> parent and irq number then irq framework take care of every thing.
>> already tested this with RTC interrupt of plama and it worked very well.
>>
> If we are tightly coupling as above then using platform_irq is an extra
> inefficiency. You both have to populate this then parse it afterwards.
> Why not just use the regmap helper? Ill admit this code is like this as
> there was a period where platform irqs in DT just was not working right!
>
> We should really agree now if we are going for loose or tight coupling
> now rather than keep switching?

Here we are hardcoding for PALMAS_ID_OTG_IRQ and so on. If we take data 
from platform then it need not and it will be completely independent of 
palma atleast on this front.
We need to populate just as:
palmas: palmas {
:::::::
     palams_usb_phy {
         compatile = ...
         interrupt-parent = <& palmas>;
         interrupt = < 10, 0,
                                 21, 0,
                             22, 0,
                             23, 0>;
}


and in code, we just need to do
irq1 = platform_get_irq(pdev, 0);
irq2 = platform_get_irq(pdev, 1);
etc..


So here, actually we do not need to use palmas one and it is completely 
independent.

Also the way you define the DT od palmas, the above one looks more 
appropriate.

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