linux-kernel - RE: [PATCH V1] input: use device managed memory in da9052 touchscreen driver

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Message-ID: <24DF37198A1E704D9811D8F72B87EB51AC050B52@NB-EX-MBX02.diasemi.com>
Date:	Fri, 10 Jan 2014 09:02:10 +0000
From:	"Opensource [Anthony Olech]" <anthony.olech.opensource@...semi.com>
To:	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	"Opensource [Anthony Olech]" <anthony.olech.opensource@...semi.com>
CC:	"linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Huqiu Liu <liuhq11@...ls.tsinghua.edu.cn>,
	David Dajun Chen <david.chen@...semi.com>
Subject: RE: [PATCH V1] input: use device managed memory in da9052
 touchscreen driver

> -----Original Message-----
> From: Dmitry Torokhov [mailto:dmitry.torokhov@...il.com]
> Sent: 09 January 2014 19:13
> To: Opensource [Anthony Olech]
> Cc: linux-input@...r.kernel.org; linux-kernel@...r.kernel.org; Huqiu Liu;
> David Dajun Chen
> Subject: Re: [PATCH V1] input: use device managed memory in da9052
> touchscreen driver
> 
> Hi Anthony,
> 
> On Thu, Jan 09, 2014 at 12:51:37PM +0000, Anthony Olech wrote:
> > The touchscreen component driver for the da9052/3 Dialog PMICs is
> > changed to use device managed memory allocation.
> >
> > This results in simpler error paths as failures in the probe()
> > function do not require explicit calls to free the devm_...
> > allocated memory.
> > The allocation functions used in this driver are:
> >     devm_kzalloc()
> >     devm_input_allocate_device()
> >     devm_request_threaded_irq()
> >
> > Suggested-by: Huqiu Liu <liuhq11@...ls.tsinghua.edu.cn>
> > Signed-off-by: Anthony Olech <anthony.olech.opensource@...semi.com>
> > ---
> > This patch is relative to linux-next repository tag next-20140109
> >
> > Many thanks to Huqiu Liu who instigated this patch.
> >
> >  drivers/input/touchscreen/da9052_tsi.c |   62 ++++++++++++++++-----------
> -----
> >  1 file changed, 30 insertions(+), 32 deletions(-)
> >
> > diff --git a/drivers/input/touchscreen/da9052_tsi.c
> > b/drivers/input/touchscreen/da9052_tsi.c
> > index ab64d58..dcc4cf1 100644
> > --- a/drivers/input/touchscreen/da9052_tsi.c
> > +++ b/drivers/input/touchscreen/da9052_tsi.c
> > @@ -233,18 +233,30 @@ static int da9052_ts_probe(struct
> platform_device *pdev)
> >  	struct da9052_tsi *tsi;
> >  	struct input_dev *input_dev;
> >  	int error;
> > +	int pdown_irq;
> > +	int ready_irq;
> >
> >  	da9052 = dev_get_drvdata(pdev->dev.parent);
> >  	if (!da9052)
> >  		return -EINVAL;
> >
> > -	tsi = kzalloc(sizeof(struct da9052_tsi), GFP_KERNEL);
> > -	input_dev = input_allocate_device();
> > -	if (!tsi || !input_dev) {
> > -		error = -ENOMEM;
> > -		goto err_free_mem;
> > -	}
> > +	pdown_irq = regmap_irq_get_virq(da9052->irq_data,
> DA9052_IRQ_PENDOWN);
> > +	if (pdown_irq < 0)
> > +		return pdown_irq;
> ...
> >
> > -	error = da9052_request_irq(tsi->da9052, DA9052_IRQ_PENDOWN,
> > -				"pendown-irq", da9052_ts_pendwn_irq, tsi);
> > +	error = devm_request_threaded_irq(&pdev->dev, pdown_irq,
> > +				NULL, da9052_ts_pendwn_irq,
> > +				IRQF_TRIGGER_LOW | IRQF_ONESHOT,
> > +				"pendown-irq", tsi);
> 
> I am uncomfortable with the touchscreen portion of this driver ignoring the
> framework of it's MFD core and mixing native IRQ management with the
> ones done through the core.
> 
> What would happen if somebody changes da9052_request_irq() to do some
> thing more than it is doing now so that your open-coded duplicate of the
> same in da9052_ts_probe() is no longer equivalent? Or
> da9052_disable_irq() no longer works correctly with IRQs allocated by this
> sub-module?
> Thanks.
> --
> Dmitry
Hi Dmitry,
unfortunately the PMIC is a multifunction device and the component drivers come
under different subsystem maintainers. Thus it is not possible to do one patch in one
go to change them all.
Tony Olech


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