Re: [PATCH] Input: egalax_ts - do not release gpio if probe successful

On Fri, Jan 13, 2017 at 12:03:43AM +0100, Gary Bisson wrote:

Hi Dmitri,

On Thu, Jan 12, 2017 at 10:30:19AM -0800, Dmitry Torokhov wrote:

quoted

Hi Gary,

On Wed, Jan 11, 2017 at 06:28:41PM +0100, Gary Bisson wrote:

quoted

Thus preventing anyone to later modify the interrupt GPIO direction
and/or state without the driver knowing.

I am afraid not releasing gpio after waking up the controller will cause
request_irq to fail if we are using the same pin for interrupt and
wakeup (as majority of current DTSes do: see
arch/arm/boot/dts/imx53-tx53-x13x.dts for example).

No, keeping the GPIO doesn't prevent from requesting the IRQ.

However it keeps other drivers/users from changing the GPIO as output
later on.

Hmm, I think _gpiod_direction_output_raw() will not let them as it
checks FLAG_USED_AS_IRQ, so as long as it's the same line it's OK. But I
guess if they are separate some other component might try to grab it and
mess with it.

OK, in this case please:

- use devm_gpiod_get
- request with GPIOD_OUT_LOW
- do not override the return value with -ENODEV (especially important
  with probe deferrals)
- lose gpiod_direction_output() call
- move everything into egalax_ts_probe() as egalax_wake_up_device() is
  no longer self-contained. 

Thanks!

-- 
Dmitry