On Thu, Oct 11, 2012 at 04:55:40PM +0800, Shawn Guo wrote:

Add LAKML ...

On Wed, Oct 10, 2012 at 09:30:36AM -0700, Dmitry Torokhov wrote:

quoted

Hi Hui,

On Wed, Oct 10, 2012 at 05:12:01PM +0800, Hui Wang wrote:

quoted

The irq_to_gpio() is old, most platforms use GENERIC_GPIO framework
and don't support this API anymore.

The i.MX6q sabrelite platform equips an egalax touchscreen controller,
and this platform already transfered to GENERIC_GPIO framework, to
support this driver, we use a more generic way to get gpio.

Unfortunately this does break the driver for platforms that do still
support irq_to_gpio and have not transitioned to device tree (yet?).
It looks like the API suffered from premature deletion...

I really do not want to add a new platform data structure with only gpio
in it, is there a better way to detect if irq_to_gpio() (even if only a
stub) is available?

If CONFIG_ARCH_HAVE_CUSTOM_GPIO_H is not enabled for an architecture,
the irq_to_gpio() in include/linux/gpio.h will tell unavailability by
returning -EINVAL.  But ARM architecture still selects ARCH_HAVE_CUSTOM_GPIO_H
because there are still some platforms having mach/gpio.h.

We may also need a stub irq_to_gpio simply returning -EINVAL into
arch/arm/include/asm/gpio.h when platform does not provide irq_to_gpio,
so that driver can detect if irq_to_gpio() is available.  And that
stub can be removed later when we deselect ARCH_HAVE_CUSTOM_GPIO_H
for ARM architecture.

Or fix the drivers using irq_to_gpio() not to use it.  I thought we had
resolved to do that already, with Grant's agreement that irq_to_gpio()
needed to die.

(Mainly because neither gpiolib nor the IRQ layer provides any assistance
for irq_to_gpio(), so it's not possible to make it work for all GPIOs in
the system, especially when GPIOs are allocated dynamically.)