[PATCH v2 1/4] irqchip: add basic infrastructure

[robherring2@gmail.com (Rob Herring)]

On 10/28/2012 04:30 AM, Thomas Petazzoni wrote:
> With the recent creation of the drivers/irqchip/ directory, it is
> desirable to move irq controller drivers here. At the moment, the only
> driver here is irq-bcm2835, the driver for the irq controller found in
> the ARM BCM2835 SoC, present in Rasberry Pi systems. This irq
> controller driver was exporting its initialization function and its
> irq handling function through a header file in
> <linux/irqchip/bcm2835.h>.
> 
> When proposing to also move another irq controller driver in
> drivers/irqchip, Rob Herring raised the very valid point that moving
> things to drivers/irqchip was good in order to remove more stuff from
> arch/arm, but if it means adding gazillions of headers files in
> include/linux/irqchip/, it would not be very nice.
> 
> So, upon the suggestion of Rob Herring and Arnd Bergmann, this commit
> introduces a small infrastructure that defines a central
> irqchip_init() function in drivers/irqchip/irqchip.c, which is meant
> to be called as the ->init_irq() callback of ARM platforms. This
> function calls of_irq_init() with an array that will progressively
> contain the compatible strings of each irq controller driver, and also
> a reference to the initialization functions of such drivers. The
> drivers/irqchip/irqchip.h header file, currently empty, is added to
> allow irq controller drivers to expose their initialization function
> to the main irqchip.c file. Note that the irq controller driver
> initialization function is responsible for setting the global
> handle_arch_irq() variable, so that ARM platforms no longer have to
> define the ->handle_irq field in their DT_MACHINE structure.
> 
> A global header, <linux/irqchip.h> is also added to expose the single
> irqchip_init() function to the reset of the kernel.
> 
> A further commit moves the BCM2835 irq controller driver to this new
> small infrastructure, therefore removing the include/linux/irqchip/
> directory.
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> Reviewed-by: Stephen Warren <swarren@wwwdotorg.org>
> ---
>  drivers/irqchip/Kconfig   |    3 ++-
>  drivers/irqchip/Makefile  |    1 +
>  drivers/irqchip/irqchip.c |   23 +++++++++++++++++++++++
>  drivers/irqchip/irqchip.h |   14 ++++++++++++++
>  include/linux/irqchip.h   |   16 ++++++++++++++++
>  5 files changed, 56 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/irqchip/irqchip.c
>  create mode 100644 drivers/irqchip/irqchip.h
>  create mode 100644 include/linux/irqchip.h
> 
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index 1bb8bf6..e0ff166 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -1 +1,2 @@
> -# empty
> +config USE_IRQCHIP
> +	bool

This should depend on OF_IRQ.

Rob