[RFC] [PATCH 2/3] of: add of_irq_count: Count the number of IRQs a node present

[Grant Likely]

On Tue, 28 May 2013 17:08:48 +0200, Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com> wrote:
> Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
> Cc: Grant Likely <grant.likely at secretlab.ca>
> Cc: Rob Herring <rob.herring at calxeda.com>
> Cc: Arnd Bergmann <arnd at arndb.de>
> Cc: Linus Walleij <linus.walleij at linaro.org>
> Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> Cc: Ralf Baechle <ralf at linux-mips.org>
> Cc: Nicolas Ferre <nicolas.ferre at atmel.com>
> ---
>  drivers/of/irq.c       |   15 +++++++++++++++
>  include/linux/of_irq.h |    1 +
>  2 files changed, 16 insertions(+)
> 
> diff --git a/drivers/of/irq.c b/drivers/of/irq.c
> index d1c5825..4426223 100644
> --- a/drivers/of/irq.c
> +++ b/drivers/of/irq.c
> @@ -362,6 +362,21 @@ int of_irq_to_resource(struct device_node *dev, int index, struct resource *r)
>  EXPORT_SYMBOL_GPL(of_irq_to_resource);
>  
>  /**
> + * of_irq_count - Count the number of IRQs a node uses
> + * @dev: pointer to device tree node
> + */
> +int of_irq_count(struct device_node *dev)

Following on from my comment on patch 1/3, How about "of_irq_count_entries()"?

> +{
> +	struct of_irq oirq;
> +	int nr = 0;
> +
> +	while (!of_irq_map_one(dev, nr, &oirq))
> +		nr++;

The concept is good, but this ends up being very inefficient. It would
be better to take the relevant parts out of of_irq_map_one() to retrieve
the value of #interrupt-cells and compare it to the size of the
interrupts property.

g.