[PATCH v1 1/3] ARM: dts: am335x-bone: add support for beaglebone NAND cape

[Gupta, Pekon]

Hi Guido,

>From: Guido Martínez
>>On Thu, Jun 26, 2014 at 03:40:44AM -0700, Tony Lindgren wrote:
>> * Pekon Gupta <pekon at ti.com> [140624 05:26]:
>> > +
>> > +&gpmc {
>> > +	ranges = <0 0 0 0x01000000>;	/* address range = 16MB (minimum GPMC partition) */
>> > +	nand at 0,0 {
>> > +		status = "disabled";
>> > +		reg = <0 0 4>;		/* device IO registers */
>>
>> Hmm so what about other capes potentially also using GPMC CS0?
>>
>> Can you please do a check with two .dtsi files trying to use
>> GPMC CS0 and see what the produced .dtb file looks like after
>> decompiling it with dtc?
>>
>> I'd assume the 16MB GPMC partition will be just fine for many
>> devices and can be also be larger if NOR needs it so maybe it
>> can be handled for almost all the cases.
>>
>> The names for devices must be unique though to avoid them
>> getting merged. And I don't know if gpmc.c skips disabled devices
>> properly.
>It doesn't. I've just sent a patch for it.
>
>http://lists.infradead.org/pipermail/linux-arm-kernel/2014-June/266966.html
>
I don't think we need above patch.
Helper macro "for_each_available_child_of_node" internally takes care
of skipping nodes with status="disabled".

$KERNEL/include/linux/of.h
#define for_each_available_child_of_node(parent, child) \
	for (child = of_get_next_available_child(parent, NULL); child != NULL; \
	     child = of_get_next_available_child(parent, child))

$KERNEL/drivers/of/base.c @@ of_get_next_available_child(...) {
	...
	if (!__of_device_is_available(next))
			continue;
	...


with regards, pekon