plat-orion multi purpose pins problem for mv78200

[saeed bishara]

On Sat, Jul 2, 2011 at 3:23 PM, Simon Guinot <simon at sequanux.org> wrote:
> Hi Joey,
>
> On Fri, Jul 01, 2011 at 03:14:48PM -0400, Joey Oravec wrote:
>> Nicola, Lennert -
>>
>> There's a problem in 3.0-rc5 when calling mv78xx0_mpp_conf() on the
>> MV78200 processor. This processor has 49 multi purpose pins but only
>> 31 GPIOs. MPP[31:0] map directly to GPIO[31:0] but the next 17 are a
>> little more complex:
>>
>> MPP[39:32] = GPIO[7:0]
>> MPP[46:40] = GPIO[23:17]
>> MPP[47] = GPIO[16]
>> MPP[48] = GPIO[8]
>> MPP[49] = GPIO[9]
>
> It doesn't seems the code was behaving differently before 3.0-rc. I mean
> before the MPP and GPIO consolidation work. It was ?
that's right, this issue was before the consolidation work.
>
>>
>> See arch/arm/plat-orion/mpp.c. Inside orion_mpp_conf() the array
>> gets processed by calling MPP_NUM() then calling
>> orion_gpio_set_valid(). As demonstrated above, the MPP number and
>> GPIO number are not interchangeable and on the MV78200 that's a
>> problem when trying to setup any MPP > 31.
>>
>> So we need to map each MPP to a given GPIO -- I don't know how the
>> mapping will differ across processors. We also need to keep-clear
>> which functions are called with an MPP number and which functions
>> are called with a GPIO number.
>
> As I don't have access to either a MV78200 device or his specification
> document, let me ask you a few questions.
>
> Does hardware allows a configuration like MPP0_GE0_COL and MPP32_GPIO
> simultaneously ?
yes, this is possible.
>
> If not (and only if not), the problem is simply mapping a MPP number on
> the correct GPIO number. Isn't it ?
>
> In that case, what about using the MPPxx_GPIO definitions (found in
> mach-mv78xx0/mpp.h) to map the right GPIO number ?
>
> For example:
>
> #define MPP32_GPIO        MPP(32, 0x1, 1, 1, 1)
>
> could be replaced by:
>
> #define MPP32_GPIO        MPP(0, 0x1, 1, 1, 1)
that won't work because the num (first number) is used as the mpp
index. see orion_mpp_conf() implementation.
I think the solution is to extend the MPP define to include the
explicit gpio number, so it will look like:
#define MPP(_num, _gpio _sel, _in, _out, _78100_A0)

saeed