[U-Boot] [PATCH] tegra: implement pinmux_avoid_func()

[Stephen Warren <swarren@wwwdotorg.org>]

On 01/22/2013 05:03 PM, Simon Glass wrote:
> Hi Stephen,
> 
> On Tue, Jan 22, 2013 at 2:14 PM, Stephen Warren <swarren@wwwdotorg.org> wrote:
>> On 01/22/2013 02:42 PM, Simon Glass wrote:
>>> Hi Stephen,
>>>
>>> On Tue, Jan 22, 2013 at 1:26 PM, Stephen Warren <swarren@wwwdotorg.org> wrote:
>>>> On 01/22/2013 02:13 PM, Simon Glass wrote:
>>>>> Hi Stephen,
>>>>>
>>>>> On Tue, Jan 22, 2013 at 8:21 AM, Stephen Warren <swarren@wwwdotorg.org> wrote:
>>>>>> From: Stephen Warren <swarren@nvidia.com>
>>>>>>
>>>>>> This selects the "safe" (non-conflicting) mux function for a pin group
>>>>>> if the current setting matches the specified function.
>>>>>>
>>>>>> Many signals can be routed to or from multiple different groups. Each
>>>>>> signal must be routed to or from only a single group at a given time.
>>>>>> Hence, if we program a particular group for a function, we must ensure
>>>>>> no other group is programmed to that same function first. This API
>>>>>> makes this easy.
>>>>>
>>>>> What is the intended use of this function? (sorry, yes, I am confused :-)
>>>>
>>>> It's a safer way of doing this:
>>>> "tegra: pinmux: fix FUNCMUX_NDFLASH_KBC_8_BIT"
>>>> http://lists.denx.de/pipermail/u-boot/2013-January/144612.html
>>>>
>>>> i.e. it address the concerns I raised here:
>>>> http://lists.denx.de/pipermail/u-boot/2013-January/144713.html
>>>>
>>>
>>> OK thank you. So is your function only intended for use with T20?
>>
>> No, I imagine that it should be used for all Tegras; I just wrote it
>> long enough ago that there was only Tegra20 at the time. I assume that
>> if Lucas wants to use this function as a pre-cursor to his NAND pinmux
>> change, he'll update it for whatever Tegra versions are checked in at
>> the time first.
>>
> Thanks, I get it.
> 
> Should Lucas consider adding a warning or some sort of indication that
> the function did nothing?

Do you mean on Tegra30 where it isn't implemented yet (no - I'd expect
to see this implemented instead) or when the current function programmed
into HW already doesn't match the value one is trying to avoid (no - I'd
expect this to be quite common).