[U-Boot] [PATCH] arch: ifc: update the IFC IP input clock

[Scott Wood]

On 09/08/2016 08:46 PM, Prabhakar Kushwaha wrote:
> 
>> -----Original Message-----
>> From: Scott Wood
>> Sent: Friday, September 09, 2016 6:05 AM
>> To: Prabhakar Kushwaha <prabhakar.kushwaha at nxp.com>; york sun
>> <york.sun at nxp.com>; u-boot at lists.denx.de
>> Subject: Re: [PATCH] arch: ifc: update the IFC IP input clock
>>
>> On 09/08/2016 07:05 PM, Prabhakar Kushwaha wrote:
>>>
>>>> -----Original Message-----
>>>> From: york sun
>>>> Sent: Thursday, September 08, 2016 9:22 PM
>>>> To: Prabhakar Kushwaha <prabhakar.kushwaha at nxp.com>; u-
>>>> boot at lists.denx.de; Scott Wood <scott.wood at nxp.com>
>>>> Subject: Re: [PATCH] arch: ifc: update the IFC IP input clock
>>>>
>>>> On 09/08/2016 02:33 AM, Prabhakar Kushwaha wrote:
>>>>
>>>> <snip>
>>>>
>>>>>>> So better to print IP clock to avoid any confusion.
>>>>>>> IFC output clock will be printed when it is actually being used during
>>>>>> synchronous NOR, syn NAND.
>>>>>>
>>>>>> I am not against changing it to internal clock. But what are you going
>>>>>> to print on the console? I think it is confusing to say IFC or local bus
>>>>>> internal clock speed. Please also check how this clock is used and make
>>>>>> sure arch.lbc_clk is still correct, after passing to Linux.
>>>>>>
>>>>> arch.lbc_clk is only being used for eLBC for device tree fixup.
>>>>> And I checked the Linux eLBC driver. Looks like it is not using used.
>>>>>
>>>>
>>>> If this clock is not used, can we drop it completely?
>>>>
>>>
>>> From my point of view Yes.
>>>
>>> Scott, Please advice
>>
>> Well, there is that patch from Matt Weber that is trying to guess the
>> IFC frequency in order to use NWAIT...  Not sure if we'll end up
>> actually using NWAIT 
> (Prabhakar, can you answer my question of whether
>> there is a better opcode to use with RNDOUT?) or ever sending a real
>> RNDOUT, or if we'll ever care about these newer NAND chips on eLBC, but
>> if U-Boot is currently writing the clock frequency into the device tree
>> I don't see why we'd rip it out.
>>
> 
> IFC frequency means IP clock or IP output clock?

External bus clock.  Which is currently being written to the device tree?

> If IP clock then other patch for eLBC still valid.  

What other patch?

> 
> For IFC: Code needs to be added for device tree fixup for PowerPC, ARM SoC. 
> It is missing for now :(

No, we don't want to introduce new clock-frequency fixups.  If we need
this on IFC we should add a clocks property.  But if we already have
clock-frequency on eLBC then no reason not to use that if needed.

-Scott