[PATCH V2] tiny-printf: Handle formatting of %p with an extra Kconfig

[Christoph Niedermaier]

From: Christoph Niedermaier
Sent: Tuesday, April 29, 2025 6:49 PM
> From: Marek Vasut <marex at denx.de>
> Sent: Tuesday, April 29, 2025 5:28 PM
>> On 4/29/25 4:47 PM, Christoph Niedermaier wrote:
>>> The formatting with %pa / %pap behaves like %x, which results in an
>>> incorrect value being output. To improve this, a new fine-tuning
>>> Kconfig SPL_USE_TINY_PRINTF_POINTER_SUPPORT for pointer formatting
>>> has been added. If it is enabled, the output of %pa / %pap should
>>> be correct, and if it is disabled, the pointer formatting is
>>> completely unsupported. In addition to indicate unsupported formatting,
>>> '?' will be output. This allows enabling pointer formatting only
>>> when needed. For SPL_NET and NET_LWIP it is selected by default.
>>> Then it also supports the formatting with %pm, %pM and %pI4.
>>>
>>> In summery this level of %p support for tiny printf is possible now:
>>>
>>> 1) The standard tiny printf won't have support for pointer formatting.
>>>     So it doesn't print misleading values for %pa, instead '?' will be
>>>     output:
>>>     %p   => ?
>>>     %pa  => ?a
>>>     %pap => ?ap
>>>
>>> 2) If SPL_USE_TINY_PRINTF_POINTER_SUPPORT is enabled or DEBUG is defined
>>>     tiny printf supports formatting %p and %pa / %pap.
>>>
>>> 3) If SPL_NET or NET_LWIP is enabled the support of pointers is extended
>>>     for %pm, %pM and %pI4.
>> If you need rich printf formatting support , enable full printf instead?
> 
> It is not about extending tiny printf with more formatting. The current
> support for pointers leads to the printing of misleading values. This patch
> removes the support for pointers, but makes the already existing pointer
> support for %pa / %pap optional. The existing support for %pm, %pM and %pI4
> enabled by SPL_NET or NET_LWIP CONF has remained functionally the same.

Sorry, I have noticed that in V2 the output of '?' is missing in the
default case. I will fix it in V3.

Regards
Christoph