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

[Christoph Niedermaier <cniedermaier@dh-electronics.com>]

From: Marek Vasut <marex@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.

Regards
Christoph