Hi Walter,
On Tue, 7 Jul 2020 at 08:08, Walter Lozano walter.lozano@collabora.com wrote:
Hi Simon
On 6/7/20 16:21, Simon Glass wrote:
Hi Walter,
On Fri, 19 Jun 2020 at 15:12, Walter Lozano walter.lozano@collabora.com wrote:
Based on several reports there is an increasing concern in the impact of adding additional features to drivers based on compatible strings. A good example of this situation is found in [1].
In order to reduce this impact and as an initial step for further reduction, propose a new way to declare compatible strings, which allows to only include the useful ones.
What are the useful ones?
The useful ones would be those that are used by the selected DTB by the current configuration. The idea of this patch is to declare all the possible compatible strings in a way that dtoc can generate code for only those which are going to be used, and in this way avoid lots of #ifdef like the ones shows in
http://patchwork.ozlabs.org/project/uboot/patch/20200525202429.2146-1-agust@...
The idea is to define compatible strings in a way to be easily parsed by dtoc, which will be responsible to build struct udevice_id [] based on the compatible strings present in the dtb.
Additional features can be easily added, such as define constants depending on the presence of compatible strings, which allows to enable code blocks only in such cases without the need of adding additional configuration options.
[1] http://patchwork.ozlabs.org/project/uboot/patch/20200525202429.2146-1-agust@...
Signed-off-by: Walter Lozano walter.lozano@collabora.com
tools/dtoc/dtb_platdata.py | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+)
I think dtoc should be able to parse the compatible strings as they are today - e.g. see the tiny-dm stuff.
Yes, I agree. My idea is that dtoc parses compatible strings as they are today but also in this new way. The reason for this is to allow dtoc to generate the code to include the useful compatible strings. Of course, this only makes sense if the idea of generating the compatible string associated code is accepted.
What do you think?
I think this is useful and better than using #ifdef in the source code for this sort of thing. We need a way to specify the driver_data value as well, right?
Re naming, perhaps DT_COMPAT() might be better than COMPATIBLE()? Or even a name that indicates that it is optional, like DT_OPT_COMPAT() ?
Regards, Simon