On 02/12/18 15:13, Frank Rowand wrote:
> + devicetree mail list
> On 02/10/18 07:52, Enrico Weigelt, metux IT consult wrote:
>> Hi folks,
>> I've regularily have the task of configuring a kernel for a given DT.
>> To make this a little bit easier, I'd like to do this automatically.
>> The tuff task here is getting a mapping between dt compatible strings
>> and corresponding CONFIG_* flags. Automatically extracting it from the
>> source code seems pretty tricky, especially w/ corner cases (eg. some
>> drivers support groups of devices, depending on config options) - IMHO
>> it will need some code changes anyways.
>> Therefore I propose a simple approach using the existing Kconfig system:
>> Add an extra (toplevel) menu and config flag naming scheme which
>> directly map DT compatible strings to config flags. For example:
>>> fsl,mpc5200-gpio <=> CONFIG_DTDEV_FSL_MPC5200_GPIO
>>> config CONFIG_DTDEV_FSL_MPC5200_GPIO
>>> tristate "fsl,mpc5200-gpio"
>>> select GPIO_MPC5200
>> Note that these flags are separate from the actual drivers - they just
>> enable them automatically. Of course they'll have to be maintained by
>> the driver maintainers.
>> What do you think about this idea ?
As you note, it can be quite tricky getting the correct kernel configuration
for a given devicetree.
There is a tool to aid this process: scripts/dtc/dt_to_config. It is not
a 100% solution, but it is very helpful.
The problem is difficult enough that this tool led to a conference talk.
The slides are at https://elinux.org/images/5/50/Dt_debugging_part_2.pdf
which is linked to from
dt_to_config and configuration issues are discussed in slides 33 - 80.