[PATCH] cmd: fdt: Add support for reading stringlist property values

[Simon Glass]

Hi Marek,

On Tue, 12 Jul 2022 at 05:47, Marek Vasut <marex at denx.de> wrote:
>
> On 7/12/22 12:58, Simon Glass wrote:
> > Hi Marek,
> >
> > On Fri, 8 Jul 2022 at 15:50, Marek Vasut <marex at denx.de> wrote:
> >>
> >> The fdt command currently handles stringlists as strings in 'fdt get value'
> >> subcommand. Since strings in FDT stringlists are separated by '\0', only
> >> the first value gets inserted into the environment variable passed to the
> >> 'fdt get value' command.
> >>
> >> Example, consider the following DT snippet:
> >>
> >> / { compatible = "foo", "bar" };
> >>
> >> The following command only reports the first string in stringlist:
> >> => fdt get value var / compatible ; print var
> >> foo
> >>
> >> It is not possible to assign list of null-terminated strings into U-Boot
> >> environment variable. Add optional 'index' parameter to the subcommand
> >> 'fdt get value <var> <path> <prop> [<index>]' which lets user specify which
> >> string within the stringlist should be assigned into the 'var' variable.
> >> The default value of 'index' is 0 in case it is not present. This way the
> >> 'fdt' command API does not change and existing scripts are not broken.
> >>
> >> The following command now reports the Nth string in stringlist, counting
> >> from zero:
> >> => fdt get value var / compatible 1 ; print var
> >> bar
> >>
> >> Signed-off-by: Marek Vasut <marex at denx.de>
> >> Cc: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> >> Cc: Simon Glass <sjg at chromium.org>
> >> Cc: Tom Rini <trini at konsulko.com>
> >> ---
> >>   cmd/fdt.c | 34 ++++++++++++++++++++++++++++------
> >>   1 file changed, 28 insertions(+), 6 deletions(-)
> >
> > Can you please add docs and a test?
>
> I was expecting this kind of question ... there is no test for the FDT
> command.
>
> > I am happy to do a starting point for a test if you like.
>
> You can implement the test for this while at it.

I sent a starting point for you, both docs and test.

Regards,
Simon