On Thu, Sep 27, 2018 at 11:49:20AM -0300, Rodrigo Exterckötter Tjäder wrote: > On Thu, Sep 27, 2018 at 5:17 AM Maxime Ripard <maxime.ripard@xxxxxxxxxxx> wrote: > > > > On Tue, Sep 25, 2018 at 02:47:59PM -0300, Rodrigo Exterckötter Tjäder wrote: > > > On Tue, Sep 25, 2018 at 6:01 AM Maxime Ripard <maxime.ripard@xxxxxxxxxxx> wrote: > > > > We can't really do that, unfortunately. If the device tree name was to > > > > change for a given board, we'd break all the build systems, boot > > > > scripts and distros out there. > > > > > > What if we keep the device tree for the version without WiFi and eMMC > > > with the current name and create new device trees for the other two > > > versions? > > > > Wifi and Bluetooth should be dealt with with overlays in this case, > > and since the eMMC is already enabled, then there's nothing to do, I > > guess. > > It's WiFi that is already enabled, not eMMC. Only one of the three > variants has WiFi. Ah, right, sorry. In the board that doesn't have an emmc, are the pins usable for something else? > We can't even remove a node from a device tree? Removing the WiFi node > from the current tree would make it correspond to the variant with the > least features. Not really. How pissed would you be if you were a user, had wifi running on your board, you upgrade your kernel, and then it's just gone? :) > About device tree overlays, I read overlay-notes.txt, but I went > looking for an example with "git grep /plugin/ arch" and it came > empty. Is this approach not used for other boards? It is, it's simply not stored in the kernel, but through other third party repos. > Does the overlay approach make the device available at boot time? That > is important for a storage device such as eMMC. > > I went with the separate dts approach because that's what I saw was > done for other similar cases, like Pine64 and Pine64+, OLinuXino-LIME2 > and its variant with eMMC, among others. Yeah, but in all these cases, it was done from day one, not after the facts. Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
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