On Thu, Oct 25, 2018 at 12:57:54PM +0200, Giulio Benetti wrote: > Hello Maxime, > > Il 24/10/2018 19:59, Maxime Ripard ha scritto: > > On Wed, Oct 24, 2018 at 03:59:56PM +0200, Giulio Benetti wrote: > > > Hello Jagan and Maxime, > > > > > > I've looked around a lot, but I can't find a way to use the board/sunxi: > > > http://git.denx.de/?p=u-boot.git;a=tree;f=board/sunxi;h=304ee6b4cc8e075759d3bd0beb250b56f6901702;hb=HEAD > > > > > > to fit what we need. > > > > > > We have 5 gpios that control the max current setting on > > > current-driver for Backlight biasing shunt kathode resistor, and I > > > don't know where to place the code to set those pins. > > > > > > I would like to avoid to create another new board if possible, since > > > board/sunxi has everything we need to make our board operative. > > > In general, is there some sort of __weak__ hooks to be used to extend an > > > existing board? > > > Because I understand that probably you wouldn't add this code I'm talking > > > about inside board/sunxi. > > > > > > This request is done with idea to upstream patch for this board. > > > > > > Can you help me? > > > > If that's backlight related, maybe you can just create a new backlight > > driver? > > If it makes sense for sure we can. > > But please can you take a look at the schematics of current-driver with > mosfets biasing power? > https://pasteboard.co/HK4ChzF.png > As you can see we bias BKL_K (Backlight Kathode) to slightly influence the > shunt(R81+R76). > I don't know how it could be useful for the others. > > We use that to handle different displays with the same board(A20 based). > > So does it make sense to write a driver? > And if yes, I would think about adding: > backlight_current.c under u-boot/drivers/video > or another option could be to write a driver under: > u-boot/drivers/power > > What do you think?
Maybe you can just create a regulator driver, with each current step describing a step, just like gpio-regulator is doing for the voltage. Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
