* Matt Porter <mporter@xxxxxx> [120911 12:05]: > On Tue, Sep 11, 2012 at 11:35:22AM -0700, Tony Lindgren wrote: > > Added Linus Walleij to Cc as well. Now I think I really managed to add Linus W to Cc, sent too fast earlier. ... > > But do you get an error then if the desired pins are not found? > > If you do get an error, then sounds like it's OK to do. > > Hrm, no. In that case, it will be completely silent (assuming we took > care of the pinmuxing in the bootloader) as it uses the dummy state. > Only with debug on will you see the information that mcspi has used > the dummy state as is the case with !DT. ... > > Well I think we should consider at least the following: > > > > 1. Always see warnings when device tree is populated with board-generic. > > If somebody wants to use bootloader only muxing with DT, they can patch > > in pinctrl_provide_dummies() somewhere. But let's assume we always > > want to see the warnings with board-generic.c and DT. > > Ok, this is clear. > > > 2. For legacy booting without DT, we should not see any warnings > > from pinctrl-single.c as it's DT based. > > Right, except anything legacy booting without DT will require that > dummy states be present otherwise it will fail probe. But I guess we should enable the dummy states only for other board-*.c files, not board-generic.c? > > 3. There may be other non-pinctrl drivers too that are not DT > > based, and in those cases we should see the warnings as well > > for in the non-DT case. > > I'm not sure what you mean here. "non-pinctrl drivers" means any driver > that is not yet pinctrl or DT enabled? It's unclear to me how this > case has a bearing on mcspi and pinctrl enablement across legacy > board-foo.c !DT booting platforms. Right, sorry I meant "non DT pinctrl drivers".. > However, I think if the approach was modified by only calling > pinctrl_provide_dummies() when we are booting with DT populated > and using board-generic.c then it will satisfy all of your > concerns. Thoughts? Hmm but shouldn't it be call pinctrl_provide_dummies() only for other boards except board-generic.c? And that is assuming we don't have any other "non DT pinctrl drivers" around. > i.e. the legacy !DT booting will have dummy states and continue > along through mcspi the way it does today, relying on board-foo level > pinmux calls (or bootloader pinmuxing). Meanwhile DT booting will now > require that a mcspi instance also require pinctrl entry in this dts. Yes agreed, except let's just produce a warning for the pinctrl errors.. > The only worrisome thing is the pinctrl requirement on DT booting is > now an implicit requirement. ..as otherwise not much will work at this point :) > > > > For board-generic.c we always want to see the warnings. And some boards > > > > insist on doing all the muxing only in the bootloader. > > > > > > Which warnings are you saying we should see in the board-generic.c > > > case? Sure, there's plenty of cases where this will be unused due to > > > somebody setting all the muxes in the bootloader and then not using > > > pinctrl data. I'll have to doublecheck but I believe that case is also > > > fine as the -single driver can't override the dummy state if the DT has > > > no pinctrl data for the spi driver. I suggest all pinctrl errors should show up as warnings with board-generic.c, but we should not exit out of the driver probe on errors. Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
