Hi Stephen, On 25 July 2016 at 10:50, Stephen Warren <swar...@wwwdotorg.org> wrote: > On 07/24/2016 08:07 PM, Simon Glass wrote: >> >> Hi Stephen, >> >> On 14 July 2016 at 22:17, Simon Glass <s...@chromium.org> wrote: >>> >>> Hi Stephen, >>> >>> On 13 July 2016 at 13:45, Stephen Warren <swar...@wwwdotorg.org> wrote: >>>> >>>> From: Stephen Warren <swar...@nvidia.com> >>>> >>>> Many SoCs allow power to be applied to or removed from portions of the >>>> SoC >>>> (power domains). This may be used to save power. This API provides the >>>> means to control such power management hardware. >>>> >>>> Signed-off-by: Stephen Warren <swar...@nvidia.com> >>>> --- >>>> I'll soon(?) send a Tegra186 power domain driver that implements this >>>> new subsystem. I'm waiting for all the relevant DT bindings to be >>>> reviewed as kernel patches first though. > > ... >>> >>> Acked-by: Simon Glass <s...@chromium.org> >>> >>> Could you add a command (with list/on/off subcommands) to control this >>> also? >> >> >> Any thoughts on this? >> >> Applied to u-boot-dm, thanks! > > > Such a command sounds like a good idea. I'm a bit too swamped to do this > immediately though. > > One issue to consider: How would the user specify which power domain to > control? There's no global namespace. Only individual drivers can parse > their own namespace, and there's no requirement that drivers identify each > powerdomain with e.g. a single integer or name, just like DT specificiers > can use multiple cells. I can think of two ways to handle this: > > a) Add a new "op" function to the driver to allow converting the cmdline > arguments the user passed to the shell command into whatever value(s) the > driver uses to identify the power domain, e.g. "cmdline_xlate()". This has > the disadvantage of requiring extra code (although we could provide a > default implementation for the common code), but has the advantage of > allowing control over any powerdomain that any driver implements. > > b) Make the command take a DT property node name and index, and have the > command look the powerdomain ID up from DT. This has the disadvantage of > limiting control to powerdomains that are already added to the DT, but does > have the advantage of not requiring any driver code.
Option 'b' sounds good. I notice with regulators that there is an extra name in the DT (regulator-name). This is used by the 'pmic' command. Should power domains have that too? Regards, Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
