Re: [PATCH v1] ARM: dts: imx6sl-evk: keep sw4 always on

[Robin Gong <yibin.gong@nxp.com>]

On 日, 2018-07-01 at 22:17 -0300, Fabio Estevam wrote:
> On Sun, Jul 1, 2018 at 10:09 PM, Anson Huang <anson.huang@nxp.com>
> wrote:
> 
> > 
> > On some new i.MX platforms, PFuze switches are used for supplying
> > GPU/VPU
> > or other non-critical modules only, these switches need to be
> > turned off by
> > runtime PM to avoid very high power leakage, like on mScale850D.
> Ok, in this case I suggest adding a new property so that the switches
> can be turned off only when the new property is present.
> 
> When this new property is absent, then we keep the current behavior
> and avoid dtb breakage.
> 
> Since MX8M support is not in place yet, this is not urgent, so I will
> send a revert and then you can re-work the patch so that it does not
> affect the old dtbs.
> 
> Do you agree with such approach?
But in fact, the original dts is not correct without 'regulator-always-
on'since SW4 is the critical DDR power rail, although, it's kept on in
the previous kernel by no switches enable/disable interfaces provided
in pfuze driver. Adding new property which can be done totally by the
common 'regulator-always-on' is not a good choice. Keep the dts patch
adding 'regulator-always-on' ahead of pfuze driver pach adding
enable/disable interface is enough for such case I think.