From mboxrd@z Thu Jan 1 00:00:00 1970 From: yibin.gong@nxp.com (Robin Gong) Date: Mon, 2 Jul 2018 02:12:52 +0000 Subject: [PATCH v1] ARM: dts: imx6sl-evk: keep sw4 always on In-Reply-To: References: <1529930051-14122-1-git-send-email-yibin.gong@nxp.com> <20180701093402.GN4348@dragon> Message-ID: <1530526335.15665.13.camel@nxp.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On ?, 2018-07-01 at 22:17 -0300, Fabio Estevam wrote: > On Sun, Jul 1, 2018 at 10:09 PM, Anson Huang > 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.?