Hello Alex, On 10/27/20 1:15 PM, Rob Herring wrote: > On Mon, Oct 26, 2020 at 4:30 PM Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx> wrote: >> >> Hello Rob, >> >> On 10/26/20 3:36 PM, Rob Herring wrote: >>> On Wed, Oct 21, 2020 at 12:28:55PM +0200, Ahmad Fatoum wrote: >>>> The stm32mp1 TAMP (Tamper and backup registers) does tamper detection >>>> and features 32 backup registers that, being in the RTC domain, may >>>> survive even with Vdd switched off. >>>> >>>> This makes it suitable for use to communicate a reboot mode from OS >>>> to bootloader via the syscon-reboot-mode binding. Add a "simple-mfd" >>>> to support probing such a child node. The actual reboot mode >>>> node could then be defined in a board.dts or fixed up by the bootloader. >>> >>> 'simple-mfd' implies there is no dependency on the parent node for the >>> child (such as the regmap perhaps). Is that the case here? >> >> No, there's a dependency and the Linux driver does syscon_node_to_regmap >> on the device tree node's parent but that's how the syscon-reboot-mode binding >> is documented: >> >> The SYSCON mapped register is retrieved from the >> parental dt-node plus the offset. So the SYSCON reboot-mode node >> should be represented as a sub-node of a "syscon", "simple-mfd" node. >> >> How would you prefer this being done instead? > > Well, probably the syscon driver could just probe any children, but > I'm not sure if that would break anyone. So I guess fine as-is. > > Reviewed-by: Rob Herring <robh@xxxxxxxxxx> Gentle ping. > > Rob > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
