Re: [PATCHv5] drivers/amba: add reset control to amba bus probe

From: Valdis KlÄtnieks
Date: Tue Aug 27 2019 - 15:25:37 EST


On Mon, 26 Aug 2019 10:42:52 -0500, Dinh Nguyen said:
> The primecell controller on some SoCs, i.e. SoCFPGA, is held in reset by
> default. Until recently, the DMA controller was brought out of reset by the
> bootloader(i.e. U-Boot). But a recent change in U-Boot, the peripherals
> that are not used are held in reset and are left to Linux to bring them
> out of reset.
>
> Add a mechanism for getting the reset property and de-assert the primecell
> module from reset if found. This is a not a hard fail if the reset properti
> is not present in the device tree node, so the driver will continue to
> probe.

Does this DTRT for both old and new U-Boots? My naive reading of this patch
says on an old U-Boot, we end up attempting to bring it out of reset even though
they had already been brought out.

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