On 28.04.2022 12:00, Krzysztof Kozlowski wrote: > On 28/04/2022 11:57, Marek Szyprowski wrote: >> On 28.04.2022 11:54, Krzysztof Kozlowski wrote: >>> On 28/04/2022 11:50, Marek Szyprowski wrote: >>>> On 27.04.2022 17:58, Krzysztof Kozlowski wrote: >>>>> pl330 DMA controller bindings documented 'dma-channels' and >>>>> 'dma-requests' properties (without leading hash sign), so fix the DTS to >>>>> match the bindings. >>>>> >>>>> Reported-by: Rob Herring <robh@xxxxxxxxxx> >>>>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx> >>>> Are those properties really needed for PL330 driver on Exynos SoCs? I've >>>> removed them and I still see the proper values read from registers and >>>> reported in the log (Exynos4210): >>>> >>>> dma-pl330 12680000.dma-controller: Loaded driver for PL330 DMAC-141330 >>>> dma-pl330 12680000.dma-controller: DBUFF-32x4bytes Num_Chans-8 >>>> Num_Peri-32 Num_Events-32 >>>> dma-pl330 12690000.dma-controller: Loaded driver for PL330 DMAC-141330 >>>> dma-pl330 12690000.dma-controller: DBUFF-32x4bytes Num_Chans-8 >>>> Num_Peri-32 Num_Events-32 >>>> dma-pl330 12850000.dma-controller: Loaded driver for PL330 DMAC-141330 >>>> dma-pl330 12850000.dma-controller: DBUFF-64x8bytes Num_Chans-8 >>>> Num_Peri-1 Num_Events-32 >>>> >>>> I also don't see any code that would read those properties. IMHO they >>>> should be simply removed at all, at least for the PL330 related nodes. >>> In current Linux implementation they indeed are not used. Nothing parses >>> them. However: >>> 1. They describe (hopefully correct) the hardware. >>> 2. They might be used by other implementations of pl330 driver. >>> >>> I would not remove them from existing sources, but indeed maybe there is >>> no need to add for new files. >> What's the point in having dt properties duplicating data that might be >> read from the driver registers? > Hm, indeed, there is no point in this. Since they are read from > registers, what was the idea behind in commit 42cf20980cde? #dma-cells is indeed required, but the rest seems to be the cargo-cult of some kind. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
