On 23/01/2024 20:22, Frank Li wrote: > On Tue, Jan 23, 2024 at 06:42:27PM +0000, Conor Dooley wrote: >> On Tue, Jan 23, 2024 at 01:02:21PM -0500, Frank Li wrote: >>> On Tue, Jan 23, 2024 at 05:51:48PM +0000, Conor Dooley wrote: >>>> On Tue, Jan 23, 2024 at 12:49:27PM -0500, Frank Li wrote: >>>>> On Tue, Jan 23, 2024 at 05:27:13PM +0000, Conor Dooley wrote: >>>>>> On Tue, Jan 23, 2024 at 12:02:05PM -0500, Frank Li wrote: >>>>>>> Add device tree binding allow platform overwrite default value of *REQIN in >>>>>>> GSBUSCFG0. >>>>>> >>>>>> Why might a platform actually want to do this? Why does this need to be >>>>>> set at the board level and being aware of which SoC is in use is not >>>>>> sufficient for the driver to set the correct values? >>>>> >>>>> In snps,dwc3.yaml, there are already similary proptery, such as >>>>> snps,incr-burst-type-adjustment. Use this method can keep whole dwc3 usb >>>>> driver keep consistent. And not all platform try enable hardware >>>>> dma_cohenrence. It is configable for difference platform. >>>> >>>> When you say "platform", what do you mean? I understand that term to >>>> mean a combination of board, soc and firmware. >>> >>> In my company's environment, "platform" is "board". I will use "board" in >>> future. Is it big difference here? >> >> Nah, that's close enough that it makes no difference here. >> >> I'd still like an explanation for why a platform would need to actually >> set these properties though, and why information about coherency cannot >> be determined from whether or not the boss the usb controller is on is >> communicated to be dma coherent via the existing devicetree properties >> for that purpose. > > Actually, I am not very clear about reason. I guest maybe treat off power > consumption and performance. > > What's your judgement about proptery, which should be in dts. Such as > reg, clk, reset, dma and irq, which is tighted with SOC. It is the fixed > value for every SOC. The board dts never change these. Then it can be deduced from the compatible and there is no need for new properties. Best regards, Krzysztof
