On Thu, Mar 23, 2023 at 12:16:23PM +0000, Akhil R wrote: > , Mar 23, 2023 at 09:26:00AM +0000, Akhil R wrote: > > > > On 22/03/2023 12:00, Akhil R wrote: > > > > >> On 22/03/2023 10:24, Akhil R wrote: > > > > >>> Allocate only one DMA channel for I2C and share it for both TX and > > RX > > > > >>> instead of using two different DMA hardware channels with the > > same > > > > >>> slave ID. Since I2C supports only half duplex, there is no impact on > > > > >>> perf with this. > > > > >>> > > > > >>> Signed-off-by: Akhil R <akhilrajeev@xxxxxxxxxx> > > > > >> > > > > >> Just to confirm. This impacts all Tegra devices from Tegra20 to the > > > > >> latest. Does this work for all Tegra and the different DMA controllers > > > > >> that they have? > > > > >> > > > > > Yes, It should. I could see in the APB DMA driver that the same channel > > > > > could be used for TX and RX and the direction is configured only during > > > > > dma_prep_*() calls. > > > > > I did not test it on a Tegra with APB DMA, but since it works very > > similar > > > > > to GPC DMA there should not be any impact. > > > > > > > > > > > > OK. BTW, this does not apply cleanly on top of -next. It appears that > > > > this is based on top "i2c: tegra: Fix PEC support for SMBUS block read" > > > > and that one needs to be applied first. This can be avoided if you send > > > > as a series. > > > > > > > Oh. Okay. I used 'git am --3way' when I tried, and the conflict went > > unnoticed. > > > Shall I send a new version on top of -next? > > > The two patches were added in different contexts and that’s why I did not > > > combine them as a series. > > > > It's usually best to combine them in a series even if they are in > > slightly different contexts. This is especially true if they cause > > conflicts between one another. If you send them as a series, you can > > resolve the conflicts yourself (you may not even have conflicts locally > > if you create the patches in the same branch), but if you send them > > separately the maintainer will end up having to resolve the conflicts > > (or apply in the right order). > > > > It's best if you resolve the conflicts because you know better than the > > maintainer (usually) or specify any dependencies to make it easier for > > the maintainer to do the right thing. > > > > But again, in the vast majority of cases, it's best to combine all the > > work on one driver in a single series before sending out. > > > Okay. Got it. I shall send a new patchset with both the patches. > Can I put the patchset as v1 or does it have to be something different? > Because this patch is in v3 and "i2c: tegra: Fix PEC support for SMBUS > block read" is v2 now. Best to keep versioning. I'd go with making the combined series v4, which is probably the least confusing. You can technically also make a combined series where each patch is at a different version, but that would probably confuse people even more. Thierry
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