On Fri, May 29, 2015 at 05:32:50PM +0300, Peter Ujfalusi wrote: > On 05/29/2015 01:18 PM, Vinod Koul wrote: > > On Fri, May 29, 2015 at 11:42:27AM +0200, Geert Uytterhoeven wrote: > >> On Fri, May 29, 2015 at 11:33 AM, Vinod Koul <vinod.koul@xxxxxxxxx> wrote: > >>> On Tue, May 26, 2015 at 04:25:57PM +0300, Peter Ujfalusi wrote: > >>>> dma_request_slave_channel_compat() 'eats' up the returned error codes which > >>>> prevents drivers using the compat call to be able to do deferred probing. > >>>> > >>>> The new wrapper is identical in functionality but it will return with error > >>>> code in case of failure and will pass the -EPROBE_DEFER to the caller in > >>>> case dma_request_slave_channel_reason() returned with it. > >>> This is okay but am worried about one more warpper, how about fixing > >>> dma_request_slave_channel_compat() > >> > >> Then all callers of dma_request_slave_channel_compat() have to be > >> modified to handle ERR_PTR first. > >> > >> The same is true for (the existing) dma_request_slave_channel_reason() > >> vs. dma_request_slave_channel(). > > Good point, looking again, I think we should rather fix > > dma_request_slave_channel_reason() as it was expected to return err code and > > add new users. Anyway users of this API do expect the reason... > > Hrm, they are for different use.dma_request_slave_channel()/_reason() is for > drivers only working via DT or ACPI while > dma_request_slave_channel_compat()/_reason() is for drivers expected to run in > DT/ACPI or legacy mode as well. > > I added the dma_request_slave_channel_compat_reason() because OMAP/daVinci > drivers are using this to request channels - they need to support DT and > legacy mode. I think we should hide these things behind the API and do this behind the hood for ACPI/DT systems. Also it makes sense to use right API and mark rest as depricated > > But it is doable to do this for both the non _compat and _compat version: > 1. change all users to check IS_ERR_OR_NULL(chan) > return the PTR_ERR if not NULL, or do whatever the driver was doing in case > of chan == NULL. > 2. change the non _compat and _compat versions to do the same as the _reason > variants, #define the _reason ones to the non _reason names > 3. Rename the _reason use to non _reason function in drivers > 4. Remove the #defines for the _reason functions > 5. Change the IS_ERR_OR_NULL(chan) to IS_ERR(chan) in all drivers > The result: > Both dma_request_slave_channel() and dma_request_slave_channel_compat() will > return ERR_PTR in case of failure or in success they will return the pinter to > chan. > > Is this what you were asking? > It is a bit broader than what this series was doing: taking care of > OMAP/daVinci drivers for deferred probing regarding to dmaengine ;) Yes but it would make sense right? I know it is a larger work but then we wouldn't want another dma_request_slave_xxx API, at some point we have stop it exapnding, perhpas now :) Yes I am all ears to stage this work and not do transition gardually.. -- ~Vinod -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
