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. 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 ;) -- Péter -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
