Hi Prafulla, On 03/28/2012 09:48 AM, Prafulla Wadaskar wrote: >> On 03/26/2012 11:58 AM, Valentin Longchamp wrote: >>> Some kirkwood based boards may need to implement such function due >> to >>> some HW designs. >> >> I see no feedback from your side on this patch. I think you should go >> through >> the marvell tree: >> >> - the spi_claim/release_bus function are already implemented in the >> SPI subsystem >> - this patch touches only a kirkwood driver >> - there is no spi u-boot tree from what I see >> >> Please keep me up to date about the status of this patch > > Hi Valentin, > I have gone through this patch and related implementation in your other > patch_series. > http://lists.denx.de/pipermail/u-boot/2012-March/120716.html > > Basically spi_claim_bus and spi_release_bus are not supported in current > Kirkwood spi driver. > These are needed if someone wish to share the same interface pins with some > other peripheral (that is your use case)
Correct, this is exactly our use case: we have the NAND Flash Controller and the SPI controller that share the same pins. > > But this is not board specific whereas, it should be feature enhancement for > Kirkwood spi driver. This is correct for the mpp part of spi_claim_bus. If you look at the actual implementation that we do in our board specific function, there is an additional step that is needed by our board design. > > You should add this support very similar to multiple CS pin selection support > added to the Kirkwood driver, no external (board specific triggers needed) > > Here are my suggestions: > 1. Configure these mpps in your board specific files as NF pins. > 2. Populate below logic for claim/release bus feature in Kirkwood spi driver. > 2.a. When spi_claim_bus will be called, backup current mpps status and > reconfigure these mpps for SPI in Kirkwood_spi driver. > 2.b. When spi_release_bus will be called, reconfigure with backed up mfg as > SPI pins > 2.c. Add check for to avoid multiple claim for same bus > OK, I agree with this, but I would add: 2.d. call weak attribute functions boad_spi_claim/release_bus at the end of spi_claim/release_bus functions -- Valentin Longchamp Embedded Software Engineer Hardware and Chip Integration ______________________________________ KEYMILE AG Schwarzenburgstr. 73 CH-3097 Liebefeld Phone +41 31 377 1318 Fax +41 31 377 1212 valentin.longch...@keymile.com www.keymile.com ______________________________________ KEYMILE: A Specialist as a Partner _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
