Hello Javier, On 16 July 2014 20:49, Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx> wrote: > Hello Mark, > > The s3c64xx SPI driver DT binding is currently broken. Commit > 3146bee ("spi: s3c64xx: Added provision for dedicated cs pin") > added a new "cs-gpio" property and made it a requirement in > order to make the driver behave in the same way that it used to. > > The motivation of the offending commit was to allow boards that > want to use the native chip select (instead of a GPIO) to work > with the s3c64xx SPI driver. Something that was not possible > before since the driver made it mandatory to specify a GPIO. > > Unfortunately the commit also changed the driver defaults since > now besides specifying a GPIO, it makes mandatory to also specify > that a GPIO is used while the default used to be the opposite. > > That mean that old FDT are not working anymore after 3146bee > so DT backward compatibility was not ensured by that commit. > > This is a follow-up series from a previous one posted by Naveen > Krishna [0] which attempts to solve the issue. > > The feedback from Naveen's series was that the patches did not > provide a clear explanation about the rationale and goal of both > the series as a whole and the individual changes [1]. > > So I tried to take Navee's series and rework them to provide > an easier to understand patch series. > > The series is composed of the following patches: > > Javier Martinez Canillas (1): > Revert "spi: s3c64xx: Added provision for dedicated cs pin" > > Naveen Krishna Chatradhi (3): > spi: s3c64xx: use the generic SPI "cs-gpios" property > spi: samsung: Update binding documentation > ARM: DTS: fix the chip select gpios definition in the SPI nodes I should have mentioned what was the issue being fixed. Your explanation is very clear. I'm working on getting the terminology correct. Thank you. > > .../devicetree/bindings/spi/spi-samsung.txt | 8 ++-- > arch/arm/boot/dts/exynos4210-smdkv310.dts | 2 +- > arch/arm/boot/dts/exynos4412-trats2.dts | 2 +- > arch/arm/boot/dts/exynos5250-smdk5250.dts | 2 +- > drivers/spi/spi-s3c64xx.c | 54 ++++++++++------------ > 5 files changed, 30 insertions(+), 38 deletions(-) > > Patch 01/04 reverts the offending commit since it not only broke > the DT binding but also introduced a confusing "cs-gpio" property > while the driver already used a property with the same name. > > Patch 02/04 fixes the DT binding for good by using the SPI core > "cs-gpios" property to specify the chip select GPIO instead of > using a custom property only used by this driver. This change > breaks backward compatibility but this has been broken for more > than a year and nobody complained so I think it's safe to change > it again in favor of using standard DT binding properties. > > A benefit of Patch 02/04 is that it allows DT and legacy boards > that need to use the built-in CS instead of a GPIO to work with > the driver which was the original motivation of the broken commit. > > Patch 03/04 updates the driver binding documentation accordingly > and patch 04/04 updates all the DTS board files in mainline. > > Best regards, > Javier > > [0]: http://www.spinics.net/lists/linux-samsung-soc/msg34163.html > [1]: http://www.spinics.net/lists/linux-samsung-soc/msg34309.html > > -- > To unsubscribe from this list: send the line "unsubscribe linux-spi" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Shine bright, (: Nav :) -- 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