[PATCH 0/4] spi: s3c64xx: fix DT binding breakage
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 .../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-samsung-soc in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 0/4] spi: s3c64xx: fix DT binding breakage
Hello Javier, On 16 July 2014 20:49, Javier Martinez Canillas javier.marti...@collabora.co.uk 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 majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html -- Shine bright, (: Nav :) -- To unsubscribe from this list: send the line unsubscribe linux-samsung-soc in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 0/4] spi: s3c64xx: fix DT binding breakage
On 07/16/2014 06:02 PM, Mark Brown wrote: On Wed, Jul 16, 2014 at 05:19:06PM +0200, Javier Martinez Canillas wrote: *sigh* Yesterday Naveen submitted another, different, patch series also attempting to improve things which I'm not seeing any reference to here. Please coordinate with Naveen about what you are doing. Yes, I answered Naveen on his latest series and told him that I thought his v6 was better and also that the commit messages where still not clearly explaining the motivation for the changes [0]. So after that I asked him in private if he wouldn't mind if I try to rework his series to make it easier to understand and he agreed on that. I should had mentioned it the cover later, sorry about that. Please take a look to this series instead of the latest that was posted by Naveen. Thanks a lot and best regards, Javier [0]: https://www.mail-archive.com/devicetree@vger.kernel.org/msg34860.html -- To unsubscribe from this list: send the line unsubscribe linux-samsung-soc in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
