On 10.06.2014 20:09, Doug Anderson wrote: > Naveen / Sylwester, > > On Tue, Jun 10, 2014 at 4:00 AM, Naveen Krishna Ch > <naveenkrishna.ch@xxxxxxxxx> wrote: >>> Can we support both "cs-gpio" and "cs-gpios" for backward compatibility ? >>> After your change all DTBs using the original pattern will not work with >>> new kernels any more. At least I would expect such backward compatibility >>> maintained for few kernel releases. >> >> The reason behind removing the "cs-gpio" or not providing backward >> compatibility was >> >> 1. Since spi-core started using "cs-gpios" string from spi device node >> several months ago. >> The spi-s3c64xx.c driver is partially broken for more than 6 months. >> >> 2. Supporting "cs-gpio" would add extra bit of code. >> >> I've corrected the dts files that were using "cs-gpio" under >> "controller-data"(child node) >> to use "cs-gpio" from spi device node (parent node). >> >> I will make another version if you insist. > > Yup, as near as I can tell this has been broken since (3146bee spi: > s3c64xx: Added provision for dedicated cs pin). That landed June 25th > of 2013 into the SPI tree. > > ...so clearly nobody was really testing Samsung's SPI driver on ToT > Linux. 1 year of unnoticed brokenness seems like enough time that we > could do away with the old code. If someone comes out of the woodwork > and claims a dire need to support the old binding then it can be added > then. > > In-tree users of this appear to be: > > arch/arm/boot/dts/exynos4210-smdkv310.dts: > cs-gpio = <&gpc1 2 0>; > arch/arm/boot/dts/exynos4412-trats2.dts: > cs-gpio = <&gpb 5 0>; > arch/arm/boot/dts/exynos5250-smdk5250.dts: > cs-gpio = <&gpa2 5 0>; > > ...and I guess nobody has bothered using the SPI flash on those boards > for the last year? On Trats2, it's actually a camera sensor, not SPI flash... Still, that's really a shame that: a) such patch went in (i.e. its brokenness was not spotted in review), b) the regression was not spotted. Anyway, IMHO this justifies removing the old binding then. Best regards, Tomasz -- 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
