2016-02-14 22:22 GMT+09:00 Youngmin Nam <ym0914@xxxxxxxxx>: > When I think about this patch, I was motivated by below patch. > > commit 135f07c3252dc77d0245714d0b413ecc711cd823 > Author: Naveen Krishna Chatradhi <ch.naveen@xxxxxxxxxxx> > Date: Mon Jul 14 17:07:16 2014 +0530 > > serial: samsung: get fifosize via device tree > > UART modules on some SoCs only differ in the fifosize of each > UART channel. Its useless to duplicate the drv_data structure > or create a compatible name for such a change. > > We can get fifosize via the device tree nodes (not mandating it). > > Also updates the documentation. > > Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@xxxxxxxxxxx> > Reviewed-by: Tomasz Figa <t.figa@xxxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > > I thought we can apply above patch to SPI also. > The fifosize should be required for fifo_lvl_mask value in SPI of Exynos series. > I think this patch is useful when we port for the new exynos7xxx SoC come out. > Because SPI of new exynos7xxx SoC has only difference on fifosize. > Please, do not top post. You skipped some of arguments from my reply instead saying "patch is useful". That is not a sufficient argument for my doubts... but let me state again the most important question: What happens if this *optional* property is not present on board with Exynos7? What value should be used? Best regards, Krzysztof > Thanks. > > > On 2016년 02월 14일 17:31, Krzysztof Kozlowski wrote: >> W dniu 14.02.2016 o 17:13, Youngmin Nam pisze: >>> Hello Krzysztof, >>> >>> As you mentioned, spi fifosize is not configurable in the given SoC. >>> The point is we can set fifosize without changing driver code. >>> For example, if some SoC in exynos7 series has different spi fifosize of on each channel with current >>> our compatible, we can't cover this situation without adding new compatible into spi driver code. >> >> Yes, because new SoC is not compatible with old ones... so a new >> compatible is required! >> >>> Whenever new SoC kind of exynos7 come out, we should add new compatible into driver code only for fifosize change. >>> I think this is not efficient. I think we can reduces this works through DT handling. >> >> I agree that this is not the most efficient possible way of setting some >> specific properties of devices but this is the way how DT works. >> >> What if the property is not present on board with Exynos7? What value >> should be used? >> >> You did not want to add a new compatible but you are adding a >> compatible-like property which apparently is required for some devices. >> >> That looks bad. It's easy to make a mistake, messes with compatibles. >> >> Best regards, >> Krzysztof >> >> -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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