This series came out of a discussion on the ARM boot-architecture list[1] about DT forwards and backwards compatibility issues. There are issues with newer DTs breaking on older, stable kernels. Some of these are difficult to solve, but cases of optional devices not having kernel support should be solvable.
I tested this on a RPi3 B with the pinctrl driver forced off. With this change, the MMC/SD and UART drivers can function without the pinctrl driver. I left the dts change out this time.
v2 and v3 of this series can be found here[2][3].
Rob
[1] https://lists.linaro.org/pipermail/boot-architecture/2018-April/000466.html [2] https://lore.kernel.org/patchwork/project/lkml/list/?series=347413 [3] https://lore.kernel.org/patchwork/project/lkml/list/?series=357344
Rob Herring (6): driver core: allow stopping deferred probe after init dt-bindings: pinctrl: add a 'pinctrl-use-default' property pinctrl: Support stopping deferred probe after initcalls iommu: Stop deferring probe at end of initcalls iommu: Remove IOMMU_OF_DECLARE PM / Domains: Stop deferring probe at the end of initcall
.../admin-guide/kernel-parameters.txt | 9 +++ .../bindings/pinctrl/pinctrl-bindings.txt | 6 ++ drivers/base/dd.c | 59 +++++++++++++++++++ drivers/base/power/domain.c | 2 +- drivers/iommu/arm-smmu-v3.c | 2 - drivers/iommu/arm-smmu.c | 7 --- drivers/iommu/exynos-iommu.c | 2 - drivers/iommu/ipmmu-vmsa.c | 3 - drivers/iommu/msm_iommu.c | 2 - drivers/iommu/of_iommu.c | 21 +------ drivers/iommu/qcom_iommu.c | 2 - drivers/iommu/rockchip-iommu.c | 2 - drivers/pinctrl/devicetree.c | 15 +++-- include/asm-generic/vmlinux.lds.h | 2 - include/linux/device.h | 2 + include/linux/of_iommu.h | 4 -- 16 files changed, 90 insertions(+), 50 deletions(-)
-- 2.17.1