| Message ID | 20190521115849.9882-1-m.szyprowski@samsung.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Exynos EHCI/OHCI: resolve conflict with the generic USB device bindings | expand |
Marek Szyprowski <m.szyprowski@samsung.com> writes: > Dear All, > > Commit 69bec7259853 ("USB: core: let USB device know device node") added > support for attaching devicetree node for USB devices. Those nodes are > children of their USB host controller. However Exynos EHCI and OHCI > driver bindings already define child-nodes for each physical root hub > port and assigns respective PHY controller and parameters to them. This > leads to the conflict. A workaround for it has been merged as commit > 01d4071486fe ("usb: exynos: add workaround for the USB device bindings > conflict"), but it disabled support for USB device binding for Exynos > EHCI/OHCI controllers. > > This patchset tries to resolve this binding conflict by changing Exynos > EHCI/OHCI bindings: PHYs are moved from the sub-nodes to a standard array > under the 'phys' property. Such solution has been suggested by Måns > Rullgård in the following thread: https://lkml.org/lkml/2019/5/13/228 > > To keep everything working during the transitional time, the changes has > been split into 2 steps. First step (patches 1-3) need to be merged before > the second one (patches 4-5). Patches from each step can be merged to > respective trees without any dependencies - the only requirement is that > second step has to be merged after merging all patches from the first one. > > This patchset has been tested on various Exynos4 boards with different > USB host controller configurations (Odroids family: X2, U3, XU3). > > Best regards > Marek Szyprowski > Samsung R&D Institute Poland > > Marek Szyprowski (5): > dt-bindings: switch Exynos EHCI/OHCI bindings to use array of generic > PHYs > ARM: dts: exynos: Add array of generic PHYs to EHCI/OHCI devices > usb: exynos: add support for getting PHYs from the standard dt array > ARM: dts: exynos: Remove obsolete port sub-nodes from EHCI/OHCI > devices > usb: exynos: Remove support for legacy PHY bindings You could retain compatibility with old devicetrees (which may be useful) by using the "phys" property if it exists and falling back on the old method if it doesn't. Then you would get this sequence of changes: 1. Update binding definition. 2. Support new binding in driver, with fallback to old. 3. Switch dts files to new binding.
Hi Måns On 2019-05-21 15:30, Måns Rullgård wrote: > Marek Szyprowski <m.szyprowski@samsung.com> writes: >> Dear All, >> >> Commit 69bec7259853 ("USB: core: let USB device know device node") added >> support for attaching devicetree node for USB devices. Those nodes are >> children of their USB host controller. However Exynos EHCI and OHCI >> driver bindings already define child-nodes for each physical root hub >> port and assigns respective PHY controller and parameters to them. This >> leads to the conflict. A workaround for it has been merged as commit >> 01d4071486fe ("usb: exynos: add workaround for the USB device bindings >> conflict"), but it disabled support for USB device binding for Exynos >> EHCI/OHCI controllers. >> >> This patchset tries to resolve this binding conflict by changing Exynos >> EHCI/OHCI bindings: PHYs are moved from the sub-nodes to a standard array >> under the 'phys' property. Such solution has been suggested by Måns >> Rullgård in the following thread: https://lkml.org/lkml/2019/5/13/228 >> >> To keep everything working during the transitional time, the changes has >> been split into 2 steps. First step (patches 1-3) need to be merged before >> the second one (patches 4-5). Patches from each step can be merged to >> respective trees without any dependencies - the only requirement is that >> second step has to be merged after merging all patches from the first one. >> >> This patchset has been tested on various Exynos4 boards with different >> USB host controller configurations (Odroids family: X2, U3, XU3). >> >> Best regards >> Marek Szyprowski >> Samsung R&D Institute Poland >> >> Marek Szyprowski (5): >> dt-bindings: switch Exynos EHCI/OHCI bindings to use array of generic >> PHYs >> ARM: dts: exynos: Add array of generic PHYs to EHCI/OHCI devices >> usb: exynos: add support for getting PHYs from the standard dt array >> ARM: dts: exynos: Remove obsolete port sub-nodes from EHCI/OHCI >> devices >> usb: exynos: Remove support for legacy PHY bindings > You could retain compatibility with old devicetrees (which may be > useful) by using the "phys" property if it exists and falling back > on the old method if it doesn't. Then you would get this sequence > of changes: > > 1. Update binding definition. > 2. Support new binding in driver, with fallback to old. > 3. Switch dts files to new binding. This is exactly what I did in this patchset. Until Patch #5 is applied, Exynos EHCI/OHCI drivers supports both ways of getting PHYs and is fully compatible with existing DTBs. This last patch should be applied at least one release later that the first 3 patches to keep everything working during the -rcX time. Compatibility with so called old DTBs is not so important, because there are no boards with Exynos4 and Exynos5 SoCs, which would not update DTB together with the kernel zImage. There have been already some significant compatibility breaks related to those SoCs during last years. Best regards
Marek Szyprowski <m.szyprowski@samsung.com> writes: > Hi Måns > > On 2019-05-21 15:30, Måns Rullgård wrote: >> Marek Szyprowski <m.szyprowski@samsung.com> writes: >>> Dear All, >>> >>> Commit 69bec7259853 ("USB: core: let USB device know device node") added >>> support for attaching devicetree node for USB devices. Those nodes are >>> children of their USB host controller. However Exynos EHCI and OHCI >>> driver bindings already define child-nodes for each physical root hub >>> port and assigns respective PHY controller and parameters to them. This >>> leads to the conflict. A workaround for it has been merged as commit >>> 01d4071486fe ("usb: exynos: add workaround for the USB device bindings >>> conflict"), but it disabled support for USB device binding for Exynos >>> EHCI/OHCI controllers. >>> >>> This patchset tries to resolve this binding conflict by changing Exynos >>> EHCI/OHCI bindings: PHYs are moved from the sub-nodes to a standard array >>> under the 'phys' property. Such solution has been suggested by Måns >>> Rullgård in the following thread: https://lkml.org/lkml/2019/5/13/228 >>> >>> To keep everything working during the transitional time, the changes has >>> been split into 2 steps. First step (patches 1-3) need to be merged before >>> the second one (patches 4-5). Patches from each step can be merged to >>> respective trees without any dependencies - the only requirement is that >>> second step has to be merged after merging all patches from the first one. >>> >>> This patchset has been tested on various Exynos4 boards with different >>> USB host controller configurations (Odroids family: X2, U3, XU3). >>> >>> Best regards >>> Marek Szyprowski >>> Samsung R&D Institute Poland >>> >>> Marek Szyprowski (5): >>> dt-bindings: switch Exynos EHCI/OHCI bindings to use array of generic >>> PHYs >>> ARM: dts: exynos: Add array of generic PHYs to EHCI/OHCI devices >>> usb: exynos: add support for getting PHYs from the standard dt array >>> ARM: dts: exynos: Remove obsolete port sub-nodes from EHCI/OHCI >>> devices >>> usb: exynos: Remove support for legacy PHY bindings >> You could retain compatibility with old devicetrees (which may be >> useful) by using the "phys" property if it exists and falling back >> on the old method if it doesn't. Then you would get this sequence >> of changes: >> >> 1. Update binding definition. >> 2. Support new binding in driver, with fallback to old. >> 3. Switch dts files to new binding. > > This is exactly what I did in this patchset. Until Patch #5 is applied, > Exynos EHCI/OHCI drivers supports both ways of getting PHYs and is fully > compatible with existing DTBs. This last patch should be applied at > least one release later that the first 3 patches to keep everything > working during the -rcX time. I'm suggesting you keep the fallback in the driver. It does no harm, and it's contained in one place. On the dts side, you're adding the new phys property without removing the old-style nodes at first. If you put the driver change first, the dts could be switched to the new style in one patch without a confusing hybrid ever existing. > Compatibility with so called old DTBs is not so important, because there > are no boards with Exynos4 and Exynos5 SoCs, which would not update DTB > together with the kernel zImage. There have been already some > significant compatibility breaks related to those SoCs during last years. You can't possibly know what's out there. Besides, isn't the general policy to not break compatibility without a very good reason?
Hi Måns, On 2019-05-22 12:54, Måns Rullgård wrote: > Marek Szyprowski <m.szyprowski@samsung.com> writes: >> On 2019-05-21 15:30, Måns Rullgård wrote: >>> Marek Szyprowski <m.szyprowski@samsung.com> writes: >>>> Commit 69bec7259853 ("USB: core: let USB device know device node") added >>>> support for attaching devicetree node for USB devices. Those nodes are >>>> children of their USB host controller. However Exynos EHCI and OHCI >>>> driver bindings already define child-nodes for each physical root hub >>>> port and assigns respective PHY controller and parameters to them. This >>>> leads to the conflict. A workaround for it has been merged as commit >>>> 01d4071486fe ("usb: exynos: add workaround for the USB device bindings >>>> conflict"), but it disabled support for USB device binding for Exynos >>>> EHCI/OHCI controllers. >>>> >>>> This patchset tries to resolve this binding conflict by changing Exynos >>>> EHCI/OHCI bindings: PHYs are moved from the sub-nodes to a standard array >>>> under the 'phys' property. Such solution has been suggested by Måns >>>> Rullgård in the following thread: https://lkml.org/lkml/2019/5/13/228 >>>> >>>> To keep everything working during the transitional time, the changes has >>>> been split into 2 steps. First step (patches 1-3) need to be merged before >>>> the second one (patches 4-5). Patches from each step can be merged to >>>> respective trees without any dependencies - the only requirement is that >>>> second step has to be merged after merging all patches from the first one. >>>> >>>> This patchset has been tested on various Exynos4 boards with different >>>> USB host controller configurations (Odroids family: X2, U3, XU3). >>>> >>>> Best regards >>>> Marek Szyprowski >>>> Samsung R&D Institute Poland >>>> >>>> Marek Szyprowski (5): >>>> dt-bindings: switch Exynos EHCI/OHCI bindings to use array of generic >>>> PHYs >>>> ARM: dts: exynos: Add array of generic PHYs to EHCI/OHCI devices >>>> usb: exynos: add support for getting PHYs from the standard dt array >>>> ARM: dts: exynos: Remove obsolete port sub-nodes from EHCI/OHCI >>>> devices >>>> usb: exynos: Remove support for legacy PHY bindings >>> You could retain compatibility with old devicetrees (which may be >>> useful) by using the "phys" property if it exists and falling back >>> on the old method if it doesn't. Then you would get this sequence >>> of changes: >>> >>> 1. Update binding definition. >>> 2. Support new binding in driver, with fallback to old. >>> 3. Switch dts files to new binding. >> This is exactly what I did in this patchset. Until Patch #5 is applied, >> Exynos EHCI/OHCI drivers supports both ways of getting PHYs and is fully >> compatible with existing DTBs. This last patch should be applied at >> least one release later that the first 3 patches to keep everything >> working during the -rcX time. > I'm suggesting you keep the fallback in the driver. It does no harm, > and it's contained in one place. > > On the dts side, you're adding the new phys property without removing > the old-style nodes at first. If you put the driver change first, the > dts could be switched to the new style in one patch without a confusing > hybrid ever existing. This was just a proposed way of applying the patches. We can change the order and apply patch #3 first, then in the next kernel release, apply patch #2 and #4 together, and the last step, 2 releases later, apply the last one. In my proposed approach (apply #2 and #3 together to the respective kernel trees for the next release), the final result is applied a release earlier. >> Compatibility with so called old DTBs is not so important, because there >> are no boards with Exynos4 and Exynos5 SoCs, which would not update DTB >> together with the kernel zImage. There have been already some >> significant compatibility breaks related to those SoCs during last years. > You can't possibly know what's out there. Besides, isn't the general > policy to not break compatibility without a very good reason? There have been already some significant changes and compatibility breaks in Exynos DTB ABI and noone complained. We can also ignore completely this patchset and keep compatibility with old DTBs just with the workaround merged in commit 01d4071486fe18ec91f78725d81c7e46557c629a ("usb: exynos: add workaround for the USB device bindings conflict")... Best regards
Dear All, Commit 69bec7259853 ("USB: core: let USB device know device node") added support for attaching devicetree node for USB devices. Those nodes are children of their USB host controller. However Exynos EHCI and OHCI driver bindings already define child-nodes for each physical root hub port and assigns respective PHY controller and parameters to them. This leads to the conflict. A workaround for it has been merged as commit 01d4071486fe ("usb: exynos: add workaround for the USB device bindings conflict"), but it disabled support for USB device binding for Exynos EHCI/OHCI controllers. This patchset tries to resolve this binding conflict by changing Exynos EHCI/OHCI bindings: PHYs are moved from the sub-nodes to a standard array under the 'phys' property. Such solution has been suggested by Måns Rullgård in the following thread: https://lkml.org/lkml/2019/5/13/228 To keep everything working during the transitional time, the changes has been split into 2 steps. First step (patches 1-3) need to be merged before the second one (patches 4-5). Patches from each step can be merged to respective trees without any dependencies - the only requirement is that second step has to be merged after merging all patches from the first one. This patchset has been tested on various Exynos4 boards with different USB host controller configurations (Odroids family: X2, U3, XU3). Best regards Marek Szyprowski Samsung R&D Institute Poland Marek Szyprowski (5): dt-bindings: switch Exynos EHCI/OHCI bindings to use array of generic PHYs ARM: dts: exynos: Add array of generic PHYs to EHCI/OHCI devices usb: exynos: add support for getting PHYs from the standard dt array ARM: dts: exynos: Remove obsolete port sub-nodes from EHCI/OHCI devices usb: exynos: Remove support for legacy PHY bindings .../devicetree/bindings/usb/exynos-usb.txt | 41 ++++++---------- arch/arm/boot/dts/exynos4.dtsi | 28 ++--------- .../boot/dts/exynos4210-universal_c210.dts | 8 +--- arch/arm/boot/dts/exynos4412-itop-elite.dts | 9 +--- arch/arm/boot/dts/exynos4412-odroidu3.dts | 8 +--- arch/arm/boot/dts/exynos4412-odroidx.dts | 5 +- arch/arm/boot/dts/exynos4412-origen.dts | 9 +--- arch/arm/boot/dts/exynos5250.dtsi | 16 ++----- arch/arm/boot/dts/exynos54xx.dtsi | 18 ++----- drivers/usb/host/ehci-exynos.c | 48 +++---------------- drivers/usb/host/ohci-exynos.c | 48 +++---------------- 11 files changed, 50 insertions(+), 188 deletions(-)