| Message ID | 20250309132959.19045-6-ansuelsmth@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [01/13] clk: en7523: convert driver to regmap API | expand |
On 10/03/2025 11:47, Christian Marangi wrote: > On Mon, Mar 10, 2025 at 10:21:45AM +0100, Krzysztof Kozlowski wrote: >> On 09/03/2025 14:29, Christian Marangi wrote: >>> Add Documentation for Airoha EN7581 SCU. >>> >>> Airoha EN7581 SoC expose registers to control miscellaneous pheriperals >>> via the SCU (System Controller Unit). >>> >>> Example of these pheriperals are reset-controller, clock-controller, >>> PCIe line speed controller and bits to configure different Serdes ports >>> for USB or Ethernet usage. >>> >>> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com> >>> --- >>> .../mfd/airoha,en7581-scu-sysctl.yaml | 68 +++++++++++++++++++ >>> 1 file changed, 68 insertions(+) >>> create mode 100644 Documentation/devicetree/bindings/mfd/airoha,en7581-scu-sysctl.yaml >>> >>> diff --git a/Documentation/devicetree/bindings/mfd/airoha,en7581-scu-sysctl.yaml b/Documentation/devicetree/bindings/mfd/airoha,en7581-scu-sysctl.yaml >>> new file mode 100644 >>> index 000000000000..d7dc66f912c1 >>> --- /dev/null >>> +++ b/Documentation/devicetree/bindings/mfd/airoha,en7581-scu-sysctl.yaml >>> @@ -0,0 +1,68 @@ >>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) >>> +%YAML 1.2 >>> +--- >>> +$id: http://devicetree.org/schemas/mfd/airoha,en7581-scu-sysctl.yaml# >>> +$schema: http://devicetree.org/meta-schemas/core.yaml# >>> + >>> +title: Airoha EN7581 SCU (System Controller Unit) >>> + >>> +maintainers: >>> + - Christian Marangi <ansuelsmth@gmail.com> >>> + >>> +description: >>> + Airoha EN7581 SoC expose registers to control miscellaneous >>> + pheriperals via the SCU (System Controller Unit). >>> + >> One more comment - there is no such thing as "sysctl" in your hardware. >> Look at the SCU binding which clearly says that it is the hardware you >> are duplicating here, so the "System Control Unit". >> >> So you have existing "This node defines the System Control Unit of the >> EN7523 SoC" and you add one more node which defines the "System Control >> Unit", so you have two "System Control Unit" device nodes? >> >> Look also what Stephen asked for: >> >> https://lore.kernel.org/all/20220106013100.842FCC36AEB@smtp.kernel.org/ >> >> so how system-controller can now became clock-controller? Now, it was >> the system controller since the beginning. >> > > The main problem here (and we had a similar problem with GPIO and PWM) > is that the Vendor (Airoha) wasn't so bright in placing the different > registers for the SoC so we have case where everything is mixed and not > one after another... > > Example we have > - CLK register part 1 > - Some bits that configure PCIe > - CLK register part 2 > - GPIO > - CLK register part 3 > - ... This does not explain that binding said "This node defines the System Control Unit". So what are you adding here if not SCU? > > The driver solution for this is syscon and the simple-mfd node > structure. Let's keep driver entirely separate, we don't talk about them and mixing arguments won't make it easier. > > Now the main problem is how to modle this in DT. There are lots of case > where the simple-mfd model is used (like the one proposed) but probably > this is not accepted anymore. But again this should be clearly stated or > we have a chicken-egg problem when other devs implement similar thing and > have to implement simple MFD driver to handle this. (and driver > maintainers say "Use the simple-mfd model like it was already done) simple-mfd has nothing to do here. Describe the hardware - what is the SCU? > > For this specific case (and to give an answer to the clock patch after > this) the problem is that this register space was originally used only > to control the clock and I wasn't aware that it was also used to control > USB. Now that I'm implementing support for it, the disaster happened. > > So In short SCU is lots of thing, both a system-controller, a > clock-controller and even a reset-controller. And you have bindings for that already. Done. > > To make it short, 2 different solution: > 1. We can keep the current node structure of the node-controller and add a > child node for the SSR part (with a dedicated compatible). No, you do not add child nodes just because you want some drivers. What is SSR? How is it a device? > 2. Those property need to be be defined in the clock-controller node? In the SCU node. Do you have only one SCU or more? > > The ideal solution is 1. Does it work for you? > > Sorry for the long post and hope you understand why this mess of > reworking the binding. > Best regards, Krzysztof
On Mon, Mar 10, 2025 at 12:41:06PM +0100, Krzysztof Kozlowski wrote: > On 10/03/2025 11:47, Christian Marangi wrote: > > On Mon, Mar 10, 2025 at 10:21:45AM +0100, Krzysztof Kozlowski wrote: > >> On 09/03/2025 14:29, Christian Marangi wrote: > >>> Add Documentation for Airoha EN7581 SCU. > >>> > >>> Airoha EN7581 SoC expose registers to control miscellaneous pheriperals > >>> via the SCU (System Controller Unit). > >>> > >>> Example of these pheriperals are reset-controller, clock-controller, > >>> PCIe line speed controller and bits to configure different Serdes ports > >>> for USB or Ethernet usage. > >>> > >>> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com> > >>> --- > >>> .../mfd/airoha,en7581-scu-sysctl.yaml | 68 +++++++++++++++++++ > >>> 1 file changed, 68 insertions(+) > >>> create mode 100644 Documentation/devicetree/bindings/mfd/airoha,en7581-scu-sysctl.yaml > >>> > >>> diff --git a/Documentation/devicetree/bindings/mfd/airoha,en7581-scu-sysctl.yaml b/Documentation/devicetree/bindings/mfd/airoha,en7581-scu-sysctl.yaml > >>> new file mode 100644 > >>> index 000000000000..d7dc66f912c1 > >>> --- /dev/null > >>> +++ b/Documentation/devicetree/bindings/mfd/airoha,en7581-scu-sysctl.yaml > >>> @@ -0,0 +1,68 @@ > >>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) > >>> +%YAML 1.2 > >>> +--- > >>> +$id: http://devicetree.org/schemas/mfd/airoha,en7581-scu-sysctl.yaml# > >>> +$schema: http://devicetree.org/meta-schemas/core.yaml# > >>> + > >>> +title: Airoha EN7581 SCU (System Controller Unit) > >>> + > >>> +maintainers: > >>> + - Christian Marangi <ansuelsmth@gmail.com> > >>> + > >>> +description: > >>> + Airoha EN7581 SoC expose registers to control miscellaneous > >>> + pheriperals via the SCU (System Controller Unit). > >>> + > >> One more comment - there is no such thing as "sysctl" in your hardware. > >> Look at the SCU binding which clearly says that it is the hardware you > >> are duplicating here, so the "System Control Unit". > >> > >> So you have existing "This node defines the System Control Unit of the > >> EN7523 SoC" and you add one more node which defines the "System Control > >> Unit", so you have two "System Control Unit" device nodes? > >> > >> Look also what Stephen asked for: > >> > >> https://lore.kernel.org/all/20220106013100.842FCC36AEB@smtp.kernel.org/ > >> > >> so how system-controller can now became clock-controller? Now, it was > >> the system controller since the beginning. > >> > > > > The main problem here (and we had a similar problem with GPIO and PWM) > > is that the Vendor (Airoha) wasn't so bright in placing the different > > registers for the SoC so we have case where everything is mixed and not > > one after another... > > > > Example we have > > - CLK register part 1 > > - Some bits that configure PCIe > > - CLK register part 2 > > - GPIO > > - CLK register part 3 > > - ... > > This does not explain that binding said "This node defines the System > Control Unit". > > So what are you adding here if not SCU? > With "This node defines the System Control Unit" I mean, the entire register space of the IP block is defined and each child specifically define each part of the IP block. > > > > The driver solution for this is syscon and the simple-mfd node > > structure. > > Let's keep driver entirely separate, we don't talk about them and mixing > arguments won't make it easier. > Ok. > > > > Now the main problem is how to modle this in DT. There are lots of case > > where the simple-mfd model is used (like the one proposed) but probably > > this is not accepted anymore. But again this should be clearly stated or > > we have a chicken-egg problem when other devs implement similar thing and > > have to implement simple MFD driver to handle this. (and driver > > maintainers say "Use the simple-mfd model like it was already done) > > simple-mfd has nothing to do here. Describe the hardware - what is the SCU? > > As I said below, SCU is just the name used in Airoha Documentation for this IP block. In this register space there are multiple things so it's not strictly a clock-controller (as it's currently defined) It was proposed as clock-controller previously as we weren't aware this IP block was used also for other usage that a strict clock controller. > > > > For this specific case (and to give an answer to the clock patch after > > this) the problem is that this register space was originally used only > > to control the clock and I wasn't aware that it was also used to control > > USB. Now that I'm implementing support for it, the disaster happened. > > > > So In short SCU is lots of thing, both a system-controller, a > > clock-controller and even a reset-controller. > > And you have bindings for that already. Done. > It's currently defined in DTS as clock-controller, should we change it to system-controller to make it more clear? > > > > To make it short, 2 different solution: > > 1. We can keep the current node structure of the node-controller and add a > > child node for the SSR part (with a dedicated compatible). > > No, you do not add child nodes just because you want some drivers. > > What is SSR? How is it a device? SSR is the name used in Documentation for the register used to configure the Serdes and PCIe port. > > > 2. Those property need to be be defined in the clock-controller node? > > In the SCU node. Do you have only one SCU or more? Strictly speaking it's one register space. One clock-controller, one reset-controller and one set of SSR registers, and from what I can understand it's ALWAYS "One device/compatible for Register space" The simple-mfd pattern can't really work for case like this where in one register space there are multiple stuff. Is everything clear now? To summarize: - no child nodes - add additional property for SSR in the SCU .yaml > > > > > The ideal solution is 1. Does it work for you? > > > > Sorry for the long post and hope you understand why this mess of > > reworking the binding. > > > > > Best regards, > Krzysztof
diff --git a/Documentation/devicetree/bindings/mfd/airoha,en7581-scu-sysctl.yaml b/Documentation/devicetree/bindings/mfd/airoha,en7581-scu-sysctl.yaml new file mode 100644 index 000000000000..d7dc66f912c1 --- /dev/null +++ b/Documentation/devicetree/bindings/mfd/airoha,en7581-scu-sysctl.yaml @@ -0,0 +1,68 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/mfd/airoha,en7581-scu-sysctl.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Airoha EN7581 SCU (System Controller Unit) + +maintainers: + - Christian Marangi <ansuelsmth@gmail.com> + +description: + Airoha EN7581 SoC expose registers to control miscellaneous + pheriperals via the SCU (System Controller Unit). + + Example of these pheriperals are reset-controller, clock-controller, + PCIe line speed controller and bits to configure different Serdes ports + for USB or Ethernet usage. + +properties: + compatible: + items: + - const: airoha,en7581-scu-sysctl + - const: syscon + - const: simple-mfd + + reg: + maxItems: 1 + + clock-controller: + type: object + $ref: /schemas/clock/airoha,en7523-scu.yaml + description: + Child node definition for EN7581 Clock controller + + system-controller: + type: object + $ref: /schemas/soc/airoha/airoha,an7581-scu-ssr.yaml + description: + Child node definition for EN7581 System Status Register + +required: + - compatible + - reg + +additionalProperties: false + +examples: + - | + #include <dt-bindings/soc/airoha,scu-ssr.h> + + system-controller@1fb00000 { + compatible = "airoha,en7581-scu-sysctl", "syscon", "simple-mfd"; + reg = <0x1fb00000 0x970>; + + clock-controller { + compatible = "airoha,en7581-scu"; + + #clock-cells = <1>; + #reset-cells = <1>; + }; + + system-controller { + compatible = "airoha,an7581-scu-ssr"; + + airoha,serdes-usb2 = <AIROHA_SCU_SSR_USB2_PCIE2>; + }; + };
Add Documentation for Airoha EN7581 SCU. Airoha EN7581 SoC expose registers to control miscellaneous pheriperals via the SCU (System Controller Unit). Example of these pheriperals are reset-controller, clock-controller, PCIe line speed controller and bits to configure different Serdes ports for USB or Ethernet usage. Signed-off-by: Christian Marangi <ansuelsmth@gmail.com> --- .../mfd/airoha,en7581-scu-sysctl.yaml | 68 +++++++++++++++++++ 1 file changed, 68 insertions(+) create mode 100644 Documentation/devicetree/bindings/mfd/airoha,en7581-scu-sysctl.yaml