Re: [PATCH 2/3] dt: bindings: add ralink RT2880 resets device tree binding documentation

Hi Rob,

On Tue, Oct 5, 2021 at 3:27 PM Rob Herring [off-list ref] wrote:

On Mon, Oct 4, 2021 at 1:23 PM Sergio Paracuellos
[off-list ref] wrote:

quoted

Hi Rob,

On Mon, Oct 4, 2021 at 8:06 PM Rob Herring [off-list ref] wrote:

quoted

On Sun, Sep 26, 2021 at 04:59:30PM +0200, Sergio Paracuellos wrote:

quoted

Adds device tree binding documentation for resets in the ralink RT2880 SoCs.

Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
---
 .../bindings/reset/ralink,rt2880-reset.yaml   | 39 +++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/reset/ralink,rt2880-reset.yaml

diff --git a/Documentation/devicetree/bindings/reset/ralink,rt2880-reset.yaml b/Documentation/devicetree/bindings/reset/ralink,rt2880-reset.yaml
new file mode 100644
index 000000000000..88eddeb4ee45
--- /dev/null
+++ b/Documentation/devicetree/bindings/reset/ralink,rt2880-reset.yaml

@@ -0,0 +1,39 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/reset/ralink,rt2880-reset.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Ralink RT2880 Reset Controller Device Tree Bindings
+
+maintainers:
+  - Sergio Paracuellos <sergio.paracuellos@gmail.com>
+
+description: |
+  Ralink RT2880 reset controller driver which supports the SoC
+  system controller supplied reset registers for the various peripherals
+  of the SoC.
+
+  See also:
+  - dt-bindings/reset/ralink-rt2880.h
+
+properties:
+  compatible:
+    const: ralink,rt2880-reset
+
+  '#reset-cells':
+    const: 1
+
+required:
+  - '#reset-cells'
+  - compatible
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/reset/ralink-rt2880.h>
+    rstctrl: reset-controller {
+      compatible = "ralink,rt2880-reset";
+      #reset-cells = <1>;

How is this h/w controlled? If this is part of a system controller, then
it needs to be documented as such. IOW, you need to document the binding
for the whole block.

Do you really need a child node here? All you need to make a system
controller a reset provider is add '#reset-cells' to it.

I am just documenting what is already mainlined (see [0]) in order to
get mt7621-dts out of staging at some point of my life. What am I
supposed to do? Should I rewrite all already mainlined code? Because
if that is the case we need to rewrite tons of things from the ralink
platform...

On the flip side, am I not supposed to review bindings because the dts
is already in staging? Code dependent on DT bindings shouldn't have
been mainlined without any documented binding.

Thanks for reviewing this. I guess I should have sent a complete
patchset with all remaining bindings and the move for the complete
binding instead of sending single binding doc patches.

Looks like the resets are part of "mediatek,mt7621-sysc" to answer my
question. Add a #reset-cell to that node (and binding) and then change
this line to "mediatek,mt7621-sysc":

        reset_dev.of_node = of_find_compatible_node(NULL, NULL,
                                                "ralink,rt2880-reset");

That's the minimal change, but really I would move the reset code to
the clock driver as that is what handles the sysc node.

It is not that easy since the code in reset.c is shared for all ralink
platforms and the mediatek,mt7621-sysc node is only for mt7621. So I
guess I have to "duplicate" the reset code and put it in the clock
driver for mt7621 as you are pointing out here. I have to also review
how other drivers are using the reset, using reset apis or directly
through the syscon.

quoted

I'd also like to know what we should do with those nodes already added
to the dtsi file that have not got associated compatible driver
mainlined. Can we just get rid of them?

Yes. Typically dts files start with minimal support.

A dts file in staging is odd. We shouldn't be adding them there.

Thanks for clarification.

Best regards,
    Sergio Paracuellos

Rob