Hi Drew,

On Fri, Jul 2, 2021 at 10:56 PM Drew Fustini [off-list ref] wrote:

On Thu, Jul 01, 2021 at 10:34:56AM +0200, Geert Uytterhoeven wrote:

quoted

On Thu, Jul 1, 2021 at 2:22 AM Drew Fustini [off-list ref] wrote:

quoted

Add bindings for the GPIO controller in the StarFive JH7100 SoC [1].

[1] https://github.com/starfive-tech/beaglev_doc

Signed-off-by: Drew Fustini <redacted>
Signed-off-by: Huan Feng <redacted>

Thanks for your patch!

quoted

--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/starfive,jh7100-gpio.yaml

@@ -0,0 +1,60 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/gpio/starfive,jh7100-gpio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: StarFive JH7100 GPIO controller
+
+maintainers:
+  - Huan Feng <huan.feng@starfivetech.com>
+  - Drew Fustini <drew@beagleboard.org>
+
+properties:
+  compatible:
+    items:
+      - const: starfive,jh7100-gpio
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    description:
+      Interrupt mapping, one per GPIO. Maximum 32 GPIOs.
+    minItems: 1
+    maxItems: 32

What about clocks and resets?

Thank you for your feedback, Geert.

GPIO controller uses clk_apb1_bus under dom0_sys.  I believe the device
tree node would use something like this:

  clocks = <&clkgen JH7100_CLK_APB1>;

I see the sifive-gpio.yaml has:

  clocks:
    maxItems: 1

Would that be the correct way to do it for the starfive gpio yaml?

Yep.

The reset for GPIO controller is presetn under dom_sys.  Do you think
know you know an example that has reset in the YAML?  Is there some code
that would actually make use of that information?

quoted

quoted

+
+  gpio-controller: true
+
+  "#gpio-cells":
+    const: 2
+
+  interrupt-controller: true
+
+  "#interrupt-cells":
+    const: 2
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - interrupt-controller
+  - "#interrupt-cells"
+  - "#gpio-cells"
+  - gpio-controller

Do you think I should add 'clocks' to 'required:'?

I'm still having issues with i2c if the GPIO block lists a clock, due to
fw_devlink dependencies.

quoted

quoted

+
+additionalProperties: false
+
+examples:
+  - |
+      gpio@11910000 {
+        compatible = "starfive,jh7100-gpio";
+        reg = <0x11910000 0x10000>;
+        gpio-controller;
+        #gpio-cells = <2>;
+        interrupt-controller;
+        #interrupt-cells = <2>;
+        interrupts = <32>;

I would add:

  clocks = <&clkgen JH7100_CLK_APB1>;

But I am not sure how reset would work?

That should become "resets = <&rstgen JH7100_RSTN_GPIO_APB>",
but we don't have the reset controller in Linux yet (we do in barebox).

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds