RE: [PATCH 0/3] Add Aspeed AST2600 I3C support

[Dylan Hung]

Hi Jeremy,

> -----Original Message-----
> From: Jeremy Kerr [mailto:jk@xxxxxxxxxxxxxxxxxxxx]
> Sent: Wednesday, August 9, 2023 8:08 AM
> To: Dylan Hung <dylan_hung@xxxxxxxxxxxxxx>;
> alexandre.belloni@xxxxxxxxxxx; robh+dt@xxxxxxxxxx;
> krzysztof.kozlowski+dt@xxxxxxxxxx; conor+dt@xxxxxxxxxx; joel@xxxxxxxxx;
> andrew@xxxxxxxx; p.zabel@xxxxxxxxxxxxxx; linux-i3c@xxxxxxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> linux-aspeed@xxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Cc: BMC-SW <BMC-SW@xxxxxxxxxxxxxx>; kobedylan@xxxxxxxxx
> Subject: Re: [PATCH 0/3] Add Aspeed AST2600 I3C support
> 
> Hi Dylan,
> 
> > This patch series introduces the necessary changes to enable I3C
> > support for the Aspeed AST2600 I3C controller. Specifically, it
> > addresses the missing pinctrl configuration and reset control for the
> > I3C functionality.
> 
> +1 for the pinctrl changes for the I3C1 and I3C2 controllers (I'll
> review and ack separately). I have been testing on I3C3 and up, but just not
> with the HVI3C on 1 & 2, hence no pinctrl definition there.
> 
> However, I don't think the other two are needed.
> 
> For 2/3 and 3/3, you're adding a reset control for the global register block
> within the per-controller driver, but we can already do that on a global basis
> with the existing syscon device. Hence this earlier change:
> 
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/dri
> vers/mfd/syscon.c?id=7d1e3bd94828ad9fc86f55253cd6fec8edd65394
> 
> For this, I have:
> 
>     &i3c {
>         i3c_global: i3c-global {
>             compatible = "aspeed,ast2600-i3c-global", "simple-mfd",
> "syscon";
>             resets = <&syscon ASPEED_RESET_I3C_DMA>;
>             reg = <0x0 0x1000>;
>         };
> 
>         i3c2: i3c-master@4000 {
>             compatible = "aspeed,ast2600-i3c";
>             reg = <0x4000 0x1000>;
>             clocks = <&syscon ASPEED_CLK_GATE_I3C2CLK>;
>             pinctrl-names = "default";
>             pinctrl-0 = <&pinctrl_i3c3_default>;
>             interrupts = <GIC_SPI 104 IRQ_TYPE_LEVEL_HIGH>;
>             aspeed,global-regs = <&i3c_global 2>;
>             status = "disabled";
>         };
> 
>         /* ... */
>     };
> 
> - with no changes needed to any bindings. I haven't needed any other resets;
> are there per-controller resets specified in the HW docs you have?
> 
> Does that work for you? If you'd like to test, feel free to use my sample dts at:
> 
> 
> https://github.com/CodeConstruct/linux/commit/05cac24705fa62d2176ecbb
> bf15d955cfe86e753
> 
> Cheers,
> 
> 
> Jeremy