On Mon, Dec 4, 2023 at 5:51 PM Inochi Amaoto <inochiama@xxxxxxxxxxx> wrote:
>
> The timer registers of aclint don't follow the clint layout and can
> be mapped on any different offset. As sg2042 uses separated timer
> and mswi for its clint, it should follow the aclint spec and have
> separated registers.
>
> The previous patch introduced a new type of T-HEAD aclint timer which
> has clint timer layout. Although it has the clint timer layout, it
> should follow the aclint spec and uses the separated mtime and mtimecmp
> regs. So a ABI change is needed to make the timer fit the aclint spec.
>
> To make T-HEAD aclint timer more closer to the aclint spec, use
> regs-names to represent the mtimecmp register, which can avoid hack
> for unsupport mtime register of T-HEAD aclint timer.
>
> Also, as T-HEAD aclint only supports mtimecmp, it is unnecessary to
> implement the whole aclint spec. To make this binding T-HEAD specific,
> only add reg-name for existed register. For details, see the discussion
> in the last link.
>
> Signed-off-by: Inochi Amaoto <inochiama@xxxxxxxxxxx>
> Fixes: 4734449f7311 ("dt-bindings: timer: Add Sophgo sg2042 CLINT timer")
> Link: https://lists.infradead.org/pipermail/opensbi/2023-October/005693.html
> Link: https://github.com/riscv/riscv-aclint/blob/main/riscv-aclint.adoc
> Link: https://lore.kernel.org/all/IA1PR20MB4953F9D77FFC76A9D236922DBBB6A@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
> ---
> .../bindings/timer/thead,c900-aclint-mtimer.yaml | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/devicetree/bindings/timer/thead,c900-aclint-mtimer.yaml b/Documentation/devicetree/bindings/timer/thead,c900-aclint-mtimer.yaml
> index fbd235650e52..2e92bcdeb423 100644
> --- a/Documentation/devicetree/bindings/timer/thead,c900-aclint-mtimer.yaml
> +++ b/Documentation/devicetree/bindings/timer/thead,c900-aclint-mtimer.yaml
> @@ -17,7 +17,12 @@ properties:
> - const: thead,c900-aclint-mtimer
>
> reg:
> - maxItems: 1
> + items:
> + - description: MTIMECMP Registers
> +
> + reg-names:
> + items:
> + - const: mtimecmp
>
> interrupts-extended:
> minItems: 1
> @@ -28,6 +33,7 @@ additionalProperties: false
> required:
> - compatible
> - reg
> + - reg-names
> - interrupts-extended
>
> examples:
> @@ -39,5 +45,6 @@ examples:
> <&cpu3intc 7>,
> <&cpu4intc 7>;
> reg = <0xac000000 0x00010000>;
> + reg-names = "mtimecmp";
> };
> ...
> --
> 2.43.0
>
Acked-by: Guo Ren <guoren@xxxxxxxxxx>
--
Best Regards
Guo Ren
