diff mbox series

[v3,08/12] arm64: dts: exynos: gs101: remove reg-io-width from serial

Message ID 20240109125814.3691033-9-tudor.ambarus@linaro.org
State Superseded
Headers show
Series GS101 Oriole: CMU_PERIC0 support and USI updates | expand

Commit Message

Tudor Ambarus Jan. 9, 2024, 12:58 p.m. UTC
Remove the reg-io-width property in order to comply with the bindings.

The entire bus (PERIC) on which the GS101 serial resides only allows
32-bit register accesses. The reg-io-width dt property is disallowed
for the "google,gs101-uart" compatible and instead the iotype is
inferred from the compatible.

Reviewed-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
---
v3: collect Peter's R-b tag
v2: new patch

 arch/arm64/boot/dts/exynos/google/gs101.dtsi | 1 -
 1 file changed, 1 deletion(-)

Comments

Sam Protsenko Jan. 16, 2024, 5:57 p.m. UTC | #1
On Tue, Jan 9, 2024 at 7:00 AM Tudor Ambarus <tudor.ambarus@linaro.org> wrote:
>
> Remove the reg-io-width property in order to comply with the bindings.
>
> The entire bus (PERIC) on which the GS101 serial resides only allows
> 32-bit register accesses. The reg-io-width dt property is disallowed
> for the "google,gs101-uart" compatible and instead the iotype is
> inferred from the compatible.
>
> Reviewed-by: Peter Griffin <peter.griffin@linaro.org>
> Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
> ---

Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>

Just out of curiosity (I probably missed the relevant discussion
earlier): what is the actual reason for moving 'reg-io-width' to the
driver's code as 'iotype'? I mean, what is the actual problem that's
being solved by this -- is it to make the earlycon functional for
gs101? I'm asking because the bus width looks like a part of HW
description, which usually belongs to dts, from the design point of
view. Anyways, that's not a concern, just trying to understand the
decision.

> v3: collect Peter's R-b tag
> v2: new patch
>
>  arch/arm64/boot/dts/exynos/google/gs101.dtsi | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/arch/arm64/boot/dts/exynos/google/gs101.dtsi b/arch/arm64/boot/dts/exynos/google/gs101.dtsi
> index d838e3a7af6e..4e5f4c748906 100644
> --- a/arch/arm64/boot/dts/exynos/google/gs101.dtsi
> +++ b/arch/arm64/boot/dts/exynos/google/gs101.dtsi
> @@ -366,7 +366,6 @@ usi_uart: usi@10a000c0 {
>                         serial_0: serial@10a00000 {
>                                 compatible = "google,gs101-uart";
>                                 reg = <0x10a00000 0xc0>;
> -                               reg-io-width = <4>;
>                                 interrupts = <GIC_SPI 634
>                                               IRQ_TYPE_LEVEL_HIGH 0>;
>                                 clocks = <&dummy_clk 0>, <&dummy_clk 0>;
> --
> 2.43.0.472.g3155946c3a-goog
>
>
Tudor Ambarus Jan. 17, 2024, 2:59 p.m. UTC | #2
On 1/16/24 17:57, Sam Protsenko wrote:
> On Tue, Jan 9, 2024 at 7:00 AM Tudor Ambarus <tudor.ambarus@linaro.org> wrote:
>> Remove the reg-io-width property in order to comply with the bindings.
>>
>> The entire bus (PERIC) on which the GS101 serial resides only allows
>> 32-bit register accesses. The reg-io-width dt property is disallowed
>> for the "google,gs101-uart" compatible and instead the iotype is
>> inferred from the compatible.
>>
>> Reviewed-by: Peter Griffin <peter.griffin@linaro.org>
>> Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
>> ---
> Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
> 
> Just out of curiosity (I probably missed the relevant discussion
> earlier): what is the actual reason for moving 'reg-io-width' to the
> driver's code as 'iotype'? I mean, what is the actual problem that's

The majority (if not all?) of the hardware blocks in GS101 SoC require
32 bit register access widths. Instead of specifying reg-io-width = 4
everywhere in the device tree, we infer it from the compatibles.

The relevant discussion is here:
https://lore.kernel.org/linux-arm-kernel/db368449-f446-47e8-81b6-a11c2a872306@linaro.org/

Cheers,
ta

> being solved by this -- is it to make the earlycon functional for
> gs101? I'm asking because the bus width looks like a part of HW
> description, which usually belongs to dts, from the design point of
> view. Anyways, that's not a concern, just trying to understand the
> decision.
diff mbox series

Patch

diff --git a/arch/arm64/boot/dts/exynos/google/gs101.dtsi b/arch/arm64/boot/dts/exynos/google/gs101.dtsi
index d838e3a7af6e..4e5f4c748906 100644
--- a/arch/arm64/boot/dts/exynos/google/gs101.dtsi
+++ b/arch/arm64/boot/dts/exynos/google/gs101.dtsi
@@ -366,7 +366,6 @@  usi_uart: usi@10a000c0 {
 			serial_0: serial@10a00000 {
 				compatible = "google,gs101-uart";
 				reg = <0x10a00000 0xc0>;
-				reg-io-width = <4>;
 				interrupts = <GIC_SPI 634
 					      IRQ_TYPE_LEVEL_HIGH 0>;
 				clocks = <&dummy_clk 0>, <&dummy_clk 0>;