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[v7,3/3] riscv: dts: thead: Add device tree VO clock controller

Message ID 20250403094425.876981-4-m.wilczynski@samsung.com (mailing list archive)
State Handled Elsewhere
Headers show
Series [v7,1/3] dt-bindings: clock: thead: Add TH1520 VO clock controller | expand

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Commit Message

Michal Wilczynski April 3, 2025, 9:44 a.m. UTC
VO clocks reside in a different address space from the AP clocks on the
T-HEAD SoC. Add the device tree node of a clock-controller to handle
VO address space as well.

Signed-off-by: Michal Wilczynski <m.wilczynski@samsung.com>
---
 arch/riscv/boot/dts/thead/th1520.dtsi | 7 +++++++
 1 file changed, 7 insertions(+)

Comments

Drew Fustini April 4, 2025, 11:16 p.m. UTC | #1
On Thu, Apr 03, 2025 at 11:44:25AM +0200, Michal Wilczynski wrote:
> VO clocks reside in a different address space from the AP clocks on the
> T-HEAD SoC. Add the device tree node of a clock-controller to handle
> VO address space as well.
> 
> Signed-off-by: Michal Wilczynski <m.wilczynski@samsung.com>
> ---
>  arch/riscv/boot/dts/thead/th1520.dtsi | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/arch/riscv/boot/dts/thead/th1520.dtsi b/arch/riscv/boot/dts/thead/th1520.dtsi
> index 527336417765..d4cba0713cab 100644
> --- a/arch/riscv/boot/dts/thead/th1520.dtsi
> +++ b/arch/riscv/boot/dts/thead/th1520.dtsi
> @@ -489,6 +489,13 @@ clk: clock-controller@ffef010000 {
>  			#clock-cells = <1>;
>  		};
>  
> +		clk_vo: clock-controller@ffef528050 {
> +			compatible = "thead,th1520-clk-vo";
> +			reg = <0xff 0xef528050 0x0 0xfb0>;

Thanks for your patch. It is great to have more of the clocks supported
upstream.

The TH1520 System User Manual shows 0xFF_EF52_8000 for VO_SUBSYS on page
205. Is there a reason you decided to use 0xFF_EF52_8050 as the base?

I see on page 213 that the first register for VO_SUBSYS starts with
VOSYS_CLK_GATE at offset 0x50. I figure you did this to have the
CCU_GATE macros use offset of 0x0 instead 0x50.

I kind of think the reg property using the actual base address
(0xFF_EF52_8000) makes more sense as that's a closer match to the tables
in the manual. But I don't have a strong preference if you think think
using 0xef528050 makes the CCU_GATE macros easier to read.

-Drew
Michal Wilczynski April 7, 2025, 3:30 p.m. UTC | #2
On 4/5/25 01:16, Drew Fustini wrote:
> On Thu, Apr 03, 2025 at 11:44:25AM +0200, Michal Wilczynski wrote:
>> VO clocks reside in a different address space from the AP clocks on the
>> T-HEAD SoC. Add the device tree node of a clock-controller to handle
>> VO address space as well.
>>
>> Signed-off-by: Michal Wilczynski <m.wilczynski@samsung.com>
>> ---
>>  arch/riscv/boot/dts/thead/th1520.dtsi | 7 +++++++
>>  1 file changed, 7 insertions(+)
>>
>> diff --git a/arch/riscv/boot/dts/thead/th1520.dtsi b/arch/riscv/boot/dts/thead/th1520.dtsi
>> index 527336417765..d4cba0713cab 100644
>> --- a/arch/riscv/boot/dts/thead/th1520.dtsi
>> +++ b/arch/riscv/boot/dts/thead/th1520.dtsi
>> @@ -489,6 +489,13 @@ clk: clock-controller@ffef010000 {
>>  			#clock-cells = <1>;
>>  		};
>>  
>> +		clk_vo: clock-controller@ffef528050 {
>> +			compatible = "thead,th1520-clk-vo";
>> +			reg = <0xff 0xef528050 0x0 0xfb0>;
> 
> Thanks for your patch. It is great to have more of the clocks supported
> upstream.
> 
> The TH1520 System User Manual shows 0xFF_EF52_8000 for VO_SUBSYS on page
> 205. Is there a reason you decided to use 0xFF_EF52_8050 as the base?
> 
> I see on page 213 that the first register for VO_SUBSYS starts with
> VOSYS_CLK_GATE at offset 0x50. I figure you did this to have the
> CCU_GATE macros use offset of 0x0 instead 0x50.
> 
> I kind of think the reg property using the actual base address
> (0xFF_EF52_8000) makes more sense as that's a closer match to the tables
> in the manual. But I don't have a strong preference if you think think
> using 0xef528050 makes the CCU_GATE macros easier to read.

Thank you for your comment.

This was discussed some time ago. The main issue was that the address
space was fragmented between clocks and resets. Initially, I proposed
using syscon as a way to abstract this, but the idea wasn't particularly
well received.

So at the start of the 0xFF_EF52_8000 there is a reset register GPU_RST_CFG
I need for resetting the GPU.

For reference, here's the earlier discussion: [1]

[1] - https://lore.kernel.org/all/1b05b11b2a8287c0ff4b6bdd079988c7.sboyd@kernel.org/

Regards,
Michał

> 
> -Drew
>
diff mbox series

Patch

diff --git a/arch/riscv/boot/dts/thead/th1520.dtsi b/arch/riscv/boot/dts/thead/th1520.dtsi
index 527336417765..d4cba0713cab 100644
--- a/arch/riscv/boot/dts/thead/th1520.dtsi
+++ b/arch/riscv/boot/dts/thead/th1520.dtsi
@@ -489,6 +489,13 @@  clk: clock-controller@ffef010000 {
 			#clock-cells = <1>;
 		};
 
+		clk_vo: clock-controller@ffef528050 {
+			compatible = "thead,th1520-clk-vo";
+			reg = <0xff 0xef528050 0x0 0xfb0>;
+			clocks = <&clk CLK_VIDEO_PLL>;
+			#clock-cells = <1>;
+		};
+
 		dmac0: dma-controller@ffefc00000 {
 			compatible = "snps,axi-dma-1.01a";
 			reg = <0xff 0xefc00000 0x0 0x1000>;