[PATCH v2 0/4] arm64: dts: ti: k3-am62{a,p}x-sk: add opp frequencies

[PATCH v2 0/4] arm64: dts: ti: k3-am62{a,p}x-sk: add opp frequencies

[Bryan Brattlof]

Hello everyone

This series adds in the OPPs for the Cortex-A53s on the AM62Ax and 
AM62Px SoC families along with the defining the 
WKUP_MMR0_WKUP0_CTRL_MMR0_JTAG_USER_ID which we can use to to properly 
limit the OPPs available for that variant.

Happy reviewing
~Bryan

Signed-off-by: Bryan Brattlof <bb@ti.com>
---
Changes in v2:
- Expanded on commit descriptions
- Split board file and SoC fdt changes into different patches
- Link to v1: https://lore.kernel.org/r/20240809-opp-v1-0-fea8efeaf963@ti.com

---
Bryan Brattlof (4):
      arm64: dts: ti: k3-am62a: add opp frequencies
      arm64: dts: ti: k3-am62a7-sk: add 1.4ghz opp entry
      arm64: dts: ti: k3-am62p: add opp frequencies
      arm64: dts: ti: k3-am62p5-sk: add 1.4ghz opp entry

 arch/arm64/boot/dts/ti/k3-am62a-wakeup.dtsi        |  5 +++
 arch/arm64/boot/dts/ti/k3-am62a7-sk.dts            |  9 ++++
 arch/arm64/boot/dts/ti/k3-am62a7.dtsi              | 51 ++++++++++++++++++++++
 .../boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi  |  5 +++
 arch/arm64/boot/dts/ti/k3-am62p5-sk.dts            |  9 ++++
 arch/arm64/boot/dts/ti/k3-am62p5.dtsi              | 47 ++++++++++++++++++++
 6 files changed, 126 insertions(+)
---
base-commit: e3cce1229c34b5c28f103361c4d6b3ef17302d5d
change-id: 20240809-opp-7f1372af677c

Best regards,
-- 
Bryan Brattlof <bb@ti.com>

[PATCH v2 1/4] arm64: dts: ti: k3-am62a: add opp frequencies

[Bryan Brattlof]

One power management technique available to the Cortex-A53s is their
ability to dynamically scale their frequency across the device's
Operating Performance Points (OPP)

The OPPs available for the Cortex-A53s on the AM62Ax can vary based on
the silicon variant used. The SoC variant is encoded into the
WKUP_MMR0_WKUP0_CTRL_MMR0_JTAG_USER_ID register which is used to limit
to only OPP entries the variant supports. A table of all these variants
can be found in it's data sheet[0] for the AM62Ax family.

Add the OPP table into the SoC's ftdi file along with the syscon node to
describe the WKUP_MMR0_WKUP0_CTRL_MMR0_JTAG_USER_ID register to detect
the SoC variant.

[0] https://www.ti.com/lit/ds/symlink/am62a3.pdf

Signed-off-by: Bryan Brattlof <bb@ti.com>
---
 arch/arm64/boot/dts/ti/k3-am62a-wakeup.dtsi |  5 +++
 arch/arm64/boot/dts/ti/k3-am62a7.dtsi       | 51 +++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)

diff --git a/arch/arm64/boot/dts/ti/k3-am62a-wakeup.dtsi b/arch/arm64/boot/dts/ti/k3-am62a-wakeup.dtsi
index f5ac101a04dfa..0b1dd5390cd3f 100644
--- a/arch/arm64/boot/dts/ti/k3-am62a-wakeup.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-am62a-wakeup.dtsi
@@ -17,6 +17,11 @@ chipid: chipid@14 {
 			reg = <0x14 0x4>;
 		};
 
+		opp_efuse_table: syscon@18 {
+			compatible = "ti,am62-opp-efuse-table", "syscon";
+			reg = <0x18 0x4>;
+		};
+
 		cpsw_mac_syscon: ethernet-mac-syscon@200 {
 			compatible = "ti,am62p-cpsw-mac-efuse", "syscon";
 			reg = <0x200 0x8>;
diff --git a/arch/arm64/boot/dts/ti/k3-am62a7.dtsi b/arch/arm64/boot/dts/ti/k3-am62a7.dtsi
index f86a23404e6dd..6c99221beb6bd 100644
--- a/arch/arm64/boot/dts/ti/k3-am62a7.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-am62a7.dtsi
@@ -48,6 +48,8 @@ cpu0: cpu@0 {
 			d-cache-line-size = <64>;
 			d-cache-sets = <128>;
 			next-level-cache = <&L2_0>;
+			operating-points-v2 = <&a53_opp_table>;
+			clocks = <&k3_clks 135 0>;
 		};
 
 		cpu1: cpu@1 {
@@ -62,6 +64,8 @@ cpu1: cpu@1 {
 			d-cache-line-size = <64>;
 			d-cache-sets = <128>;
 			next-level-cache = <&L2_0>;
+			operating-points-v2 = <&a53_opp_table>;
+			clocks = <&k3_clks 136 0>;
 		};
 
 		cpu2: cpu@2 {
@@ -76,6 +80,8 @@ cpu2: cpu@2 {
 			d-cache-line-size = <64>;
 			d-cache-sets = <128>;
 			next-level-cache = <&L2_0>;
+			operating-points-v2 = <&a53_opp_table>;
+			clocks = <&k3_clks 137 0>;
 		};
 
 		cpu3: cpu@3 {
@@ -90,6 +96,51 @@ cpu3: cpu@3 {
 			d-cache-line-size = <64>;
 			d-cache-sets = <128>;
 			next-level-cache = <&L2_0>;
+			operating-points-v2 = <&a53_opp_table>;
+			clocks = <&k3_clks 138 0>;
+		};
+	};
+
+	a53_opp_table: opp-table {
+		compatible = "operating-points-v2-ti-cpu";
+		opp-shared;
+		syscon = <&opp_efuse_table>;
+
+		opp-200000000 {
+			opp-hz = /bits/ 64 <200000000>;
+			opp-supported-hw = <0x01 0x0007>;
+			clock-latency-ns = <6000000>;
+		};
+
+		opp-400000000 {
+			opp-hz = /bits/ 64 <400000000>;
+			opp-supported-hw = <0x01 0x0007>;
+			clock-latency-ns = <6000000>;
+		};
+
+		opp-600000000 {
+			opp-hz = /bits/ 64 <600000000>;
+			opp-supported-hw = <0x01 0x0007>;
+			clock-latency-ns = <6000000>;
+		};
+
+		opp-800000000 {
+			opp-hz = /bits/ 64 <800000000>;
+			opp-supported-hw = <0x01 0x0007>;
+			clock-latency-ns = <6000000>;
+		};
+
+		opp-1000000000 {
+			opp-hz = /bits/ 64 <1000000000>;
+			opp-supported-hw = <0x01 0x0006>;
+			clock-latency-ns = <6000000>;
+		};
+
+		opp-1250000000 {
+			opp-hz = /bits/ 64 <1250000000>;
+			opp-supported-hw = <0x01 0x0004>;
+			clock-latency-ns = <6000000>;
+			opp-suspend;
 		};
 	};
 

-- 
2.45.2

[PATCH v2 2/4] arm64: dts: ti: k3-am62a7-sk: add 1.4ghz opp entry

[Bryan Brattlof]

The AM62Ax reference board is capable of supplying 0v85 to the VDD_CORE
which allows the Cortex-A53s to operate at 1.4GHz according to chapter
7.5 of the SoC's data sheet[0]. Append the 1.4Ghz entry to the OPP table
to enable this OPP

[0] https://www.ti.com/lit/ds/symlink/am62a3.pdf

Signed-off-by: Bryan Brattlof <bb@ti.com>
---
 arch/arm64/boot/dts/ti/k3-am62a7-sk.dts | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/arm64/boot/dts/ti/k3-am62a7-sk.dts b/arch/arm64/boot/dts/ti/k3-am62a7-sk.dts
index 67faf46d7a35a..a6f0d87a50d8a 100644
--- a/arch/arm64/boot/dts/ti/k3-am62a7-sk.dts
+++ b/arch/arm64/boot/dts/ti/k3-am62a7-sk.dts
@@ -68,6 +68,15 @@ wkup_r5fss0_core0_memory_region: r5f-dma-memory@9c900000 {
 		};
 	};
 
+	opp-table {
+		/* Requires VDD_CORE at 0v85 */
+		opp-1400000000 {
+			opp-hz = /bits/ 64 <1400000000>;
+			opp-supported-hw = <0x01 0x0004>;
+			clock-latency-ns = <6000000>;
+		};
+	};
+
 	vmain_pd: regulator-0 {
 		/* TPS25750 PD CONTROLLER OUTPUT */
 		compatible = "regulator-fixed";

-- 
2.45.2

[PATCH v2 3/4] arm64: dts: ti: k3-am62p: add opp frequencies

[Bryan Brattlof]

ONe power management technique available to the Cortex-A53s is their
ability to dynamically scale their frequency across the device's
Operating Performance Points (OPP)

The OPPs available for the Cortex-A53s on the AM62Px can vary based on
the silicon variant used. The SoC variant is encoded into the
WKUP_MMR0_WKUP0_CTRL_MMR0_JTAG_USER_ID register which is used to limit
the OPP entries the SoC supports. A table of all these variants can be
found in its data sheet[0] for the AM62Px processor family.

Add the OPP table into the SoC's ftdi file along with the syscon node to
describe the WKUP_MMR0_WKUP0_CTRL_MMR0_JTAG_USER_ID register to detect
the SoC variant.

Signed-off-by: Bryan Brattlof <bb@ti.com>
---
 .../boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi  |  5 +++
 arch/arm64/boot/dts/ti/k3-am62p5.dtsi              | 47 ++++++++++++++++++++++
 2 files changed, 52 insertions(+)

diff --git a/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi b/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi
index 315d0092e7366..6f32135f00a55 100644
--- a/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi
@@ -20,6 +20,11 @@ chipid: chipid@14 {
 			bootph-all;
 		};
 
+		opp_efuse_table: syscon@18 {
+			compatible = "ti,am62-opp-efuse-table", "syscon";
+			reg = <0x18 0x4>;
+		};
+
 		cpsw_mac_syscon: ethernet-mac-syscon@200 {
 			compatible = "ti,am62p-cpsw-mac-efuse", "syscon";
 			reg = <0x200 0x8>;
diff --git a/arch/arm64/boot/dts/ti/k3-am62p5.dtsi b/arch/arm64/boot/dts/ti/k3-am62p5.dtsi
index 41f479dca4555..140587d02e88e 100644
--- a/arch/arm64/boot/dts/ti/k3-am62p5.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-am62p5.dtsi
@@ -47,6 +47,7 @@ cpu0: cpu@0 {
 			d-cache-line-size = <64>;
 			d-cache-sets = <128>;
 			next-level-cache = <&l2_0>;
+			operating-points-v2 = <&a53_opp_table>;
 			clocks = <&k3_clks 135 0>;
 		};
 
@@ -62,6 +63,7 @@ cpu1: cpu@1 {
 			d-cache-line-size = <64>;
 			d-cache-sets = <128>;
 			next-level-cache = <&l2_0>;
+			operating-points-v2 = <&a53_opp_table>;
 			clocks = <&k3_clks 136 0>;
 		};
 
@@ -77,6 +79,7 @@ cpu2: cpu@2 {
 			d-cache-line-size = <64>;
 			d-cache-sets = <128>;
 			next-level-cache = <&l2_0>;
+			operating-points-v2 = <&a53_opp_table>;
 			clocks = <&k3_clks 137 0>;
 		};
 
@@ -92,10 +95,54 @@ cpu3: cpu@3 {
 			d-cache-line-size = <64>;
 			d-cache-sets = <128>;
 			next-level-cache = <&l2_0>;
+			operating-points-v2 = <&a53_opp_table>;
 			clocks = <&k3_clks 138 0>;
 		};
 	};
 
+	a53_opp_table: opp-table {
+		compatible = "operating-points-v2-ti-cpu";
+		opp-shared;
+		syscon = <&opp_efuse_table>;
+
+		opp-200000000 {
+			opp-hz = /bits/ 64 <200000000>;
+			opp-supported-hw = <0x01 0x0007>;
+			clock-latency-ns = <6000000>;
+		};
+
+		opp-400000000 {
+			opp-hz = /bits/ 64 <400000000>;
+			opp-supported-hw = <0x01 0x0007>;
+			clock-latency-ns = <6000000>;
+		};
+
+		opp-600000000 {
+			opp-hz = /bits/ 64 <600000000>;
+			opp-supported-hw = <0x01 0x0007>;
+			clock-latency-ns = <6000000>;
+		};
+
+		opp-800000000 {
+			opp-hz = /bits/ 64 <800000000>;
+			opp-supported-hw = <0x01 0x0007>;
+			clock-latency-ns = <6000000>;
+		};
+
+		opp-1000000000 {
+			opp-hz = /bits/ 64 <1000000000>;
+			opp-supported-hw = <0x01 0x0006>;
+			clock-latency-ns = <6000000>;
+		};
+
+		opp-1250000000 {
+			opp-hz = /bits/ 64 <1250000000>;
+			opp-supported-hw = <0x01 0x0004>;
+			clock-latency-ns = <6000000>;
+			opp-suspend;
+		};
+	};
+
 	l2_0: l2-cache0 {
 		compatible = "cache";
 		cache-unified;

-- 
2.45.2

[PATCH v2 4/4] arm64: dts: ti: k3-am62p5-sk: add 1.4ghz opp entry

[Bryan Brattlof]

The AM62Px reference board is capable of supplying 0v85 to the VDD_CORE
which allows the Cortex-A53s to operate at 1.4GHz according to chapter
6.6 of the SoC's data sheet[0] . Append the 1.4Ghz entry to the OPP
table to enable this frequency

[0] https://www.ti.com/lit/ds/symlink/am62p-q1.pdf

Signed-off-by: Bryan Brattlof <bb@ti.com>
---
 arch/arm64/boot/dts/ti/k3-am62p5-sk.dts | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/arm64/boot/dts/ti/k3-am62p5-sk.dts b/arch/arm64/boot/dts/ti/k3-am62p5-sk.dts
index ff65955551a32..ab5d7a5fc6118 100644
--- a/arch/arm64/boot/dts/ti/k3-am62p5-sk.dts
+++ b/arch/arm64/boot/dts/ti/k3-am62p5-sk.dts
@@ -128,6 +128,15 @@ led-0 {
 		};
 	};
 
+	opp-table {
+		/* Requires VDD_CORE at 0v85 */
+		opp-1400000000 {
+			opp-hz = /bits/ 64 <1400000000>;
+			opp-supported-hw = <0x01 0x0004>;
+			clock-latency-ns = <6000000>;
+		};
+	};
+
 	tlv320_mclk: clk-0 {
 		#clock-cells = <0>;
 		compatible = "fixed-clock";

-- 
2.45.2

Re: [PATCH v2 3/4] arm64: dts: ti: k3-am62p: add opp frequencies

[Dhruva Gole]

Hi Bryan,

On Aug 23, 2024 at 16:54:30 -0500, Bryan Brattlof wrote:
> ONe power management technique available to the Cortex-A53s is their

s/ONe/One

> ability to dynamically scale their frequency across the device's
> Operating Performance Points (OPP)
> 
> The OPPs available for the Cortex-A53s on the AM62Px can vary based on
> the silicon variant used. The SoC variant is encoded into the
> WKUP_MMR0_WKUP0_CTRL_MMR0_JTAG_USER_ID register which is used to limit
> the OPP entries the SoC supports. A table of all these variants can be
> found in its data sheet[0] for the AM62Px processor family.

Error 404! Not found [0] ;)

> 
> Add the OPP table into the SoC's ftdi file along with the syscon node to

What is ftdi?

> describe the WKUP_MMR0_WKUP0_CTRL_MMR0_JTAG_USER_ID register to detect
> the SoC variant.
> 
> Signed-off-by: Bryan Brattlof <bb@ti.com>
> ---
>  .../boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi  |  5 +++
>  arch/arm64/boot/dts/ti/k3-am62p5.dtsi              | 47 ++++++++++++++++++++++
>  2 files changed, 52 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi b/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi
> index 315d0092e7366..6f32135f00a55 100644
> --- a/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi
> +++ b/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi
> @@ -20,6 +20,11 @@ chipid: chipid@14 {
>  			bootph-all;
>  		};
>  
> +		opp_efuse_table: syscon@18 {
> +			compatible = "ti,am62-opp-efuse-table", "syscon";

Huh, curious why I don't see this particular compatible in am62 itself..
Also, I am still not clear where this discussion got left off: (If it's
related)
https://lore.kernel.org/all/5chxjwybmsxq73pagtlw4zr2asbtxov7ezrpn5j37cr77bmepa@fejdlxomfgae/

In AM625, I see
k3-am625.dtsi:111: col 14: syscon = <&wkup_conf>;

But the approach you've used here seems different. Is there a
justification given on which one should be used/why somewhere that I can
refer?

> +			reg = <0x18 0x4>;
> +		};
> +
>  		cpsw_mac_syscon: ethernet-mac-syscon@200 {
>  			compatible = "ti,am62p-cpsw-mac-efuse", "syscon";
>  			reg = <0x200 0x8>;
> diff --git a/arch/arm64/boot/dts/ti/k3-am62p5.dtsi b/arch/arm64/boot/dts/ti/k3-am62p5.dtsi
> index 41f479dca4555..140587d02e88e 100644
> --- a/arch/arm64/boot/dts/ti/k3-am62p5.dtsi
> +++ b/arch/arm64/boot/dts/ti/k3-am62p5.dtsi
> @@ -47,6 +47,7 @@ cpu0: cpu@0 {
>  			d-cache-line-size = <64>;
>  			d-cache-sets = <128>;
>  			next-level-cache = <&l2_0>;
> +			operating-points-v2 = <&a53_opp_table>;
>  			clocks = <&k3_clks 135 0>;
>  		};
>  
> @@ -62,6 +63,7 @@ cpu1: cpu@1 {
>  			d-cache-line-size = <64>;
>  			d-cache-sets = <128>;
>  			next-level-cache = <&l2_0>;
> +			operating-points-v2 = <&a53_opp_table>;
>  			clocks = <&k3_clks 136 0>;
>  		};
>  
> @@ -77,6 +79,7 @@ cpu2: cpu@2 {
>  			d-cache-line-size = <64>;
>  			d-cache-sets = <128>;
>  			next-level-cache = <&l2_0>;
> +			operating-points-v2 = <&a53_opp_table>;
>  			clocks = <&k3_clks 137 0>;
>  		};
>  
> @@ -92,10 +95,54 @@ cpu3: cpu@3 {
>  			d-cache-line-size = <64>;
>  			d-cache-sets = <128>;
>  			next-level-cache = <&l2_0>;
> +			operating-points-v2 = <&a53_opp_table>;
>  			clocks = <&k3_clks 138 0>;
>  		};
>  	};
>  
> +	a53_opp_table: opp-table {
> +		compatible = "operating-points-v2-ti-cpu";
> +		opp-shared;
> +		syscon = <&opp_efuse_table>;
> +
> +		opp-200000000 {
> +			opp-hz = /bits/ 64 <200000000>;
> +			opp-supported-hw = <0x01 0x0007>;
> +			clock-latency-ns = <6000000>;
> +		};
> +
> +		opp-400000000 {
> +			opp-hz = /bits/ 64 <400000000>;
> +			opp-supported-hw = <0x01 0x0007>;
> +			clock-latency-ns = <6000000>;
> +		};
> +
> +		opp-600000000 {
> +			opp-hz = /bits/ 64 <600000000>;
> +			opp-supported-hw = <0x01 0x0007>;
> +			clock-latency-ns = <6000000>;
> +		};
> +
> +		opp-800000000 {
> +			opp-hz = /bits/ 64 <800000000>;
> +			opp-supported-hw = <0x01 0x0007>;
> +			clock-latency-ns = <6000000>;
> +		};
> +
> +		opp-1000000000 {
> +			opp-hz = /bits/ 64 <1000000000>;
> +			opp-supported-hw = <0x01 0x0006>;
> +			clock-latency-ns = <6000000>;
> +		};
> +
> +		opp-1250000000 {
> +			opp-hz = /bits/ 64 <1250000000>;
> +			opp-supported-hw = <0x01 0x0004>;
> +			clock-latency-ns = <6000000>;
> +			opp-suspend;
> +		};
> +	};
> +

-- 
Best regards,
Dhruva

Re: [PATCH v2 3/4] arm64: dts: ti: k3-am62p: add opp frequencies

[Bryan Brattlof]

On August 26, 2024 thus sayeth Dhruva Gole:
> Hi Bryan,
> 
> On Aug 23, 2024 at 16:54:30 -0500, Bryan Brattlof wrote:
> > ONe power management technique available to the Cortex-A53s is their
> 
> s/ONe/One
> 
> > ability to dynamically scale their frequency across the device's
> > Operating Performance Points (OPP)
> > 
> > The OPPs available for the Cortex-A53s on the AM62Px can vary based on
> > the silicon variant used. The SoC variant is encoded into the
> > WKUP_MMR0_WKUP0_CTRL_MMR0_JTAG_USER_ID register which is used to limit
> > the OPP entries the SoC supports. A table of all these variants can be
> > found in its data sheet[0] for the AM62Px processor family.
> 
> Error 404! Not found [0] ;)
> 

Oops. I'll fix these up

> > 
> > Add the OPP table into the SoC's ftdi file along with the syscon node to
> 
> What is ftdi?

FTDI is a chip, what I tried to type out was fdti or Flattened Device 
Tree Includes :)

> 
> > describe the WKUP_MMR0_WKUP0_CTRL_MMR0_JTAG_USER_ID register to detect
> > the SoC variant.
> > 
> > Signed-off-by: Bryan Brattlof <bb@ti.com>
> > ---
> >  .../boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi  |  5 +++
> >  arch/arm64/boot/dts/ti/k3-am62p5.dtsi              | 47 ++++++++++++++++++++++
> >  2 files changed, 52 insertions(+)
> > 
> > diff --git a/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi b/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi
> > index 315d0092e7366..6f32135f00a55 100644
> > --- a/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi
> > +++ b/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi
> > @@ -20,6 +20,11 @@ chipid: chipid@14 {
> >  			bootph-all;
> >  		};
> >  
> > +		opp_efuse_table: syscon@18 {
> > +			compatible = "ti,am62-opp-efuse-table", "syscon";
> 
> Huh, curious why I don't see this particular compatible in am62 itself..
> Also, I am still not clear where this discussion got left off: (If it's
> related)
> https://lore.kernel.org/all/5chxjwybmsxq73pagtlw4zr2asbtxov7ezrpn5j37cr77bmepa@fejdlxomfgae/
> 
> In AM625, I see
> k3-am625.dtsi:111: col 14: syscon = <&wkup_conf>;
> 
> But the approach you've used here seems different. Is there a
> justification given on which one should be used/why somewhere that I can
> refer?

Labeling the entire &wkup_conf as a syscon node is kinda abusing what 
the syscon node is used for. There are a lot of things inside that 
WKUP_CTRL_MMR that do not belong under the miscellaneous registers 
category. For the 62A and 62P we've chosen to label &wkup_conf as a bus 
with little syscon sub-nodes inside of it.  

I don't think the discussion[0] ever finalized but we started going that 
direction with new SoCs, looks like the older SoCs never received the 
cleanup.

~Bryan

[0] https://lore.kernel.org/all/e7114cb4-e24f-4e78-a89f-4e2e2e704b8a@ti.com/

Re: [PATCH v2 3/4] arm64: dts: ti: k3-am62p: add opp frequencies

[Vignesh Raghavendra]

On 26/08/24 21:41, Bryan Brattlof wrote:
> On August 26, 2024 thus sayeth Dhruva Gole:
>> Hi Bryan,
>>
>> On Aug 23, 2024 at 16:54:30 -0500, Bryan Brattlof wrote:
>>> ONe power management technique available to the Cortex-A53s is their
>>
>> s/ONe/One
>>
>>> ability to dynamically scale their frequency across the device's
>>> Operating Performance Points (OPP)
>>>
>>> The OPPs available for the Cortex-A53s on the AM62Px can vary based on
>>> the silicon variant used. The SoC variant is encoded into the
>>> WKUP_MMR0_WKUP0_CTRL_MMR0_JTAG_USER_ID register which is used to limit
>>> the OPP entries the SoC supports. A table of all these variants can be
>>> found in its data sheet[0] for the AM62Px processor family.
>>
>> Error 404! Not found [0] ;)
>>
> 
> Oops. I'll fix these up
> 
>>>
>>> Add the OPP table into the SoC's ftdi file along with the syscon node to
>>
>> What is ftdi?
> 
> FTDI is a chip, what I tried to type out was fdti or Flattened Device 
> Tree Includes :)
> 
>>
>>> describe the WKUP_MMR0_WKUP0_CTRL_MMR0_JTAG_USER_ID register to detect
>>> the SoC variant.
>>>
>>> Signed-off-by: Bryan Brattlof <bb@ti.com>
>>> ---
>>>  .../boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi  |  5 +++
>>>  arch/arm64/boot/dts/ti/k3-am62p5.dtsi              | 47 ++++++++++++++++++++++
>>>  2 files changed, 52 insertions(+)
>>>
>>> diff --git a/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi b/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi
>>> index 315d0092e7366..6f32135f00a55 100644
>>> --- a/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi
>>> +++ b/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-wakeup.dtsi
>>> @@ -20,6 +20,11 @@ chipid: chipid@14 {
>>>  			bootph-all;
>>>  		};
>>>  
>>> +		opp_efuse_table: syscon@18 {
>>> +			compatible = "ti,am62-opp-efuse-table", "syscon";
>>
>> Huh, curious why I don't see this particular compatible in am62 itself..
>> Also, I am still not clear where this discussion got left off: (If it's
>> related)
>> https://lore.kernel.org/all/5chxjwybmsxq73pagtlw4zr2asbtxov7ezrpn5j37cr77bmepa@fejdlxomfgae/
>>
>> In AM625, I see
>> k3-am625.dtsi:111: col 14: syscon = <&wkup_conf>;
>>
>> But the approach you've used here seems different. Is there a
>> justification given on which one should be used/why somewhere that I can
>> refer?
> 
> Labeling the entire &wkup_conf as a syscon node is kinda abusing what 
> the syscon node is used for. There are a lot of things inside that 
> WKUP_CTRL_MMR that do not belong under the miscellaneous registers 
> category. For the 62A and 62P we've chosen to label &wkup_conf as a bus 
> with little syscon sub-nodes inside of it.  
> 
> I don't think the discussion[0] ever finalized but we started going that 
> direction with new SoCs, looks like the older SoCs never received the 
> cleanup.

This patch seems to be in the right direction. Marking entire wkup_conf
as "syscon", "simple-mfd" is wrong and needs to be addressed in
k3-am62-wakeup.dtsi similar to how other child-nodes in wkup_conf are
implemented in same file.

[...]

-- 
Regards
Vignesh