[v2,02/19] PM / devfreq: exynos: Add documentation for generic exynos bus frequency driver
diff mbox

Message ID 1449634091-1842-3-git-send-email-cw00.choi@samsung.com
State New, archived
Headers show

Commit Message

Chanwoo Choi Dec. 9, 2015, 4:07 a.m. UTC
This patch adds the documentation for generic exynos bus frequency
driver.

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
---
 .../devicetree/bindings/devfreq/exynos-bus.txt     | 94 ++++++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/devfreq/exynos-bus.txt

Comments

Krzysztof Kozlowski Dec. 10, 2015, 12:39 a.m. UTC | #1
On 09.12.2015 13:07, Chanwoo Choi wrote:
> This patch adds the documentation for generic exynos bus frequency
> driver.
> 
> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
> ---
>  .../devicetree/bindings/devfreq/exynos-bus.txt     | 94 ++++++++++++++++++++++
>  1 file changed, 94 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/devfreq/exynos-bus.txt
> 
> diff --git a/Documentation/devicetree/bindings/devfreq/exynos-bus.txt b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
> new file mode 100644
> index 000000000000..54a1f9c46c88
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
> @@ -0,0 +1,94 @@
> +* Generic Exynos Bus frequency device
> +
> +The Samsung Exynos SoC have many buses for data transfer between DRAM
> +and sub-blocks in SoC. Almost Exynos SoC have the common architecture
> +for buses. Generally, the each bus of Exynos SoC includes the source clock
> +and power line and then is able to change the clock according to the usage
> +of each buses on runtime. When gathering the usage of each buses on runtime,
> +thie driver uses the PPMU (Platform Performance Monitoring Unit) which

s/thie/the/

> +is able to measure the current load of sub-blocks.
> +
> +There are a little different composition among Exynos SoC because each Exynos
> +SoC has the different sub-blocks. So, this difference should be specified
> +in devicetree file instead of each device driver. In result, this driver
> +is able to support the bus frequency for all Exynos SoCs.
> +
> +Required properties for bus device:
> +- compatible: Should be "samsung,exynos-bus".
> +- clock-names : the name of clock used by the bus, "bus".
> +- clocks : phandles for clock specified in "clock-names" property.
> +- #clock-cells: should be 1.

This is a clock consumer, right? So the clock-cells is not valid here.

> +- operating-points-v2: the OPP table including frequency/voltage information
> +  to support DVFS (Dynamic Voltage/Frequency Scaling) feature.
> +- vdd-supply: the regulator to provide the buses with the voltage.
> +- devfreq-events: the devfreq-event device to monitor the curret utilization

s/curret/current/

> +  of buses.
> +
> +Optional properties for bus device:
> +- exynos,saturation-ratio: the percentage value which is used to calibrate
> +                   the performance count againt total cycle count.

s/againt/against/

> +
> +Example1:
> +	Show the AXI buses of Exynos3250 SoC. Exynos3250 divides the buses to
> +	power line (regulator). The MIF (Memory Interface) AXI bus is used to
> +	transfer data between DRAM and CPU and uses the VDD_MIF regualtor.
> +
> +	- power line(VDD_MIF) --> bus for DMC (Dynamic Memory Controller) block
> +
> +	- MIF bus's frequency/voltage table
> +	-----------------------
> +	|Lv| Freq   | Voltage |
> +	-----------------------
> +	|L1| 50000  |800000   |
> +	|L2| 100000 |800000   |
> +	|L3| 134000 |800000   |
> +	|L4| 200000 |800000   |
> +	|L5| 400000 |875000   |
> +	-----------------------
> +
> +Example2 :
> +	The bus of DMC (Dynamic Memory Controller) block in exynos3250.dtsi
> +	are listed below:

s/are/is/ (one bus is listed)

> +
> +	bus_dmc: bus_dmc {
> +		compatible = "samsung,exynos-bus";
> +		clocks = <&cmu_dmc CLK_DIV_DMC>;
> +		clock-names = "bus";
> +		operating-points-v2 = <&bus_dmc_opp_table>;
> +		status = "disabled";
> +	};
> +
> +	bus_dmc_opp_table: opp_table0 {
> +		compatible = "operating-points-v2";
> +		opp-shared;
> +
> +		opp00 {

Maybe use convention with frequency, like:
	opp@50000000
This also used in opp.txt examples.


> +			opp-hz = /bits/ 64 <50000000>;
> +			opp-microvolt = <800000>;
> +		};
> +		opp01 {
> +			opp-hz = /bits/ 64 <100000000>;
> +			opp-microvolt = <800000>;
> +		};
> +		opp02 {
> +			opp-hz = /bits/ 64 <134000000>;
> +			opp-microvolt = <800000>;
> +		};
> +		opp03 {
> +			opp-hz = /bits/ 64 <200000000>;
> +			opp-microvolt = <800000>;
> +		};
> +		opp04 {
> +			opp-hz = /bits/ 64 <400000000>;
> +			opp-microvolt = <875000>;
> +		};
> +	};
> +
> +	Usage case to handle the frequency and voltage of bus on runtime
> +	in exynos3250-rinato.dts are listed below:

s/are/is/

> +
> +	&bus_dmc {
> +		devfreq-events = <&ppmu_dmc0_3>, <&ppmu_dmc1_3>;
> +		vdd-supply = <&buck1_reg>;	/* VDD_MIF */
> +		status = "okay";
> +	};
> 

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Chanwoo Choi Dec. 10, 2015, 12:49 a.m. UTC | #2
Hi,

On 2015? 12? 10? 09:39, Krzysztof Kozlowski wrote:
> On 09.12.2015 13:07, Chanwoo Choi wrote:
>> This patch adds the documentation for generic exynos bus frequency
>> driver.
>>
>> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
>> ---
>>  .../devicetree/bindings/devfreq/exynos-bus.txt     | 94 ++++++++++++++++++++++
>>  1 file changed, 94 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/devfreq/exynos-bus.txt
>>
>> diff --git a/Documentation/devicetree/bindings/devfreq/exynos-bus.txt b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
>> new file mode 100644
>> index 000000000000..54a1f9c46c88
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
>> @@ -0,0 +1,94 @@
>> +* Generic Exynos Bus frequency device
>> +
>> +The Samsung Exynos SoC have many buses for data transfer between DRAM
>> +and sub-blocks in SoC. Almost Exynos SoC have the common architecture
>> +for buses. Generally, the each bus of Exynos SoC includes the source clock
>> +and power line and then is able to change the clock according to the usage
>> +of each buses on runtime. When gathering the usage of each buses on runtime,
>> +thie driver uses the PPMU (Platform Performance Monitoring Unit) which
> 
> s/thie/the/

OK.

> 
>> +is able to measure the current load of sub-blocks.
>> +
>> +There are a little different composition among Exynos SoC because each Exynos
>> +SoC has the different sub-blocks. So, this difference should be specified
>> +in devicetree file instead of each device driver. In result, this driver
>> +is able to support the bus frequency for all Exynos SoCs.
>> +
>> +Required properties for bus device:
>> +- compatible: Should be "samsung,exynos-bus".
>> +- clock-names : the name of clock used by the bus, "bus".
>> +- clocks : phandles for clock specified in "clock-names" property.
>> +- #clock-cells: should be 1.
> 
> This is a clock consumer, right? So the clock-cells is not valid here.

You're right. I'll remove '#clock-cells'.

> 
>> +- operating-points-v2: the OPP table including frequency/voltage information
>> +  to support DVFS (Dynamic Voltage/Frequency Scaling) feature.
>> +- vdd-supply: the regulator to provide the buses with the voltage.
>> +- devfreq-events: the devfreq-event device to monitor the curret utilization
> 
> s/curret/current/
> 
>> +  of buses.
>> +
>> +Optional properties for bus device:
>> +- exynos,saturation-ratio: the percentage value which is used to calibrate
>> +                   the performance count againt total cycle count.
> 
> s/againt/against/

OK.

> 
>> +
>> +Example1:
>> +	Show the AXI buses of Exynos3250 SoC. Exynos3250 divides the buses to
>> +	power line (regulator). The MIF (Memory Interface) AXI bus is used to
>> +	transfer data between DRAM and CPU and uses the VDD_MIF regualtor.
>> +
>> +	- power line(VDD_MIF) --> bus for DMC (Dynamic Memory Controller) block
>> +
>> +	- MIF bus's frequency/voltage table
>> +	-----------------------
>> +	|Lv| Freq   | Voltage |
>> +	-----------------------
>> +	|L1| 50000  |800000   |
>> +	|L2| 100000 |800000   |
>> +	|L3| 134000 |800000   |
>> +	|L4| 200000 |800000   |
>> +	|L5| 400000 |875000   |
>> +	-----------------------
>> +
>> +Example2 :
>> +	The bus of DMC (Dynamic Memory Controller) block in exynos3250.dtsi
>> +	are listed below:
> 
> s/are/is/ (one bus is listed)

OK.

> 
>> +
>> +	bus_dmc: bus_dmc {
>> +		compatible = "samsung,exynos-bus";
>> +		clocks = <&cmu_dmc CLK_DIV_DMC>;
>> +		clock-names = "bus";
>> +		operating-points-v2 = <&bus_dmc_opp_table>;
>> +		status = "disabled";
>> +	};
>> +
>> +	bus_dmc_opp_table: opp_table0 {
>> +		compatible = "operating-points-v2";
>> +		opp-shared;
>> +
>> +		opp00 {
> 
> Maybe use convention with frequency, like:
> 	opp@50000000
> This also used in opp.txt examples.

In the Documentations/devicetree/bindings/opp/opp.txt,
the example uses the 'opp@0x'. I check the opp.txt of Linux 4.4-rc4.

> 
> 
>> +			opp-hz = /bits/ 64 <50000000>;
>> +			opp-microvolt = <800000>;
>> +		};
>> +		opp01 {
>> +			opp-hz = /bits/ 64 <100000000>;
>> +			opp-microvolt = <800000>;
>> +		};
>> +		opp02 {
>> +			opp-hz = /bits/ 64 <134000000>;
>> +			opp-microvolt = <800000>;
>> +		};
>> +		opp03 {
>> +			opp-hz = /bits/ 64 <200000000>;
>> +			opp-microvolt = <800000>;
>> +		};
>> +		opp04 {
>> +			opp-hz = /bits/ 64 <400000000>;
>> +			opp-microvolt = <875000>;
>> +		};
>> +	};
>> +
>> +	Usage case to handle the frequency and voltage of bus on runtime
>> +	in exynos3250-rinato.dts are listed below:
> 
> s/are/is/

OK.

> 
>> +
>> +	&bus_dmc {
>> +		devfreq-events = <&ppmu_dmc0_3>, <&ppmu_dmc1_3>;
>> +		vdd-supply = <&buck1_reg>;	/* VDD_MIF */
>> +		status = "okay";
>> +	};

Thanks for your review.

Regards,
Chanwoo Choi

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Krzysztof Kozlowski Dec. 10, 2015, 1:25 a.m. UTC | #3
On 10.12.2015 09:49, Chanwoo Choi wrote:
> Hi,
> 
(...)

>>
>>> +
>>> +	bus_dmc: bus_dmc {
>>> +		compatible = "samsung,exynos-bus";
>>> +		clocks = <&cmu_dmc CLK_DIV_DMC>;
>>> +		clock-names = "bus";
>>> +		operating-points-v2 = <&bus_dmc_opp_table>;
>>> +		status = "disabled";
>>> +	};
>>> +
>>> +	bus_dmc_opp_table: opp_table0 {
>>> +		compatible = "operating-points-v2";
>>> +		opp-shared;
>>> +
>>> +		opp00 {
>>
>> Maybe use convention with frequency, like:
>> 	opp@50000000
>> This also used in opp.txt examples.
> 
> In the Documentations/devicetree/bindings/opp/opp.txt,
> the example uses the 'opp@0x'. I check the opp.txt of Linux 4.4-rc4.

Yes, it was changed by Viresh in "PM / OPP: Rename OPP nodes as
opp@<opp-hz>". You can find the most actual bindings in linux-next.

Best regards,
Krzysztof



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Chanwoo Choi Dec. 10, 2015, 1:33 a.m. UTC | #4
On 2015? 12? 10? 10:25, Krzysztof Kozlowski wrote:
> On 10.12.2015 09:49, Chanwoo Choi wrote:
>> Hi,
>>
> (...)
> 
>>>
>>>> +
>>>> +	bus_dmc: bus_dmc {
>>>> +		compatible = "samsung,exynos-bus";
>>>> +		clocks = <&cmu_dmc CLK_DIV_DMC>;
>>>> +		clock-names = "bus";
>>>> +		operating-points-v2 = <&bus_dmc_opp_table>;
>>>> +		status = "disabled";
>>>> +	};
>>>> +
>>>> +	bus_dmc_opp_table: opp_table0 {
>>>> +		compatible = "operating-points-v2";
>>>> +		opp-shared;
>>>> +
>>>> +		opp00 {
>>>
>>> Maybe use convention with frequency, like:
>>> 	opp@50000000
>>> This also used in opp.txt examples.
>>
>> In the Documentations/devicetree/bindings/opp/opp.txt,
>> the example uses the 'opp@0x'. I check the opp.txt of Linux 4.4-rc4.
> 
> Yes, it was changed by Viresh in "PM / OPP: Rename OPP nodes as
> opp@<opp-hz>". You can find the most actual bindings in linux-next.

OK. I'll.

Best Regards,
Chanwoo Choi

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Patch
diff mbox

diff --git a/Documentation/devicetree/bindings/devfreq/exynos-bus.txt b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
new file mode 100644
index 000000000000..54a1f9c46c88
--- /dev/null
+++ b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
@@ -0,0 +1,94 @@ 
+* Generic Exynos Bus frequency device
+
+The Samsung Exynos SoC have many buses for data transfer between DRAM
+and sub-blocks in SoC. Almost Exynos SoC have the common architecture
+for buses. Generally, the each bus of Exynos SoC includes the source clock
+and power line and then is able to change the clock according to the usage
+of each buses on runtime. When gathering the usage of each buses on runtime,
+thie driver uses the PPMU (Platform Performance Monitoring Unit) which
+is able to measure the current load of sub-blocks.
+
+There are a little different composition among Exynos SoC because each Exynos
+SoC has the different sub-blocks. So, this difference should be specified
+in devicetree file instead of each device driver. In result, this driver
+is able to support the bus frequency for all Exynos SoCs.
+
+Required properties for bus device:
+- compatible: Should be "samsung,exynos-bus".
+- clock-names : the name of clock used by the bus, "bus".
+- clocks : phandles for clock specified in "clock-names" property.
+- #clock-cells: should be 1.
+- operating-points-v2: the OPP table including frequency/voltage information
+  to support DVFS (Dynamic Voltage/Frequency Scaling) feature.
+- vdd-supply: the regulator to provide the buses with the voltage.
+- devfreq-events: the devfreq-event device to monitor the curret utilization
+  of buses.
+
+Optional properties for bus device:
+- exynos,saturation-ratio: the percentage value which is used to calibrate
+                   the performance count againt total cycle count.
+
+Example1:
+	Show the AXI buses of Exynos3250 SoC. Exynos3250 divides the buses to
+	power line (regulator). The MIF (Memory Interface) AXI bus is used to
+	transfer data between DRAM and CPU and uses the VDD_MIF regualtor.
+
+	- power line(VDD_MIF) --> bus for DMC (Dynamic Memory Controller) block
+
+	- MIF bus's frequency/voltage table
+	-----------------------
+	|Lv| Freq   | Voltage |
+	-----------------------
+	|L1| 50000  |800000   |
+	|L2| 100000 |800000   |
+	|L3| 134000 |800000   |
+	|L4| 200000 |800000   |
+	|L5| 400000 |875000   |
+	-----------------------
+
+Example2 :
+	The bus of DMC (Dynamic Memory Controller) block in exynos3250.dtsi
+	are listed below:
+
+	bus_dmc: bus_dmc {
+		compatible = "samsung,exynos-bus";
+		clocks = <&cmu_dmc CLK_DIV_DMC>;
+		clock-names = "bus";
+		operating-points-v2 = <&bus_dmc_opp_table>;
+		status = "disabled";
+	};
+
+	bus_dmc_opp_table: opp_table0 {
+		compatible = "operating-points-v2";
+		opp-shared;
+
+		opp00 {
+			opp-hz = /bits/ 64 <50000000>;
+			opp-microvolt = <800000>;
+		};
+		opp01 {
+			opp-hz = /bits/ 64 <100000000>;
+			opp-microvolt = <800000>;
+		};
+		opp02 {
+			opp-hz = /bits/ 64 <134000000>;
+			opp-microvolt = <800000>;
+		};
+		opp03 {
+			opp-hz = /bits/ 64 <200000000>;
+			opp-microvolt = <800000>;
+		};
+		opp04 {
+			opp-hz = /bits/ 64 <400000000>;
+			opp-microvolt = <875000>;
+		};
+	};
+
+	Usage case to handle the frequency and voltage of bus on runtime
+	in exynos3250-rinato.dts are listed below:
+
+	&bus_dmc {
+		devfreq-events = <&ppmu_dmc0_3>, <&ppmu_dmc1_3>;
+		vdd-supply = <&buck1_reg>;	/* VDD_MIF */
+		status = "okay";
+	};