Re: [PATCH v2 14/19] ARM: dts: Add bus nodes using VDD_INT for Exynos4x12

Chanwoo Choi
2015-12-10T06:08:43Z

On 2015년 12월 10일 14:57, Krzysztof Kozlowski wrote:
> On 09.12.2015 13:08, Chanwoo Choi wrote:
>> This patch adds the bus noes using VDD_INT for Exynos4x12 SoC.
>> Exynos4x12 has the following AXI buses to translate data between
>> DRAM and sub-blocks.
>>
>> Following list specifies the detailed relation between DRAM and sub-blocks:
>> - ACLK100 clock for PERIL/PERIR/MFC(PCLK)
>> - ACLK160 clock for CAM/TV/LCD
>> : The minimum clock of ACLK160 should be over 160MHz.
>> When drop the clock under 160MHz, show the broken image.
>> - ACLK133 clock for FSYS
>> - GDL clock for LEFTBUS
>> - GDR clock for RIGHTBUS
>> - SCLK_MFC clock for MFC
>>
>> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
>> ---
>> arch/arm/boot/dts/exynos4x12.dtsi | 112 ++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 112 insertions(+)
>>
>> diff --git a/arch/arm/boot/dts/exynos4x12.dtsi b/arch/arm/boot/dts/exynos4x12.dtsi
>> index 3bcf0939755e..8bc4aee156b5 100644
>> --- a/arch/arm/boot/dts/exynos4x12.dtsi
>> +++ b/arch/arm/boot/dts/exynos4x12.dtsi
>> @@ -354,6 +354,118 @@
>> opp-microvolt = <950000>;
>> };
>> };
>> +
>> + bus_leftbus: bus_leftbus {
>> + compatible = "samsung,exynos-bus";
>> + clocks = <&clock CLK_DIV_GDL>;
>> + clock-names = "bus";
>> + operating-points-v2 = <&bus_leftbus_opp_table>;
>> + status = "disabled";
>> + };
>> +
>> + bus_rightbus: bus_rightbus {
>> + compatible = "samsung,exynos-bus";
>> + clocks = <&clock CLK_DIV_GDR>;
>> + clock-names = "bus";
>> + operating-points-v2 = <&bus_leftbus_opp_table>;
>> + status = "disabled";
>> + };
>
> These two nodes are symmetrical. The MFC below and other buses in other
> DTS share opps. How about changing the binding so multiple clocks could
> be specified at once ("bus0", "bus1")? I think there is no need for a
> bus device for each clock.

The your commented method is possible.

But, I focus on implementing the generic bus frequency driver.

If specific bus device-tree node includes the one more clocks,
when adding the new Exynos SoC, the exynos-bus.c should be added
for new Exynos SoC. Because, each Exynos SoC has the different
set of bus device.

If we use my approach, we don't need to modify the exynos-bus.c
driver to support for the bus frequency of new Exynos SoC.

Best Regards,
Chanwoo Choi

>
> Best regards,
> Krzysztof
>
>> +
>> + bus_display: bus_display {
>> + compatible = "samsung,exynos-bus";
>> + clocks = <&clock CLK_ACLK160>;
>> + clock-names = "bus";
>> + operating-points-v2 = <&bus_display_opp_table>;
>> + status = "disabled";
>> + };
>> +
>> + bus_fsys: bus_fsys {
>> + compatible = "samsung,exynos-bus";
>> + clocks = <&clock CLK_ACLK133>;
>> + clock-names = "bus";
>> + operating-points-v2 = <&bus_fsys_opp_table>;
>> + status = "disabled";
>> + };
>> +
>> + bus_peri: bus_peri {
>> + compatible = "samsung,exynos-bus";
>> + clocks = <&clock CLK_ACLK100>;
>> + clock-names = "bus";
>> + operating-points-v2 = <&bus_peri_opp_table>;
>> + status = "disabled";
>> + };
>> +
>> + bus_mfc: bus_mfc {
>> + compatible = "samsung,exynos-bus";
>> + clocks = <&clock CLK_SCLK_MFC>;
>> + clock-names = "bus";
>> + operating-points-v2 = <&bus_leftbus_opp_table>;
>> + status = "disabled";
>> + };
>> +
>> + bus_leftbus_opp_table: opp_table3 {
>> + compatible = "operating-points-v2";
>> + opp-shared;
>> +
>> + opp00 {
>> + opp-hz = /bits/ 64 <100000000>;
>> + opp-microvolt = <900000>;
>> + };
>> + opp01 {
>> + opp-hz = /bits/ 64 <134000000>;
>> + opp-microvolt = <925000>;
>> + };
>> + opp02 {
>> + opp-hz = /bits/ 64 <160000000>;
>> + opp-microvolt = <950000>;
>> + };
>> + opp03 {
>> + opp-hz = /bits/ 64 <200000000>;
>> + opp-microvolt = <1000000>;
>> + };
>> + };
>> +
>> + bus_display_opp_table: opp_table4 {
>> + compatible = "operating-points-v2";
>> + opp-shared;
>> +
>> + opp00 {
>> + opp-hz = /bits/ 64 <160000000>;
>> + opp-microvolt = <950000>;
>> + };
>> + opp01 {
>> + opp-hz = /bits/ 64 <200000000>;
>> + opp-microvolt = <1000000>;
>> + };
>> + };
>> +
>> + bus_fsys_opp_table: opp_table5 {
>> + compatible = "operating-points-v2";
>> + opp-shared;
>> +
>> + opp00 {
>> + opp-hz = /bits/ 64 <100000000>;
>> + opp-microvolt = <900000>;
>> + };
>> + opp01 {
>> + opp-hz = /bits/ 64 <134000000>;
>> + opp-microvolt = <925000>;
>> + };
>> + };
>> +
>> + bus_peri_opp_table: opp_table6 {
>> + compatible = "operating-points-v2";
>> + opp-shared;
>> +
>> + opp00 {
>> + opp-hz = /bits/ 64 <50000000>;
>> + opp-microvolt = <900000>;
>> + };
>> + opp01 {
>> + opp-hz = /bits/ 64 <100000000>;
>> + opp-microvolt = <925000>;
>> + };
>> + };
>> };
>>
>> &combiner {
>>
>
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