Hi Mark, On 03/14/2014 02:53 AM, Mark Rutland wrote: > On Thu, Mar 13, 2014 at 08:17:29AM +0000, Chanwoo Choi wrote: >> This patch add busfreq driver for Exynos4210/Exynos4x12 memory interface >> and bus to support DVFS(Dynamic Voltage Frequency Scaling) according to PPMU >> counters. PPMU (Performance Profiling Monitorings Units) of Exynos4 SoC provides >> PPMU counters for DMC(Dynamic Memory Controller) to check memory bus utilization >> and then busfreq driver adjusts dynamically the operating frequency/voltage >> by using DEVFREQ Subsystem. >> >> Signed-off-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx> >> --- >> .../devicetree/bindings/devfreq/exynos4_bus.txt | 49 ++++++++++++++++++++++ >> 1 file changed, 49 insertions(+) >> create mode 100644 Documentation/devicetree/bindings/devfreq/exynos4_bus.txt >> >> diff --git a/Documentation/devicetree/bindings/devfreq/exynos4_bus.txt b/Documentation/devicetree/bindings/devfreq/exynos4_bus.txt >> new file mode 100644 >> index 0000000..2a83fcc >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/devfreq/exynos4_bus.txt >> @@ -0,0 +1,49 @@ >> + >> +Exynos4210/4x12 busfreq driver >> +----------------------------- >> + >> +Exynos4210/4x12 Soc busfreq driver with devfreq for Memory bus frequency/voltage >> +scaling according to PPMU counters of memory controllers >> + >> +Required properties: >> +- compatible : should contain Exynos4 SoC type as follwoing: >> + - "samsung,exynos4x12-busfreq" for Exynos4x12 >> + - "samsung,exynos4210-busfreq" for Exynos4210 > > Is there a device called "busfreq"? What device does this binding > describe? I'll add detailed description of busfreq as following: "busfreq(bus frequendcy)" driver means that busfreq driver control dynamically memory bus frequency/voltage by checking memory bus utilization to optimize power-consumption. When checking memeory bus utilization, exynos4_busfreq driver would use PPMU(Performance Profiling Monitoring Units). > >> +- reg : offset and length of the ppmudmc0/1 >> + - PPMU (Performance Profiling Monitoring Units) > > You seem to require a particular order here. It would be good to be > explicit about it. OK, I'll modify it as following: the offset and length of the PPMU_DMC0 / PPMU_DMC1 PPMU_DMC0/PPMU_DMC1 show memory buy utilization to exynos4_bus driver. > >> + : It is to profile performance event of DMC(Dynamic Memory >> + Controller) So, exynos4_bus.c can check memory bus utilization >> + by using PPMU of Exynos4 SoC. > > This is superfluous, and Linux-specific. The binding document shouldn't > need to refer to drivers. I'll remove this description. > >> +- clocks : clock number of ppmudmc0/1 >> +- clock-names : clock name of ppmudmc0/1 > > Are these two clocks, or one clock with a slash in the name? > > Please list each name separately. I'll expalin clocks as following: "ppmudmc0", "ppmudmc1" > >> +- vdd_int-supply: regulator for interface block of Exynos4 >> + >> +Optional properties: >> +- vdd_mif-supply: regulator for DMC block of Exynos4x12 if Exynos4x12 Soc >> +- regs-name : register name of ppmudmc0/1 > > This is completely nonstandard. Did you mean reg-names? I'll remove it about 'regs-name'. > > Please be explicit about the names you expect. Write them in full, > quoted, and describe the relationship to the reg property. > >> + >> +All the required listed above must be defined under code busfreq with devfreq > > I'm having some difficulty figuring out what exactly this is intended to > mean. I'll add detailed opeation method and role of exynos4_busfreq driver. Thanks, Chanwoo Choi -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
