[PATCHv3 2/8] devfreq: exynos: Add documentation for generic exynos memory bus frequency driver
From: viresh.kumar@linaro.org (Viresh Kumar)
Date: 2015-01-20 07:19:20
Also in:
linux-pm, linux-samsung-soc, lkml
On 9 January 2015 at 02:48, Rob Herring [off-list ref] wrote:
Adding Viresh.
Sorry for being too late, I was very busy with other cpufreq stuff I was doing and saved this thread for later as it required me to understand it properly..
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+Required properties for memory bus block: +- clock-names : the name of clock used by the memory bus, "memory-bus". +- clocks : phandles for clock specified in "clock-names" property. +- #clock-cells: should be 1. +- frequency: the frequency table to support DVFS feature.So you have just defined a new OPP table format. We already have one and Viresh is working to create a more extendable one. He asked about what's needed in devfreq, so Viresh here you go. :)
I failed to understand what's new here, probably I need more clarity on what we are doing here.. So, this is what I see from OPPs point of view, everything else stripped out.
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+ memory_bus_int: memory_bus at 1 {
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+ operating-points = < + 400000 950000 + 200000 950000 + 133000 925000 + 100000 850000 + 80000 850000 + 50000 850000>;
So these are the OPPs your "groups" support and below ones are the frequencies that each block will support. Right ?
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+ blocks {
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+ frequency = < + 100000 + 100000 + 100000 + 100000
Why this replication here ?
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+ 50000 + 50000>; + };
How are the above two tables (operating-points and frequency) related here? What about the voltages at which these frequencies are possible ?
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+ display_block: memory_bus_block2 {
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+ frequency = < + 200000 + 160000 + 100000 + 80000 + 80000 + 50000>; + };
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+ isp_block: memory_bus_block3 {
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+ frequency = < + 200000 + 200000 + 100000 + 80000 + 50000 + 50000>; + };
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+ gps_block: memory_bus_block4 {
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+ frequency = < + 300000 + 200000 + 133000 + 100000 + 50000 + 50000>; + };
same for others as well..