Re: [PATCHv3 2/8] devfreq: exynos: Add documentation for generic exynos memory bus frequency driver

From: Chanwoo Choi
Date: Wed Jan 21 2015 - 01:13:11 EST


On 01/21/2015 01:37 PM, Viresh Kumar wrote:
> On 21 January 2015 at 09:50, Chanwoo Choi <cw00.choi@xxxxxxxxxxx> wrote:
>> If the clock will be stayed on highest voltage, will reduce
>> the considerable benefit of power-consumption.
>
> But this is exactly what you must be doing right now as well..
> I think I didn't make it clear enough with an example. Let me
> try..
>
> This is how I feel it should look like:
>
> memory_bus_int: memory_bus@1 {
> // Regulator is shared for all below
> blocks {
> peri_block: memory_bus_block1 {
> operating-points = <
> 100000 850000
> 50000 850000>;
> };
>
> display_block: memory_bus_block2 {
> operating-points = <
> 200000 950000
> 160000 950000
> 100000 925000
> 80000 850000
> 50000 850000>;
> };
>
> isp_block: memory_bus_block3 {
> operating-points = <
> 200000 950000
> 100000 925000
> 80000 850000
> 50000 850000>;
> };
>
> gps_block: memory_bus_block4 {
> operating-points = <
> 300000 950000
> 200000 950000
> 133000 925000
> 100000 850000
> 50000 850000>;
> };
>
>
> Now suppose these are the requirements from all the blocks
> at any point of time:
> - block1: 100000 850000
> - block2: 100000 925000
> - block3: 80000 850000
> - block4: 133000 925000
>
> Now, all of them can control freq separately and we don't need to
> worry for that. But regulator is shared between them. We can check
> what's the highest voltage requested at this point of time and can
> switch to that.
>
> i.e. 925000 in this case. And that's not the highest possible one.
> And you will reach to similar conclusion with your current code as
> well I believe.
>

OK, I understand.
I'll try to update exynos memory bus according to your comment.

Thanks
Chanwoo








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