linux-kernel - Re: [PATCH 2/2] DTS: dra7: Add "opp_high" opp node to support 1.5 GHz SoC operation

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Date:   Mon, 6 Feb 2017 09:24:55 -0600
From:   Dave Gerlach <d-gerlach@...com>
To:     Lukasz Majewski <lukma@...x.de>
CC:     Benoît Cousson <bcousson@...libre.com>,
        <linux-omap@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        Kishon Vijay Abraham I <kishon@...com>,
        "Menon, Nishanth" <nm@...com>
Subject: Re: [PATCH 2/2] DTS: dra7: Add "opp_high" opp node to support 1.5
 GHz SoC operation

Hi,
On 02/06/2017 08:24 AM, Lukasz Majewski wrote:
> Hi Dave,
> 
>> On 02/03/2017 09:24 AM, Lukasz Majewski wrote:
>>> The "opp_high" property brings support for 1.5 GHz CPU frequency
>>> for TI's am57xx line of processors.
>>>
>>> Signed-off-by: Lukasz Majewski <lukma@...x.de>
>>> ---
>>>  arch/arm/boot/dts/dra7.dtsi | 5 +++++
>>>  1 file changed, 5 insertions(+)
>>>
>>
>> This can't be blindly enabled for all am57xx SoCs, there is a
>> forthcoming ti-cpufreq [1] driver that is needed that will decided
>> which OPPs can and cannot be enabled for the specific variant in use.
> 
> Do you know if there is ongoing work on using Avs0 voltage (encoded in
> efuse) to control the per SoC PMIC voltage value when switching to
> opp_high (1.5 GHz)?

Yes, Viresh Kumar introduced multi-regulator support in the OPP core recently
[1] which I wrote a test driver for here [2] which hooks into the OPP framework
to do both ABB regulator scaling and also programs the AVS0 voltages. The
current implementation I have cleaned up will depend on the ti-cpufreq driver so
once that is merged I will send the AVS0 and ABB support driver upstream as
well. If you are curious you can look at current internal implementation here [3].

Regards,
Dave

[1] http://www.spinics.net/lists/devicetree/msg153212.html
[2] https://www.spinics.net/lists/kernel/msg2384336.html
[3]
http://git.ti.com/ti-linux-kernel/ti-linux-kernel/blobs/ti-lsk-linux-4.9.y/drivers/base/power/opp/ti-opp-supply.c


> 
> 
>>
>> Regards,
>> Dave
>>
>> [1] http://www.spinics.net/lists/devicetree/msg158967.html
>>
>>> diff --git a/arch/arm/boot/dts/dra7.dtsi
>>> b/arch/arm/boot/dts/dra7.dtsi index a860a56..5e678cd 100644
>>> --- a/arch/arm/boot/dts/dra7.dtsi
>>> +++ b/arch/arm/boot/dts/dra7.dtsi
>>> @@ -108,6 +108,11 @@
>>>  			opp-hz = /bits/ 64 <1176000000>;
>>>  			opp-microvolt = <1160000 885000 1160000>;
>>>  		};
>>> +
>>> +		opp_high@...0000000 {
>>> +			opp-hz = /bits/ 64 <1500000000>;
>>> +			opp-microvolt = <1210000 950000 1250000>;
>>> +		};
>>>  	};
>>>
>>>  	/*
>>>
>>
> 
> 
> 
> 
> Best regards,
> 
> Lukasz Majewski
> 
> --
> 
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