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Re: [PATCH v2 3/3] ARM: dts: dra7: Add syscon-pllreset syscon to SATA PHY

Started byKishon Vijay Abraham I <kishon@ti.com>
First post2015-07-15 13:30 +0200
Last post2015-07-15 17:00 +0200
Articles 4 — 4 participants

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  Re: [PATCH v2 3/3] ARM: dts: dra7: Add syscon-pllreset syscon to  SATA PHY Kishon Vijay Abraham I <kishon@ti.com> - 2015-07-15 13:30 +0200
    Re: [PATCH v2 3/3] ARM: dts: dra7: Add syscon-pllreset syscon to  SATA PHY Tony Lindgren <tony@atomide.com> - 2015-07-15 14:10 +0200
      Re: [PATCH v2 3/3] ARM: dts: dra7: Add syscon-pllreset syscon to  SATA PHY Roger Quadros <rogerq@ti.com> - 2015-07-15 15:50 +0200
        Re: [PATCH v2 3/3] ARM: dts: dra7: Add syscon-pllreset syscon to  SATA PHY Tero Kristo <t-kristo@ti.com> - 2015-07-15 17:00 +0200

#1184702 — Re: [PATCH v2 3/3] ARM: dts: dra7: Add syscon-pllreset syscon to SATA PHY

FromKishon Vijay Abraham I <kishon@ti.com>
Date2015-07-15 13:30 +0200
SubjectRe: [PATCH v2 3/3] ARM: dts: dra7: Add syscon-pllreset syscon to SATA PHY
Message-ID<pMt2W-62p-11@gated-at.bofh.it>
Hi Roger,

On Tuesday 02 June 2015 02:40 PM, Roger Quadros wrote:
> This register is required to be passed to the SATA PHY driver
> to workaround errata i783 (SATA Lockup After SATA DPLL Unlock/Relock).
> 
> Signed-off-by: Roger Quadros <rogerq@ti.com>
> Signed-off-by: Sekhar Nori <nsekhar@ti.com>
> ---
>  arch/arm/boot/dts/dra7.dtsi | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/arm/boot/dts/dra7.dtsi b/arch/arm/boot/dts/dra7.dtsi
> index f03a091..260f300 100644
> --- a/arch/arm/boot/dts/dra7.dtsi
> +++ b/arch/arm/boot/dts/dra7.dtsi
> @@ -1135,6 +1135,7 @@
>  				ctrl-module = <&omap_control_sata>;
>  				clocks = <&sys_clkin1>, <&sata_ref_clk>;
>  				clock-names = "sysclk", "refclk";
> +				syscon-pllreset = <&dra7_ctrl_core 0x3fc>;

I think all users of syscon should be made child node of scm_conf. Tony and
Tero, is that right?

If so, then we might have to modify the driver too.

Cheers
Kishon
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#1184726

FromTony Lindgren <tony@atomide.com>
Date2015-07-15 14:10 +0200
Message-ID<pMtFE-71X-17@gated-at.bofh.it>
In reply to#1184702
* Kishon Vijay Abraham I <kishon@ti.com> [150715 04:24]:
> Hi Roger,
> 
> On Tuesday 02 June 2015 02:40 PM, Roger Quadros wrote:
> > This register is required to be passed to the SATA PHY driver
> > to workaround errata i783 (SATA Lockup After SATA DPLL Unlock/Relock).
> > 
> > Signed-off-by: Roger Quadros <rogerq@ti.com>
> > Signed-off-by: Sekhar Nori <nsekhar@ti.com>
> > ---
> >  arch/arm/boot/dts/dra7.dtsi | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/arch/arm/boot/dts/dra7.dtsi b/arch/arm/boot/dts/dra7.dtsi
> > index f03a091..260f300 100644
> > --- a/arch/arm/boot/dts/dra7.dtsi
> > +++ b/arch/arm/boot/dts/dra7.dtsi
> > @@ -1135,6 +1135,7 @@
> >  				ctrl-module = <&omap_control_sata>;
> >  				clocks = <&sys_clkin1>, <&sata_ref_clk>;
> >  				clock-names = "sysclk", "refclk";
> > +				syscon-pllreset = <&dra7_ctrl_core 0x3fc>;
> 
> I think all users of syscon should be made child node of scm_conf. Tony and
> Tero, is that right?
> 
> If so, then we might have to modify the driver too.

Yeah there should not be much need to use syscon outside scm_conf
area and for I2C devices. If there's some other misc register area
in dra7 in addition to scm_conf then it might make sense to use it.

But in general, for the SCM registers, just a normal loadable kernel
driver module doing of_ioremap on a dedicated range of registers is
always a better option :)

Regrds,

Tony
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#1184810

FromRoger Quadros <rogerq@ti.com>
Date2015-07-15 15:50 +0200
Message-ID<pMvep-GL-5@gated-at.bofh.it>
In reply to#1184726
Hi,

On 15/07/15 15:07, Tony Lindgren wrote:
> * Kishon Vijay Abraham I <kishon@ti.com> [150715 04:24]:
>> Hi Roger,
>>
>> On Tuesday 02 June 2015 02:40 PM, Roger Quadros wrote:
>>> This register is required to be passed to the SATA PHY driver
>>> to workaround errata i783 (SATA Lockup After SATA DPLL Unlock/Relock).
>>>
>>> Signed-off-by: Roger Quadros <rogerq@ti.com>
>>> Signed-off-by: Sekhar Nori <nsekhar@ti.com>
>>> ---
>>>  arch/arm/boot/dts/dra7.dtsi | 1 +
>>>  1 file changed, 1 insertion(+)
>>>
>>> diff --git a/arch/arm/boot/dts/dra7.dtsi b/arch/arm/boot/dts/dra7.dtsi
>>> index f03a091..260f300 100644
>>> --- a/arch/arm/boot/dts/dra7.dtsi
>>> +++ b/arch/arm/boot/dts/dra7.dtsi
>>> @@ -1135,6 +1135,7 @@
>>>  				ctrl-module = <&omap_control_sata>;
>>>  				clocks = <&sys_clkin1>, <&sata_ref_clk>;
>>>  				clock-names = "sysclk", "refclk";
>>> +				syscon-pllreset = <&dra7_ctrl_core 0x3fc>;
>>
>> I think all users of syscon should be made child node of scm_conf. Tony and
>> Tero, is that right?

It can't be child of scm_conf as the address is outside it's range.
Looks like I have to add a new child to scm node that maps beyond
the dra7_pmx_core padconf address range.

>>
>> If so, then we might have to modify the driver too.
> 
> Yeah there should not be much need to use syscon outside scm_conf
> area and for I2C devices. If there's some other misc register area
> in dra7 in addition to scm_conf then it might make sense to use it.
> 
> But in general, for the SCM registers, just a normal loadable kernel
> driver module doing of_ioremap on a dedicated range of registers is
> always a better option :)
> 

Lets take for example this register CTRL_CORE_SMA_SW_0.
It has the SATA PLL_SOFT_RESET bit, EMIF1/2 gating control bits
and ISOLATE bit.

I don't see this fitting in any driver except the syscon approach.

cheers,
-roger
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#1184848

FromTero Kristo <t-kristo@ti.com>
Date2015-07-15 17:00 +0200
Message-ID<pMwka-2xg-9@gated-at.bofh.it>
In reply to#1184810
On 07/15/2015 04:47 PM, Roger Quadros wrote:
> Hi,
>
> On 15/07/15 15:07, Tony Lindgren wrote:
>> * Kishon Vijay Abraham I <kishon@ti.com> [150715 04:24]:
>>> Hi Roger,
>>>
>>> On Tuesday 02 June 2015 02:40 PM, Roger Quadros wrote:
>>>> This register is required to be passed to the SATA PHY driver
>>>> to workaround errata i783 (SATA Lockup After SATA DPLL Unlock/Relock).
>>>>
>>>> Signed-off-by: Roger Quadros <rogerq@ti.com>
>>>> Signed-off-by: Sekhar Nori <nsekhar@ti.com>
>>>> ---
>>>>   arch/arm/boot/dts/dra7.dtsi | 1 +
>>>>   1 file changed, 1 insertion(+)
>>>>
>>>> diff --git a/arch/arm/boot/dts/dra7.dtsi b/arch/arm/boot/dts/dra7.dtsi
>>>> index f03a091..260f300 100644
>>>> --- a/arch/arm/boot/dts/dra7.dtsi
>>>> +++ b/arch/arm/boot/dts/dra7.dtsi
>>>> @@ -1135,6 +1135,7 @@
>>>>   				ctrl-module = <&omap_control_sata>;
>>>>   				clocks = <&sys_clkin1>, <&sata_ref_clk>;
>>>>   				clock-names = "sysclk", "refclk";
>>>> +				syscon-pllreset = <&dra7_ctrl_core 0x3fc>;
>>>
>>> I think all users of syscon should be made child node of scm_conf. Tony and
>>> Tero, is that right?
>
> It can't be child of scm_conf as the address is outside it's range.
> Looks like I have to add a new child to scm node that maps beyond
> the dra7_pmx_core padconf address range.
>
>>>
>>> If so, then we might have to modify the driver too.
>>
>> Yeah there should not be much need to use syscon outside scm_conf
>> area and for I2C devices. If there's some other misc register area
>> in dra7 in addition to scm_conf then it might make sense to use it.
>>
>> But in general, for the SCM registers, just a normal loadable kernel
>> driver module doing of_ioremap on a dedicated range of registers is
>> always a better option :)
>>
>
> Lets take for example this register CTRL_CORE_SMA_SW_0.
> It has the SATA PLL_SOFT_RESET bit, EMIF1/2 gating control bits
> and ISOLATE bit.
>
> I don't see this fitting in any driver except the syscon approach.
>
> cheers,
> -roger
>

Yea I think scm_conf can generally contain lots of weird registers that 
can have multiple users / use-cases. This is the junk-yard of SoC 
features the designers had no idea where to put them; so they put it 
under scm_conf.

I'd say in some cases we are probably forced to map to it from other 
drivers, this is one of the reasons it is a syscon map in the first 
place, and generally speaking, they should not be children of scm_conf 
in the DT layout.

You could probably add a "dummy" node under scm_conf which maps to the 
scm register, and which you would refer to from the sata driver.

-Tero
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