linux-kernel - Re: [PATCH v2 2/7] ARM: Exynos: add support for sub-power domains

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Message-id: <54A670D6.3060100@samsung.com>
Date:	Fri, 02 Jan 2015 11:20:06 +0100
From:	Marek Szyprowski <m.szyprowski@...sung.com>
To:	amit daniel kachhap <amit.daniel@...sung.com>,
	Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	LAK <linux-arm-kernel@...ts.infradead.org>,
	"linux-samsung-soc@...r.kernel.org" 
	<linux-samsung-soc@...r.kernel.org>, Kukjin Kim <kgene@...nel.org>,
	Inki Dae <inki.dae@...sung.com>,
	Tobias Jakobi <Liquid.Acid@....net>,
	Daniel Drake <drake@...lessm.com>,
	Andrzej Hajda <a.hajda@...sung.com>,
	Tomasz Figa <tomasz.figa@...il.com>,
	Pankaj Dubey <pankaj.dubey@...sung.com>,
	Ulf Hansson <ulf.hansson@...aro.org>
Subject: Re: [PATCH v2 2/7] ARM: Exynos: add support for sub-power domains

Hello,

On 2014-12-04 04:45, amit daniel kachhap wrote:
> On Wed, Dec 3, 2014 at 6:03 PM, Marek Szyprowski
> <m.szyprowski@...sung.com> wrote:
>> This patch adds support for making one power domain a sub-domain of
>> other domain. This is useful for modeling power dependences for devices
>> like TV Mixer or Camera ISP, which needs to have more than one power
>> domain enabled to be operational.
>>
>> Signed-off-by: Marek Szyprowski <m.szyprowski@...sung.com>
>> ---
>>   Documentation/devicetree/bindings/arm/exynos/power_domain.txt |  2 ++
>>   arch/arm/mach-exynos/pm_domains.c                             | 11 ++++++++++-
>>   2 files changed, 12 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt
>> index abde1ea8a119..b884358ebb1a 100644
>> --- a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt
>> +++ b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt
>> @@ -22,6 +22,8 @@ Optional Properties:
>>          - pclkN, clkN: Pairs of parent of input clock and input clock to the
>>                  devices in this power domain. Maximum of 4 pairs (N = 0 to 3)
>>                  are supported currently.
>> +- samsung,power-domain: phandle to a master power domain that the given domain
>> +                      is a part of
>>
>>   Node of a device using power domains must have a samsung,power-domain property
>>   defined with a phandle to respective power domain.
>> diff --git a/arch/arm/mach-exynos/pm_domains.c b/arch/arm/mach-exynos/pm_domains.c
>> index 20f267121b3e..fa9a47ddad81 100644
>> --- a/arch/arm/mach-exynos/pm_domains.c
>> +++ b/arch/arm/mach-exynos/pm_domains.c
>> @@ -108,7 +108,7 @@ static int exynos_pd_power_off(struct generic_pm_domain *domain)
>>   static __init int exynos4_pm_init_power_domain(void)
>>   {
>>          struct platform_device *pdev;
>> -       struct device_node *np;
>> +       struct device_node *np, *master_np;
>>
>>          for_each_compatible_node(np, NULL, "samsung,exynos4210-pd") {
>>                  struct exynos_pm_domain *pd;
>> @@ -159,6 +159,15 @@ no_clk:
>>
>>                  pm_genpd_init(&pd->pd, NULL, !on);
>>                  of_genpd_add_provider_simple(np, &pd->pd);
>> +
>> +               /* make master and slave hierarchy */
>> +               master_np = of_parse_phandle(np, "samsung,power-domain", 0);
>> +               if (!master_np)
>> +                       master_np = of_parse_phandle(np, "power-domains", 0);
>> +               if (master_np) {
>> +                       pm_genpd_add_subdomain_names(master_np->name, np->name);
>> +                       of_node_put(master_np);
>> +               }
>>          }
> Hi Marek,
>
> In the my patch series posted earlier i added this feature in a
> slightly different way. (https://lkml.org/lkml/2014/11/24/320)
> Parent PD's are not added in the same loop but in the second loop.
> This will make sure that the parents PD are registered before the
> child PD's and we can get away from the assumption of child/parent
> PD's position in the Device Tree. This is a still a work in progress.
> Also posted a patch earlier regarding this,
> http://www.spinics.net/lists/linux-samsung-soc/msg39836.html.

Right, your approach seems to be more error prone. Do you plan to resend 
your
patch with the parent domain phandle renamed to generic 'power-domains' 
property,
like Geert suggested?

I would like to send Exynos4 HDMI patches based on top of your work and 
have them
finally merged (they are waiting since v3.17...)

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

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