diff mbox series

[V2,10/15] cpufreq: mediatek: Make sram regulator optional

Message ID 20220408045908.21671-11-rex-bc.chen@mediatek.com (mailing list archive)
State Superseded, archived
Headers show
Series cpufreq: mediatek: Cleanup and support MT8183 and MT8186 | expand

Commit Message

Rex-BC Chen (陳柏辰) April 8, 2022, 4:59 a.m. UTC
From: Jia-Wei Chang <jia-wei.chang@mediatek.com>

For some MediaTek SoCs, like MT8186, it's possible that the sram regulator
is shared between CPU and CCI.

Signed-off-by: Jia-Wei Chang <jia-wei.chang@mediatek.com>
---
 drivers/cpufreq/mediatek-cpufreq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

AngeloGioacchino Del Regno April 8, 2022, 1:37 p.m. UTC | #1
Il 08/04/22 06:59, Rex-BC Chen ha scritto:
> From: Jia-Wei Chang <jia-wei.chang@mediatek.com>
> 
> For some MediaTek SoCs, like MT8186, it's possible that the sram regulator
> is shared between CPU and CCI.
> 
> Signed-off-by: Jia-Wei Chang <jia-wei.chang@mediatek.com>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Kevin Hilman April 8, 2022, 8:32 p.m. UTC | #2
Rex-BC Chen <rex-bc.chen@mediatek.com> writes:

> From: Jia-Wei Chang <jia-wei.chang@mediatek.com>
>
> For some MediaTek SoCs, like MT8186, it's possible that the sram regulator
> is shared between CPU and CCI.
>
> Signed-off-by: Jia-Wei Chang <jia-wei.chang@mediatek.com>

nit: missing your sign-off.

> ---
>  drivers/cpufreq/mediatek-cpufreq.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
> index 9e9bce0ff235..8f688d47e64b 100644
> --- a/drivers/cpufreq/mediatek-cpufreq.c
> +++ b/drivers/cpufreq/mediatek-cpufreq.c
> @@ -435,7 +435,7 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
>  	}
>  
>  	/* Both presence and absence of sram regulator are valid cases. */
> -	info->sram_reg = regulator_get_exclusive(cpu_dev, "sram");
> +	info->sram_reg = regulator_get_optional(cpu_dev, "sram");

The changelog says that this regulator may be shared with CCI, so I
understand it's no longer exclusive.  But here you make it optional,
which should be explained in the changelog.  If it's not actually
optional, then it should just be normal "get".

Kevin
Rex-BC Chen (陳柏辰) April 14, 2022, 10:53 a.m. UTC | #3
On Fri, 2022-04-08 at 13:32 -0700, Kevin Hilman wrote:
> Rex-BC Chen <rex-bc.chen@mediatek.com> writes:
> 
> > From: Jia-Wei Chang <jia-wei.chang@mediatek.com>
> > 
> > For some MediaTek SoCs, like MT8186, it's possible that the sram
> > regulator
> > is shared between CPU and CCI.
> > 
> > Signed-off-by: Jia-Wei Chang <jia-wei.chang@mediatek.com>
> 
> nit: missing your sign-off.
> 
> > ---
> >  drivers/cpufreq/mediatek-cpufreq.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/cpufreq/mediatek-cpufreq.c
> > b/drivers/cpufreq/mediatek-cpufreq.c
> > index 9e9bce0ff235..8f688d47e64b 100644
> > --- a/drivers/cpufreq/mediatek-cpufreq.c
> > +++ b/drivers/cpufreq/mediatek-cpufreq.c
> > @@ -435,7 +435,7 @@ static int mtk_cpu_dvfs_info_init(struct
> > mtk_cpu_dvfs_info *info, int cpu)
> >  	}
> >  
> >  	/* Both presence and absence of sram regulator are valid cases.
> > */
> > -	info->sram_reg = regulator_get_exclusive(cpu_dev, "sram");
> > +	info->sram_reg = regulator_get_optional(cpu_dev, "sram");
> 
> The changelog says that this regulator may be shared with CCI, so I
> understand it's no longer exclusive.  But here you make it optional,
> which should be explained in the changelog.  If it's not actually
> optional, then it should just be normal "get".
> 
> Kevin

Hello Kevin,

Since cpufreq and cci devfreq might share the same sram regulator in
MediaTek SoC, it is no longer exclusive as you mentioned.

The reason to use regulator_get_optional is we hope regulator framework
can return error for error handling rather than a dummy handler from
regulator_get api.

I will add this to commit message in next version.

Thanks.

BRs,
Rex
Kevin Hilman April 14, 2022, 5:20 p.m. UTC | #4
Rex-BC Chen <rex-bc.chen@mediatek.com> writes:

> On Fri, 2022-04-08 at 13:32 -0700, Kevin Hilman wrote:
>> Rex-BC Chen <rex-bc.chen@mediatek.com> writes:
>> 
>> > From: Jia-Wei Chang <jia-wei.chang@mediatek.com>
>> > 
>> > For some MediaTek SoCs, like MT8186, it's possible that the sram
>> > regulator
>> > is shared between CPU and CCI.
>> > 
>> > Signed-off-by: Jia-Wei Chang <jia-wei.chang@mediatek.com>
>> 
>> nit: missing your sign-off.
>> 
>> > ---
>> >  drivers/cpufreq/mediatek-cpufreq.c | 2 +-
>> >  1 file changed, 1 insertion(+), 1 deletion(-)
>> > 
>> > diff --git a/drivers/cpufreq/mediatek-cpufreq.c
>> > b/drivers/cpufreq/mediatek-cpufreq.c
>> > index 9e9bce0ff235..8f688d47e64b 100644
>> > --- a/drivers/cpufreq/mediatek-cpufreq.c
>> > +++ b/drivers/cpufreq/mediatek-cpufreq.c
>> > @@ -435,7 +435,7 @@ static int mtk_cpu_dvfs_info_init(struct
>> > mtk_cpu_dvfs_info *info, int cpu)
>> >  	}
>> >  
>> >  	/* Both presence and absence of sram regulator are valid cases.
>> > */
>> > -	info->sram_reg = regulator_get_exclusive(cpu_dev, "sram");
>> > +	info->sram_reg = regulator_get_optional(cpu_dev, "sram");
>> 
>> The changelog says that this regulator may be shared with CCI, so I
>> understand it's no longer exclusive.  But here you make it optional,
>> which should be explained in the changelog.  If it's not actually
>> optional, then it should just be normal "get".
>> 
>> Kevin
>
> Hello Kevin,
>
> Since cpufreq and cci devfreq might share the same sram regulator in
> MediaTek SoC, it is no longer exclusive as you mentioned.
>
> The reason to use regulator_get_optional is we hope regulator framework
> can return error for error handling rather than a dummy handler from
> regulator_get api.
>
> I will add this to commit message in next version.

OK, sounds good.

Thanks,

Kevin
diff mbox series

Patch

diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
index 9e9bce0ff235..8f688d47e64b 100644
--- a/drivers/cpufreq/mediatek-cpufreq.c
+++ b/drivers/cpufreq/mediatek-cpufreq.c
@@ -435,7 +435,7 @@  static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
 	}
 
 	/* Both presence and absence of sram regulator are valid cases. */
-	info->sram_reg = regulator_get_exclusive(cpu_dev, "sram");
+	info->sram_reg = regulator_get_optional(cpu_dev, "sram");
 	if (IS_ERR(info->sram_reg))
 		info->sram_reg = NULL;
 	else {