linux-kernel - Re: [PATCH v2 2/4] soc: mediatek: pm-domains: Add default power off flag

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Message-ID: <32fbc5c6-88e4-7cdc-2491-5226d819db37@gmail.com>
Date:   Tue, 27 Oct 2020 11:25:55 +0100
From:   Matthias Brugger <matthias.bgg@...il.com>
To:     Weiyi Lu <weiyi.lu@...iatek.com>,
        Enric Balletbo Serra <eballetbo@...il.com>,
        Nicolas Boichat <drinkcat@...omium.org>,
        Rob Herring <robh@...nel.org>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, linux-mediatek@...ts.infradead.org,
        srv_heupstream@...iatek.com
Subject: Re: [PATCH v2 2/4] soc: mediatek: pm-domains: Add default power off
 flag



On 22/10/2020 14:47, Weiyi Lu wrote:
> For some power domain, like conn on MT8192, it should be default OFF.
> Because the power on/off control relies the function of connectivity chip
> and its firmware. And if project choose other chip vendor solution,
> those necessary connectivity functions will not provided.
> 
> Signed-off-by: Weiyi Lu <weiyi.lu@...iatek.com>
> ---
>   drivers/soc/mediatek/mtk-pm-domains.c | 23 +++++++++++++++++------
>   1 file changed, 17 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/soc/mediatek/mtk-pm-domains.c b/drivers/soc/mediatek/mtk-pm-domains.c
> index b7ccf94..50a7ae1 100644
> --- a/drivers/soc/mediatek/mtk-pm-domains.c
> +++ b/drivers/soc/mediatek/mtk-pm-domains.c
> @@ -24,6 +24,7 @@
>   #define MTK_SCPD_ACTIVE_WAKEUP		BIT(0)
>   #define MTK_SCPD_FWAIT_SRAM		BIT(1)
>   #define MTK_SCPD_SRAM_ISO		BIT(2)
> +#define MTK_SCPD_KEEP_DEFAULT_OFF	BIT(3)
>   #define MTK_SCPD_CAPS(_scpd, _x)	((_scpd)->data->caps & (_x))
>   
>   #define SPM_VDE_PWR_CON			0x0210
> @@ -506,17 +507,26 @@ static int scpsys_add_one_domain(struct scpsys *scpsys, struct device_node *node
>   	 * software.  The unused domains will be switched off during
>   	 * late_init time.
>   	 */
> -	ret = scpsys_power_on(&pd->genpd);
> -	if (ret < 0) {
> -		dev_err_probe(scpsys->dev, ret, "failed to power on domain %pOFN\n", node);
> -		goto err_unprepare_clocks;
> +	if (MTK_SCPD_CAPS(pd, MTK_SCPD_KEEP_DEFAULT_OFF)) {
> +		if (scpsys_domain_is_on(pd))
> +			dev_warn(scpsys->dev,
> +				 "A default off power domain %pOFN has been ON\n", node);
> +	} else {
> +		ret = scpsys_power_on(&pd->genpd);
> +		if (ret < 0) {
> +			dev_err_probe(scpsys->dev, ret, "failed to power on domain %pOFN\n", node);
> +			goto err_unprepare_clocks;
> +		}
>   	}
>   
>   	pd->genpd.name = node->name;
>   	pd->genpd.power_off = scpsys_power_off;
>   	pd->genpd.power_on = scpsys_power_on;
>   
> -	pm_genpd_init(&pd->genpd, NULL, false);
> +	if (MTK_SCPD_CAPS(pd, MTK_SCPD_KEEP_DEFAULT_OFF))
> +		pm_genpd_init(&pd->genpd, NULL, true);
> +	else
> +		pm_genpd_init(&pd->genpd, NULL, false);
>   
>   	scpsys->domains[id] = &pd->genpd;
>   	return 0;
> @@ -603,7 +613,8 @@ static void scpsys_remove_one_domain(struct scpsys_domain *pd)
>   			"failed to remove domain '%s' : %d - state may be inconsistent\n",
>   			pd->genpd.name, ret);
>   
> -	scpsys_power_off(&pd->genpd);
> +	if (!MTK_SCPD_CAPS(pd, MTK_SCPD_KEEP_DEFAULT_OFF))
> +		scpsys_power_off(&pd->genpd);

Is that really needed? Turning the domain off when it's already off shouldn't hurt.

Regards,
Matthias