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Date:   Thu, 22 Jun 2023 10:39:21 +0200
From:   Markus Schneider-Pargmann <msp@baylibre.com>
To:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
Cc:     Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Chun-Jie Chen <chun-jie.chen@mediatek.com>,
        Tinghan Shen <tinghan.shen@mediatek.com>,
        Fabien Parent <parent.f@gmail.com>, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org,
        Alexandre Bailon <abailon@baylibre.com>,
        Fabien Parent <fparent@baylibre.com>
Subject: Re: [PATCH v5 6/8] soc: mediatek: Add support for WAY_EN operations
Message-ID: <20230622083921.tc3wsl6jyluenmru@blmsp>
References: <20230619085344.2885311-1-msp@baylibre.com>
 <20230619085344.2885311-7-msp@baylibre.com>
 <590f9a11-a153-abaf-0f99-9496882ee929@collabora.com>
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On Mon, Jun 19, 2023 at 11:29:18AM +0200, AngeloGioacchino Del Regno wrote:
> Il 19/06/23 10:53, Markus Schneider-Pargmann ha scritto:
> > From: Alexandre Bailon <abailon@baylibre.com>
> > 
> > This updates the power domain to support WAY_EN operations. WAY_EN
> > operations on mt8365 are using a different component to check for the
> > acknowledgment, namely the infracfg-nao component. Also to enable a way
> > it the bit needs to be cleared while disabling a way needs a bit to be
> > set. To support these two operations two flags are added,
> > BUS_PROT_INVERTED and BUS_PROT_STA_COMPONENT_INFRA_NAO. Additionally
> > another regmap is created if the INFRA_NAO capability is set.
> > 
> > This operation is required by the mt8365 for the MM power domain.
> > 
> > Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
> > Signed-off-by: Fabien Parent <fparent@baylibre.com>
> > Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
> > ---
> >   drivers/soc/mediatek/mtk-pm-domains.c | 39 +++++++++++++++++++++++----
> >   drivers/soc/mediatek/mtk-pm-domains.h |  7 +++--
> >   2 files changed, 39 insertions(+), 7 deletions(-)
> > 
> > diff --git a/drivers/soc/mediatek/mtk-pm-domains.c b/drivers/soc/mediatek/mtk-pm-domains.c
> > index 3cdf62c0b6bd..4659f0a0aa08 100644
> > --- a/drivers/soc/mediatek/mtk-pm-domains.c
> > +++ b/drivers/soc/mediatek/mtk-pm-domains.c
> > @@ -44,6 +44,7 @@ struct scpsys_domain {
> >   	struct clk_bulk_data *clks;
> >   	int num_subsys_clks;
> >   	struct clk_bulk_data *subsys_clks;
> > +	struct regmap *infracfg_nao;
> >   	struct regmap *infracfg;
> >   	struct regmap *smi;
> >   	struct regulator *supply;
> > @@ -127,13 +128,26 @@ static struct regmap *scpsys_bus_protect_get_regmap(struct scpsys_domain *pd,
> >   		return pd->infracfg;
> >   }
> > +static struct regmap *scpsys_bus_protect_get_sta_regmap(struct scpsys_domain *pd,
> > +							const struct scpsys_bus_prot_data *bpd)
> > +{
> > +	if (bpd->flags & BUS_PROT_STA_COMPONENT_INFRA_NAO)
> > +		return pd->infracfg_nao;
> > +	else
> > +		return scpsys_bus_protect_get_regmap(pd, bpd);
> > +}
> > +
> >   static int scpsys_bus_protect_clear(struct scpsys_domain *pd,
> >   				    const struct scpsys_bus_prot_data *bpd)
> >   {
> > +	struct regmap *sta_regmap = scpsys_bus_protect_get_sta_regmap(pd, bpd);
> >   	struct regmap *regmap = scpsys_bus_protect_get_regmap(pd, bpd);
> > +	u32 expected_ack;
> >   	u32 val;
> >   	u32 sta_mask = bpd->bus_prot_sta_mask;
> > +	expected_ack = (bpd->flags & BUS_PROT_STA_COMPONENT_INFRA_NAO ? sta_mask : 0);
> > +
> >   	if (bpd->flags & BUS_PROT_REG_UPDATE)
> >   		regmap_clear_bits(regmap, bpd->bus_prot_clr, bpd->bus_prot_set_clr_mask);
> >   	else
> > @@ -142,14 +156,15 @@ static int scpsys_bus_protect_clear(struct scpsys_domain *pd,
> >   	if (bpd->flags & BUS_PROT_IGNORE_CLR_ACK)
> >   		return 0;
> > -	return regmap_read_poll_timeout(regmap, bpd->bus_prot_sta,
> > -					val, !(val & sta_mask),
> > +	return regmap_read_poll_timeout(sta_regmap, bpd->bus_prot_sta,
> > +					val, (val & sta_mask) == expected_ack,
> >   					MTK_POLL_DELAY_US, MTK_POLL_TIMEOUT);
> >   }
> >   static int scpsys_bus_protect_set(struct scpsys_domain *pd,
> >   				  const struct scpsys_bus_prot_data *bpd)
> >   {
> > +	struct regmap *sta_regmap = scpsys_bus_protect_get_sta_regmap(pd, bpd);
> >   	struct regmap *regmap = scpsys_bus_protect_get_regmap(pd, bpd);
> >   	u32 val;
> >   	u32 sta_mask = bpd->bus_prot_sta_mask;
> > @@ -159,7 +174,7 @@ static int scpsys_bus_protect_set(struct scpsys_domain *pd,
> >   	else
> >   		regmap_write(regmap, bpd->bus_prot_set, bpd->bus_prot_set_clr_mask);
> > -	return regmap_read_poll_timeout(regmap, bpd->bus_prot_sta,
> > +	return regmap_read_poll_timeout(sta_regmap, bpd->bus_prot_sta,
> >   					val, (val & sta_mask) == sta_mask,
> >   					MTK_POLL_DELAY_US, MTK_POLL_TIMEOUT);
> >   }
> > @@ -173,7 +188,10 @@ static int scpsys_bus_protect_enable(struct scpsys_domain *pd)
> >   		if (!bpd->bus_prot_set_clr_mask)
> >   			break;
> > -		ret = scpsys_bus_protect_set(pd, bpd);
> > +		if (bpd->flags & BUS_PROT_INVERTED)
> > +			ret = scpsys_bus_protect_clear(pd, bpd);
> > +		else
> > +			ret = scpsys_bus_protect_set(pd, bpd);
> >   		if (ret)
> >   			return ret;
> >   	}
> > @@ -190,7 +208,10 @@ static int scpsys_bus_protect_disable(struct scpsys_domain *pd)
> >   		if (!bpd->bus_prot_set_clr_mask)
> >   			continue;
> > -		ret = scpsys_bus_protect_clear(pd, bpd);
> > +		if (bpd->flags & BUS_PROT_INVERTED)
> > +			ret = scpsys_bus_protect_set(pd, bpd);
> > +		else
> > +			ret = scpsys_bus_protect_clear(pd, bpd);
> >   		if (ret)
> >   			return ret;
> >   	}
> > @@ -377,6 +398,14 @@ generic_pm_domain *scpsys_add_one_domain(struct scpsys *scpsys, struct device_no
> >   			return ERR_CAST(pd->smi);
> >   	}
> > +	pd->infracfg_nao = syscon_regmap_lookup_by_phandle(node, "mediatek,infracfg-nao");
> 
> If we don't expect infracfg-nao to be present, what's the point about trying to
> get a regmap handle and then failing only if we do expect it to be there?
> 
> At this point you can just do...
> 
> 	if (MTK_SCPD_CAPS(pd, MTK_SCPD_HAS_INFRA_NAO)) {
> 		pd->infracfg_nao = syscon_regmap_lookup_by_phandle(...);
> 		if (IS_ERR(....))
> 			return ....
> 	}

Yes! My code looks stupid. Thanks!

> 
> > +	if (IS_ERR(pd->infracfg_nao)) {
> > +		if (MTK_SCPD_CAPS(pd, MTK_SCPD_HAS_INFRA_NAO))
> > +			return ERR_CAST(pd->infracfg_nao);
> > +
> > +		pd->infracfg_nao = NULL;
> > +	}
> > +
> >   	num_clks = of_clk_get_parent_count(node);
> >   	if (num_clks > 0) {
> >   		/* Calculate number of subsys_clks */
> > diff --git a/drivers/soc/mediatek/mtk-pm-domains.h b/drivers/soc/mediatek/mtk-pm-domains.h
> > index 356788263db2..562d4e92ce16 100644
> > --- a/drivers/soc/mediatek/mtk-pm-domains.h
> > +++ b/drivers/soc/mediatek/mtk-pm-domains.h
> > @@ -11,6 +11,7 @@
> >   /* can't set MTK_SCPD_KEEP_DEFAULT_OFF at the same time */
> >   #define MTK_SCPD_ALWAYS_ON		BIT(5)
> >   #define MTK_SCPD_EXT_BUCK_ISO		BIT(6)
> > +#define MTK_SCPD_HAS_INFRA_NAO		BIT(7)
> >   #define MTK_SCPD_CAPS(_scpd, _x)	((_scpd)->data->caps & (_x))
> >   #define SPM_VDE_PWR_CON			0x0210
> > @@ -45,8 +46,10 @@
> >   enum scpsys_bus_prot_flags {
> >   	BUS_PROT_REG_UPDATE = BIT(1),
> >   	BUS_PROT_IGNORE_CLR_ACK = BIT(2),
> > -	BUS_PROT_COMPONENT_INFRA = BIT(3),
> > -	BUS_PROT_COMPONENT_SMI = BIT(4),
> > +	BUS_PROT_INVERTED = BIT(3),
> 
> I get the reason why you're setting inverted as bit 3, but at that point you can
> just set BUS_PROT_COMPONENT_INFRA to bit 4 from the very beginning, instead of
> using bit 3 for that and then changing them all in a subsequent commit (this one).

Yes, I was torn between making the commits independent and avoiding this
move later on. I decided for the first. If you prefer I can set it to
the correct bits right from the beginning.

Best,
Markus