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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Hsin-Yi Wang <hsinyi@chromium.org>,
        "chun-jie.chen" <chun-jie.chen@mediatek.com>,
        Enric Balletbo i Serra <enric.balletbo@collabora.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.12 250/292] soc: mtk-pm-domains: do not register smi node as syscon
Date:   Mon, 19 Jul 2021 16:55:12 +0200
Message-Id: <20210719144951.166395323@linuxfoundation.org>
In-Reply-To: <20210719144942.514164272@linuxfoundation.org>
References: <20210719144942.514164272@linuxfoundation.org>
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From: Hsin-Yi Wang <hsinyi@chromium.org>

[ Upstream commit eed6ff1bb2da65067d928f4ab322c7d75f944fa4 ]

Mediatek requires mmsys clocks to be unprepared during suspend,
otherwise system has chances to hang.

syscon_regmap_lookup_by_phandle_optional() will attach and prepare the
first clock in smi node, leading to additional prepare to the clock
which is not balanced with the prepare/unprepare pair in resume/suspend
callbacks.

If a power domain node requests an smi node and the smi node's first
clock is an mmsys clock, it will results in an unstable suspend resume.

Fixes: f414854c8843 ("soc: mediatek: pm-domains: Add SMI block as bus protection block")
Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Reviewed-by: chun-jie.chen <chun-jie.chen@mediatek.com>
Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Link: https://lore.kernel.org/r/20210601035905.2970384-2-hsinyi@chromium.org
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/soc/mediatek/mtk-pm-domains.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/soc/mediatek/mtk-pm-domains.c b/drivers/soc/mediatek/mtk-pm-domains.c
index 0af00efa0ef8..22fa52f0e86e 100644
--- a/drivers/soc/mediatek/mtk-pm-domains.c
+++ b/drivers/soc/mediatek/mtk-pm-domains.c
@@ -297,6 +297,7 @@ generic_pm_domain *scpsys_add_one_domain(struct scpsys *scpsys, struct device_no
 	const struct scpsys_domain_data *domain_data;
 	struct scpsys_domain *pd;
 	struct device_node *root_node = scpsys->dev->of_node;
+	struct device_node *smi_node;
 	struct property *prop;
 	const char *clk_name;
 	int i, ret, num_clks;
@@ -352,9 +353,13 @@ generic_pm_domain *scpsys_add_one_domain(struct scpsys *scpsys, struct device_no
 	if (IS_ERR(pd->infracfg))
 		return ERR_CAST(pd->infracfg);
 
-	pd->smi = syscon_regmap_lookup_by_phandle_optional(node, "mediatek,smi");
-	if (IS_ERR(pd->smi))
-		return ERR_CAST(pd->smi);
+	smi_node = of_parse_phandle(node, "mediatek,smi", 0);
+	if (smi_node) {
+		pd->smi = device_node_to_regmap(smi_node);
+		of_node_put(smi_node);
+		if (IS_ERR(pd->smi))
+			return ERR_CAST(pd->smi);
+	}
 
 	num_clks = of_clk_get_parent_count(node);
 	if (num_clks > 0) {
-- 
2.30.2