[PATCH 5.12 250/292] soc: mtk-pm-domains: do not register smi node as syscon

From: Greg Kroah-Hartman
Date: Mon Jul 19 2021 - 14:24:41 EST

From: Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx>

[ 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

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@xxxxxxxxxxxx>
Reviewed-by: chun-jie.chen <chun-jie.chen@xxxxxxxxxxxx>
Reviewed-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210601035905.2970384-2-hsinyi@xxxxxxxxxxxx
Signed-off-by: Matthias Brugger <matthias.bgg@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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) {