soc: mtk-pm-domains: do not register smi node as syscon

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>

diff --git a/drivers/soc/mediatek/mtk-pm-domains.c b/drivers/soc/mediatek/mtk-pm-domains.c
index 0af00ef..22fa52f 100644 (file)
--- 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) {