linux-kernel - [PATCH v2 2/2] clk: mediatek: mt8183: Enable need_runtime

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Date: Tue,  2 Jan 2024 16:12:53 +0800
From: Pin-yen Lin <treapking@...omium.org>
To: Michael Turquette <mturquette@...libre.com>,
	Stephen Boyd <sboyd@...nel.org>,
	Matthias Brugger <matthias.bgg@...il.com>,
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
Cc: Pin-yen Lin <treapking@...omium.org>,
	Chen-Yu Tsai <wenst@...omium.org>,
	linux-arm-kernel@...ts.infradead.org,
	linux-clk@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Weiyi Lu <weiyi.lu@...iatek.com>,
	linux-mediatek@...ts.infradead.org
Subject: [PATCH v2 2/2] clk: mediatek: mt8183: Enable need_runtime_pm on mt8183-mfgcfg

mt8183-mfgcfg has a mutual dependency with genpd during the probing
stage, so enable need_runtim_pm to prevent a deadlock in the following
call stack:

CPU0:  genpd_lock --> clk_prepare_lock
genpd_power_off_work_fn()
 genpd_lock()
 generic_pm_domain::power_off()
    clk_unprepare()
      clk_prepare_lock()

CPU1: clk_prepare_lock --> genpd_lock
clk_register()
  __clk_core_init()
    clk_prepare_lock()
    clk_pm_runtime_get()
      genpd_lock()

Do a runtime PM get at the probe function to make sure clk_register()
won't acquire the genpd lock.

Fixes: acddfc2c261b ("clk: mediatek: Add MT8183 clock support")
Signed-off-by: Pin-yen Lin <treapking@...omium.org>
---

(no changes since v1)

 drivers/clk/mediatek/clk-mt8183-mfgcfg.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/clk/mediatek/clk-mt8183-mfgcfg.c b/drivers/clk/mediatek/clk-mt8183-mfgcfg.c
index ba504e19d420..62d876e150e1 100644
--- a/drivers/clk/mediatek/clk-mt8183-mfgcfg.c
+++ b/drivers/clk/mediatek/clk-mt8183-mfgcfg.c
@@ -29,6 +29,7 @@ static const struct mtk_gate mfg_clks[] = {
 static const struct mtk_clk_desc mfg_desc = {
 	.clks = mfg_clks,
 	.num_clks = ARRAY_SIZE(mfg_clks),
+	.need_runtime_pm = true,
 };
 
 static const struct of_device_id of_match_clk_mt8183_mfg[] = {
-- 
2.43.0.472.g3155946c3a-goog