[PATCH v3 1/2] clk: mediatek: Introduce need_pm_runtime to mtk_clk_desc

Pin-yen Lin
2024-01-08T08:18:49Z

Introduce a new need_pm_runtime variable to mtk_clk_desc to indicate
this clock controller needs runtime PM for its operations.
Also do a runtime PM get on the clock controller during the
probing stage to workaround a possible deadlock.

Signed-off-by: Pin-yen Lin <treapking@chromium.org>
---

Changes in v3:
- Update the commit message and the comments before runtime PM call

Changes in v2:
- Fix the order of error handling
- Update the commit message and add a comment before the runtime PM call

drivers/clk/mediatek/clk-mtk.c | 19 +++++++++++++++++++
drivers/clk/mediatek/clk-mtk.h | 2 ++
2 files changed, 21 insertions(+)

diff --git a/drivers/clk/mediatek/clk-mtk.c b/drivers/clk/mediatek/clk-mtk.c
index 2e55368dc4d8..ba1d1c495bc2 100644
--- a/drivers/clk/mediatek/clk-mtk.c
+++ b/drivers/clk/mediatek/clk-mtk.c
@@ -13,6 +13,7 @@
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
#include <linux/slab.h>

#include "clk-mtk.h"
@@ -494,6 +495,18 @@ static int __mtk_clk_simple_probe(struct platform_device *pdev,
return IS_ERR(base) ? PTR_ERR(base) : -ENOMEM;
}

+
+ if (mcd->need_runtime_pm) {
+ devm_pm_runtime_enable(&pdev->dev);
+ /*
+ * Do a pm_runtime_resume_and_get() to workaround a possible
+ * deadlock between clk_register() and the genpd framework.
+ */
+ r = pm_runtime_resume_and_get(&pdev->dev);
+ if (r)
+ return r;
+ }
+
/* Calculate how many clk_hw_onecell_data entries to allocate */
num_clks = mcd->num_clks + mcd->num_composite_clks;
num_clks += mcd->num_fixed_clks + mcd->num_factor_clks;
@@ -574,6 +587,9 @@ static int __mtk_clk_simple_probe(struct platform_device *pdev,
goto unregister_clks;
}

+ if (mcd->need_runtime_pm)
+ pm_runtime_put(&pdev->dev);
+
return r;

unregister_clks:
@@ -604,6 +620,9 @@ static int __mtk_clk_simple_probe(struct platform_device *pdev,
free_base:
if (mcd->shared_io && base)
iounmap(base);
+
+ if (mcd->need_runtime_pm)
+ pm_runtime_put(&pdev->dev);
return r;
}

diff --git a/drivers/clk/mediatek/clk-mtk.h b/drivers/clk/mediatek/clk-mtk.h
index 22096501a60a..c17fe1c2d732 100644
--- a/drivers/clk/mediatek/clk-mtk.h
+++ b/drivers/clk/mediatek/clk-mtk.h
@@ -237,6 +237,8 @@ struct mtk_clk_desc {

int (*clk_notifier_func)(struct device *dev, struct clk *clk);
unsigned int mfg_clk_idx;
+
+ bool need_runtime_pm;
};

int mtk_clk_pdev_probe(struct platform_device *pdev);
--
2.43.0.472.g3155946c3a-goog