[PATCH 1/2] drm/arm/malidp: fix ignored clk_prepare_enable() in runtime PM resume

[Gustavo Kenji Mendonça Kaneko]

malidp_runtime_pm_resume() calls clk_prepare_enable() three times
without checking the return value. If any clock fails to enable, the
driver silently proceeds with unclocked hardware, leading to undefined
behavior.

Use clk_bulk_prepare_enable() which atomically enables all clocks and
automatically rolls back successfully enabled clocks on failure. This
is consistent with how the suspend path already uses
clk_bulk_disable_unprepare() in malidp_runtime_pm_suspend().

This issue was found by code review without access to Mali DP hardware.

Signed-off-by: Gustavo Kenji Mendonça Kaneko <kaneko.dev@xxxxx>
---
 drivers/gpu/drm/arm/malidp_drv.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c
index b765f6c9eea4..1e4336c3a2fa 100644
--- a/drivers/gpu/drm/arm/malidp_drv.c
+++ b/drivers/gpu/drm/arm/malidp_drv.c
@@ -689,10 +689,17 @@ static int malidp_runtime_pm_resume(struct device *dev)
 	struct drm_device *drm = dev_get_drvdata(dev);
 	struct malidp_drm *malidp = drm_to_malidp(drm);
 	struct malidp_hw_device *hwdev = malidp->dev;
+	struct clk_bulk_data clks[] = {
+		{ .clk = hwdev->pclk },
+		{ .clk = hwdev->aclk },
+		{ .clk = hwdev->mclk },
+	};
+	int err;
+
+	err = clk_bulk_prepare_enable(ARRAY_SIZE(clks), clks);
+	if (err)
+		return err;
 
-	clk_prepare_enable(hwdev->pclk);
-	clk_prepare_enable(hwdev->aclk);
-	clk_prepare_enable(hwdev->mclk);
 	hwdev->pm_suspended = false;
 	malidp_de_irq_hw_init(hwdev);
 	malidp_se_irq_hw_init(hwdev);
-- 
2.54.0