[PATCH v2] drm/bridge: cdns-dsi: Split pm_ops into runtime_pm and system_sleep ops

[Abhash Kumar Jha <a-kumar2@ti.com>]

If runtime-pm has already suspended the device and a system suspend
occurs, then we see a kernel crash when disabling and unpreparing the
clocks.

Use pm_runtime_force_suspend/resume in system_sleep pm callbacks to let
runtime-pm take care of the coordination between system suspend and
itself. This ensures that they do not interfere with each other.

Signed-off-by: Abhash Kumar Jha <a-kumar2@ti.com>
---
Hi,

If a device is runtime_pm suspended and a system wide suspend is triggered,
we see a kernel crash. Hence split the power management ops into separate
system_sleep and runtime_pm ops.

Changes in v2:
- Improve the commit description and subject.
- Link to v1: https://lore.kernel.org/all/20260109060312.2853133-1-a-kumar2@ti.com/

Thanks,
Abhash

 .../gpu/drm/bridge/cadence/cdns-dsi-core.c    | 32 +++++++++++++------
 1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
index 09b289f0fcbf..25eaf0192013 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
@@ -1230,7 +1230,18 @@ static const struct mipi_dsi_host_ops cdns_dsi_ops = {
 	.transfer = cdns_dsi_transfer,
 };
 
-static int __maybe_unused cdns_dsi_resume(struct device *dev)
+static int cdns_dsi_runtime_suspend(struct device *dev)
+{
+	struct cdns_dsi *dsi = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(dsi->dsi_sys_clk);
+	clk_disable_unprepare(dsi->dsi_p_clk);
+	reset_control_assert(dsi->dsi_p_rst);
+
+	return 0;
+}
+
+static int cdns_dsi_runtime_resume(struct device *dev)
 {
 	struct cdns_dsi *dsi = dev_get_drvdata(dev);
 
@@ -1241,18 +1252,21 @@ static int __maybe_unused cdns_dsi_resume(struct device *dev)
 	return 0;
 }
 
-static int __maybe_unused cdns_dsi_suspend(struct device *dev)
+static int cdns_dsi_suspend(struct device *dev)
 {
-	struct cdns_dsi *dsi = dev_get_drvdata(dev);
+	return pm_runtime_force_suspend(dev);
+}
 
-	clk_disable_unprepare(dsi->dsi_sys_clk);
-	clk_disable_unprepare(dsi->dsi_p_clk);
-	reset_control_assert(dsi->dsi_p_rst);
-	return 0;
+static int cdns_dsi_resume(struct device *dev)
+{
+	return pm_runtime_force_resume(dev);
 }
 
-static UNIVERSAL_DEV_PM_OPS(cdns_dsi_pm_ops, cdns_dsi_suspend, cdns_dsi_resume,
-			    NULL);
+static const struct dev_pm_ops cdns_dsi_pm_ops = {
+	SET_RUNTIME_PM_OPS(cdns_dsi_runtime_suspend,
+			cdns_dsi_runtime_resume, NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(cdns_dsi_suspend, cdns_dsi_resume)
+};
 
 static int cdns_dsi_drm_probe(struct platform_device *pdev)
 {
-- 
2.34.1