drm: Call drm_atomic_helper_shutdown() at shutdown time for misc drivers

Based on grepping through the source code these drivers appear to be
missing a call to drm_atomic_helper_shutdown() at system shutdown
time. Among other things, this means that if a panel is in use that it
won't be cleanly powered off at system shutdown time.

The fact that we should call drm_atomic_helper_shutdown() in the case
of OS shutdown/restart comes straight out of the kernel doc "driver
instance overview" in drm_drv.c.

All of the drivers in this patch were fairly straightforward to fix
since they already had a call to drm_atomic_helper_shutdown() at
remove/unbind time but were just lacking one at system shutdown. The
only hitch is that some of these drivers use the component model to
register/unregister their DRM devices. The shutdown callback is part
of the original device. The typical solution here, based on how other
DRM drivers do this, is to keep track of whether the device is bound
based on drvdata. In most cases the drvdata is the drm_device, so we
can just make sure it is NULL when the device is not bound. In some
drivers, this required minor code changes. To make things simpler,
drm_atomic_helper_shutdown() has been modified to consider a NULL
drm_device as a noop in the patch ("drm/atomic-helper:
drm_atomic_helper_shutdown(NULL) should be a noop").

Suggested-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Tested-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Tested-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Reviewed-by: Sui Jingfeng <suijingfeng@loongson.cn>
Tested-by: Sui Jingfeng <suijingfeng@loongson.cn>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230901163944.RFT.2.I9115e5d094a43e687978b0699cc1fe9f2a3452ea@changeid

5 files changed, 29 insertions, 0 deletions

diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_drv.c b/drivers/gpu/drm/arm/display/komeda/komeda_drv.c
index cb2a2be24c5f..cc57ea4e13ae 100644
--- a/drivers/gpu/drm/arm/display/komeda/komeda_drv.c
+++ b/drivers/gpu/drm/arm/display/komeda/komeda_drv.c
@@ -45,6 +45,14 @@ static void komeda_platform_remove(struct platform_device *pdev)
 	devm_kfree(dev, mdrv);
 }
 
+static void komeda_platform_shutdown(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct komeda_drv *mdrv = dev_get_drvdata(dev);
+
+	komeda_kms_shutdown(mdrv->kms);
+}
+
 static int komeda_platform_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -142,6 +150,7 @@ static const struct dev_pm_ops komeda_pm_ops = {
 static struct platform_driver komeda_platform_driver = {
 	.probe	= komeda_platform_probe,
 	.remove_new = komeda_platform_remove,
+	.shutdown = komeda_platform_shutdown,
 	.driver	= {
 		.name = "komeda",
 		.of_match_table	= komeda_of_match,
diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_kms.c b/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
index 9299026701f3..fe46b0ebefea 100644
--- a/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
+++ b/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
@@ -340,3 +340,10 @@ void komeda_kms_detach(struct komeda_kms_dev *kms)
 	komeda_kms_cleanup_private_objs(kms);
 	drm->dev_private = NULL;
 }
+
+void komeda_kms_shutdown(struct komeda_kms_dev *kms)
+{
+	struct drm_device *drm = &kms->base;
+
+	drm_atomic_helper_shutdown(drm);
+}
diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_kms.h b/drivers/gpu/drm/arm/display/komeda/komeda_kms.h
index 6ef655326357..a4048724564d 100644
--- a/drivers/gpu/drm/arm/display/komeda/komeda_kms.h
+++ b/drivers/gpu/drm/arm/display/komeda/komeda_kms.h
@@ -190,5 +190,6 @@ void komeda_crtc_flush_and_wait_for_flip_done(struct komeda_crtc *kcrtc,
 
 struct komeda_kms_dev *komeda_kms_attach(struct komeda_dev *mdev);
 void komeda_kms_detach(struct komeda_kms_dev *kms);
+void komeda_kms_shutdown(struct komeda_kms_dev *kms);
 
 #endif /*_KOMEDA_KMS_H_*/
diff --git a/drivers/gpu/drm/arm/hdlcd_drv.c b/drivers/gpu/drm/arm/hdlcd_drv.c
index aa06f9838015..32be9e370049 100644
--- a/drivers/gpu/drm/arm/hdlcd_drv.c
+++ b/drivers/gpu/drm/arm/hdlcd_drv.c
@@ -372,6 +372,11 @@ static void hdlcd_remove(struct platform_device *pdev)
 	component_master_del(&pdev->dev, &hdlcd_master_ops);
 }
 
+static void hdlcd_shutdown(struct platform_device *pdev)
+{
+	drm_atomic_helper_shutdown(platform_get_drvdata(pdev));
+}
+
 static const struct of_device_id  hdlcd_of_match[] = {
 	{ .compatible	= "arm,hdlcd" },
 	{},
@@ -399,6 +404,7 @@ static SIMPLE_DEV_PM_OPS(hdlcd_pm_ops, hdlcd_pm_suspend, hdlcd_pm_resume);
 static struct platform_driver hdlcd_platform_driver = {
 	.probe		= hdlcd_probe,
 	.remove_new	= hdlcd_remove,
+	.shutdown	= hdlcd_shutdown,
 	.driver	= {
 		.name = "hdlcd",
 		.pm = &hdlcd_pm_ops,
diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c
index 62329d5dd992..6682131d2910 100644
--- a/drivers/gpu/drm/arm/malidp_drv.c
+++ b/drivers/gpu/drm/arm/malidp_drv.c
@@ -941,6 +941,11 @@ static void malidp_platform_remove(struct platform_device *pdev)
 	component_master_del(&pdev->dev, &malidp_master_ops);
 }
 
+static void malidp_platform_shutdown(struct platform_device *pdev)
+{
+	drm_atomic_helper_shutdown(platform_get_drvdata(pdev));
+}
+
 static int __maybe_unused malidp_pm_suspend(struct device *dev)
 {
 	struct drm_device *drm = dev_get_drvdata(dev);
@@ -982,6 +987,7 @@ static const struct dev_pm_ops malidp_pm_ops = {
 static struct platform_driver malidp_platform_driver = {
 	.probe		= malidp_platform_probe,
 	.remove_new	= malidp_platform_remove,
+	.shutdown	= malidp_platform_shutdown,
 	.driver	= {
 		.name = "mali-dp",
 		.pm = &malidp_pm_ops,