[PATCH v4 8/9] drm/vgem/vgem_drv convert to use faux_device

Greg Kroah-Hartman
2025-02-10T12:31:07Z

The vgem driver does not need to create a platform device, as there is
no real platform resources associated it, it only did so because it was
simple to do that in order to get a device to use for resource
management of drm resources. Change the driver to use the faux device
instead as this is NOT a real platform device.

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@gmail.com>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
v4: - api tweaked due to parent pointer added to faux_device create
function.
v3: new patch in the series. For an example of the api working, does
not have to be merged at this time, but I can take it if the
maintainers give an ack.
drivers/gpu/drm/vgem/vgem_drv.c | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c
index 2752ab4f1c97..260c64733972 100644
--- a/drivers/gpu/drm/vgem/vgem_drv.c
+++ b/drivers/gpu/drm/vgem/vgem_drv.c
@@ -32,7 +32,7 @@

#include <linux/dma-buf.h>
#include <linux/module.h>
-#include <linux/platform_device.h>
+#include <linux/device/faux.h>
#include <linux/shmem_fs.h>
#include <linux/vmalloc.h>

@@ -52,7 +52,7 @@

static struct vgem_device {
struct drm_device drm;
- struct platform_device *platform;
+ struct faux_device *faux_dev;
} *vgem_device;

static int vgem_open(struct drm_device *dev, struct drm_file *file)
@@ -127,27 +127,27 @@ static const struct drm_driver vgem_driver = {
static int __init vgem_init(void)
{
int ret;
- struct platform_device *pdev;
+ struct faux_device *fdev;

- pdev = platform_device_register_simple("vgem", -1, NULL, 0);
- if (IS_ERR(pdev))
- return PTR_ERR(pdev);
+ fdev = faux_device_create("vgem", NULL, NULL);
+ if (!fdev)
+ return -ENODEV;

- if (!devres_open_group(&pdev->dev, NULL, GFP_KERNEL)) {
+ if (!devres_open_group(&fdev->dev, NULL, GFP_KERNEL)) {
ret = -ENOMEM;
goto out_unregister;
}

- dma_coerce_mask_and_coherent(&pdev->dev,
+ dma_coerce_mask_and_coherent(&fdev->dev,
DMA_BIT_MASK(64));

- vgem_device = devm_drm_dev_alloc(&pdev->dev, &vgem_driver,
+ vgem_device = devm_drm_dev_alloc(&fdev->dev, &vgem_driver,
struct vgem_device, drm);
if (IS_ERR(vgem_device)) {
ret = PTR_ERR(vgem_device);
goto out_devres;
}
- vgem_device->platform = pdev;
+ vgem_device->faux_dev = fdev;

/* Final step: expose the device/driver to userspace */
ret = drm_dev_register(&vgem_device->drm, 0);
@@ -157,19 +157,19 @@ static int __init vgem_init(void)
return 0;

out_devres:
- devres_release_group(&pdev->dev, NULL);
+ devres_release_group(&fdev->dev, NULL);
out_unregister:
- platform_device_unregister(pdev);
+ faux_device_destroy(fdev);
return ret;
}

static void __exit vgem_exit(void)
{
- struct platform_device *pdev = vgem_device->platform;
+ struct faux_device *fdev = vgem_device->faux_dev;

drm_dev_unregister(&vgem_device->drm);
- devres_release_group(&pdev->dev, NULL);
- platform_device_unregister(pdev);
+ devres_release_group(&fdev->dev, NULL);
+ faux_device_destroy(fdev);
}

module_init(vgem_init);
--
2.48.1