drm/shmobile: Convert to Linux IRQ interfaces

Drop the DRM IRQ midlayer in favor of Linux IRQ interfaces. DRM's
IRQ helpers are mostly useful for UMS drivers. Modern KMS drivers
don't benefit from using it.

v3:
	* return error if (ret < 0) (Geert)
	* remove duplicate error message (Geert)
v2:
	* handle errors in platform_get_irq() (Geert, Sergei)
	* store IRQ number in struct shmob_drm_device (Laurent)
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210720080941.23646-1-tzimmermann@suse.de

drivers/gpu/drm/shmobile/shmob_drm_drv.c

@@ -18,7 +18,6 @@
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_gem_cma_helper.h>
-#include <drm/drm_irq.h>
 #include <drm/drm_probe_helper.h>
 #include <drm/drm_vblank.h>
 
@@ -130,7 +129,6 @@ DEFINE_DRM_GEM_CMA_FOPS(shmob_drm_fops);
 
 static const struct drm_driver shmob_drm_driver = {
 	.driver_features	= DRIVER_GEM | DRIVER_MODESET,
-	.irq_handler		= shmob_drm_irq,
 	DRM_GEM_CMA_DRIVER_OPS,
 	.fops			= &shmob_drm_fops,
 	.name			= "shmob-drm",
@@ -183,7 +181,7 @@ static int shmob_drm_remove(struct platform_device *pdev)
 
 	drm_dev_unregister(ddev);
 	drm_kms_helper_poll_fini(ddev);
-	drm_irq_uninstall(ddev);
+	free_irq(sdev->irq, ddev);
 	drm_dev_put(ddev);
 
 	return 0;
@@ -258,7 +256,13 @@ static int shmob_drm_probe(struct platform_device *pdev)
 		goto err_modeset_cleanup;
 	}
 
-	ret = drm_irq_install(ddev, platform_get_irq(pdev, 0));
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0)
+		goto err_modeset_cleanup;
+	sdev->irq = ret;
+
+	ret = request_irq(sdev->irq, shmob_drm_irq, 0, ddev->driver->name,
+			  ddev);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed to install IRQ handler\n");
 		goto err_modeset_cleanup;
@@ -275,7 +279,7 @@ static int shmob_drm_probe(struct platform_device *pdev)
 	return 0;
 
 err_irq_uninstall:
-	drm_irq_uninstall(ddev);
+	free_irq(sdev->irq, ddev);
 err_modeset_cleanup:
 	drm_kms_helper_poll_fini(ddev);
 err_free_drm_dev:

drivers/gpu/drm/shmobile/shmob_drm_drv.h

@@ -29,6 +29,7 @@ struct shmob_drm_device {
 	u32 lddckr;
 	u32 ldmt1r;
 
+	unsigned int irq;
 	spinlock_t irq_lock;		/* Protects hardware LDINTR register */
 
 	struct drm_device *ddev;