drm/fsl-dcu: 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. DRM IRQ callbacks are now being called
directly or inlined.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210803090704.32152-5-tzimmermann@suse.de

drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c

@@ -23,7 +23,6 @@
 #include <drm/drm_fb_cma_helper.h>
 #include <drm/drm_fb_helper.h>
 #include <drm/drm_gem_cma_helper.h>
-#include <drm/drm_irq.h>
 #include <drm/drm_modeset_helper.h>
 #include <drm/drm_probe_helper.h>
 #include <drm/drm_vblank.h>
@@ -51,7 +50,7 @@ static const struct regmap_config fsl_dcu_regmap_config = {
 	.volatile_reg = fsl_dcu_drm_is_volatile_reg,
 };
 
-static void fsl_dcu_irq_uninstall(struct drm_device *dev)
+static void fsl_dcu_irq_reset(struct drm_device *dev)
 {
 	struct fsl_dcu_drm_device *fsl_dev = dev->dev_private;
 
@@ -59,6 +58,45 @@ static void fsl_dcu_irq_uninstall(struct drm_device *dev)
 	regmap_write(fsl_dev->regmap, DCU_INT_MASK, ~0);
 }
 
+static irqreturn_t fsl_dcu_drm_irq(int irq, void *arg)
+{
+	struct drm_device *dev = arg;
+	struct fsl_dcu_drm_device *fsl_dev = dev->dev_private;
+	unsigned int int_status;
+	int ret;
+
+	ret = regmap_read(fsl_dev->regmap, DCU_INT_STATUS, &int_status);
+	if (ret) {
+		dev_err(dev->dev, "read DCU_INT_STATUS failed\n");
+		return IRQ_NONE;
+	}
+
+	if (int_status & DCU_INT_STATUS_VBLANK)
+		drm_handle_vblank(dev, 0);
+
+	regmap_write(fsl_dev->regmap, DCU_INT_STATUS, int_status);
+
+	return IRQ_HANDLED;
+}
+
+static int fsl_dcu_irq_install(struct drm_device *dev, unsigned int irq)
+{
+	if (irq == IRQ_NOTCONNECTED)
+		return -ENOTCONN;
+
+	fsl_dcu_irq_reset(dev);
+
+	return request_irq(irq, fsl_dcu_drm_irq, 0, dev->driver->name, dev);
+}
+
+static void fsl_dcu_irq_uninstall(struct drm_device *dev)
+{
+	struct fsl_dcu_drm_device *fsl_dev = dev->dev_private;
+
+	fsl_dcu_irq_reset(dev);
+	free_irq(fsl_dev->irq, dev);
+}
+
 static int fsl_dcu_load(struct drm_device *dev, unsigned long flags)
 {
 	struct fsl_dcu_drm_device *fsl_dev = dev->dev_private;
@@ -73,13 +111,13 @@ static int fsl_dcu_load(struct drm_device *dev, unsigned long flags)
 	ret = drm_vblank_init(dev, dev->mode_config.num_crtc);
 	if (ret < 0) {
 		dev_err(dev->dev, "failed to initialize vblank\n");
-		goto done;
+		goto done_vblank;
 	}
 
-	ret = drm_irq_install(dev, fsl_dev->irq);
+	ret = fsl_dcu_irq_install(dev, fsl_dev->irq);
 	if (ret < 0) {
 		dev_err(dev->dev, "failed to install IRQ handler\n");
-		goto done;
+		goto done_irq;
 	}
 
 	if (legacyfb_depth != 16 && legacyfb_depth != 24 &&
@@ -90,11 +128,11 @@ static int fsl_dcu_load(struct drm_device *dev, unsigned long flags)
 	}
 
 	return 0;
-done:
+done_irq:
 	drm_kms_helper_poll_fini(dev);
 
 	drm_mode_config_cleanup(dev);
-	drm_irq_uninstall(dev);
+done_vblank:
 	dev->dev_private = NULL;
 
 	return ret;
@@ -106,41 +144,17 @@ static void fsl_dcu_unload(struct drm_device *dev)
 	drm_kms_helper_poll_fini(dev);
 
 	drm_mode_config_cleanup(dev);
-	drm_irq_uninstall(dev);
+	fsl_dcu_irq_uninstall(dev);
 
 	dev->dev_private = NULL;
 }
 
-static irqreturn_t fsl_dcu_drm_irq(int irq, void *arg)
-{
-	struct drm_device *dev = arg;
-	struct fsl_dcu_drm_device *fsl_dev = dev->dev_private;
-	unsigned int int_status;
-	int ret;
-
-	ret = regmap_read(fsl_dev->regmap, DCU_INT_STATUS, &int_status);
-	if (ret) {
-		dev_err(dev->dev, "read DCU_INT_STATUS failed\n");
-		return IRQ_NONE;
-	}
-
-	if (int_status & DCU_INT_STATUS_VBLANK)
-		drm_handle_vblank(dev, 0);
-
-	regmap_write(fsl_dev->regmap, DCU_INT_STATUS, int_status);
-
-	return IRQ_HANDLED;
-}
-
 DEFINE_DRM_GEM_CMA_FOPS(fsl_dcu_drm_fops);
 
 static const struct drm_driver fsl_dcu_drm_driver = {
 	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
 	.load			= fsl_dcu_load,
 	.unload			= fsl_dcu_unload,
-	.irq_handler		= fsl_dcu_drm_irq,
-	.irq_preinstall		= fsl_dcu_irq_uninstall,
-	.irq_uninstall		= fsl_dcu_irq_uninstall,
 	DRM_GEM_CMA_DRIVER_OPS,
 	.fops			= &fsl_dcu_drm_fops,
 	.name			= "fsl-dcu-drm",