drm/meson/dw-hdmi: convert to of_drm_find_and_get_bridge()

of_drm_find_bridge() is deprecated. Move to its replacement
of_drm_find_and_get_bridge() which gets a bridge reference, and ensure it
is put when done.

dw_hdmi->bridge is used only in dw_hdmi_top_thread_irq(), so in order to
avoid potential use-after-free ensure the irq is freed before putting the
dw_hdmi->bridge reference.

Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Acked-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patch.msgid.link/20260109-drm-bridge-alloc-getput-drm_of_find_bridge-3-v2-2-8d7a3dbacdf4@bootlin.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
index 0d7c68b29dfff43ef276734368b15da9ee497919..fef1702acb1453f2d24aa0a98052357a740092c8 100644 (file)
--- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
+++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
@@ -778,7 +778,7 @@ static int meson_dw_hdmi_bind(struct device *dev, struct device *master,
        if (IS_ERR(meson_dw_hdmi->hdmi))
                return PTR_ERR(meson_dw_hdmi->hdmi);
 
-       meson_dw_hdmi->bridge = of_drm_find_bridge(pdev->dev.of_node);
+       meson_dw_hdmi->bridge = of_drm_find_and_get_bridge(pdev->dev.of_node);
 
        DRM_DEBUG_DRIVER("HDMI controller initialized\n");
 
@@ -789,8 +789,12 @@ static void meson_dw_hdmi_unbind(struct device *dev, struct device *master,
                                   void *data)
 {
        struct meson_dw_hdmi *meson_dw_hdmi = dev_get_drvdata(dev);
+       struct platform_device *pdev = to_platform_device(dev);
+       int irq = platform_get_irq(pdev, 0);
 
+       devm_free_irq(dev, irq, meson_dw_hdmi);
        dw_hdmi_unbind(meson_dw_hdmi->hdmi);
+       drm_bridge_put(meson_dw_hdmi->bridge);
 }
 
 static const struct component_ops meson_dw_hdmi_ops = {