drm/meson: dw-hdmi: Ensure that clocks are enabled before touching the TOP registers

Removing the meson-dw-hdmi module and re-inserting it results in a hang
as the driver writes to HDMITX_TOP_SW_RESET. Similar effects can be seen
when booting with mainline u-boot and using the u-boot provided DT (which
is highly desirable).

The reason for the hang seem to be that the clocks are not always
enabled by the time we enter meson_dw_hdmi_init(). Moving this call
*after* dw_hdmi_probe() ensures that the clocks are enabled.

Fixes: 1374b8375c2e ("drm/meson: dw_hdmi: add resume/suspend hooks")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201116200744.495826-5-maz@kernel.org

diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
index 68826cf..7f8eea4 100644 (file)
--- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
+++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
@@ -1073,8 +1073,6 @@ static int meson_dw_hdmi_bind(struct device *dev, struct device *master,
 
        DRM_DEBUG_DRIVER("encoder initialized\n");
 
-       meson_dw_hdmi_init(meson_dw_hdmi);
-
        /* Bridge / Connector */
 
        dw_plat_data->priv_data = meson_dw_hdmi;
@@ -1097,6 +1095,8 @@ 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_init(meson_dw_hdmi);
+
        next_bridge = of_drm_find_bridge(pdev->dev.of_node);
        if (next_bridge)
                drm_bridge_attach(encoder, next_bridge,