[PATCH 5.10 144/717] drm/meson: dw-hdmi: Ensure that clocks are enabled before touching the TOP registers

Greg Kroah-Hartman
2020-12-28T14:07:34Z

From: Marc Zyngier <maz@kernel.org>

[ Upstream commit b33340e33acdfe5ca6a5aa1244709575ae1e0432 ]

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
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/meson/meson_dw_hdmi.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
index 68826cf9993fc..7f8eea4941472 100644
--- 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,
--
2.27.0