[PATCH v8 02/13] drm/bridge: cdns-dsi: Fix phy de-init and flag it so

Aradhya Bhatia
2025-01-26T19:16:25Z

From: Aradhya Bhatia <a-bhatia1@ti.com>

The driver code doesn't have a Phy de-initialization path as yet, and so
it does not clear the phy_initialized flag while suspending. This is a
problem because after resume the driver looks at this flag to determine
if a Phy re-initialization is required or not. It is in fact required
because the hardware is resuming from a suspend, but the driver does not
carry out any re-initialization causing the D-Phy to not work at all.

Call the counterparts of phy_init() and phy_power_on(), that are
phy_exit() and phy_power_off(), from _bridge_post_disable(), and clear
the flags so that the Phy can be initialized again when required.

Fixes: fced5a364dee ("drm/bridge: cdns: Convert to phy framework")
Cc: Stable List <stable@vger.kernel.org>
Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
Signed-off-by: Aradhya Bhatia <aradhya.bhatia@linux.dev>
---
drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
index 2f897ea5e80a..b0a1a6774ea6 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
@@ -680,6 +680,11 @@ static void cdns_dsi_bridge_post_disable(struct drm_bridge *bridge)
struct cdns_dsi_input *input = bridge_to_cdns_dsi_input(bridge);
struct cdns_dsi *dsi = input_to_dsi(input);

+ dsi->phy_initialized = false;
+ dsi->link_initialized = false;
+ phy_power_off(dsi->dphy);
+ phy_exit(dsi->dphy);
+
pm_runtime_put(dsi->base.dev);
}

@@ -1152,7 +1157,6 @@ static int __maybe_unused cdns_dsi_suspend(struct device *dev)
clk_disable_unprepare(dsi->dsi_sys_clk);
clk_disable_unprepare(dsi->dsi_p_clk);
reset_control_assert(dsi->dsi_p_rst);
- dsi->link_initialized = false;
return 0;
}

--
2.34.1