From 9294914dd5507eca56566c470c56327f46dfd4fa Mon Sep 17 00:00:00 2001 From: AngeloGioacchino Del Regno Date: Wed, 5 Jan 2022 10:08:02 +0100 Subject: drm/bridge: parade-ps8640: Link device to ensure suspend/resume order Entering suspend while the display attached to this bridge is still on makes the resume sequence to resume the bridge first, display last: when this happens, we get a timeout while resuming the bridge, as its MCU will get stuck due to the display being unpowered. On the other hand, on mt8173-elm, closing the lid makes the display to get powered off first, bridge last, so at resume time the sequence is swapped (compared to the first example) and everything just works as expected. Add a stateless device link to the DRM device that this bridge belongs to, ensuring a correct resume sequence and solving the unability to correctly resume bridge operation in the first mentioned example. Signed-off-by: AngeloGioacchino Del Regno Signed-off-by: Robert Foss Link: https://patchwork.freedesktop.org/patch/msgid/20220105090802.73564-1-angelogioacchino.delregno@collabora.com Reviewed-by: Robert Foss --- drivers/gpu/drm/bridge/parade-ps8640.c | 29 ++++++++++++++++++++++++++--- 1 file changed, 26 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c index 818704bf5e86..54723f068884 100644 --- a/drivers/gpu/drm/bridge/parade-ps8640.c +++ b/drivers/gpu/drm/bridge/parade-ps8640.c @@ -102,6 +102,7 @@ struct ps8640 { struct regulator_bulk_data supplies[2]; struct gpio_desc *gpio_reset; struct gpio_desc *gpio_powerdown; + struct device_link *link; bool pre_enabled; }; @@ -456,14 +457,36 @@ static int ps8640_bridge_attach(struct drm_bridge *bridge, return ret; } + ps_bridge->link = device_link_add(bridge->dev->dev, dev, DL_FLAG_STATELESS); + if (!ps_bridge->link) { + dev_err(dev, "failed to create device link"); + ret = -EINVAL; + goto err_devlink; + } + /* Attach the panel-bridge to the dsi bridge */ - return drm_bridge_attach(bridge->encoder, ps_bridge->panel_bridge, - &ps_bridge->bridge, flags); + ret = drm_bridge_attach(bridge->encoder, ps_bridge->panel_bridge, + &ps_bridge->bridge, flags); + if (ret) + goto err_bridge_attach; + + return 0; + +err_bridge_attach: + device_link_del(ps_bridge->link); +err_devlink: + drm_dp_aux_unregister(&ps_bridge->aux); + + return ret; } static void ps8640_bridge_detach(struct drm_bridge *bridge) { - drm_dp_aux_unregister(&bridge_to_ps8640(bridge)->aux); + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); + + drm_dp_aux_unregister(&ps_bridge->aux); + if (ps_bridge->link) + device_link_del(ps_bridge->link); } static struct edid *ps8640_bridge_get_edid(struct drm_bridge *bridge, -- cgit v1.2.3