From: Tomasz Figa <tfiga@chromium.org>
Date: Mon, 23 Apr 2018 12:49:59 +0200
Subject: drm/rockchip: analogix_dp: Do not call Analogix code before bind
Git-commit: a4169609def769c66f88140678970b2be6f64ac7
Patch-mainline: v4.18-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Driver callbacks, such as system suspend or resume can be called any
time, specifically they can be called before the component bind
callback. Let's use dp->adp pointer as a safeguard and skip calling
Analogix entry points if it is an ERR_PTR().

Signed-off-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180423105003.9004-24-enric.balletbo@collabora.com

Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/rockchip/analogix_dp-rockchip.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
+++ b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
@@ -368,6 +368,8 @@ static void rockchip_dp_unbind(struct de
 	analogix_dp_unbind(dp->adp);
 	rockchip_drm_psr_unregister(&dp->encoder);
 	dp->encoder.funcs->destroy(&dp->encoder);
+
+	dp->adp = ERR_PTR(-ENODEV);
 }
 
 static const struct component_ops rockchip_dp_component_ops = {
@@ -391,6 +393,7 @@ static int rockchip_dp_probe(struct plat
 		return -ENOMEM;
 
 	dp->dev = dev;
+	dp->adp = ERR_PTR(-ENODEV);
 	dp->plat_data.panel = panel;
 
 	ret = rockchip_dp_of_probe(dp);
@@ -414,6 +417,9 @@ static int rockchip_dp_suspend(struct de
 {
 	struct rockchip_dp_device *dp = dev_get_drvdata(dev);
 
+	if (IS_ERR(dp->adp))
+		return 0;
+
 	return analogix_dp_suspend(dp->adp);
 }
 
@@ -421,6 +427,9 @@ static int rockchip_dp_resume(struct dev
 {
 	struct rockchip_dp_device *dp = dev_get_drvdata(dev);
 
+	if (IS_ERR(dp->adp))
+		return 0;
+
 	return analogix_dp_resume(dp->adp);
 }
 #endif