From: Lloyd Atkinson <latkinso@codeaurora.org>
Date: Tue, 16 Jan 2018 16:26:01 -0500
Subject: drm/msm/dsi: check for failure on retrieving pll in dsi manager
Git-commit: f0efc831d9439589efaf6406695470eca93ba08d
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Make msm_dsi_pll_init consistently return an error code instead
of NULL when pll initialization fails so that later pll
retrieval can check against an error code. Add checks for these
failures after retrieval of src_pll to avoid invalid pointer
dereferences later in msm_dsi_pll_get_clk_provider.

Signed-off-by: Lloyd Atkinson <latkinso@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/msm/dsi/dsi_manager.c |    4 ++++
 drivers/gpu/drm/msm/dsi/phy/dsi_phy.c |    6 +++---
 drivers/gpu/drm/msm/dsi/pll/dsi_pll.c |    2 +-
 3 files changed, 8 insertions(+), 4 deletions(-)

--- a/drivers/gpu/drm/msm/dsi/dsi_manager.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_manager.c
@@ -88,6 +88,8 @@ static int dsi_mgr_setup_components(int
 
 		msm_dsi_phy_set_usecase(msm_dsi->phy, MSM_DSI_PHY_STANDALONE);
 		src_pll = msm_dsi_phy_get_pll(msm_dsi->phy);
+		if (IS_ERR(src_pll))
+			return PTR_ERR(src_pll);
 		ret = msm_dsi_host_set_src_pll(msm_dsi->host, src_pll);
 	} else if (!other_dsi) {
 		ret = 0;
@@ -116,6 +118,8 @@ static int dsi_mgr_setup_components(int
 		msm_dsi_phy_set_usecase(clk_slave_dsi->phy,
 					MSM_DSI_PHY_SLAVE);
 		src_pll = msm_dsi_phy_get_pll(clk_master_dsi->phy);
+		if (IS_ERR(src_pll))
+			return PTR_ERR(src_pll);
 		ret = msm_dsi_host_set_src_pll(msm_dsi->host, src_pll);
 		if (ret)
 			return ret;
--- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy.c
+++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy.c
@@ -503,10 +503,10 @@ static int dsi_phy_driver_probe(struct p
 		goto fail;
 
 	phy->pll = msm_dsi_pll_init(pdev, phy->cfg->type, phy->id);
-	if (!phy->pll)
+	if (IS_ERR_OR_NULL(phy->pll))
 		dev_info(dev,
-			"%s: pll init failed, need separate pll clk driver\n",
-			__func__);
+			"%s: pll init failed: %ld, need separate pll clk driver\n",
+			__func__, PTR_ERR(phy->pll));
 
 	dsi_phy_disable_resource(phy);
 
--- a/drivers/gpu/drm/msm/dsi/pll/dsi_pll.c
+++ b/drivers/gpu/drm/msm/dsi/pll/dsi_pll.c
@@ -173,7 +173,7 @@ struct msm_dsi_pll *msm_dsi_pll_init(str
 
 	if (IS_ERR(pll)) {
 		dev_err(dev, "%s: failed to init DSI PLL\n", __func__);
-		return NULL;
+		return pll;
 	}
 
 	pll->type = type;