[PATCH v2 1/3] drm/msm/dsi: check for failure on retrieving pll in dsi manager

[Lloyd Atkinson <latkinso@xxxxxxxxxxxxxx>]

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@xxxxxxxxxxxxxx>
---
 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(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_manager.c b/drivers/gpu/drm/msm/dsi/dsi_manager.c
index 8552481..1a54fd6 100644
--- 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 id)
 
 		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 id)
 		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;
diff --git a/drivers/gpu/drm/msm/dsi/phy/dsi_phy.c b/drivers/gpu/drm/msm/dsi/phy/dsi_phy.c
index 790ca28..c8bfaa7 100644
--- 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 platform_device *pdev)
 		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);
 
diff --git a/drivers/gpu/drm/msm/dsi/pll/dsi_pll.c b/drivers/gpu/drm/msm/dsi/pll/dsi_pll.c
index bc289f5..491f08d 100644
--- 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(struct platform_device *pdev,
 
 	if (IS_ERR(pll)) {
 		dev_err(dev, "%s: failed to init DSI PLL\n", __func__);
-		return NULL;
+		return pll;
 	}
 
 	pll->type = type;
-- 
QUALCOMM Canada, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

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