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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Sibi Sankar <sibis@codeaurora.org>,
        Sean Paul <seanpaul@chromium.org>,
        Rob Clark <robdclark@chromium.org>
Subject: [PATCH 5.3 067/148] drm/msm/dsi: Fix return value check for clk_get_parent
Date:   Thu, 10 Oct 2019 10:35:28 +0200
Message-Id: <20191010083615.502085657@linuxfoundation.org>
In-Reply-To: <20191010083609.660878383@linuxfoundation.org>
References: <20191010083609.660878383@linuxfoundation.org>
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From: Sean Paul <seanpaul@chromium.org>

commit 5fb9b797d5ccf311ae4aba69e86080d47668b5f7 upstream.

clk_get_parent returns an error pointer upon failure, not NULL. So the
checks as they exist won't catch a failure. This patch changes the
checks and the return values to properly handle an error pointer.

Fixes: c4d8cfe516dc ("drm/msm/dsi: add implementation for helper functions")
Cc: Sibi Sankar <sibis@codeaurora.org>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Rob Clark <robdclark@chromium.org>
Cc: <stable@vger.kernel.org> # v4.19+
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/msm/dsi/dsi_host.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -421,15 +421,15 @@ static int dsi_clk_init(struct msm_dsi_h
 	}
 
 	msm_host->byte_clk_src = clk_get_parent(msm_host->byte_clk);
-	if (!msm_host->byte_clk_src) {
-		ret = -ENODEV;
+	if (IS_ERR(msm_host->byte_clk_src)) {
+		ret = PTR_ERR(msm_host->byte_clk_src);
 		pr_err("%s: can't find byte_clk clock. ret=%d\n", __func__, ret);
 		goto exit;
 	}
 
 	msm_host->pixel_clk_src = clk_get_parent(msm_host->pixel_clk);
-	if (!msm_host->pixel_clk_src) {
-		ret = -ENODEV;
+	if (IS_ERR(msm_host->pixel_clk_src)) {
+		ret = PTR_ERR(msm_host->pixel_clk_src);
 		pr_err("%s: can't find pixel_clk clock. ret=%d\n", __func__, ret);
 		goto exit;
 	}