From f65727be3fa5f252c8d982d15023aab8255ded19 Mon Sep 17 00:00:00 2001
From: Vitalii Mordan <mordan@ispras.ru>
Date: Fri, 14 Feb 2025 18:46:32 +0300
Subject: [PATCH] gpu: cdns-mhdp8546: fix call balance of mhdp->clk handling
routines
If the clock mhdp->clk was not enabled in cdns_mhdp_probe(), it should not
be disabled in any path.
The return value of clk_prepare_enable() is not checked. If mhdp->clk was
not enabled, it may be disabled in the error path of cdns_mhdp_probe()
(e.g., if cdns_mhdp_load_firmware() fails) or in cdns_mhdp_remove() after
a successful cdns_mhdp_probe() call.
Use the devm_clk_get_enabled() helper function to ensure proper call
balance for mhdp->clk.
Found by Linux Verification Center (linuxtesting.org) with Klever.
Fixes: fb43aa0acdfd ("drm: bridge: Add support for Cadence MHDP8546 DPI/DP bridge")
Signed-off-by: Vitalii Mordan <mordan@ispras.ru>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20250214154632.1907425-1-mordan@ispras.ru
---
drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
index 25345c3274e34..01eeae7309e57 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
@@ -2463,9 +2463,9 @@ static int cdns_mhdp_probe(struct platform_device *pdev)
if (!mhdp)
return -ENOMEM;
- clk = devm_clk_get(dev, NULL);
+ clk = devm_clk_get_enabled(dev, NULL);
if (IS_ERR(clk)) {
- dev_err(dev, "couldn't get clk: %ld\n", PTR_ERR(clk));
+ dev_err(dev, "couldn't get and enable clk: %ld\n", PTR_ERR(clk));
return PTR_ERR(clk);
}
@@ -2504,14 +2504,12 @@ static int cdns_mhdp_probe(struct platform_device *pdev)
mhdp->info = of_device_get_match_data(dev);
- clk_prepare_enable(clk);
-
pm_runtime_enable(dev);
ret = pm_runtime_resume_and_get(dev);
if (ret < 0) {
dev_err(dev, "pm_runtime_resume_and_get failed\n");
pm_runtime_disable(dev);
- goto clk_disable;
+ return ret;
}
if (mhdp->info && mhdp->info->ops && mhdp->info->ops->init) {
@@ -2590,8 +2588,6 @@ plat_fini:
runtime_put:
pm_runtime_put_sync(dev);
pm_runtime_disable(dev);
-clk_disable:
- clk_disable_unprepare(mhdp->clk);
return ret;
}
@@ -2632,8 +2628,6 @@ static void cdns_mhdp_remove(struct platform_device *pdev)
cancel_work_sync(&mhdp->modeset_retry_work);
flush_work(&mhdp->hpd_work);
/* Ignoring mhdp->hdcp.check_work and mhdp->hdcp.prop_work here. */
-
- clk_disable_unprepare(mhdp->clk);
}
static const struct of_device_id mhdp_ids[] = {
--
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