6.12-stable review patch. If anyone has any objections, please let me know.
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From: Vitalii Mordan mordan@ispras.ru
[ Upstream commit f65727be3fa5f252c8d982d15023aab8255ded19 ]
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-morda... Signed-off-by: Sasha Levin sashal@kernel.org --- 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 41f72d458487f..9ba2a667a1f3a 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 @@ static int cdns_mhdp_probe(struct platform_device *pdev) 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[] = {