[PATCH v4 1/2] i2c: imx-lpi2c: properly unwind resources on probe failure

[carlos.song at oss.nxp.com]

From: Carlos Song <carlos.song at nxp.com>

When probe fails after clk_bulk_prepare_enable() succeeds but before
runtime PM is initialized, the enabled clocks are never disabled.
Additionally, calling pm_runtime_put_sync() in the error path can
trigger the runtime suspend callback, which may attempt to disable
clocks that have not been fully set up, leading to potential issues
during error unwinding.

Introduce two new error labels: clk_disable to explicitly invoke
clk_bulk_disable_unprepare(), and free_irq to release the IRQ via
devm_free_irq(). Replace pm_runtime_put_sync() with the sequence of
pm_runtime_disable(), pm_runtime_set_suspended() and
pm_runtime_put_noidle() to bypass the runtime suspend callback during
error recovery. Update all goto targets so that each failure site
releases only the resources acquired up to that point.

Signed-off-by: Carlos Song <carlos.song at nxp.com>
---
 drivers/i2c/busses/i2c-imx-lpi2c.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c
index cd4da50c4dd9..fbb9c0b0a99c 100644
--- a/drivers/i2c/busses/i2c-imx-lpi2c.c
+++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
@@ -1520,21 +1520,25 @@ static int lpi2c_imx_probe(struct platform_device *pdev)
 
 	ret = clk_bulk_prepare_enable(lpi2c_imx->num_clks, lpi2c_imx->clks);
 	if (ret)
-		return ret;
+		goto free_irq;
 
 	/*
 	 * Lock the parent clock rate to avoid getting parent clock upon
 	 * each transfer
 	 */
 	ret = devm_clk_rate_exclusive_get(&pdev->dev, lpi2c_imx->clks[0].clk);
-	if (ret)
-		return dev_err_probe(&pdev->dev, ret,
-				     "can't lock I2C peripheral clock rate\n");
+	if (ret) {
+		dev_err_probe(&pdev->dev, ret,
+			      "can't lock I2C peripheral clock rate\n");
+		goto clk_disable;
+	}
 
 	lpi2c_imx->rate_per = clk_get_rate(lpi2c_imx->clks[0].clk);
-	if (!lpi2c_imx->rate_per)
-		return dev_err_probe(&pdev->dev, -EINVAL,
-				     "can't get I2C peripheral clock rate\n");
+	if (!lpi2c_imx->rate_per) {
+		ret = dev_err_probe(&pdev->dev, -EINVAL,
+				    "can't get I2C peripheral clock rate\n");
+		goto clk_disable;
+	}
 
 	if (lpi2c_imx->hwdata->need_prepare_unprepare_clk)
 		pm_runtime_set_autosuspend_delay(&pdev->dev, I2C_PM_LONG_TIMEOUT_MS);
@@ -1576,8 +1580,13 @@ static int lpi2c_imx_probe(struct platform_device *pdev)
 
 rpm_disable:
 	pm_runtime_dont_use_autosuspend(&pdev->dev);
-	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
+clk_disable:
+	clk_bulk_disable_unprepare(lpi2c_imx->num_clks, lpi2c_imx->clks);
+free_irq:
+	devm_free_irq(&pdev->dev, lpi2c_imx->irq, lpi2c_imx);
 
 	return ret;
 }
-- 
2.43.0