[PATCH v7 07/12] gpio: mxc: use __free guard for runtime PM cleanup

[Peng Fan (OSS)]

From: Peng Fan <peng.fan at nxp.com>

Use a scope-based cleanup guard to disable runtime PM and drop the
probe-scoped pm_runtime_get_noresume() reference on error paths.  Disarm
it with retain_and_null_ptr() before the success-path
pm_runtime_put_autosuspend().

The guard keeps the required order: pm_runtime_disable() runs before
pm_runtime_put_noidle(), so dropping the reference cannot trigger a
runtime suspend callback while probe is still unwinding.

Signed-off-by: Peng Fan <peng.fan at nxp.com>
---
 drivers/gpio/gpio-mxc.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpio-mxc.c b/drivers/gpio/gpio-mxc.c
index 21c74b244c1f..68857730b5e3 100644
--- a/drivers/gpio/gpio-mxc.c
+++ b/drivers/gpio/gpio-mxc.c
@@ -28,6 +28,20 @@
 #include <linux/of.h>
 #include <linux/bug.h>
 
+static void mxc_gpio_pm_release(struct device *dev)
+{
+	if (!dev)
+		return;
+
+	if (pm_runtime_enabled(dev))
+		pm_runtime_disable(dev);
+
+	pm_runtime_put_noidle(dev);
+}
+
+DEFINE_FREE(mxc_gpio_pm_cleanup, struct device *,
+	    mxc_gpio_pm_release(_T))
+
 #define IMX_SCU_WAKEUP_OFF		0
 #define IMX_SCU_WAKEUP_LOW_LVL		4
 #define IMX_SCU_WAKEUP_FALL_EDGE	5
@@ -487,6 +501,9 @@ static int mxc_gpio_probe(struct platform_device *pdev)
 		return PTR_ERR(port->clk);
 
 	pm_runtime_get_noresume(dev);
+
+	struct device *pm_guard __free(mxc_gpio_pm_cleanup) = dev;
+
 	pm_runtime_set_active(dev);
 	pm_runtime_enable(dev);
 
@@ -562,6 +579,8 @@ static int mxc_gpio_probe(struct platform_device *pdev)
 	mxc_update_irq_chained_handler(port, true);
 
 	platform_set_drvdata(pdev, port);
+
+	retain_and_null_ptr(pm_guard);
 	pm_runtime_put_autosuspend(dev);
 
 	return 0;
@@ -569,8 +588,6 @@ static int mxc_gpio_probe(struct platform_device *pdev)
 out_irqdomain_remove:
 	irq_domain_remove(port->domain);
 out_bgio:
-	pm_runtime_disable(dev);
-	pm_runtime_put_noidle(dev);
 	dev_info(dev, "%s failed with errno %d\n", __func__, err);
 	return err;
 }

-- 
2.51.0