[PATCH v2 2/3] usb: chipidea: ci_hdrc_imx: fix call balance of regulator routines

[Fedor Pchelkin]

Upon encountering errors during the HSIC pinctrl handling section the
regulator should be disabled.

Use devm_add_action_or_reset() to let the regulator-disabling routine be
handled by device resource management stack.

Found by Linux Verification Center (linuxtesting.org).

Fixes: 4d6141288c33 ("usb: chipidea: imx: pinctrl for HSIC is optional")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Fedor Pchelkin <pchelkin@xxxxxxxxx>
---
v2: simplify the patch taking advantage of devm-helper (Frank Li)

It looks like devm_regulator_get_enable_optional() exists for this very
use case utilized in the driver but it's not present in old supported
stable kernels and I may say those dependency-patches wouldn't apply there
cleanly. So fix the problem first, further code simplification is a
subject to cleanup patch.

 drivers/usb/chipidea/ci_hdrc_imx.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/chipidea/ci_hdrc_imx.c b/drivers/usb/chipidea/ci_hdrc_imx.c
index 619779eef333..d942b3c72640 100644
--- a/drivers/usb/chipidea/ci_hdrc_imx.c
+++ b/drivers/usb/chipidea/ci_hdrc_imx.c
@@ -336,6 +336,13 @@ static int ci_hdrc_imx_notify_event(struct ci_hdrc *ci, unsigned int event)
 	return ret;
 }
 
+static void ci_hdrc_imx_disable_regulator(void *arg)
+{
+	struct ci_hdrc_imx_data *data = arg;
+
+	regulator_disable(data->hsic_pad_regulator);
+}
+
 static int ci_hdrc_imx_probe(struct platform_device *pdev)
 {
 	struct ci_hdrc_imx_data *data;
@@ -394,6 +401,13 @@ static int ci_hdrc_imx_probe(struct platform_device *pdev)
 					"Failed to enable HSIC pad regulator\n");
 				goto err_put;
 			}
+			ret = devm_add_action_or_reset(dev,
+					ci_hdrc_imx_disable_regulator, data);
+			if (ret) {
+				dev_err(dev,
+					"Failed to add regulator devm action\n");
+				goto err_put;
+			}
 		}
 	}
 
@@ -432,11 +446,11 @@ static int ci_hdrc_imx_probe(struct platform_device *pdev)
 
 	ret = imx_get_clks(dev);
 	if (ret)
-		goto disable_hsic_regulator;
+		goto qos_remove_request;
 
 	ret = imx_prepare_enable_clks(dev);
 	if (ret)
-		goto disable_hsic_regulator;
+		goto qos_remove_request;
 
 	ret = clk_prepare_enable(data->clk_wakeup);
 	if (ret)
@@ -526,10 +540,7 @@ static int ci_hdrc_imx_probe(struct platform_device *pdev)
 	clk_disable_unprepare(data->clk_wakeup);
 err_wakeup_clk:
 	imx_disable_unprepare_clks(dev);
-disable_hsic_regulator:
-	if (data->hsic_pad_regulator)
-		/* don't overwrite original ret (cf. EPROBE_DEFER) */
-		regulator_disable(data->hsic_pad_regulator);
+qos_remove_request:
 	if (pdata.flags & CI_HDRC_PMQOS)
 		cpu_latency_qos_remove_request(&data->pm_qos_req);
 	data->ci_pdev = NULL;
@@ -557,8 +568,6 @@ static void ci_hdrc_imx_remove(struct platform_device *pdev)
 		clk_disable_unprepare(data->clk_wakeup);
 		if (data->plat_data->flags & CI_HDRC_PMQOS)
 			cpu_latency_qos_remove_request(&data->pm_qos_req);
-		if (data->hsic_pad_regulator)
-			regulator_disable(data->hsic_pad_regulator);
 	}
 	if (data->usbmisc_data)
 		put_device(data->usbmisc_data->dev);
-- 
2.48.1