[PATCH v3 1/2] hwmon: (lenovo-ec-sensors): Convert to devm_request_region()

[Kean Ren]

Replace manual request_region()/release_region() with
devm_request_region().  This lets the device-managed framework
handle I/O region lifetime automatically and fixes:

- A double release_region() when probe fails after acquiring the
  I/O region: the probe error path releases it, and then
  lenovo_ec_init() releases it again on the same error path.

- A release-after-use window in lenovo_ec_exit() where
  release_region() was called before platform_device_unregister(),
  leaving the hwmon device active with a released I/O region.

- Missing release_region() in lenovo_ec_probe() if
  devm_hwmon_device_register_with_info() fails.

Remove all four manual release_region() calls that are now handled
automatically and replace request_region with
devm_request_region, use dev_err replace pr_err.

Also remove the now-unnecessary braces around the single-statement
if body.

Reviewed-by: Mark Pearson <mpearson-lenovo@xxxxxxxxx>
Signed-off-by: Kean Ren <rh_king@xxxxxxx>
---
Changes in v3: Corrected bug description.

 drivers/hwmon/lenovo-ec-sensors.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/drivers/hwmon/lenovo-ec-sensors.c b/drivers/hwmon/lenovo-ec-sensors.c
index 8681bbf6665b..a16cc5e4053a 100644
--- a/drivers/hwmon/lenovo-ec-sensors.c
+++ b/drivers/hwmon/lenovo-ec-sensors.c
@@ -519,8 +519,8 @@ static int lenovo_ec_probe(struct platform_device *pdev)
 	if (!ec_data)
 		return -ENOMEM;
 
-	if (!request_region(IO_REGION_START, IO_REGION_LENGTH, "LNV-WKS")) {
-		pr_err(":request fail\n");
+	if (!devm_request_region(dev, IO_REGION_START, IO_REGION_LENGTH, "LNV-WKS")) {
+		dev_err(dev, "Failed to request I/O region\n");
 		return -EIO;
 	}
 
@@ -540,10 +540,8 @@ static int lenovo_ec_probe(struct platform_device *pdev)
 	if ((inb_p(MCHP_EMI0_EC_DATA_BYTE0) != 'M') &&
 	    (inb_p(MCHP_EMI0_EC_DATA_BYTE1) != 'C') &&
 	    (inb_p(MCHP_EMI0_EC_DATA_BYTE2) != 'H') &&
-	    (inb_p(MCHP_EMI0_EC_DATA_BYTE3) != 'P')) {
-		release_region(IO_REGION_START, IO_REGION_LENGTH);
+	    (inb_p(MCHP_EMI0_EC_DATA_BYTE3) != 'P'))
 		return -ENODEV;
-	}
 
 	dmi_id = dmi_first_match(thinkstation_dmi_table);
 
@@ -577,7 +575,6 @@ static int lenovo_ec_probe(struct platform_device *pdev)
 		lenovo_ec_chip_info.info = lenovo_ec_hwmon_info_p8;
 		break;
 	default:
-		release_region(IO_REGION_START, IO_REGION_LENGTH);
 		return -ENODEV;
 	}
 
@@ -606,10 +603,8 @@ static int __init lenovo_ec_init(void)
 		platform_create_bundle(&lenovo_ec_sensors_platform_driver,
 				       lenovo_ec_probe, NULL, 0, NULL, 0);
 
-	if (IS_ERR(lenovo_ec_sensors_platform_device)) {
-		release_region(IO_REGION_START, IO_REGION_LENGTH);
+	if (IS_ERR(lenovo_ec_sensors_platform_device))
 		return PTR_ERR(lenovo_ec_sensors_platform_device);
-	}
 
 	return 0;
 }
@@ -617,7 +612,6 @@ module_init(lenovo_ec_init);
 
 static void __exit lenovo_ec_exit(void)
 {
-	release_region(IO_REGION_START, IO_REGION_LENGTH);
 	platform_device_unregister(lenovo_ec_sensors_platform_device);
 	platform_driver_unregister(&lenovo_ec_sensors_platform_driver);
 }
-- 
2.53.0