carl9170: devres-ing hwrng_register usage

devres will take care of freeing the hwrng once it is no longer needed.
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/d1c16490462a9371ab3cc16a018ef5e08382a35e.1646250537.git.chunkeey@gmail.com

drivers/net/wireless/ath/carl9170/carl9170.h

@@ -458,7 +458,6 @@ struct ar9170 {
 # define CARL9170_HWRNG_CACHE_SIZE	CARL9170_MAX_CMD_PAYLOAD_LEN
 	struct {
 		struct hwrng rng;
-		bool initialized;
 		char name[30 + 1];
 		u16 cache[CARL9170_HWRNG_CACHE_SIZE / sizeof(u16)];
 		unsigned int cache_idx;

drivers/net/wireless/ath/carl9170/main.c

@@ -1539,7 +1539,7 @@ static int carl9170_rng_get(struct ar9170 *ar)
 
 	BUILD_BUG_ON(RB > CARL9170_MAX_CMD_PAYLOAD_LEN);
 
-	if (!IS_ACCEPTING_CMD(ar) || !ar->rng.initialized)
+	if (!IS_ACCEPTING_CMD(ar))
 		return -EAGAIN;
 
 	count = ARRAY_SIZE(ar->rng.cache);
@@ -1585,14 +1585,6 @@ static int carl9170_rng_read(struct hwrng *rng, u32 *data)
 	return sizeof(u16);
 }
 
-static void carl9170_unregister_hwrng(struct ar9170 *ar)
-{
-	if (ar->rng.initialized) {
-		hwrng_unregister(&ar->rng.rng);
-		ar->rng.initialized = false;
-	}
-}
-
 static int carl9170_register_hwrng(struct ar9170 *ar)
 {
 	int err;
@@ -1603,25 +1595,14 @@ static int carl9170_register_hwrng(struct ar9170 *ar)
 	ar->rng.rng.data_read = carl9170_rng_read;
 	ar->rng.rng.priv = (unsigned long)ar;
 
-	if (WARN_ON(ar->rng.initialized))
-		return -EALREADY;
-
-	err = hwrng_register(&ar->rng.rng);
+	err = devm_hwrng_register(&ar->udev->dev, &ar->rng.rng);
 	if (err) {
 		dev_err(&ar->udev->dev, "Failed to register the random "
 			"number generator (%d)\n", err);
 		return err;
 	}
 
-	ar->rng.initialized = true;
-
-	err = carl9170_rng_get(ar);
-	if (err) {
-		carl9170_unregister_hwrng(ar);
-		return err;
-	}
-
-	return 0;
+	return carl9170_rng_get(ar);
 }
 #endif /* CONFIG_CARL9170_HWRNG */
 
@@ -2064,10 +2045,6 @@ void carl9170_unregister(struct ar9170 *ar)
 	}
 #endif /* CONFIG_CARL9170_WPC */
 
-#ifdef CONFIG_CARL9170_HWRNG
-	carl9170_unregister_hwrng(ar);
-#endif /* CONFIG_CARL9170_HWRNG */
-
 	carl9170_cancel_worker(ar);
 	cancel_work_sync(&ar->restart_work);