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From: Wolfram Sang <wsa+renesas@sang-engineering.com>
To: linux-watchdog@vger.kernel.org
Cc: linux-renesas-soc@vger.kernel.org,
	Guenter Roeck <linux@roeck-us.net>,
	Wolfram Sang <wsa+renesas@sang-engineering.com>,
	Wim Van Sebroeck <wim@linux-watchdog.org>,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2 01/16] watchdog: refactor watchdog_init_timeout
Date: Tue, 16 Apr 2019 12:25:00 +0200
Message-ID: <20190416102515.12269-2-wsa+renesas@sang-engineering.com> (raw)
In-Reply-To: <20190416102515.12269-1-wsa+renesas@sang-engineering.com>

The function is not easy to read and has a problem: -EINVAL is returned
when the module parameter is invalid but the DT parameter is OK.

Refactor the code to have the same pattern of checks for the module
parameter and DT. Further ones can be easily added in the future if the
need arises. The above mentioned problem is fixed, too.

Some documentation is added to describe the different handlings of '0'
for the module parameter and the DT property.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 drivers/watchdog/watchdog_core.c | 33 +++++++++++++++++++--------------
 1 file changed, 19 insertions(+), 14 deletions(-)

diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
index eb8fa25f8eb2..21e53cc49977 100644
--- a/drivers/watchdog/watchdog_core.c
+++ b/drivers/watchdog/watchdog_core.c
@@ -105,9 +105,12 @@ static void watchdog_check_min_max_timeout(struct watchdog_device *wdd)
  * timeout module parameter (if it is valid value) or the timeout-sec property
  * (only if it is a valid value and the timeout_parm is out of bounds).
  * If none of them are valid then we keep the old value (which should normally
- * be the default timeout value).
+ * be the default timeout value). Note that for the module parameter, '0' means
+ * 'use default' while it is an invalid value for the timeout-sec property.
+ * It should simply be dropped if you want to use the default value then.
  *
- * A zero is returned on success and -EINVAL for failure.
+ * A zero is returned on success or -EINVAL if all provided values are out of
+ * bounds.
  */
 int watchdog_init_timeout(struct watchdog_device *wdd,
 				unsigned int timeout_parm, struct device *dev)
@@ -117,22 +120,24 @@ int watchdog_init_timeout(struct watchdog_device *wdd,
 
 	watchdog_check_min_max_timeout(wdd);
 
-	/* try to get the timeout module parameter first */
-	if (!watchdog_timeout_invalid(wdd, timeout_parm) && timeout_parm) {
-		wdd->timeout = timeout_parm;
-		return ret;
-	}
-	if (timeout_parm)
+	/* check the driver supplied value (likely a module parameter) first */
+	if (timeout_parm) {
+		if (!watchdog_timeout_invalid(wdd, timeout_parm)) {
+			wdd->timeout = timeout_parm;
+			return 0;
+		}
 		ret = -EINVAL;
+	}
 
 	/* try to get the timeout_sec property */
-	if (dev == NULL || dev->of_node == NULL)
-		return ret;
-	of_property_read_u32(dev->of_node, "timeout-sec", &t);
-	if (!watchdog_timeout_invalid(wdd, t) && t)
-		wdd->timeout = t;
-	else
+	if (dev && dev->of_node &&
+	    of_property_read_u32(dev->of_node, "timeout-sec", &t) == 0) {
+		if (t && !watchdog_timeout_invalid(wdd, t)) {
+			wdd->timeout = t;
+			return 0;
+		}
 		ret = -EINVAL;
+	}
 
 	return ret;
 }
-- 
2.11.0


  reply index

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-16 10:24 [PATCH v2 00/16] watchdog: refactor init_timeout and update users Wolfram Sang
2019-04-16 10:25 ` Wolfram Sang [this message]
2019-04-16 13:23   ` [PATCH v2 01/16] watchdog: refactor watchdog_init_timeout Guenter Roeck
2019-04-16 10:25 ` [PATCH v2 02/16] watchdog: add error messages when initializing timeout fails Wolfram Sang
2019-04-16 10:25 ` [PATCH v2 03/16] watchdog: cadence_wdt: drop warning after calling watchdog_init_timeout Wolfram Sang
2019-04-16 10:25 ` [PATCH v2 04/16] watchdog: cadence_wdt: still probe if user supplied timeout is invalid Wolfram Sang
2019-04-16 10:25 ` [PATCH v2 05/16] watchdog: ebc-c384_wdt: drop warning after calling watchdog_init_timeout Wolfram Sang
2019-04-16 10:28   ` William Breathitt Gray
2019-04-16 10:25 ` [PATCH v2 06/16] watchdog: hpwdt: " Wolfram Sang
2019-04-16 20:34   ` Jerry Hoemann
2019-04-16 20:48     ` Guenter Roeck
2019-04-16 20:55       ` Wolfram Sang
2019-04-16 21:20         ` Guenter Roeck
2019-04-16 22:17           ` Wolfram Sang
2019-04-16 22:38             ` Guenter Roeck
2019-04-17 19:45               ` Wolfram Sang
2019-04-17 20:17                 ` Guenter Roeck
2019-04-17 21:18                   ` Wolfram Sang
2019-04-17 22:00                     ` Guenter Roeck
2019-04-24  8:38                 ` Geert Uytterhoeven
2019-04-24 12:57                   ` Guenter Roeck
2019-04-16 20:50     ` Wolfram Sang
2019-04-16 21:14       ` Guenter Roeck
2019-04-16 10:25 ` [PATCH v2 07/16] watchdog: i6300esb: " Wolfram Sang
2019-04-16 10:25 ` [PATCH v2 08/16] watchdog: imx_sc_wdt: " Wolfram Sang
2019-04-16 10:25 ` [PATCH v2 09/16] watchdog: ni903x_wdt: " Wolfram Sang
2019-04-16 10:25 ` [PATCH v2 10/16] watchdog: nic7018_wdt: " Wolfram Sang
2019-04-16 10:25 ` [PATCH v2 11/16] watchdog: renesas_wdt: " Wolfram Sang
2019-04-16 10:25 ` [PATCH v2 12/16] watchdog: sp5100_tco: " Wolfram Sang
2019-04-16 10:25 ` [PATCH v2 13/16] watchdog: st_lpc_wdt: " Wolfram Sang
2019-04-16 10:25 ` [PATCH v2 14/16] watchdog: stm32_iwdg: " Wolfram Sang
2019-04-16 10:25 ` [PATCH v2 15/16] watchdog: xen_wdt: " Wolfram Sang
2019-04-16 10:25 ` [PATCH v2 16/16] watchdog: ziirave_wdt: " Wolfram Sang

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