Re: [PATCH v2 04/11] watchdog: rzg2l_wdt: Check return status of pm_runtime_put()

From: Guenter Roeck
Date: Wed Jan 31 2024 - 08:21:32 EST


On 1/31/24 03:00, claudiu beznea wrote:


On 31.01.2024 12:41, Biju Das wrote:
Hi Claudiu,

-----Original Message-----
From: claudiu beznea <claudiu.beznea@xxxxxxxxx>
Sent: Wednesday, January 31, 2024 10:36 AM
Subject: Re: [PATCH v2 04/11] watchdog: rzg2l_wdt: Check return status of
pm_runtime_put()

Hi, Biju,

On 31.01.2024 12:32, Biju Das wrote:
Hi Claudiu,

Thanks for the feedback.

-----Original Message-----
From: Claudiu <claudiu.beznea@xxxxxxxxx>
Sent: Wednesday, January 31, 2024 10:20 AM
Subject: [PATCH v2 04/11] watchdog: rzg2l_wdt: Check return status of
pm_runtime_put()

From: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>

pm_runtime_put() may return an error code. Check its return status.

Along with it the rzg2l_wdt_set_timeout() function was updated to
propagate the result of rzg2l_wdt_stop() to its caller.

Fixes: 2cbc5cd0b55f ("watchdog: Add Watchdog Timer driver for
RZ/G2L")
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
---

Changes in v2:
- propagate the return code of rzg2l_wdt_stop() to it's callers

drivers/watchdog/rzg2l_wdt.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/watchdog/rzg2l_wdt.c
b/drivers/watchdog/rzg2l_wdt.c index d87d4f50180c..7bce093316c4
100644
--- a/drivers/watchdog/rzg2l_wdt.c
+++ b/drivers/watchdog/rzg2l_wdt.c
@@ -144,9 +144,13 @@ static int rzg2l_wdt_start(struct
watchdog_device
*wdev) static int rzg2l_wdt_stop(struct watchdog_device *wdev) {
struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
+ int ret;

rzg2l_wdt_reset(priv);
- pm_runtime_put(wdev->parent);
+
+ ret = pm_runtime_put(wdev->parent);
+ if (ret < 0)
+ return ret;

Do we need to check the return code? So far we didn't hit this
condition.
If you are planning to do it, then just

return pm_runtime_put(wdev->parent);

pm_runtime_put() may return 1 if the device is suspended (which is not
considered error) as explained here:

Oops, I missed that discussion. Out of curiosity,
What watchdog framework/consumer is going to do with a
Non-error return value of 1?

Looking at this:
https://elixir.bootlin.com/linux/latest/source/drivers/watchdog/watchdog_dev.c#L809

it seems that the positive values are not considered errors thus, indeed,
we may return directly:

return pm_runtime_put();

Guenter,

With this (and previous discussion from [1]), are you OK to change it like:

return pm_runtime_put();


Instead of looking at the source, I would kindly ask you to look at the API.

Guenter