Re: [PATCH v2 4/4] watchdog: jz4740: Make probe function __init_or_module

From: Paul Cercueil
Date: Sat Jun 08 2019 - 06:01:50 EST

Hi Christophe,

Le sam. 8 juin 2019 à 9:51, Christophe Leroy <christophe.leroy@xxxxxx> a écrit :
Hi Paul,

Le 07/06/2019 à 18:24, Paul Cercueil a écrit :
This allows the probe function to be dropped after the kernel finished
its initialization, in the case where the driver was not compiled as a

I'm not sure that's what __init_or_module flag does.

As far as I understand, this flag makes the function being dropped only when the kernel is built without modules support, ie without CONFIG_MODULES. See

So it doesn't depend on the driver being built-in or compiled as a module?

In addition, I'm not sure you can simply define a probe function as __init. What if someone tries to unbind and rebind the device through sysfs for instance ?

Ouch. I feel stupid now.

It seems there is a special function called __platform_driver_probe() for registering devices when the probe function is to be in __init, see

Yes, but only usable by drivers that won't defer probe, and it removes the bind/unbind attributes from sysfs,
so it shouldn't be used for non-critical drivers, I think.


Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>

v2: New patch

drivers/watchdog/jz4740_wdt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/watchdog/jz4740_wdt.c b/drivers/watchdog/jz4740_wdt.c
index 7519d80c5d05..2061788c1939 100644
--- a/drivers/watchdog/jz4740_wdt.c
+++ b/drivers/watchdog/jz4740_wdt.c
@@ -157,7 +157,7 @@ static const struct of_device_id jz4740_wdt_of_matches[] = {
MODULE_DEVICE_TABLE(of, jz4740_wdt_of_matches);
-static int jz4740_wdt_probe(struct platform_device *pdev)
+static int __init_or_module jz4740_wdt_probe(struct platform_device *pdev)
struct device *dev = &pdev->dev;
struct jz4740_wdt_drvdata *drvdata;