On 12/22/2015 07:33 AM, Damien Riegel wrote:
On Mon, Dec 21, 2015 at 03:28:39PM -0800, Guenter Roeck wrote:
On 12/21/2015 09:31 AM, Damien Riegel wrote:
On Sun, Dec 20, 2015 at 01:04:59PM -0800, Guenter Roeck wrote:
The watchdog character device is currently created in watchdog_dev.c,
and the watchdog device in watchdog_core.c. This results in
cross-dependencies, since device creation needs to know the watchdog
character device number as well as the watchdog class, both of which
reside in watchdog_dev.c.
Create the watchdog device in watchdog_dev.c to simplify the code.
Inspired by earlier patch set from Damien Riegel.
Hi Guenter,
The main purpose of my patch was to inverse the device creation and the
cdev registration to avoid a racy situation, bu you have dropped that in
this version. Is there a reason for that?
Every other driver I looked at does it in the same order (cdev first, device
second). I don't really know if doing it differently has any undesired
side effect, so I wanted to play safe.
It would help a lot if someone listening to this exchange can confirm
that it is ok to create the device first, followed by the character device.
The issue is that some drivers use watchdog_device->dev in their
watchdog_ops functions. With a quick grep, I could spot 3 examples:
- bcm2835_wdt_stop in bcm2835_wdt.c
- gpio_wdt_hwping in gpio_wdt.c
- a21_wdt_set_timeout in mena21_wdt.c
Maybe we should simply fix these drivers and keep watchdog_device->dev
for core internal usage?
Yes, I have been thinking about that - essentially move the ->dev pointer
to the internal data structure and either use pr_ functions in those drivers,
or save a pointer to the platform device (if available) and use it.
I think I'll start working on a follow-up patch set to do just that.
Guenter
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