Re: [PATCH] watchdog_dev: Use device tree alias for naming watchdogs

From: Guenter Roeck
Date: Wed Sep 02 2015 - 16:19:27 EST


Hi Justin,

On Wed, Sep 02, 2015 at 11:00:17AM -0700, Justin Chen wrote:
> Currently there is no way to easily differentiate multiple
> watchdog devices. The watchdogs are named by the order they
> are probed.
> 1st probed watchdog: /dev/watchdog0
> 2nd probed watchdog: /dev/watchdog1
> ...
>
> This change uses the alias of the watchdog device node for
> the name of the watchdog.
> aliases {
> watchdog0 = "/...../...."
> watchdog3 = "/..../....."
> watchdog2 = "/..../....."
> ...
> }
>
> This will translate to...
> /dev/watchdog0
> /dev/watchdog3
> /dev/watchdog2
>
> v2
> Assign alias number to id in watchdog_core instead of watchdog_dev.
> If failed to get id, fallback to original ida_simple_get call.
>
> Signed-off-by: Justin Chen <justinpopo6@xxxxxxxxx>

Minor nitpick: the changelog should be after the '---'.

Other than that, I really like it. Well done.

Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>

Thanks,
Guenter

> ---
> drivers/watchdog/watchdog_core.c | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
> index 1a80594..873f139 100644
> --- a/drivers/watchdog/watchdog_core.c
> +++ b/drivers/watchdog/watchdog_core.c
> @@ -139,7 +139,7 @@ EXPORT_SYMBOL_GPL(watchdog_init_timeout);
>
> static int __watchdog_register_device(struct watchdog_device *wdd)
> {
> - int ret, id, devno;
> + int ret, id = -1, devno;
>
> if (wdd == NULL || wdd->info == NULL || wdd->ops == NULL)
> return -EINVAL;
> @@ -157,7 +157,18 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
> */
>
> mutex_init(&wdd->lock);
> - id = ida_simple_get(&watchdog_ida, 0, MAX_DOGS, GFP_KERNEL);
> +
> + /* Use alias for watchdog id if possible */
> + if (wdd->parent) {
> + ret = of_alias_get_id(wdd->parent->of_node, "watchdog");
> + if (ret >= 0)
> + id = ida_simple_get(&watchdog_ida, ret,
> + ret + 1, GFP_KERNEL);
> + }
> +
> + if (id < 0)
> + id = ida_simple_get(&watchdog_ida, 0, MAX_DOGS, GFP_KERNEL);
> +
> if (id < 0)
> return id;
> wdd->id = id;
> --
> 2.1.0
>
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