On Mon, Aug 5, 2024 at 12:19 PM Herve Codina <herve.codina@xxxxxxxxxxx> wrote:
>
> From: Clément Léger <clement.leger@xxxxxxxxxxx>
>
> Syscon releasing is not supported.
> Without release function, unbinding a driver that uses syscon whether
> explicitly or due to a module removal left the used syscon in a in-use
> state.
>
> For instance a syscon_node_to_regmap() call from a consumer retrieve a
retrieves?
> syscon regmap instance. Internally, syscon_node_to_regmap() can create
> syscon instance and add it to the existing syscon list. No API is
> available to release this syscon instance, remove it from the list and
> free it when it is not used anymore.
>
> Introduce reference counting in syscon in order to keep track of syscon
> usage using syscon_{get,put}() and add a device managed version of
> syscon_regmap_lookup_by_phandle(), to automatically release the syscon
> instance on the consumer removal.
...
> - if (!syscon)
> + if (!syscon) {
> syscon = of_syscon_register(np, check_res);
> + if (IS_ERR(syscon))
> + return ERR_CAST(syscon);
> + } else {
> + syscon_get(syscon);
> + }
if (syscon)
return syscon_get();
?
> + return syscon;
...
> +static struct regmap *__devm_syscon_get(struct device *dev,
> + struct syscon *syscon)
> +{
> + struct syscon **ptr;
> +
> + if (IS_ERR(syscon))
> + return ERR_CAST(syscon);
> +
> + ptr = devres_alloc(devm_syscon_release, sizeof(struct syscon *), GFP_KERNEL);
> + if (!ptr) {
> + syscon_put(syscon);
> + return ERR_PTR(-ENOMEM);
> + }
> +
> + *ptr = syscon;
> + devres_add(dev, ptr);
> +
> + return syscon->regmap;
Can't the devm_add_action_or_reset() be used in this case? If so,
perhaps a comment to explain why?
> +}
--
With Best Regards,
Andy Shevchenko
