Re: [PATCH v2 2/2] gpu: host1x: Stop open-coding of_device_uevent()

[Rob Herring <robh@kernel.org>]

On Fri, Jun 09, 2023 at 05:56:34PM +0200, Miquel Raynal wrote:
> There is apparently no reasons to open-code of_device_uevent() besides:
> - The helper receives a struct device while we want to use the of_node
>   member of the struct device *parent*.
> - of_device_uevent() could not be called by modules because of a missing
>   EXPORT_SYMBOL*().
> 
> In practice, the former point is not very constraining, just calling
> of_device_uevent(dev->parent, ...) would have made the trick.
> 
> The latter point is more an observation rather than a real blocking
> point because nothing prevented of_uevent() (called by the inline
> function of_device_uevent()) to be exported to modules. In practice,
> this helper is now exported, so nothing prevent us from using
> of_device_uevent() anymore.
> 
> Let's use the core helper directly instead of open-coding it.
> 
> Cc: Thierry Reding <thierry.reding@gmail.com>
> Cc: David Airlie <airlied@gmail.com>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: Mikko Perttunen <mperttunen@nvidia.com>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Frank Rowand <frowand.list@gmail.com>
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> 
> ---
> 
> This patch depends on the changes performed earlier in the series under
> the drivers/of/ folder.
> ---
>  drivers/gpu/host1x/bus.c | 29 ++++++-----------------------
>  1 file changed, 6 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/gpu/host1x/bus.c b/drivers/gpu/host1x/bus.c
> index 4d16a3396c4a..dae589b83be1 100644
> --- a/drivers/gpu/host1x/bus.c
> +++ b/drivers/gpu/host1x/bus.c
> @@ -338,32 +338,15 @@ static int host1x_device_match(struct device *dev, struct device_driver *drv)
>  	return strcmp(dev_name(dev), drv->name) == 0;
>  }
>  
> +/*
> + * Note that this is really only needed for backwards compatibility
> + * with libdrm, which parses this information from sysfs and will
> + * fail if it can't find the OF_FULLNAME, specifically.
> + */
>  static int host1x_device_uevent(const struct device *dev,
>  				struct kobj_uevent_env *env)
>  {
> -	struct device_node *np = dev->parent->of_node;
> -	unsigned int count = 0;
> -	struct property *p;
> -	const char *compat;
> -
> -	/*
> -	 * This duplicates most of of_device_uevent(), but the latter cannot
> -	 * be called from modules and operates on dev->of_node, which is not
> -	 * available in this case.
> -	 *
> -	 * Note that this is really only needed for backwards compatibility
> -	 * with libdrm, which parses this information from sysfs and will
> -	 * fail if it can't find the OF_FULLNAME, specifically.
> -	 */
> -	add_uevent_var(env, "OF_NAME=%pOFn", np);
> -	add_uevent_var(env, "OF_FULLNAME=%pOF", np);
> -
> -	of_property_for_each_string(np, "compatible", p, compat) {
> -		add_uevent_var(env, "OF_COMPATIBLE_%u=%s", count, compat);
> -		count++;
> -	}
> -
> -	add_uevent_var(env, "OF_COMPATIBLE_N=%u", count);
> +	of_device_uevent((const struct device *)&dev->parent, env);

Why do you have the cast and the "&"?

Rob