Re: [RFC v2 1/4] drm: Add support to find drm_panel by name

[Jani Nikula <jani.nikula@intel.com>]

On Fri, 02 Jan 2015, Shobhit Kumar <shobhit.kumar@intel.com> wrote:
> For scenarios where OF is not available, we can use panel identification by
> name.
>
> Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
> ---
>  drivers/gpu/drm/drm_panel.c | 18 ++++++++++++++++++
>  include/drm/drm_panel.h     |  3 +++
>  2 files changed, 21 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
> index 2ef988e..773ebd6 100644
> --- a/drivers/gpu/drm/drm_panel.c
> +++ b/drivers/gpu/drm/drm_panel.c
> @@ -95,6 +95,24 @@ struct drm_panel *of_drm_find_panel(struct device_node *np)
>  EXPORT_SYMBOL(of_drm_find_panel);
>  #endif
>  
> +struct drm_panel *name_drm_find_panel(const char *name)
> +{
> +	struct drm_panel *panel;
> +
> +	mutex_lock(&panel_lock);
> +
> +	list_for_each_entry(panel, &panel_list, list) {
> +		if (strcmp(panel->name, name) == 0) {
> +			mutex_unlock(&panel_lock);
> +			return panel;
> +		}
> +	}
> +
> +	mutex_unlock(&panel_lock);
> +	return NULL;
> +}
> +EXPORT_SYMBOL(name_drm_find_panel);

This patch needs to be sent to drm-devel.

The name should probably be something like drm_find_panel_by_name.

I have a slightly uneasy feeling about handing out drm_panel pointers
(both from here and of_drm_find_panel) without refcounting. If the panel
driver gets removed, whoever called the find functions will have a
dangling pointer. I supposed this will be discussed on drm-devel.

BR,
Jani.

> +
>  MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
>  MODULE_DESCRIPTION("DRM panel infrastructure");
>  MODULE_LICENSE("GPL and additional rights");
> diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
> index 1fbcc96..b120b5d 100644
> --- a/include/drm/drm_panel.h
> +++ b/include/drm/drm_panel.h
> @@ -74,6 +74,7 @@ struct drm_panel {
>  	struct drm_device *drm;
>  	struct drm_connector *connector;
>  	struct device *dev;
> +	char name[NAME_MAX];
>  
>  	const struct drm_panel_funcs *funcs;
>  
> @@ -137,4 +138,6 @@ static inline struct drm_panel *of_drm_find_panel(struct device_node *np)
>  }
>  #endif
>  
> +struct drm_panel *name_drm_find_panel(const char *name);
> +
>  #endif
> -- 
> 1.9.1
>

-- 
Jani Nikula, Intel Open Source Technology Center
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