Nouveau - Oct 2022 - [PATCH v5 12/22] drm/connector: Add a function to lookup a TV mode by its name

Den 13.10.2022 15.18, skrev Maxime Ripard:
> As part of the command line parsing rework coming in the next patches,
> we'll need to lookup drm_connector_tv_mode values by their name,
already
> defined in drm_tv_mode_enum_list.
> 
> In order to avoid any code duplication, let's do a function that will
> perform a lookup of a TV mode name and return its value.
> 
> Signed-off-by: Maxime Ripard <maxime at cerno.tech>
> ---
>  drivers/gpu/drm/drm_connector.c | 24 ++++++++++++++++++++++++
>  include/drm/drm_connector.h     |  2 ++
>  2 files changed, 26 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_connector.c
b/drivers/gpu/drm/drm_connector.c
> index 820f4c730b38..30611c616435 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
> @@ -991,6 +991,30 @@ static const struct drm_prop_enum_list
drm_tv_mode_enum_list[] = {
>  };
>  DRM_ENUM_NAME_FN(drm_get_tv_mode_name, drm_tv_mode_enum_list)
>  
> +/**
> + * drm_get_tv_mode_from_name - Translates a TV mode name into its enum
value
> + * @name: TV Mode name we want to convert
> + * @len: Length of @name
> + *
> + * Translates @name into an enum drm_connector_tv_mode.
> + *
> + * Returns: the enum value on success, a negative errno otherwise.
> + */
> +int drm_get_tv_mode_from_name(const char *name, size_t len)
Do we really need to pass in length here?
item->name has to always be NUL terminated otherwise things would break
elsewhere, so it shouldn't be necessary AFAICS.

Noralf.
> +{
> +	unsigned int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(drm_tv_mode_enum_list); i++) {
> +		const struct drm_prop_enum_list *item = &drm_tv_mode_enum_list[i];
> +
> +		if (strlen(item->name) == len && !strncmp(item->name,
name, len))
> +			return item->type;
> +	}
> +
> +	return -EINVAL;
> +}
> +EXPORT_SYMBOL(drm_get_tv_mode_from_name);
> +
>  static const struct drm_prop_enum_list drm_tv_select_enum_list[] = {
>  	{ DRM_MODE_SUBCONNECTOR_Automatic, "Automatic" }, /* DVI-I and
TV-out */
>  	{ DRM_MODE_SUBCONNECTOR_Composite, "Composite" }, /* TV-out */
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index a501db7d2222..a33f24a76738 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -1864,6 +1864,8 @@ const char *drm_get_dp_subconnector_name(int val);
>  const char *drm_get_content_protection_name(int val);
>  const char *drm_get_hdcp_content_type_name(int val);
>  
> +int drm_get_tv_mode_from_name(const char *name, size_t len);
> +
>  int drm_mode_create_dvi_i_properties(struct drm_device *dev);
>  void drm_connector_attach_dp_subconnector_property(struct drm_connector
*connector);
>  
>

On Mon, Oct 17, 2022 at 12:44:45PM +0200, Noralf Tr?nnes
wrote:
> Den 13.10.2022 15.18, skrev Maxime Ripard:
> > As part of the command line parsing rework coming in the next patches,
> > we'll need to lookup drm_connector_tv_mode values by their name,
already
> > defined in drm_tv_mode_enum_list.
> > 
> > In order to avoid any code duplication, let's do a function that
will
> > perform a lookup of a TV mode name and return its value.
> > 
> > Signed-off-by: Maxime Ripard <maxime at cerno.tech>
> > ---
> >  drivers/gpu/drm/drm_connector.c | 24 ++++++++++++++++++++++++
> >  include/drm/drm_connector.h     |  2 ++
> >  2 files changed, 26 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_connector.c
b/drivers/gpu/drm/drm_connector.c
> > index 820f4c730b38..30611c616435 100644
> > --- a/drivers/gpu/drm/drm_connector.c
> > +++ b/drivers/gpu/drm/drm_connector.c
> > @@ -991,6 +991,30 @@ static const struct drm_prop_enum_list
drm_tv_mode_enum_list[] = {
> >  };
> >  DRM_ENUM_NAME_FN(drm_get_tv_mode_name, drm_tv_mode_enum_list)
> >  
> > +/**
> > + * drm_get_tv_mode_from_name - Translates a TV mode name into its
enum value
> > + * @name: TV Mode name we want to convert
> > + * @len: Length of @name
> > + *
> > + * Translates @name into an enum drm_connector_tv_mode.
> > + *
> > + * Returns: the enum value on success, a negative errno otherwise.
> > + */
> > +int drm_get_tv_mode_from_name(const char *name, size_t len)
> 
> Do we really need to pass in length here? item->name has to always be
> NUL terminated otherwise things would break elsewhere, so it shouldn't
> be necessary AFAICS.
The only user so far is the command-line parsing code, and we might very
well have an option after the tv_mode, something like
720x480i,tv_mode=NTSC,rotate=180

In this case, we won't get a NULL-terminated name.

Maxime