All of lore.kernel.org
 help / color / mirror / Atom feed
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: Neil Armstrong <narmstrong@baylibre.com>,
	David Airlie <airlied@linux.ie>,
	dri-devel@lists.freedesktop.org,
	Thierry Reding <thierry.reding@gmail.com>,
	linux-samsung-soc@vger.kernel.org,
	linux-rockchip@lists.infradead.org,
	Tomi Valkeinen <tomi.valkeinen@ti.com>,
	NXP Linux Team <linux-imx@nxp.com>,
	Jagan Teki <jagan@amarulasolutions.com>,
	Jitao Shi <jitao.shi@mediatek.com>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	linux-mediatek@lists.infradead.org,
	Abhinav Kumar <abhinavk@codeaurora.org>,
	linux-tegra@vger.kernel.org, Sean Paul <sean@poorly.run>,
	linux-arm-kernel@lists.infradead.org,
	Purism Kernel Team <kernel@puri.sm>,
	linux-renesas-soc@vger.kernel.org,
	Boris Brezillon <boris.brezillon@collabora.com>
Subject: Re: [PATCH v2 01/25] drm/drm_panel: no error when no callback
Date: Mon, 9 Dec 2019 02:50:18 +0200	[thread overview]
Message-ID: <20191209005018.GJ14311@pendragon.ideasonboard.com> (raw)
In-Reply-To: <20191207140353.23967-2-sam@ravnborg.org>

Hi Sam,

Thank you for the patch.

On Sat, Dec 07, 2019 at 03:03:29PM +0100, Sam Ravnborg wrote:
> The callbacks in drm_panel_funcs are optional, so do not
> return an error just because no callback is assigned.
> 
> v2:
> - Document what functions in drm_panel_funcs are optional (Laurent)
> - Return -EOPNOTSUPP if get_modes() is not assigned (Laurent)
>   (Sam: -EOPNOTSUPP seems to best error code in this situation)
> 
> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Maxime Ripard <mripard@kernel.org>
> Cc: Thierry Reding <thierry.reding@gmail.com>
> Cc: Sam Ravnborg <sam@ravnborg.org>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> ---
>  drivers/gpu/drm/drm_panel.c | 35 +++++++++++++++++++++++++----------
>  include/drm/drm_panel.h     | 18 ++++++++++++++++--
>  2 files changed, 41 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
> index ed7985c0535a..4ab7229fb22b 100644
> --- a/drivers/gpu/drm/drm_panel.c
> +++ b/drivers/gpu/drm/drm_panel.c
> @@ -151,10 +151,13 @@ EXPORT_SYMBOL(drm_panel_detach);
>   */
>  int drm_panel_prepare(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->prepare)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->prepare)
>  		return panel->funcs->prepare(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return 0;
>  }
>  EXPORT_SYMBOL(drm_panel_prepare);
>  
> @@ -171,10 +174,13 @@ EXPORT_SYMBOL(drm_panel_prepare);
>   */
>  int drm_panel_unprepare(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->unprepare)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->unprepare)
>  		return panel->funcs->unprepare(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return 0;
>  }
>  EXPORT_SYMBOL(drm_panel_unprepare);
>  
> @@ -190,10 +196,13 @@ EXPORT_SYMBOL(drm_panel_unprepare);
>   */
>  int drm_panel_enable(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->enable)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->enable)
>  		return panel->funcs->enable(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return 0;
>  }
>  EXPORT_SYMBOL(drm_panel_enable);
>  
> @@ -209,10 +218,13 @@ EXPORT_SYMBOL(drm_panel_enable);
>   */
>  int drm_panel_disable(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->disable)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->disable)
>  		return panel->funcs->disable(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return 0;
>  }
>  EXPORT_SYMBOL(drm_panel_disable);
>  
> @@ -228,10 +240,13 @@ EXPORT_SYMBOL(drm_panel_disable);
>   */
>  int drm_panel_get_modes(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->get_modes)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->get_modes)
>  		return panel->funcs->get_modes(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return -EOPNOTSUPP;
>  }
>  EXPORT_SYMBOL(drm_panel_get_modes);
>  
> diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
> index ce8da64022b4..d71655b2634c 100644
> --- a/include/drm/drm_panel.h
> +++ b/include/drm/drm_panel.h
> @@ -65,6 +65,8 @@ struct drm_panel_funcs {
>  	 * @prepare:
>  	 *
>  	 * Turn on panel and perform set up.
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*prepare)(struct drm_panel *panel);
>  
> @@ -72,6 +74,8 @@ struct drm_panel_funcs {
>  	 * @enable:
>  	 *
>  	 * Enable panel (turn on back light, etc.).
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*enable)(struct drm_panel *panel);
>  
> @@ -79,6 +83,8 @@ struct drm_panel_funcs {
>  	 * @disable:
>  	 *
>  	 * Disable panel (turn off back light, etc.).
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*disable)(struct drm_panel *panel);
>  
> @@ -86,14 +92,20 @@ struct drm_panel_funcs {
>  	 * @unprepare:
>  	 *
>  	 * Turn off panel.
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*unprepare)(struct drm_panel *panel);
>  
>  	/**
>  	 * @get_modes:
>  	 *
> -	 * Add modes to the connector that the panel is attached to and
> -	 * return the number of modes added.
> +	 * Add modes to the connector that the panel is attached to.
> +	 *
> +	 * This function is mandatory.
> +	 *
> +	 * Returns the number of modes added, -EOPNOTSUPP if callback
> +	 * is missing, -EINVAL if panel is NULL.

This applies to drm_panel_get_modes, not &drm_panel_funcs.get_modes.
Here you should just have

 	 *
 	 * Add modes to the connector that the panel is attached to and
 	 * return the number of modes added.
+	 *
+	 * This function is mandatory.
 	 */
 	int (*get_modes)(struct drm_panel *panel);
 
>  	 */
>  	int (*get_modes)(struct drm_panel *panel);
>  
> @@ -102,6 +114,8 @@ struct drm_panel_funcs {
>  	 *
>  	 * Copy display timings into the provided array and return
>  	 * the number of display timings available.
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*get_timings)(struct drm_panel *panel, unsigned int num_timings,
>  			   struct display_timing *timings);

-- 
Regards,

Laurent Pinchart
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

WARNING: multiple messages have this Message-ID
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: dri-devel@lists.freedesktop.org,
	Thierry Reding <thierry.reding@gmail.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Abhinav Kumar <abhinavk@codeaurora.org>,
	Andrzej Hajda <a.hajda@samsung.com>,
	Benjamin Gaignard <benjamin.gaignard@linaro.org>,
	Boris Brezillon <boris.brezillon@collabora.com>,
	Daniel Vetter <daniel@ffwll.ch>, David Airlie <airlied@linux.ie>,
	Jagan Teki <jagan@amarulasolutions.com>,
	Jitao Shi <jitao.shi@mediatek.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org,
	linux-renesas-soc@vger.kernel.org,
	linux-rockchip@lists.infradead.org,
	linux-samsung-soc@vger.kernel.org, linux-tegra@vger.kernel.org,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Neil Armstrong <narmstrong@baylibre.com>,
	NXP Linux Team <linux-imx@nxp.com>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Purism Kernel Team <kernel@puri.sm>, Sean Paul <sean@poorly.run>,
	Stefan Agner <stefan@agner.ch>,
	Tomi Valkeinen <tomi.valkeinen@ti.com>
Subject: Re: [PATCH v2 01/25] drm/drm_panel: no error when no callback
Date: Mon, 9 Dec 2019 02:50:18 +0200	[thread overview]
Message-ID: <20191209005018.GJ14311@pendragon.ideasonboard.com> (raw)
In-Reply-To: <20191207140353.23967-2-sam@ravnborg.org>

Hi Sam,

Thank you for the patch.

On Sat, Dec 07, 2019 at 03:03:29PM +0100, Sam Ravnborg wrote:
> The callbacks in drm_panel_funcs are optional, so do not
> return an error just because no callback is assigned.
> 
> v2:
> - Document what functions in drm_panel_funcs are optional (Laurent)
> - Return -EOPNOTSUPP if get_modes() is not assigned (Laurent)
>   (Sam: -EOPNOTSUPP seems to best error code in this situation)
> 
> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Maxime Ripard <mripard@kernel.org>
> Cc: Thierry Reding <thierry.reding@gmail.com>
> Cc: Sam Ravnborg <sam@ravnborg.org>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> ---
>  drivers/gpu/drm/drm_panel.c | 35 +++++++++++++++++++++++++----------
>  include/drm/drm_panel.h     | 18 ++++++++++++++++--
>  2 files changed, 41 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
> index ed7985c0535a..4ab7229fb22b 100644
> --- a/drivers/gpu/drm/drm_panel.c
> +++ b/drivers/gpu/drm/drm_panel.c
> @@ -151,10 +151,13 @@ EXPORT_SYMBOL(drm_panel_detach);
>   */
>  int drm_panel_prepare(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->prepare)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->prepare)
>  		return panel->funcs->prepare(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return 0;
>  }
>  EXPORT_SYMBOL(drm_panel_prepare);
>  
> @@ -171,10 +174,13 @@ EXPORT_SYMBOL(drm_panel_prepare);
>   */
>  int drm_panel_unprepare(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->unprepare)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->unprepare)
>  		return panel->funcs->unprepare(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return 0;
>  }
>  EXPORT_SYMBOL(drm_panel_unprepare);
>  
> @@ -190,10 +196,13 @@ EXPORT_SYMBOL(drm_panel_unprepare);
>   */
>  int drm_panel_enable(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->enable)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->enable)
>  		return panel->funcs->enable(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return 0;
>  }
>  EXPORT_SYMBOL(drm_panel_enable);
>  
> @@ -209,10 +218,13 @@ EXPORT_SYMBOL(drm_panel_enable);
>   */
>  int drm_panel_disable(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->disable)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->disable)
>  		return panel->funcs->disable(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return 0;
>  }
>  EXPORT_SYMBOL(drm_panel_disable);
>  
> @@ -228,10 +240,13 @@ EXPORT_SYMBOL(drm_panel_disable);
>   */
>  int drm_panel_get_modes(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->get_modes)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->get_modes)
>  		return panel->funcs->get_modes(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return -EOPNOTSUPP;
>  }
>  EXPORT_SYMBOL(drm_panel_get_modes);
>  
> diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
> index ce8da64022b4..d71655b2634c 100644
> --- a/include/drm/drm_panel.h
> +++ b/include/drm/drm_panel.h
> @@ -65,6 +65,8 @@ struct drm_panel_funcs {
>  	 * @prepare:
>  	 *
>  	 * Turn on panel and perform set up.
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*prepare)(struct drm_panel *panel);
>  
> @@ -72,6 +74,8 @@ struct drm_panel_funcs {
>  	 * @enable:
>  	 *
>  	 * Enable panel (turn on back light, etc.).
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*enable)(struct drm_panel *panel);
>  
> @@ -79,6 +83,8 @@ struct drm_panel_funcs {
>  	 * @disable:
>  	 *
>  	 * Disable panel (turn off back light, etc.).
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*disable)(struct drm_panel *panel);
>  
> @@ -86,14 +92,20 @@ struct drm_panel_funcs {
>  	 * @unprepare:
>  	 *
>  	 * Turn off panel.
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*unprepare)(struct drm_panel *panel);
>  
>  	/**
>  	 * @get_modes:
>  	 *
> -	 * Add modes to the connector that the panel is attached to and
> -	 * return the number of modes added.
> +	 * Add modes to the connector that the panel is attached to.
> +	 *
> +	 * This function is mandatory.
> +	 *
> +	 * Returns the number of modes added, -EOPNOTSUPP if callback
> +	 * is missing, -EINVAL if panel is NULL.

This applies to drm_panel_get_modes, not &drm_panel_funcs.get_modes.
Here you should just have

 	 *
 	 * Add modes to the connector that the panel is attached to and
 	 * return the number of modes added.
+	 *
+	 * This function is mandatory.
 	 */
 	int (*get_modes)(struct drm_panel *panel);
 
>  	 */
>  	int (*get_modes)(struct drm_panel *panel);
>  
> @@ -102,6 +114,8 @@ struct drm_panel_funcs {
>  	 *
>  	 * Copy display timings into the provided array and return
>  	 * the number of display timings available.
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*get_timings)(struct drm_panel *panel, unsigned int num_timings,
>  			   struct display_timing *timings);

-- 
Regards,

Laurent Pinchart

WARNING: multiple messages have this Message-ID
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: Neil Armstrong <narmstrong@baylibre.com>,
	David Airlie <airlied@linux.ie>,
	Linus Walleij <linus.walleij@linaro.org>,
	dri-devel@lists.freedesktop.org,
	Andrzej Hajda <a.hajda@samsung.com>,
	Thierry Reding <thierry.reding@gmail.com>,
	Benjamin Gaignard <benjamin.gaignard@linaro.org>,
	Stefan Agner <stefan@agner.ch>,
	linux-samsung-soc@vger.kernel.org,
	linux-rockchip@lists.infradead.org,
	Tomi Valkeinen <tomi.valkeinen@ti.com>,
	NXP Linux Team <linux-imx@nxp.com>,
	Jagan Teki <jagan@amarulasolutions.com>,
	Jitao Shi <jitao.shi@mediatek.com>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	linux-mediatek@lists.infradead.org,
	Abhinav Kumar <abhinavk@codeaurora.org>,
	linux-tegra@vger.kernel.org, Sean Paul <sean@poorly.run>,
	linux-arm-kernel@lists.infradead.org,
	Purism Kernel Team <kernel@puri.sm>,
	linux-renesas-soc@vger.kernel.org,
	Boris Brezillon <boris.brezillon@collabora.com>,
	Daniel Vetter <daniel@ffwll.ch>
Subject: Re: [PATCH v2 01/25] drm/drm_panel: no error when no callback
Date: Mon, 9 Dec 2019 02:50:18 +0200	[thread overview]
Message-ID: <20191209005018.GJ14311@pendragon.ideasonboard.com> (raw)
In-Reply-To: <20191207140353.23967-2-sam@ravnborg.org>

Hi Sam,

Thank you for the patch.

On Sat, Dec 07, 2019 at 03:03:29PM +0100, Sam Ravnborg wrote:
> The callbacks in drm_panel_funcs are optional, so do not
> return an error just because no callback is assigned.
> 
> v2:
> - Document what functions in drm_panel_funcs are optional (Laurent)
> - Return -EOPNOTSUPP if get_modes() is not assigned (Laurent)
>   (Sam: -EOPNOTSUPP seems to best error code in this situation)
> 
> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Maxime Ripard <mripard@kernel.org>
> Cc: Thierry Reding <thierry.reding@gmail.com>
> Cc: Sam Ravnborg <sam@ravnborg.org>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> ---
>  drivers/gpu/drm/drm_panel.c | 35 +++++++++++++++++++++++++----------
>  include/drm/drm_panel.h     | 18 ++++++++++++++++--
>  2 files changed, 41 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
> index ed7985c0535a..4ab7229fb22b 100644
> --- a/drivers/gpu/drm/drm_panel.c
> +++ b/drivers/gpu/drm/drm_panel.c
> @@ -151,10 +151,13 @@ EXPORT_SYMBOL(drm_panel_detach);
>   */
>  int drm_panel_prepare(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->prepare)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->prepare)
>  		return panel->funcs->prepare(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return 0;
>  }
>  EXPORT_SYMBOL(drm_panel_prepare);
>  
> @@ -171,10 +174,13 @@ EXPORT_SYMBOL(drm_panel_prepare);
>   */
>  int drm_panel_unprepare(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->unprepare)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->unprepare)
>  		return panel->funcs->unprepare(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return 0;
>  }
>  EXPORT_SYMBOL(drm_panel_unprepare);
>  
> @@ -190,10 +196,13 @@ EXPORT_SYMBOL(drm_panel_unprepare);
>   */
>  int drm_panel_enable(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->enable)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->enable)
>  		return panel->funcs->enable(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return 0;
>  }
>  EXPORT_SYMBOL(drm_panel_enable);
>  
> @@ -209,10 +218,13 @@ EXPORT_SYMBOL(drm_panel_enable);
>   */
>  int drm_panel_disable(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->disable)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->disable)
>  		return panel->funcs->disable(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return 0;
>  }
>  EXPORT_SYMBOL(drm_panel_disable);
>  
> @@ -228,10 +240,13 @@ EXPORT_SYMBOL(drm_panel_disable);
>   */
>  int drm_panel_get_modes(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->get_modes)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->get_modes)
>  		return panel->funcs->get_modes(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return -EOPNOTSUPP;
>  }
>  EXPORT_SYMBOL(drm_panel_get_modes);
>  
> diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
> index ce8da64022b4..d71655b2634c 100644
> --- a/include/drm/drm_panel.h
> +++ b/include/drm/drm_panel.h
> @@ -65,6 +65,8 @@ struct drm_panel_funcs {
>  	 * @prepare:
>  	 *
>  	 * Turn on panel and perform set up.
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*prepare)(struct drm_panel *panel);
>  
> @@ -72,6 +74,8 @@ struct drm_panel_funcs {
>  	 * @enable:
>  	 *
>  	 * Enable panel (turn on back light, etc.).
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*enable)(struct drm_panel *panel);
>  
> @@ -79,6 +83,8 @@ struct drm_panel_funcs {
>  	 * @disable:
>  	 *
>  	 * Disable panel (turn off back light, etc.).
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*disable)(struct drm_panel *panel);
>  
> @@ -86,14 +92,20 @@ struct drm_panel_funcs {
>  	 * @unprepare:
>  	 *
>  	 * Turn off panel.
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*unprepare)(struct drm_panel *panel);
>  
>  	/**
>  	 * @get_modes:
>  	 *
> -	 * Add modes to the connector that the panel is attached to and
> -	 * return the number of modes added.
> +	 * Add modes to the connector that the panel is attached to.
> +	 *
> +	 * This function is mandatory.
> +	 *
> +	 * Returns the number of modes added, -EOPNOTSUPP if callback
> +	 * is missing, -EINVAL if panel is NULL.

This applies to drm_panel_get_modes, not &drm_panel_funcs.get_modes.
Here you should just have

 	 *
 	 * Add modes to the connector that the panel is attached to and
 	 * return the number of modes added.
+	 *
+	 * This function is mandatory.
 	 */
 	int (*get_modes)(struct drm_panel *panel);
 
>  	 */
>  	int (*get_modes)(struct drm_panel *panel);
>  
> @@ -102,6 +114,8 @@ struct drm_panel_funcs {
>  	 *
>  	 * Copy display timings into the provided array and return
>  	 * the number of display timings available.
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*get_timings)(struct drm_panel *panel, unsigned int num_timings,
>  			   struct display_timing *timings);

-- 
Regards,

Laurent Pinchart

_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek

WARNING: multiple messages have this Message-ID
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: Neil Armstrong <narmstrong@baylibre.com>,
	David Airlie <airlied@linux.ie>,
	Linus Walleij <linus.walleij@linaro.org>,
	dri-devel@lists.freedesktop.org,
	Andrzej Hajda <a.hajda@samsung.com>,
	Thierry Reding <thierry.reding@gmail.com>,
	Benjamin Gaignard <benjamin.gaignard@linaro.org>,
	Stefan Agner <stefan@agner.ch>,
	linux-samsung-soc@vger.kernel.org,
	linux-rockchip@lists.infradead.org,
	Tomi Valkeinen <tomi.valkeinen@ti.com>,
	NXP Linux Team <linux-imx@nxp.com>,
	Jagan Teki <jagan@amarulasolutions.com>,
	Jitao Shi <jitao.shi@mediatek.com>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	linux-mediatek@lists.infradead.org,
	Abhinav Kumar <abhinavk@codeaurora.org>,
	linux-tegra@vger.kernel.org, Sean Paul <sean@poorly.run>,
	linux-arm-kernel@lists.infradead.org,
	Purism Kernel Team <kernel@puri.sm>,
	linux-renesas-soc@vger.kernel.org,
	Boris Brezillon <boris.brezillon@collabora.com>,
	Daniel Vetter <daniel@ffwll.ch>
Subject: Re: [PATCH v2 01/25] drm/drm_panel: no error when no callback
Date: Mon, 9 Dec 2019 02:50:18 +0200	[thread overview]
Message-ID: <20191209005018.GJ14311@pendragon.ideasonboard.com> (raw)
In-Reply-To: <20191207140353.23967-2-sam@ravnborg.org>

Hi Sam,

Thank you for the patch.

On Sat, Dec 07, 2019 at 03:03:29PM +0100, Sam Ravnborg wrote:
> The callbacks in drm_panel_funcs are optional, so do not
> return an error just because no callback is assigned.
> 
> v2:
> - Document what functions in drm_panel_funcs are optional (Laurent)
> - Return -EOPNOTSUPP if get_modes() is not assigned (Laurent)
>   (Sam: -EOPNOTSUPP seems to best error code in this situation)
> 
> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Maxime Ripard <mripard@kernel.org>
> Cc: Thierry Reding <thierry.reding@gmail.com>
> Cc: Sam Ravnborg <sam@ravnborg.org>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> ---
>  drivers/gpu/drm/drm_panel.c | 35 +++++++++++++++++++++++++----------
>  include/drm/drm_panel.h     | 18 ++++++++++++++++--
>  2 files changed, 41 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
> index ed7985c0535a..4ab7229fb22b 100644
> --- a/drivers/gpu/drm/drm_panel.c
> +++ b/drivers/gpu/drm/drm_panel.c
> @@ -151,10 +151,13 @@ EXPORT_SYMBOL(drm_panel_detach);
>   */
>  int drm_panel_prepare(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->prepare)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->prepare)
>  		return panel->funcs->prepare(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return 0;
>  }
>  EXPORT_SYMBOL(drm_panel_prepare);
>  
> @@ -171,10 +174,13 @@ EXPORT_SYMBOL(drm_panel_prepare);
>   */
>  int drm_panel_unprepare(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->unprepare)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->unprepare)
>  		return panel->funcs->unprepare(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return 0;
>  }
>  EXPORT_SYMBOL(drm_panel_unprepare);
>  
> @@ -190,10 +196,13 @@ EXPORT_SYMBOL(drm_panel_unprepare);
>   */
>  int drm_panel_enable(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->enable)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->enable)
>  		return panel->funcs->enable(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return 0;
>  }
>  EXPORT_SYMBOL(drm_panel_enable);
>  
> @@ -209,10 +218,13 @@ EXPORT_SYMBOL(drm_panel_enable);
>   */
>  int drm_panel_disable(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->disable)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->disable)
>  		return panel->funcs->disable(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return 0;
>  }
>  EXPORT_SYMBOL(drm_panel_disable);
>  
> @@ -228,10 +240,13 @@ EXPORT_SYMBOL(drm_panel_disable);
>   */
>  int drm_panel_get_modes(struct drm_panel *panel)
>  {
> -	if (panel && panel->funcs && panel->funcs->get_modes)
> +	if (!panel)
> +		return -EINVAL;
> +
> +	if (panel->funcs && panel->funcs->get_modes)
>  		return panel->funcs->get_modes(panel);
>  
> -	return panel ? -ENOSYS : -EINVAL;
> +	return -EOPNOTSUPP;
>  }
>  EXPORT_SYMBOL(drm_panel_get_modes);
>  
> diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
> index ce8da64022b4..d71655b2634c 100644
> --- a/include/drm/drm_panel.h
> +++ b/include/drm/drm_panel.h
> @@ -65,6 +65,8 @@ struct drm_panel_funcs {
>  	 * @prepare:
>  	 *
>  	 * Turn on panel and perform set up.
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*prepare)(struct drm_panel *panel);
>  
> @@ -72,6 +74,8 @@ struct drm_panel_funcs {
>  	 * @enable:
>  	 *
>  	 * Enable panel (turn on back light, etc.).
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*enable)(struct drm_panel *panel);
>  
> @@ -79,6 +83,8 @@ struct drm_panel_funcs {
>  	 * @disable:
>  	 *
>  	 * Disable panel (turn off back light, etc.).
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*disable)(struct drm_panel *panel);
>  
> @@ -86,14 +92,20 @@ struct drm_panel_funcs {
>  	 * @unprepare:
>  	 *
>  	 * Turn off panel.
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*unprepare)(struct drm_panel *panel);
>  
>  	/**
>  	 * @get_modes:
>  	 *
> -	 * Add modes to the connector that the panel is attached to and
> -	 * return the number of modes added.
> +	 * Add modes to the connector that the panel is attached to.
> +	 *
> +	 * This function is mandatory.
> +	 *
> +	 * Returns the number of modes added, -EOPNOTSUPP if callback
> +	 * is missing, -EINVAL if panel is NULL.

This applies to drm_panel_get_modes, not &drm_panel_funcs.get_modes.
Here you should just have

 	 *
 	 * Add modes to the connector that the panel is attached to and
 	 * return the number of modes added.
+	 *
+	 * This function is mandatory.
 	 */
 	int (*get_modes)(struct drm_panel *panel);
 
>  	 */
>  	int (*get_modes)(struct drm_panel *panel);
>  
> @@ -102,6 +114,8 @@ struct drm_panel_funcs {
>  	 *
>  	 * Copy display timings into the provided array and return
>  	 * the number of display timings available.
> +	 *
> +	 * This function is optional.
>  	 */
>  	int (*get_timings)(struct drm_panel *panel, unsigned int num_timings,
>  			   struct display_timing *timings);

-- 
Regards,

Laurent Pinchart

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2019-12-09  0:50 UTC|newest]

Thread overview: 128+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-07 14:03 [PATCH v2 0/25] drm/panel infrastructure + backlight update Sam Ravnborg
2019-12-07 14:03 ` Sam Ravnborg
2019-12-07 14:03 ` Sam Ravnborg
2019-12-07 14:03 ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 01/25] drm/drm_panel: no error when no callback Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 19:08   ` Michał Mirosław
2019-12-08  8:41     ` Sam Ravnborg
2019-12-09  0:50   ` Laurent Pinchart [this message]
2019-12-09  0:50     ` Laurent Pinchart
2019-12-09  0:50     ` Laurent Pinchart
2019-12-09  0:50     ` Laurent Pinchart
2019-12-07 14:03 ` [PATCH v2 02/25] drm/panel: add backlight support Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-09  0:55   ` Laurent Pinchart
2019-12-09  0:55     ` Laurent Pinchart
2019-12-09  0:55     ` Laurent Pinchart
2019-12-09  0:55     ` Laurent Pinchart
2019-12-13 13:30   ` Linus Walleij
2019-12-13 13:30     ` Linus Walleij
2019-12-13 13:30     ` Linus Walleij
2019-12-13 13:30     ` Linus Walleij
2019-12-13 13:30     ` Linus Walleij
2019-12-07 14:03 ` [PATCH v2 03/25] drm/panel: simple: use drm_panel " Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 04/25] drm: get drm_bridge_panel connector via helper Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-10 14:48   ` [PATCH] drm/bridge: panel: export drm_panel_bridge_connector Mihail Atanassov
2019-12-10 14:48     ` Mihail Atanassov
2019-12-10 16:26     ` Laurent Pinchart
2019-12-10 16:26       ` Laurent Pinchart
2019-12-10 17:28       ` Mihail Atanassov
2019-12-10 17:28         ` Mihail Atanassov
2019-12-07 14:03 ` [PATCH v2 05/25] drm/panel: add drm_connector argument to get_modes() Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 06/25] drm/panel: decouple connector from drm_panel Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 07/25] drm/panel: drop drm_device " Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 08/25] drm/panel: feiyang-fy07024di26a30d: use drm_panel backlight support Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 09/25] drm/panel: ilitek-ili9881c: " Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 10/25] drm/panel: innolux-p079zca: " Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 11/25] drm/panel: kingdisplay-kd097d04: " Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 12/25] drm/panel: lvds: " Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 13/25] drm/panel: olimex-lcd-olinuxino: " Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 14/25] drm/panel: osd-osd101t2587-53ts: " Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 15/25] drm/panel: panasonic-vvx10f034n00: " Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 16/25] drm/panel: raydium-rm68200: " Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 17/25] drm/panel: rocktech-jh057n00900: " Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 18/25] drm/panel: ronbo-rb070d30: " Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 19/25] drm/panel: seiko-43wvf1g: " Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 20/25] drm/panel: sharp-lq101r1sx01: " Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 21/25] drm/panel: sharp-ls043t1le01: " Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 22/25] drm/panel: sitronix-st7701: " Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 23/25] drm/panel: sitronix-st7789v: " Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 24/25] drm/panel: tpo-td028ttec1: " Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03 ` [PATCH v2 25/25] drm/panel: tpo-tpg110: " Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-07 14:03   ` Sam Ravnborg
2019-12-09 22:04 ` [PATCH v2 0/25] drm/panel infrastructure + backlight update Sam Ravnborg
2019-12-09 22:04   ` Sam Ravnborg
2019-12-09 22:04   ` Sam Ravnborg
2019-12-09 22:04   ` Sam Ravnborg

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20191209005018.GJ14311@pendragon.ideasonboard.com \
    --to=laurent.pinchart@ideasonboard.com \
    --cc=abhinavk@codeaurora.org \
    --cc=airlied@linux.ie \
    --cc=boris.brezillon@collabora.com \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=jagan@amarulasolutions.com \
    --cc=jitao.shi@mediatek.com \
    --cc=kernel@pengutronix.de \
    --cc=kernel@puri.sm \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-imx@nxp.com \
    --cc=linux-mediatek@lists.infradead.org \
    --cc=linux-renesas-soc@vger.kernel.org \
    --cc=linux-rockchip@lists.infradead.org \
    --cc=linux-samsung-soc@vger.kernel.org \
    --cc=linux-tegra@vger.kernel.org \
    --cc=narmstrong@baylibre.com \
    --cc=sam@ravnborg.org \
    --cc=sean@poorly.run \
    --cc=thierry.reding@gmail.com \
    --cc=tomi.valkeinen@ti.com \
    --subject='Re: [PATCH v2 01/25] drm/drm_panel: no error when no callback' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.