Re: [PATCH v8 1/4] drm/panel: Add helper for reading DT rotation

On Mon, Oct 7, 2019 at 9:38 AM Sean Paul sean@poorly.run wrote:

On Wed, Sep 25, 2019 at 03:58:30PM -0700, Derek Basehore wrote:

...

This adds a helper function for reading the rotation (panel orientation) from the device tree.

Signed-off-by: Derek Basehore dbasehore@chromium.org Reviewed-by: Sam Ravnborg sam@ravnborg.org

The patch LGTM, but I don't see it used anywhere later in the patch? Is there a panel driver incoming?

Yeah, the boe-tv101wum-nl6 panel will use it. It's not in the patch currently sent upstream since I don't want to step on their toes, but I plan on sending a patch to add it as soon as that is merged.

I could hold back on this patch until that panel driver is merged too. Another alternative is to throw this into the generic drm_panel code, but there's no obvious place to put it since DRM seems to leave reading the DTS up to the panel drivers themselves.

Sean

...

---

drivers/gpu/drm/drm_panel.c | 43 +++++++++++++++++++++++++++++++++++++ include/drm/drm_panel.h | 9 ++++++++ 2 files changed, 52 insertions(+)

diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c index 6b0bf42039cf..0909b53b74e6 100644 --- a/drivers/gpu/drm/drm_panel.c +++ b/drivers/gpu/drm/drm_panel.c @@ -264,6 +264,49 @@ struct drm_panel *of_drm_find_panel(const struct device_node *np) return ERR_PTR(-EPROBE_DEFER); } EXPORT_SYMBOL(of_drm_find_panel);

+/**

• • of_drm_get_panel_orientation - look up the orientation of the panel through
• • the "rotation" binding from a device tree node
• • @np: device tree node of the panel
• • @orientation: orientation enum to be filled in
• • Looks up the rotation of a panel in the device tree. The orientation of the
• • panel is expressed as a property name "rotation" in the device tree. The
• • rotation in the device tree is counter clockwise.
• • Return: 0 when a valid rotation value (0, 90, 180, or 270) is read or the
• • rotation property doesn't exist. -EERROR otherwise.
• */

+int of_drm_get_panel_orientation(const struct device_node *np,

•                          enum drm_panel_orientation *orientation)
  

+{

• int rotation, ret;
  

• ret = of_property_read_u32(np, "rotation", &rotation);
  

• if (ret == -EINVAL) {
  

•         /* Don't return an error if there's no rotation property. */
  

•         *orientation = DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
  

•         return 0;
  

• }
  

• if (ret < 0)
  

•         return ret;
  

• if (rotation == 0)
  

•         *orientation = DRM_MODE_PANEL_ORIENTATION_NORMAL;
  

• else if (rotation == 90)
  

•         *orientation = DRM_MODE_PANEL_ORIENTATION_RIGHT_UP;
  

• else if (rotation == 180)
  

•         *orientation = DRM_MODE_PANEL_ORIENTATION_BOTTOM_UP;
  

• else if (rotation == 270)
  

•         *orientation = DRM_MODE_PANEL_ORIENTATION_LEFT_UP;
  

• else
  

•         return -EINVAL;
  

• return 0;
  

+} +EXPORT_SYMBOL(of_drm_get_panel_orientation); #endif

MODULE_AUTHOR("Thierry Reding treding@nvidia.com"); diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h index 624bd15ecfab..d16158deacdc 100644 --- a/include/drm/drm_panel.h +++ b/include/drm/drm_panel.h @@ -34,6 +34,8 @@ struct drm_device; struct drm_panel; struct display_timing;

+enum drm_panel_orientation;

/**

• struct drm_panel_funcs - perform operations on a given panel

@@ -165,11 +167,18 @@ int drm_panel_get_modes(struct drm_panel *panel);

#if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL) struct drm_panel *of_drm_find_panel(const struct device_node *np); +int of_drm_get_panel_orientation(const struct device_node *np,

•                          enum drm_panel_orientation *orientation);
  

#else static inline struct drm_panel *of_drm_find_panel(const struct device_node *np) { return ERR_PTR(-ENODEV); } +static inline int of_drm_get_panel_orientation(const struct device_node *np,

•         enum drm_panel_orientation *orientation)
  

+{

• return -ENODEV;
  

+} #endif

#endif

2.23.0.351.gc4317032e6-goog

-- Sean Paul, Software Engineer, Google / Chromium OS