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Subject[PATCH v4 3/7] drm: rcar-du: lvds: Get dual link configuration from DT
Date
For dual-LVDS configurations, it is now possible to mark the
DT port nodes for the sink with boolean properties (like
dual-lvds-even-pixels and dual-lvds-odd-pixels) to let drivers
know the encoders need to be configured in dual-LVDS mode.

Rework the implementation of rcar_lvds_parse_dt_companion
to make use of the DT markers while keeping backward
compatibility.

Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>

---
v3->v4:
* New patch extracted from patch:
"drm: rcar-du: lvds: Add dual-LVDS panels support"
---
drivers/gpu/drm/rcar-du/rcar_lvds.c | 56 +++++++++++++++++++++++++++++++------
1 file changed, 47 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
index 3cb0a83..6c1f171 100644
--- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
+++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
@@ -669,8 +669,10 @@ EXPORT_SYMBOL_GPL(rcar_lvds_dual_link);
static int rcar_lvds_parse_dt_companion(struct rcar_lvds *lvds)
{
const struct of_device_id *match;
- struct device_node *companion;
+ struct device_node *companion, *p0, *p1;
+ struct rcar_lvds *companion_lvds;
struct device *dev = lvds->dev;
+ int dual_link;
int ret = 0;

/* Locate the companion LVDS encoder for dual-link operation, if any. */
@@ -689,13 +691,55 @@ static int rcar_lvds_parse_dt_companion(struct rcar_lvds *lvds)
goto done;
}

+ /*
+ * We need to work out if the sink is expecting us to function in
+ * dual-link mode. We do this by looking at the DT port nodes we are
+ * connected to, if they are marked as expecting even pixels and
+ * odd pixels than we need to enable vertical stripe output.
+ */
+ p0 = of_graph_get_port_by_id(dev->of_node, 1);
+ p1 = of_graph_get_port_by_id(companion, 1);
+ dual_link = drm_of_lvds_get_dual_link_pixel_order(p0, p1);
+ of_node_put(p0);
+ of_node_put(p1);
+ if (dual_link >= DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS) {
+ lvds->dual_link = true;
+ } else if (lvds->next_bridge && lvds->next_bridge->timings) {
+ /*
+ * Early dual-link bridge specific implementations populate the
+ * timings field of drm_bridge, read the dual_link flag off the
+ * bridge directly for backward compatibility.
+ */
+ lvds->dual_link = lvds->next_bridge->timings->dual_link;
+ }
+
+ if (!lvds->dual_link) {
+ dev_dbg(dev, "Single-link configuration detected\n");
+ goto done;
+ }
+
lvds->companion = of_drm_find_bridge(companion);
if (!lvds->companion) {
ret = -EPROBE_DEFER;
goto done;
}

- dev_dbg(dev, "Found companion encoder %pOF\n", companion);
+ dev_dbg(dev,
+ "Dual-link configuration detected (companion encoder %pOF)\n",
+ companion);
+
+ companion_lvds = bridge_to_rcar_lvds(lvds->companion);
+
+ /*
+ * FIXME: We should not be messing with the companion encoder private
+ * data from the primary encoder, we should rather let the companion
+ * encoder work things out on its own. However, the companion encoder
+ * doesn't hold a reference to the primary encoder, and
+ * drm_of_lvds_get_dual_link_pixel_order needs to be given references
+ * to the output ports of both encoders, therefore leave it like this
+ * for the time being.
+ */
+ companion_lvds->dual_link = true;

done:
of_node_put(companion);
@@ -739,13 +783,7 @@ static int rcar_lvds_parse_dt(struct rcar_lvds *lvds)
if (ret)
goto done;

- if ((lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK) &&
- lvds->next_bridge)
- lvds->dual_link = lvds->next_bridge->timings
- ? lvds->next_bridge->timings->dual_link
- : false;
-
- if (lvds->dual_link)
+ if (lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK)
ret = rcar_lvds_parse_dt_companion(lvds);

done:
--
2.7.4
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