[PATCH 4.19.y-cip 04/17] drm: rcar-du: lvds: Add support for dual-link mode


Biju Das <biju.das.jz@...>
 

From: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

commit fa440d870358fd01eeedd212a1ad918a3b2771d5 upstream.

In dual-link mode the LVDS0 encoder transmits even-numbered pixels, and
sends odd-numbered pixels to the LVDS1 encoder for transmission on a
separate link.

To implement support for this mode of operation, determine if the LVDS
connection operates in dual-link mode by querying the next device in the
pipeline, locate the companion encoder, and control it directly through
its bridge operations.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Tested-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
drivers/gpu/drm/rcar-du/rcar_lvds.c | 107 ++++++++++++++++++++++++----
drivers/gpu/drm/rcar-du/rcar_lvds.h | 5 ++
2 files changed, 99 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
index 067017d25993..0774bd00dfac 100644
--- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
+++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
@@ -65,6 +65,9 @@ struct rcar_lvds {

struct drm_display_mode display_mode;
enum rcar_lvds_mode mode;
+
+ struct drm_bridge *companion;
+ bool dual_link;
};

#define bridge_to_rcar_lvds(b) \
@@ -399,11 +402,6 @@ static void rcar_lvds_enable(struct drm_bridge *bridge)
{
struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
const struct drm_display_mode *mode = &lvds->display_mode;
- /*
- * FIXME: We should really retrieve the CRTC through the state, but how
- * do we get a state pointer?
- */
- struct drm_crtc *crtc = lvds->bridge.encoder->crtc;
u32 lvdhcr;
u32 lvdcr0;
int ret;
@@ -412,6 +410,10 @@ static void rcar_lvds_enable(struct drm_bridge *bridge)
if (ret < 0)
return;

+ /* Enable the companion LVDS encoder in dual-link mode. */
+ if (lvds->dual_link && lvds->companion)
+ lvds->companion->funcs->enable(lvds->companion);
+
/*
* Hardcode the channels and control signals routing for now.
*
@@ -434,17 +436,33 @@ static void rcar_lvds_enable(struct drm_bridge *bridge)
rcar_lvds_write(lvds, LVDCHCR, lvdhcr);

if (lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK) {
- /* Disable dual-link mode. */
- rcar_lvds_write(lvds, LVDSTRIPE, 0);
+ /*
+ * Configure vertical stripe based on the mode of operation of
+ * the connected device.
+ */
+ rcar_lvds_write(lvds, LVDSTRIPE,
+ lvds->dual_link ? LVDSTRIPE_ST_ON : 0);
}

- /* PLL clock configuration. */
- lvds->info->pll_setup(lvds, mode->clock * 1000);
+ /*
+ * PLL clock configuration on all instances but the companion in
+ * dual-link mode.
+ */
+ if (!lvds->dual_link || lvds->companion)
+ lvds->info->pll_setup(lvds, mode->clock * 1000);

/* Set the LVDS mode and select the input. */
lvdcr0 = lvds->mode << LVDCR0_LVMD_SHIFT;
- if (drm_crtc_index(crtc) == 2)
- lvdcr0 |= LVDCR0_DUSEL;
+
+ if (lvds->bridge.encoder) {
+ /*
+ * FIXME: We should really retrieve the CRTC through the state,
+ * but how do we get a state pointer?
+ */
+ if (drm_crtc_index(lvds->bridge.encoder->crtc) == 2)
+ lvdcr0 |= LVDCR0_DUSEL;
+ }
+
rcar_lvds_write(lvds, LVDCR0, lvdcr0);

/* Turn all the channels on. */
@@ -507,6 +525,10 @@ static void rcar_lvds_disable(struct drm_bridge *bridge)
rcar_lvds_write(lvds, LVDCR1, 0);
rcar_lvds_write(lvds, LVDPLLCR, 0);

+ /* Disable the companion LVDS encoder in dual-link mode. */
+ if (lvds->dual_link && lvds->companion)
+ lvds->companion->funcs->disable(lvds->companion);
+
clk_disable_unprepare(lvds->clocks.mod);
}

@@ -623,10 +645,57 @@ static const struct drm_bridge_funcs rcar_lvds_bridge_ops = {
.mode_set = rcar_lvds_mode_set,
};

+bool rcar_lvds_dual_link(struct drm_bridge *bridge)
+{
+ struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
+
+ return lvds->dual_link;
+}
+EXPORT_SYMBOL_GPL(rcar_lvds_dual_link);
+
/* -----------------------------------------------------------------------------
* Probe & Remove
*/

+static int rcar_lvds_parse_dt_companion(struct rcar_lvds *lvds)
+{
+ const struct of_device_id *match;
+ struct device_node *companion;
+ struct device *dev = lvds->dev;
+ int ret = 0;
+
+ /* Locate the companion LVDS encoder for dual-link operation, if any. */
+ companion = of_parse_phandle(dev->of_node, "renesas,companion", 0);
+ if (!companion) {
+ dev_err(dev, "Companion LVDS encoder not found\n");
+ return -ENXIO;
+ }
+
+ /*
+ * Sanity check: the companion encoder must have the same compatible
+ * string.
+ */
+ match = of_match_device(dev->driver->of_match_table, dev);
+ if (!of_device_is_compatible(companion, match->compatible)) {
+ dev_err(dev, "Companion LVDS encoder is invalid\n");
+ ret = -ENXIO;
+ 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);
+
+done:
+ of_node_put(companion);
+
+ return ret;
+}
+
static int rcar_lvds_parse_dt(struct rcar_lvds *lvds)
{
struct device_node *local_output = NULL;
@@ -677,14 +746,26 @@ static int rcar_lvds_parse_dt(struct rcar_lvds *lvds)

if (is_bridge) {
lvds->next_bridge = of_drm_find_bridge(remote);
- if (!lvds->next_bridge)
+ if (!lvds->next_bridge) {
ret = -EPROBE_DEFER;
+ goto done;
+ }
+
+ if (lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK)
+ lvds->dual_link = lvds->next_bridge->timings
+ ? lvds->next_bridge->timings->dual_link
+ : false;
} else {
lvds->panel = of_drm_find_panel(remote);
- if (IS_ERR(lvds->panel))
+ if (IS_ERR(lvds->panel)) {
ret = PTR_ERR(lvds->panel);
+ goto done;
+ }
}

+ if (lvds->dual_link)
+ ret = rcar_lvds_parse_dt_companion(lvds);
+
done:
of_node_put(local_output);
of_node_put(remote_input);
diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.h b/drivers/gpu/drm/rcar-du/rcar_lvds.h
index a709cae1bc32..222ec0e60785 100644
--- a/drivers/gpu/drm/rcar-du/rcar_lvds.h
+++ b/drivers/gpu/drm/rcar-du/rcar_lvds.h
@@ -15,6 +15,7 @@ struct drm_bridge;
#if IS_ENABLED(CONFIG_DRM_RCAR_LVDS)
int rcar_lvds_clk_enable(struct drm_bridge *bridge, unsigned long freq);
void rcar_lvds_clk_disable(struct drm_bridge *bridge);
+bool rcar_lvds_dual_link(struct drm_bridge *bridge);
#else
static inline int rcar_lvds_clk_enable(struct drm_bridge *bridge,
unsigned long freq)
@@ -22,6 +23,10 @@ static inline int rcar_lvds_clk_enable(struct drm_bridge *bridge,
return -ENOSYS;
}
static inline void rcar_lvds_clk_disable(struct drm_bridge *bridge) { }
+static inline bool rcar_lvds_dual_link(struct drm_bridge *bridge)
+{
+ return false;
+}
#endif /* CONFIG_DRM_RCAR_LVDS */

#endif /* __RCAR_LVDS_H__ */
--
2.17.1

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