The A20 and other SoC with two TCONs (A31, R40, etc.) can use its second
TCON as the secondary LVDS link in a dual-link setup, with the TCON0 being
the main link. Extend a bit the parsing code to leverage the DRM dual-link
code, register only the LVDS output on the primary TCON, and add the needed
bits to setup the TCON properly.
Reviewed-by: Chen-Yu Tsai <w...@csie.org>
Signed-off-by: Maxime Ripard <max...@cerno.tech>
---
drivers/gpu/drm/sun4i/sun4i_tcon.c | 36 ++++++++++++++++++++++++++++++
drivers/gpu/drm/sun4i/sun4i_tcon.h | 4 ++++
2 files changed, 40 insertions(+)
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c
b/drivers/gpu/drm/sun4i/sun4i_tcon.c
index 32757175f86b..005c37831eb6 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
@@ -475,6 +475,10 @@ static void sun4i_tcon0_mode_set_lvds(struct sun4i_tcon
*tcon,
SUN4I_TCON0_BASIC2_V_BACKPORCH(bp));
reg = SUN4I_TCON0_LVDS_IF_CLK_SEL_TCON0;
+
+ if (tcon->lvds_dual_link)
+ reg |= SUN4I_TCON0_LVDS_IF_DUAL_LINK;
+
if (sun4i_tcon_get_pixel_depth(encoder) == 24)
reg |= SUN4I_TCON0_LVDS_IF_BITWIDTH_24BITS;
else
@@ -903,6 +907,16 @@ static int sun4i_tcon_register_panel(struct drm_device
*drm,
!of_device_is_compatible(remote, "panel-lvds"))
return sun4i_rgb_init(drm, tcon);
+ /*
+ * Only the TCON0 will be relevant for the LVDS output, so if
+ * our ID is something else, let's prevent our TCON from
+ * registering its own LVDS output
+ */
+ if (tcon->id) {
+ dev_dbg(dev, "TCON used as an LVDS secondary link.");
+ return 0;
+ }
+
/*
* This can only be made optional since we've had DT
* nodes without the LVDS reset properties.
@@ -939,6 +953,28 @@ static int sun4i_tcon_register_panel(struct drm_device
*drm,
}
}
+ /*
+ * If we don't have a second TCON, we will never be able to do
+ * dual-link LVDS, so we don't have much more to do.
+ */
+ companion = of_parse_phandle(dev->of_node, "link-companion", 0);
+ if (!companion)
+ return sun4i_lvds_init(drm, tcon);
+
+ /*
+ * Let's do a sanity check on the dual-link setup to make sure
+ * everything is properly described.
+ */
+ ret = drm_of_lvds_get_dual_link_pixel_order(dev->of_node, 1, 0,
+ companion, 1, 0);
+ if (ret < 0) {
+ dev_err(dev, "Invalid Dual-Link Configuration.\n");
+ return ret;
+ }
+
+ dev_info(dev, "Primary TCON, enabling LVDS Dual-Link");
+ tcon->lvds_dual_link = true;
+
return sun4i_lvds_init(drm, tcon);
}
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.h
b/drivers/gpu/drm/sun4i/sun4i_tcon.h
index ee555318e3c2..f6a589828f94 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.h
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.h
@@ -98,6 +98,7 @@
#define SUN4I_TCON0_LVDS_IF_REG 0x84
#define SUN4I_TCON0_LVDS_IF_EN BIT(31)
+#define SUN4I_TCON0_LVDS_IF_DUAL_LINK BIT(30)
#define SUN4I_TCON0_LVDS_IF_BITWIDTH_MASK BIT(26)
#define SUN4I_TCON0_LVDS_IF_BITWIDTH_18BITS (1 << 26)
#define SUN4I_TCON0_LVDS_IF_BITWIDTH_24BITS (0 << 26)
@@ -280,6 +281,9 @@ struct sun4i_tcon {
/* Associated crtc */
struct sun4i_crtc *crtc;
+ /* Is the LVDS link a dual-channel link? */
+ bool lvds_dual_link;
+
int id;
/* TCON list management */
--
2.29.2
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