The A20 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.
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 d03ad75f9900..ed2abf6eb18b 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
@@ -487,6 +487,9 @@ static void sun4i_tcon0_mode_set_lvds(struct sun4i_tcon
*tcon,
else
reg |= SUN4I_TCON0_LVDS_IF_DATA_POL_NORMAL;
+ 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
@@ -896,6 +899,16 @@ static int sun4i_tcon_register_panel(struct drm_device
*drm,
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_info(dev, "Secondary TCON, disabling panel output");
+ return 0;
+ }
+
+ /*
* This can only be made optional since we've had DT
* nodes without the LVDS reset properties.
*
@@ -941,6 +954,28 @@ static int sun4i_tcon_register_panel(struct drm_device
*drm,
return -ENODEV;
}
+ /*
+ * 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, "allwinner,lvds-companion",
0);
+ if (!companion)
+ return 0;
+
+ /*
+ * 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);
}
@@ -1500,6 +1535,7 @@ static const struct sun4i_tcon_quirks
sun7i_a20_tcon0_quirks = {
};
static const struct sun4i_tcon_quirks sun7i_a20_quirks = {
+ .supports_lvds = true,
.has_channel_0 = true,
.has_channel_1 = true,
.dclk_min_div = 4,
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.h
b/drivers/gpu/drm/sun4i/sun4i_tcon.h
index cfbf4e6c1679..51c4e09cdd13 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)
@@ -274,6 +275,9 @@ 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 */
--
git-series 0.9.1
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