[PATCH v2 24/30] drm/sun4i: mixer: Convert heuristics to quirk

Jernej Skrabec
2025-11-04T18:10:33Z

Determination if FCC unit can be used for VI layer alpha depends on
number of VI channels. This info won't be available anymore in future
to VI layer driver because of DE33 way of allocating planes from same
pool to different mixers.

While order is slightly changed, it doesn't affect anything due to
double buffering of registers. New order keeps related registers
together and quirk separate.

Reviewed-by: Chen-Yu Tsai <wens@kernel.org>
Tested-by: Ryan Walklin <ryan@testtoast.com>
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
---
Changes in v2:
- updated commit message

drivers/gpu/drm/sun4i/sun8i_mixer.c | 9 +++++++++
drivers/gpu/drm/sun4i/sun8i_mixer.h | 3 +++
drivers/gpu/drm/sun4i/sun8i_vi_layer.c | 12 +++++++-----
3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/sun4i/sun8i_mixer.c b/drivers/gpu/drm/sun4i/sun8i_mixer.c
index 267a6f75feb2..78bbfbe62833 100644
--- a/drivers/gpu/drm/sun4i/sun8i_mixer.c
+++ b/drivers/gpu/drm/sun4i/sun8i_mixer.c
@@ -707,6 +707,7 @@ static const struct sun8i_mixer_cfg sun8i_a83t_mixer0_cfg = {
.de_type = SUN8I_MIXER_DE2,
.scaler_mask = 0xf,
.scanline_yuv = 2048,
+ .de2_fcc_alpha = 1,
.ui_num = 3,
.vi_num = 1,
};
@@ -716,6 +717,7 @@ static const struct sun8i_mixer_cfg sun8i_a83t_mixer1_cfg = {
.de_type = SUN8I_MIXER_DE2,
.scaler_mask = 0x3,
.scanline_yuv = 2048,
+ .de2_fcc_alpha = 1,
.ui_num = 1,
.vi_num = 1,
};
@@ -726,6 +728,7 @@ static const struct sun8i_mixer_cfg sun8i_h3_mixer0_cfg = {
.mod_rate = 432000000,
.scaler_mask = 0xf,
.scanline_yuv = 2048,
+ .de2_fcc_alpha = 1,
.ui_num = 3,
.vi_num = 1,
};
@@ -736,6 +739,7 @@ static const struct sun8i_mixer_cfg sun8i_r40_mixer0_cfg = {
.mod_rate = 297000000,
.scaler_mask = 0xf,
.scanline_yuv = 2048,
+ .de2_fcc_alpha = 1,
.ui_num = 3,
.vi_num = 1,
};
@@ -746,6 +750,7 @@ static const struct sun8i_mixer_cfg sun8i_r40_mixer1_cfg = {
.mod_rate = 297000000,
.scaler_mask = 0x3,
.scanline_yuv = 2048,
+ .de2_fcc_alpha = 1,
.ui_num = 1,
.vi_num = 1,
};
@@ -766,6 +771,7 @@ static const struct sun8i_mixer_cfg sun20i_d1_mixer0_cfg = {
.mod_rate = 297000000,
.scaler_mask = 0x3,
.scanline_yuv = 2048,
+ .de2_fcc_alpha = 1,
.ui_num = 1,
.vi_num = 1,
};
@@ -776,6 +782,7 @@ static const struct sun8i_mixer_cfg sun20i_d1_mixer1_cfg = {
.mod_rate = 297000000,
.scaler_mask = 0x1,
.scanline_yuv = 1024,
+ .de2_fcc_alpha = 1,
.ui_num = 0,
.vi_num = 1,
};
@@ -786,6 +793,7 @@ static const struct sun8i_mixer_cfg sun50i_a64_mixer0_cfg = {
.mod_rate = 297000000,
.scaler_mask = 0xf,
.scanline_yuv = 4096,
+ .de2_fcc_alpha = 1,
.ui_num = 3,
.vi_num = 1,
};
@@ -796,6 +804,7 @@ static const struct sun8i_mixer_cfg sun50i_a64_mixer1_cfg = {
.mod_rate = 297000000,
.scaler_mask = 0x3,
.scanline_yuv = 2048,
+ .de2_fcc_alpha = 1,
.ui_num = 1,
.vi_num = 1,
};
diff --git a/drivers/gpu/drm/sun4i/sun8i_mixer.h b/drivers/gpu/drm/sun4i/sun8i_mixer.h
index d14188cdfab3..def07afd37e1 100644
--- a/drivers/gpu/drm/sun4i/sun8i_mixer.h
+++ b/drivers/gpu/drm/sun4i/sun8i_mixer.h
@@ -176,6 +176,8 @@ enum sun8i_mixer_type {
* a functional block.
* @de_type: sun8i_mixer_type enum representing the display engine generation.
* @scaline_yuv: size of a scanline for VI scaler for YUV formats.
+ * @de2_fcc_alpha: use FCC for missing DE2 VI alpha capability
+ * Most DE2 cores has FCC. If number of VI planes is one, enable this.
* @map: channel map for DE variants processing YUV separately (DE33)
*/
struct sun8i_mixer_cfg {
@@ -186,6 +188,7 @@ struct sun8i_mixer_cfg {
unsigned long mod_rate;
unsigned int de_type;
unsigned int scanline_yuv;
+ unsigned int de2_fcc_alpha : 1;
unsigned int map[6];
};

diff --git a/drivers/gpu/drm/sun4i/sun8i_vi_layer.c b/drivers/gpu/drm/sun4i/sun8i_vi_layer.c
index 44e699910b70..8eb3f167e664 100644
--- a/drivers/gpu/drm/sun4i/sun8i_vi_layer.c
+++ b/drivers/gpu/drm/sun4i/sun8i_vi_layer.c
@@ -48,14 +48,16 @@ static void sun8i_vi_layer_update_attributes(struct sun8i_layer *layer,
val |= (state->alpha == DRM_BLEND_ALPHA_OPAQUE) ?
SUN50I_MIXER_CHAN_VI_LAYER_ATTR_ALPHA_MODE_PIXEL :
SUN50I_MIXER_CHAN_VI_LAYER_ATTR_ALPHA_MODE_COMBINED;
- } else if (mixer->cfg->vi_num == 1) {
+ }
+
+ regmap_write(layer->regs,
+ SUN8I_MIXER_CHAN_VI_LAYER_ATTR(ch_base, layer->overlay), val);
+
+ if (mixer->cfg->de2_fcc_alpha) {
regmap_write(layer->regs,
SUN8I_MIXER_FCC_GLOBAL_ALPHA_REG,
SUN8I_MIXER_FCC_GLOBAL_ALPHA(state->alpha >> 8));
}
-
- regmap_write(layer->regs,
- SUN8I_MIXER_CHAN_VI_LAYER_ATTR(ch_base, layer->overlay), val);
}

static void sun8i_vi_layer_update_coord(struct sun8i_layer *layer,
@@ -450,7 +452,7 @@ struct sun8i_layer *sun8i_vi_layer_init_one(struct drm_device *drm,
return ERR_PTR(ret);
}

- if (mixer->cfg->vi_num == 1 || mixer->cfg->de_type >= SUN8I_MIXER_DE3) {
+ if (mixer->cfg->de2_fcc_alpha || mixer->cfg->de_type >= SUN8I_MIXER_DE3) {
ret = drm_plane_create_alpha_property(&layer->plane);
if (ret) {
dev_err(drm->dev, "Couldn't add alpha property\n");
--
2.51.2