[PATCH 1/1] Support LVDS output on Allwinner A20

From: Andrey Lebedev
Date: Mon Feb 10 2020 - 14:56:40 EST


A20 SoC (found in Cubieboard 2 among others) requires different LVDS set
up procedure than A33. Timing controller (tcon) driver only implements
sun6i-style procedure, that doesn't work on A20 (sun7i).

The support for such procedure is ported from u-boot and follows u-boot
naming convention: SUN6I* for sun6i-style procedure, and SUN4I for other
(which happens to be compatible with A20).
---
drivers/gpu/drm/sun4i/sun4i_tcon.c | 91 ++++++++++++++++++++----------
drivers/gpu/drm/sun4i/sun4i_tcon.h | 12 ++++
2 files changed, 73 insertions(+), 30 deletions(-)

diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
index c81cdce6ed55..78896e907ca9 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
@@ -114,46 +114,74 @@ static void sun4i_tcon_channel_set_status(struct sun4i_tcon *tcon, int channel,
}
}

+static void sun4i_tcon_lvds_sun6i_enable(struct sun4i_tcon *tcon,
+ const struct drm_encoder *encoder) {
+ u8 val;
+ regmap_write(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
+ SUN6I_TCON0_LVDS_ANA0_C(2) |
+ SUN6I_TCON0_LVDS_ANA0_V(3) |
+ SUN6I_TCON0_LVDS_ANA0_PD(2) |
+ SUN6I_TCON0_LVDS_ANA0_EN_LDO);
+ udelay(2);
+
+ regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
+ SUN6I_TCON0_LVDS_ANA0_EN_MB,
+ SUN6I_TCON0_LVDS_ANA0_EN_MB);
+ udelay(2);
+
+ regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
+ SUN6I_TCON0_LVDS_ANA0_EN_DRVC,
+ SUN6I_TCON0_LVDS_ANA0_EN_DRVC);
+
+ if (sun4i_tcon_get_pixel_depth(encoder) == 18)
+ val = 7;
+ else
+ val = 0xf;
+
+ regmap_write_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
+ SUN6I_TCON0_LVDS_ANA0_EN_DRVD(0xf),
+ SUN6I_TCON0_LVDS_ANA0_EN_DRVD(val));
+
+}
+
+static void sun4i_tcon_lvds_sun4i_enable(struct sun4i_tcon *tcon) {
+ regmap_write(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
+ SUN4I_TCON0_LVDS_ANA0_CK_EN |
+ SUN4I_TCON0_LVDS_ANA0_REG_V |
+ SUN4I_TCON0_LVDS_ANA0_REG_C |
+ SUN4I_TCON0_LVDS_ANA0_EN_MB |
+ SUN4I_TCON0_LVDS_ANA0_PD |
+ SUN4I_TCON0_LVDS_ANA0_DCHS);
+
+ udelay(2); /* delay at least 1200 ns */
+ regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA1_REG,
+ SUN4I_TCON0_LVDS_ANA1_INIT,
+ SUN4I_TCON0_LVDS_ANA1_INIT);
+ udelay(1); /* delay at least 1200 ns */
+ regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA1_REG,
+ SUN4I_TCON0_LVDS_ANA1_UPDATE,
+ SUN4I_TCON0_LVDS_ANA1_UPDATE);
+}
+
+
static void sun4i_tcon_lvds_set_status(struct sun4i_tcon *tcon,
const struct drm_encoder *encoder,
bool enabled)
{
if (enabled) {
- u8 val;
-
+ // Enable LVDS interface
regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_IF_REG,
SUN4I_TCON0_LVDS_IF_EN,
SUN4I_TCON0_LVDS_IF_EN);

- /*
- * As their name suggest, these values only apply to the A31
- * and later SoCs. We'll have to rework this when merging
- * support for the older SoCs.
- */
- regmap_write(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
- SUN6I_TCON0_LVDS_ANA0_C(2) |
- SUN6I_TCON0_LVDS_ANA0_V(3) |
- SUN6I_TCON0_LVDS_ANA0_PD(2) |
- SUN6I_TCON0_LVDS_ANA0_EN_LDO);
- udelay(2);
-
- regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
- SUN6I_TCON0_LVDS_ANA0_EN_MB,
- SUN6I_TCON0_LVDS_ANA0_EN_MB);
- udelay(2);
-
- regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
- SUN6I_TCON0_LVDS_ANA0_EN_DRVC,
- SUN6I_TCON0_LVDS_ANA0_EN_DRVC);
-
- if (sun4i_tcon_get_pixel_depth(encoder) == 18)
- val = 7;
- else
- val = 0xf;
+ // Perform SoC-specific setup procedure
+ if (tcon->quirks->sun6i_lvds_init) {
+ sun4i_tcon_lvds_sun6i_enable(tcon, encoder);
+ }
+ else {
+ sun4i_tcon_lvds_sun4i_enable(tcon);
+ }

- regmap_write_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
- SUN6I_TCON0_LVDS_ANA0_EN_DRVD(0xf),
- SUN6I_TCON0_LVDS_ANA0_EN_DRVD(val));
} else {
regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_IF_REG,
SUN4I_TCON0_LVDS_IF_EN, 0);
@@ -1454,6 +1482,7 @@ static const struct sun4i_tcon_quirks sun6i_a31s_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,
@@ -1464,11 +1493,13 @@ static const struct sun4i_tcon_quirks sun7i_a20_quirks = {
static const struct sun4i_tcon_quirks sun8i_a33_quirks = {
.has_channel_0 = true,
.has_lvds_alt = true,
+ .sun6i_lvds_init = true,
.dclk_min_div = 1,
};

static const struct sun4i_tcon_quirks sun8i_a83t_lcd_quirks = {
.supports_lvds = true,
+ .sun6i_lvds_init = true,
.has_channel_0 = true,
.dclk_min_div = 1,
};
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.h b/drivers/gpu/drm/sun4i/sun4i_tcon.h
index a62ec826ae71..973901c1bee5 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.h
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.h
@@ -193,6 +193,13 @@
#define SUN4I_TCON_MUX_CTRL_REG 0x200

#define SUN4I_TCON0_LVDS_ANA0_REG 0x220
+#define SUN4I_TCON0_LVDS_ANA0_DCHS BIT(16)
+#define SUN4I_TCON0_LVDS_ANA0_PD BIT(20) | BIT(21)
+#define SUN4I_TCON0_LVDS_ANA0_EN_MB BIT(22)
+#define SUN4I_TCON0_LVDS_ANA0_REG_C BIT(24) | BIT(25)
+#define SUN4I_TCON0_LVDS_ANA0_REG_V BIT(26) | BIT(27)
+#define SUN4I_TCON0_LVDS_ANA0_CK_EN BIT(29) | BIT(28)
+
#define SUN6I_TCON0_LVDS_ANA0_EN_MB BIT(31)
#define SUN6I_TCON0_LVDS_ANA0_EN_LDO BIT(30)
#define SUN6I_TCON0_LVDS_ANA0_EN_DRVC BIT(24)
@@ -201,6 +208,10 @@
#define SUN6I_TCON0_LVDS_ANA0_V(x) (((x) & 3) << 8)
#define SUN6I_TCON0_LVDS_ANA0_PD(x) (((x) & 3) << 4)

+#define SUN4I_TCON0_LVDS_ANA1_REG 0x224
+#define SUN4I_TCON0_LVDS_ANA1_INIT (0x1f << 26 | 0x1f << 10)
+#define SUN4I_TCON0_LVDS_ANA1_UPDATE (0x1f << 16 | 0x1f << 00)
+
#define SUN4I_TCON1_FILL_CTL_REG 0x300
#define SUN4I_TCON1_FILL_BEG0_REG 0x304
#define SUN4I_TCON1_FILL_END0_REG 0x308
@@ -224,6 +235,7 @@ struct sun4i_tcon_quirks {
bool needs_de_be_mux; /* sun6i needs mux to select backend */
bool needs_edp_reset; /* a80 edp reset needed for tcon0 access */
bool supports_lvds; /* Does the TCON support an LVDS output? */
+ bool sun6i_lvds_init; /* Requires sun6i lvds initialization? */
u8 dclk_min_div; /* minimum divider for TCON0 DCLK */

/* callback to handle tcon muxing options */
--
2.20.1