drm/meson: dw-hdmi: add bandgap setting for g12

When no mode is set, the utility pin appears to be grounded. No signal
is getting through.

This is problematic because ARC and eARC use this line and may do so even
if no display mode is set.

This change enable the bandgap setting on g12 chip, which fix the problem
with the utility pin. This is done by restoring init values on PHY init and
disable.

Fixes: 3b7c123 ("drm/meson: Add G12A support for the DW-HDMI Glue")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20240426160256.3089978-3-jbrunet@baylibre.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240426160256.3089978-3-jbrunet@baylibre.com

Author: jbrun3t

drivers/gpu/drm/meson/meson_dw_hdmi.c

@@ -106,6 +106,8 @@
 #define HHI_HDMI_CLK_CNTL	0x1cc /* 0x73 */
 #define HHI_HDMI_PHY_CNTL0	0x3a0 /* 0xe8 */
 #define HHI_HDMI_PHY_CNTL1	0x3a4 /* 0xe9 */
+#define  PHY_CNTL1_INIT		0x03900000
+#define  PHY_INVERT		BIT(17)
 #define HHI_HDMI_PHY_CNTL2	0x3a8 /* 0xea */
 #define HHI_HDMI_PHY_CNTL3	0x3ac /* 0xeb */
 #define HHI_HDMI_PHY_CNTL4	0x3b0 /* 0xec */
@@ -130,6 +132,8 @@ struct meson_dw_hdmi_data {
 				    unsigned int addr);
 	void		(*dwc_write)(struct meson_dw_hdmi *dw_hdmi,
 				     unsigned int addr, unsigned int data);
+	u32 cntl0_init;
+	u32 cntl1_init;
 };
 
 struct meson_dw_hdmi {
@@ -458,7 +462,9 @@ static void dw_hdmi_phy_disable(struct dw_hdmi *hdmi,
 
 	DRM_DEBUG_DRIVER("\n");
 
-	regmap_write(priv->hhi, HHI_HDMI_PHY_CNTL0, 0);
+	/* Fallback to init mode */
+	regmap_write(priv->hhi, HHI_HDMI_PHY_CNTL1, dw_hdmi->data->cntl1_init);
+	regmap_write(priv->hhi, HHI_HDMI_PHY_CNTL0, dw_hdmi->data->cntl0_init);
 }
 
 static enum drm_connector_status dw_hdmi_read_hpd(struct dw_hdmi *hdmi,
@@ -576,18 +582,31 @@ static const struct regmap_config meson_dw_hdmi_regmap_config = {
 	.fast_io = true,
 };
 
-static const struct meson_dw_hdmi_data meson_dw_hdmi_gx_data = {
+static const struct meson_dw_hdmi_data meson_dw_hdmi_gxbb_data = {
 	.top_read = dw_hdmi_top_read,
 	.top_write = dw_hdmi_top_write,
 	.dwc_read = dw_hdmi_dwc_read,
 	.dwc_write = dw_hdmi_dwc_write,
+	.cntl0_init = 0x0,
+	.cntl1_init = PHY_CNTL1_INIT | PHY_INVERT,
+};
+
+static const struct meson_dw_hdmi_data meson_dw_hdmi_gxl_data = {
+	.top_read = dw_hdmi_top_read,
+	.top_write = dw_hdmi_top_write,
+	.dwc_read = dw_hdmi_dwc_read,
+	.dwc_write = dw_hdmi_dwc_write,
+	.cntl0_init = 0x0,
+	.cntl1_init = PHY_CNTL1_INIT,
 };
 
 static const struct meson_dw_hdmi_data meson_dw_hdmi_g12a_data = {
 	.top_read = dw_hdmi_g12a_top_read,
 	.top_write = dw_hdmi_g12a_top_write,
 	.dwc_read = dw_hdmi_g12a_dwc_read,
 	.dwc_write = dw_hdmi_g12a_dwc_write,
+	.cntl0_init = 0x000b4242, /* Bandgap */
+	.cntl1_init = PHY_CNTL1_INIT,
 };
 
 static void meson_dw_hdmi_init(struct meson_dw_hdmi *meson_dw_hdmi)
@@ -626,18 +645,8 @@ static void meson_dw_hdmi_init(struct meson_dw_hdmi *meson_dw_hdmi)
 	meson_dw_hdmi->data->top_write(meson_dw_hdmi, HDMITX_TOP_BIST_CNTL, BIT(12));
 
 	/* Setup PHY */
-	regmap_update_bits(priv->hhi, HHI_HDMI_PHY_CNTL1,
-			   0xffff << 16, 0x0390 << 16);
-
-	/* BIT_INVERT */
-	if (dw_hdmi_is_compatible(meson_dw_hdmi, "amlogic,meson-gxl-dw-hdmi") ||
-	    dw_hdmi_is_compatible(meson_dw_hdmi, "amlogic,meson-gxm-dw-hdmi") ||
-	    dw_hdmi_is_compatible(meson_dw_hdmi, "amlogic,meson-g12a-dw-hdmi"))
-		regmap_update_bits(priv->hhi, HHI_HDMI_PHY_CNTL1,
-				   BIT(17), 0);
-	else
-		regmap_update_bits(priv->hhi, HHI_HDMI_PHY_CNTL1,
-				   BIT(17), BIT(17));
+	regmap_write(priv->hhi, HHI_HDMI_PHY_CNTL1, meson_dw_hdmi->data->cntl1_init);
+	regmap_write(priv->hhi, HHI_HDMI_PHY_CNTL0, meson_dw_hdmi->data->cntl0_init);
 
 	/* Enable HDMI-TX Interrupt */
 	meson_dw_hdmi->data->top_write(meson_dw_hdmi, HDMITX_TOP_INTR_STAT_CLR,
@@ -848,11 +857,11 @@ static const struct dev_pm_ops meson_dw_hdmi_pm_ops = {
 
 static const struct of_device_id meson_dw_hdmi_of_table[] = {
 	{ .compatible = "amlogic,meson-gxbb-dw-hdmi",
-	  .data = &meson_dw_hdmi_gx_data },
+	  .data = &meson_dw_hdmi_gxbb_data },
 	{ .compatible = "amlogic,meson-gxl-dw-hdmi",
-	  .data = &meson_dw_hdmi_gx_data },
+	  .data = &meson_dw_hdmi_gxl_data },
 	{ .compatible = "amlogic,meson-gxm-dw-hdmi",
-	  .data = &meson_dw_hdmi_gx_data },
+	  .data = &meson_dw_hdmi_gxl_data },
 	{ .compatible = "amlogic,meson-g12a-dw-hdmi",
 	  .data = &meson_dw_hdmi_g12a_data },
 	{ }