[PATCH v6 5/5] drm/tidss: Enable Dual and Duplicate Modes for OLDI

[Aradhya Bhatia <a-bhatia1@ti.com>]

The AM625 DSS IP contains 2 OLDI TXes which can work together to enable 2
cloned displays of or even a single dual-link display with higher
resolutions like WUXGA (1920x1200@60fps) with a reduced OLDI clock
frequency.

Configure the necessary register to enable and disable the OLDI TXes
with required modes configurations.

Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
---
 drivers/gpu/drm/tidss/tidss_dispc.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/tidss/tidss_dispc.c b/drivers/gpu/drm/tidss/tidss_dispc.c
index f26129fb1d8f..cf43de6216a5 100644
--- a/drivers/gpu/drm/tidss/tidss_dispc.c
+++ b/drivers/gpu/drm/tidss/tidss_dispc.c
@@ -1012,8 +1012,8 @@ static void dispc_enable_oldi(struct dispc_device *dispc, u32 hw_videoport,
 	int count = 0;
 
 	/*
-	 * For the moment DUALMODESYNC, MASTERSLAVE, MODE, and SRC
-	 * bits of DISPC_VP_DSS_OLDI_CFG are set statically to 0.
+	 * For the moment MASTERSLAVE, and SRC bits of DISPC_VP_DSS_OLDI_CFG are
+	 * always set to 0.
 	 */
 
 	if (fmt->data_width == 24)
@@ -1030,6 +1030,26 @@ static void dispc_enable_oldi(struct dispc_device *dispc, u32 hw_videoport,
 
 	oldi_cfg |= BIT(0); /* ENABLE */
 
+	switch (dispc->oldi_mode) {
+	case OLDI_SINGLE_LINK_SINGLE_MODE:
+		/* All configuration is done for this mode.  */
+		break;
+
+	case OLDI_SINGLE_LINK_CLONE_MODE:
+		oldi_cfg |= BIT(5); /* CLONE MODE */
+		break;
+
+	case OLDI_DUAL_LINK_MODE:
+		oldi_cfg |= BIT(11); /* DUALMODESYNC */
+		oldi_cfg |= BIT(3); /* data-mapping field also indicates dual-link mode */
+		break;
+
+	default:
+		dev_warn(dispc->dev, "%s: Incorrect oldi mode. Returning.\n",
+			 __func__);
+		return;
+	}
+
 	dispc_vp_write(dispc, hw_videoport, DISPC_VP_DSS_OLDI_CFG, oldi_cfg);
 
 	while (!(oldi_reset_bit & dispc_read(dispc, DSS_SYSSTATUS)) &&
-- 
2.38.1