linux-kernel - [RFC PATCH v5 6/6] drm/tidss: Enable Dual and Duplicate Modes for OLDI

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Message-ID: <20220928175223.15225-7-a-bhatia1@ti.com>
Date:   Wed, 28 Sep 2022 23:22:23 +0530
From:   Aradhya Bhatia <a-bhatia1@...com>
To:     Tomi Valkeinen <tomba@...nel.org>, Jyri Sarha <jyri.sarha@....fi>,
        Rob Herring <robh+dt@...nel.org>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>
CC:     Nishanth Menon <nm@...com>, Vignesh Raghavendra <vigneshr@...com>,
        Rahul T R <r-ravikumar@...com>,
        DRI Development List <dri-devel@...ts.freedesktop.org>,
        Devicetree List <devicetree@...r.kernel.org>,
        Linux Kernel List <linux-kernel@...r.kernel.org>
Subject: [RFC PATCH v5 6/6] drm/tidss: Enable Dual and Duplicate Modes for OLDI

The AM625 DSS IP contains 2 OLDI TXes which can work to enable 2
duplicated displays of smaller resolutions or enable a single Dual Link
display with a higher resolution (1920x1200).

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

Signed-off-by: Aradhya Bhatia <a-bhatia1@...com>
---
 drivers/gpu/drm/tidss/tidss_dispc.c | 28 ++++++++++++++++++++++++++--
 1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/tidss/tidss_dispc.c b/drivers/gpu/drm/tidss/tidss_dispc.c
index 68444e0cd8d7..fd7f49535f0c 100644
--- a/drivers/gpu/drm/tidss/tidss_dispc.c
+++ b/drivers/gpu/drm/tidss/tidss_dispc.c
@@ -1003,8 +1003,8 @@ 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
+	 * set statically to 0.
 	 */
 
 	if (fmt->data_width == 24)
@@ -1021,6 +1021,30 @@ static void dispc_enable_oldi(struct dispc_device *dispc, u32 hw_videoport,
 
 	oldi_cfg |= BIT(0); /* ENABLE */
 
+	switch (dispc->oldi_mode) {
+	case OLDI_MODE_OFF:
+		oldi_cfg &= ~BIT(0); /* DISABLE */
+		break;
+
+	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)) &&
-- 
2.37.0