linux-kernel - [RFC PATCH 3/3] drm: bridge: samsung-dsim: Remove init quirk for Exynos

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Date:   Tue, 18 Apr 2023 12:42:53 +0200
From:   Frieder Schrempf <frieder@...s.de>
To:     Andrzej Hajda <andrzej.hajda@...el.com>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...il.com>,
        dri-devel@...ts.freedesktop.org, Inki Dae <inki.dae@...sung.com>,
        Jagan Teki <jagan@...rulasolutions.com>,
        linux-kernel@...r.kernel.org,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Robert Foss <rfoss@...nel.org>
Cc:     Frieder Schrempf <frieder.schrempf@...tron.de>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Jonas Karlman <jonas@...boo.se>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Marek Vasut <marex@...x.de>
Subject: [RFC PATCH 3/3] drm: bridge: samsung-dsim: Remove init quirk for Exynos

From: Frieder Schrempf <frieder.schrempf@...tron.de>

Assuming that with the init flow fixed to meet the documentation at
[1] and the pre_enable_prev_first flag set in downstream bridge/panel
drivers which require it, we can use the default flow for Exynos as
already done for i.MX8M.

[1] https://docs.kernel.org/gpu/drm-kms-helpers.html#mipi-dsi-bridge-operation

Signed-off-by: Frieder Schrempf <frieder.schrempf@...tron.de>
---
I have no idea if my assumptions are correct and if this works at all.
There's a very good chance it doesn't...
---
 drivers/gpu/drm/bridge/samsung-dsim.c | 39 ++++++++-------------------
 1 file changed, 11 insertions(+), 28 deletions(-)

diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
index 9775779721d9..8c68b767ae50 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -1336,18 +1336,12 @@ static void samsung_dsim_atomic_pre_enable(struct drm_bridge *bridge,
 
 	dsi->state |= DSIM_STATE_ENABLED;
 
-	/*
-	 * For Exynos-DSIM the downstream bridge, or panel are expecting
-	 * the host initialization during DSI transfer.
-	 */
-	if (!samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) {
-		ret = samsung_dsim_init(dsi);
-		if (ret)
-			return;
+	ret = samsung_dsim_init(dsi);
+	if (ret)
+		return;
 
-		samsung_dsim_set_display_mode(dsi);
-		samsung_dsim_set_display_enable(dsi, true);
-	}
+	samsung_dsim_set_display_mode(dsi);
+	samsung_dsim_set_display_enable(dsi, true);
 }
 
 static void samsung_dsim_atomic_enable(struct drm_bridge *bridge,
@@ -1356,14 +1350,9 @@ static void samsung_dsim_atomic_enable(struct drm_bridge *bridge,
 	struct samsung_dsim *dsi = bridge_to_dsi(bridge);
 	u32 reg;
 
-	if (samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) {
-		samsung_dsim_set_display_mode(dsi);
-		samsung_dsim_set_display_enable(dsi, true);
-	} else {
-		reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG);
-		reg &= ~DSIM_FORCE_STOP_STATE;
-		samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg);
-	}
+	reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG);
+	reg &= ~DSIM_FORCE_STOP_STATE;
+	samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg);
 
 	dsi->state |= DSIM_STATE_VIDOUT_AVAILABLE;
 }
@@ -1377,11 +1366,9 @@ static void samsung_dsim_atomic_disable(struct drm_bridge *bridge,
 	if (!(dsi->state & DSIM_STATE_ENABLED))
 		return;
 
-	if (!samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) {
-		reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG);
-		reg |= DSIM_FORCE_STOP_STATE;
-		samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg);
-	}
+	reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG);
+	reg |= DSIM_FORCE_STOP_STATE;
+	samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg);
 
 	dsi->state &= ~DSIM_STATE_VIDOUT_AVAILABLE;
 }
@@ -1680,10 +1667,6 @@ static ssize_t samsung_dsim_host_transfer(struct mipi_dsi_host *host,
 	if (!(dsi->state & DSIM_STATE_ENABLED))
 		return -EINVAL;
 
-	ret = samsung_dsim_init(dsi);
-	if (ret)
-		return ret;
-
 	ret = mipi_dsi_create_packet(&xfer.packet, msg);
 	if (ret < 0)
 		return ret;
-- 
2.40.0