[PATCH v16 06/16] drm: exynos: dsi: Handle proper host initialization

[Jagan Teki]

From: Marek Szyprowski <m.szyprowski at samsung.com>

Host transfer() in the DSI master will invoke only when the DSI commands
are sent from DSI devices like DSI Panel or DSI bridges and this host
the transfer wouldn't invoke for I2C-based-DSI bridge drivers.

Handling DSI host initialization in transfer calls misses the controller
setup for I2C configured DSI bridges.

This patch updates the DSI host initialization by calling host to init
from bridge pre_enable as the bridge pre_enable API is invoked by core
as it is common across all classes of DSI device drivers.

The host init during pre_enable is conditional and not invoked for Exynos
as existing downstream drm panels and bridges in Exynos are expecting
the host initialization during DSI transfer.

Reviewed-by: Marek Vasut <marex at denx.de>
Reviewed-by: Frieder Schrempf <frieder.schrempf at kontron.de>
Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
Signed-off-by: Jagan Teki <jagan at amarulasolutions.com>
---
Changes for v16, v15, v13:
- none 
Changes for v12:
- collect RB from Marek
Changes for v11:
- collect RB from Frieder
Changes for v10:
- update the to simple logic to handle all platforms
Changs for v9 - v8:
- none
Changes for v2:
- check initialized state in samsung_dsim_init
Changes for v1:
- keep DSI init in host transfer

 drivers/gpu/drm/exynos/exynos_drm_dsi.c | 27 +++++++++++++++++++------
 1 file changed, 21 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
index 0f0834ebbdf3..eb33c2bcac16 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
@@ -254,6 +254,9 @@ struct exynos_dsi_transfer {
 #define DSIM_STATE_CMD_LPM		BIT(2)
 #define DSIM_STATE_VIDOUT_AVAILABLE	BIT(3)
 
+#define exynos_dsi_hw_is_exynos(hw) \
+	((hw) >= DSIM_TYPE_EXYNOS3250 && (hw) <= DSIM_TYPE_EXYNOS5433)
+
 enum exynos_dsi_type {
 	DSIM_TYPE_EXYNOS3250,
 	DSIM_TYPE_EXYNOS4210,
@@ -1343,6 +1346,9 @@ static int exynos_dsi_init(struct exynos_dsi *dsi)
 {
 	const struct exynos_dsi_driver_data *driver_data = dsi->driver_data;
 
+	if (dsi->state & DSIM_STATE_INITIALIZED)
+		return 0;
+
 	exynos_dsi_reset(dsi);
 	exynos_dsi_enable_irq(dsi);
 
@@ -1355,6 +1361,8 @@ static int exynos_dsi_init(struct exynos_dsi *dsi)
 	exynos_dsi_set_phy_ctrl(dsi);
 	exynos_dsi_init_link(dsi);
 
+	dsi->state |= DSIM_STATE_INITIALIZED;
+
 	return 0;
 }
 
@@ -1410,6 +1418,16 @@ static void exynos_dsi_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 (!exynos_dsi_hw_is_exynos(dsi->plat_data->hw_type)) {
+		ret = exynos_dsi_init(dsi);
+		if (ret)
+			return;
+	}
 }
 
 static void exynos_dsi_atomic_enable(struct drm_bridge *bridge,
@@ -1601,12 +1619,9 @@ static ssize_t exynos_dsi_host_transfer(struct mipi_dsi_host *host,
 	if (!(dsi->state & DSIM_STATE_ENABLED))
 		return -EINVAL;
 
-	if (!(dsi->state & DSIM_STATE_INITIALIZED)) {
-		ret = exynos_dsi_init(dsi);
-		if (ret)
-			return ret;
-		dsi->state |= DSIM_STATE_INITIALIZED;
-	}
+	ret = exynos_dsi_init(dsi);
+	if (ret)
+		return ret;
 
 	ret = mipi_dsi_create_packet(&xfer.packet, msg);
 	if (ret < 0)
-- 
2.25.1