[PATCH] drm/bridge: ti-sn65dsi83: Move PLL initialization to atomic_enable

[Paul Geurts]

Some MIPI DSI encoder drivers, like the Samsung DSI controller found in
i.MX8M Mini, enable the DSI clock on encoder enable. The sn65dsi83
pre_enable is executed before the DSIM encoder enable. As the DSI input
clock is the PLL input clock, the PLL cannot be locked in pre_enable.

Enable and lock the PLL in enable instead of pre_enable, to make sure
the input clock is available.

Fixes: dd9e329af723 ("drm/bridge: ti-sn65dsi83: Fix enable/disable flow to meet spec")
Signed-off-by: Paul Geurts <paul.geurts@xxxxxxxxxxxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/bridge/ti-sn65dsi83.c | 35 +++++++++++++--------------
 1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi83.c b/drivers/gpu/drm/bridge/ti-sn65dsi83.c
index 17a885244e1e..018e524c473c 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi83.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi83.c
@@ -525,7 +525,6 @@ static void sn65dsi83_atomic_pre_enable(struct drm_bridge *bridge,
 	struct drm_crtc *crtc;
 	bool lvds_format_24bpp;
 	bool lvds_format_jeida;
-	unsigned int pval;
 	__le16 le16val;
 	u16 val;
 	int ret;
@@ -670,6 +669,21 @@ static void sn65dsi83_atomic_pre_enable(struct drm_bridge *bridge,
 		     mode->vsync_start - mode->vdisplay);
 	regmap_write(ctx->regmap, REG_VID_CHA_TEST_PATTERN, 0x00);
 
+	devm_add_action(ctx->dev, sn65dsi83_release_resources, ctx);
+err_exit:
+	drm_bridge_exit(idx);
+}
+
+static void sn65dsi83_atomic_enable(struct drm_bridge *bridge,
+				    struct drm_atomic_state *state)
+{
+	struct sn65dsi83 *ctx = bridge_to_sn65dsi83(bridge);
+	unsigned int pval;
+	int idx, ret;
+
+	if (!drm_bridge_enter(bridge, &idx))
+		return;
+
 	/* Enable PLL */
 	regmap_write(ctx->regmap, REG_RC_PLL_EN, REG_RC_PLL_EN_PLL_EN);
 	usleep_range(3000, 4000);
@@ -680,7 +694,7 @@ static void sn65dsi83_atomic_pre_enable(struct drm_bridge *bridge,
 		dev_err(ctx->dev, "failed to lock PLL, ret=%i\n", ret);
 		/* On failure, disable PLL again and exit. */
 		regmap_write(ctx->regmap, REG_RC_PLL_EN, 0x00);
-		goto err_add_action;
+		goto out;
 	}
 
 	/* Trigger reset after CSR register update. */
@@ -689,22 +703,6 @@ static void sn65dsi83_atomic_pre_enable(struct drm_bridge *bridge,
 	/* Wait for 10ms after soft reset as specified in datasheet */
 	usleep_range(10000, 12000);
 
-err_add_action:
-	devm_add_action(ctx->dev, sn65dsi83_release_resources, ctx);
-err_exit:
-	drm_bridge_exit(idx);
-}
-
-static void sn65dsi83_atomic_enable(struct drm_bridge *bridge,
-				    struct drm_atomic_state *state)
-{
-	struct sn65dsi83 *ctx = bridge_to_sn65dsi83(bridge);
-	unsigned int pval;
-	int idx;
-
-	if (!drm_bridge_enter(bridge, &idx))
-		return;
-
 	/* Clear all errors that got asserted during initialization. */
 	regmap_read(ctx->regmap, REG_IRQ_STAT, &pval);
 	regmap_write(ctx->regmap, REG_IRQ_STAT, pval);
@@ -724,6 +722,7 @@ static void sn65dsi83_atomic_enable(struct drm_bridge *bridge,
 		sn65dsi83_monitor_start(ctx);
 	}
 
+out:
 	drm_bridge_exit(idx);
 }
 
-- 
2.39.2