[PATCH v2] drm/bridge: nwl-dsi: Get MIPI DSI controller and PHY ready in ->mode_set()

[Liu Ying]

Some MIPI DSI panel drivers like 'raydium,rm68200' send
MIPI_DCS_SET_DISPLAY_ON commands in panel_funcs->prepare(), which
requires the MIPI DSI controller and PHY to be ready beforehand.
Without this patch, the nwl-dsi driver gets the MIPI DSI controller
and PHY ready in bridge_funcs->pre_enable(), which happens after
the panel_funcs->prepare(). So, this patch shifts the bridge operation
ealier from bridge_funcs->pre_enable() to bridge_funcs->mode_set().
This way, more MIPI DSI panels can connect to this nwl-dsi bridge.
Care is taken to make sure bridge_funcs->mode_set()/atomic_disable()
are called in pairs, which includes removing a check on unchanged HS
clock rate and forcing a full modeset when only connector's DPMS is
brought out of "Off" status.

Cc: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
Cc: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
Cc: Robert Foss <robert.foss@xxxxxxxxxx>
Cc: Laurent Pinchart <Laurent.pinchart@xxxxxxxxxxxxxxxx>
Cc: Jonas Karlman <jonas@xxxxxxxxx>
Cc: Jernej Skrabec <jernej.skrabec@xxxxxxxx>
Cc: David Airlie <airlied@xxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: Guido Günther <agx@xxxxxxxxxxx>
Cc: Robert Chiras <robert.chiras@xxxxxxx>
Cc: NXP Linux Team <linux-imx@xxxxxxx>
Signed-off-by: Liu Ying <victor.liu@xxxxxxx>
---
v1->v2:
* Fix commit message typo - s/unchange/unchanged/

 drivers/gpu/drm/bridge/nwl-dsi.c | 86 +++++++++++++++++++++-------------------
 1 file changed, 46 insertions(+), 40 deletions(-)

diff --git a/drivers/gpu/drm/bridge/nwl-dsi.c b/drivers/gpu/drm/bridge/nwl-dsi.c
index be6bfc5..229f0b1 100644
--- a/drivers/gpu/drm/bridge/nwl-dsi.c
+++ b/drivers/gpu/drm/bridge/nwl-dsi.c
@@ -21,6 +21,7 @@
 #include <linux/sys_soc.h>
 #include <linux/time64.h>
 
+#include <drm/drm_atomic_state_helper.h>
 #include <drm/drm_bridge.h>
 #include <drm/drm_mipi_dsi.h>
 #include <drm/drm_of.h>
@@ -661,7 +662,7 @@ static irqreturn_t nwl_dsi_irq_handler(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
-static int nwl_dsi_enable(struct nwl_dsi *dsi)
+static int nwl_dsi_mode_set(struct nwl_dsi *dsi)
 {
 	struct device *dev = dsi->dev;
 	union phy_configure_opts *phy_cfg = &dsi->phy_cfg;
@@ -748,7 +749,9 @@ static int nwl_dsi_disable(struct nwl_dsi *dsi)
 	return 0;
 }
 
-static void nwl_dsi_bridge_disable(struct drm_bridge *bridge)
+static void
+nwl_dsi_bridge_atomic_disable(struct drm_bridge *bridge,
+			      struct drm_bridge_state *old_bridge_state)
 {
 	struct nwl_dsi *dsi = bridge_to_dsi(bridge);
 	int ret;
@@ -809,17 +812,6 @@ static int nwl_dsi_get_dphy_params(struct nwl_dsi *dsi,
 	return 0;
 }
 
-static bool nwl_dsi_bridge_mode_fixup(struct drm_bridge *bridge,
-				      const struct drm_display_mode *mode,
-				      struct drm_display_mode *adjusted_mode)
-{
-	/* At least LCDIF + NWL needs active high sync */
-	adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC);
-	adjusted_mode->flags &= ~(DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC);
-
-	return true;
-}
-
 static enum drm_mode_status
 nwl_dsi_bridge_mode_valid(struct drm_bridge *bridge,
 			  const struct drm_display_info *info,
@@ -837,6 +829,29 @@ nwl_dsi_bridge_mode_valid(struct drm_bridge *bridge,
 	return MODE_OK;
 }
 
+static int nwl_dsi_bridge_atomic_check(struct drm_bridge *bridge,
+				       struct drm_bridge_state *bridge_state,
+				       struct drm_crtc_state *crtc_state,
+				       struct drm_connector_state *conn_state)
+{
+	struct drm_display_mode *adjusted_mode = &crtc_state->adjusted_mode;
+
+	/* At least LCDIF + NWL needs active high sync */
+	adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC);
+	adjusted_mode->flags &= ~(DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC);
+
+	/*
+	 * Do a full modeset if crtc_state->active is changed to be true.
+	 * This ensures our ->mode_set() is called to get the DSI controller
+	 * and the PHY ready to send DCS commands, when only the connector's
+	 * DPMS is brought out of "Off" status.
+	 */
+	if (crtc_state->active_changed && crtc_state->active)
+		crtc_state->mode_changed = true;
+
+	return 0;
+}
+
 static void
 nwl_dsi_bridge_mode_set(struct drm_bridge *bridge,
 			const struct drm_display_mode *mode,
@@ -852,13 +867,6 @@ nwl_dsi_bridge_mode_set(struct drm_bridge *bridge,
 	if (ret < 0)
 		return;
 
-	/*
-	 * If hs clock is unchanged, we're all good - all parameters are
-	 * derived from it atm.
-	 */
-	if (new_cfg.mipi_dphy.hs_clk_rate == dsi->phy_cfg.mipi_dphy.hs_clk_rate)
-		return;
-
 	phy_ref_rate = clk_get_rate(dsi->phy_ref_clk);
 	DRM_DEV_DEBUG_DRIVER(dev, "PHY at ref rate: %lu\n", phy_ref_rate);
 	/* Save the new desired phy config */
@@ -866,14 +874,8 @@ nwl_dsi_bridge_mode_set(struct drm_bridge *bridge,
 
 	memcpy(&dsi->mode, adjusted_mode, sizeof(dsi->mode));
 	drm_mode_debug_printmodeline(adjusted_mode);
-}
 
-static void nwl_dsi_bridge_pre_enable(struct drm_bridge *bridge)
-{
-	struct nwl_dsi *dsi = bridge_to_dsi(bridge);
-	int ret;
-
-	pm_runtime_get_sync(dsi->dev);
+	pm_runtime_get_sync(dev);
 
 	if (clk_prepare_enable(dsi->lcdif_clk) < 0)
 		return;
@@ -883,27 +885,29 @@ static void nwl_dsi_bridge_pre_enable(struct drm_bridge *bridge)
 	/* Step 1 from DSI reset-out instructions */
 	ret = reset_control_deassert(dsi->rst_pclk);
 	if (ret < 0) {
-		DRM_DEV_ERROR(dsi->dev, "Failed to deassert PCLK: %d\n", ret);
+		DRM_DEV_ERROR(dev, "Failed to deassert PCLK: %d\n", ret);
 		return;
 	}
 
 	/* Step 2 from DSI reset-out instructions */
-	nwl_dsi_enable(dsi);
+	nwl_dsi_mode_set(dsi);
 
 	/* Step 3 from DSI reset-out instructions */
 	ret = reset_control_deassert(dsi->rst_esc);
 	if (ret < 0) {
-		DRM_DEV_ERROR(dsi->dev, "Failed to deassert ESC: %d\n", ret);
+		DRM_DEV_ERROR(dev, "Failed to deassert ESC: %d\n", ret);
 		return;
 	}
 	ret = reset_control_deassert(dsi->rst_byte);
 	if (ret < 0) {
-		DRM_DEV_ERROR(dsi->dev, "Failed to deassert BYTE: %d\n", ret);
+		DRM_DEV_ERROR(dev, "Failed to deassert BYTE: %d\n", ret);
 		return;
 	}
 }
 
-static void nwl_dsi_bridge_enable(struct drm_bridge *bridge)
+static void
+nwl_dsi_bridge_atomic_enable(struct drm_bridge *bridge,
+			     struct drm_bridge_state *old_bridge_state)
 {
 	struct nwl_dsi *dsi = bridge_to_dsi(bridge);
 	int ret;
@@ -948,14 +952,16 @@ static void nwl_dsi_bridge_detach(struct drm_bridge *bridge)
 }
 
 static const struct drm_bridge_funcs nwl_dsi_bridge_funcs = {
-	.pre_enable = nwl_dsi_bridge_pre_enable,
-	.enable     = nwl_dsi_bridge_enable,
-	.disable    = nwl_dsi_bridge_disable,
-	.mode_fixup = nwl_dsi_bridge_mode_fixup,
-	.mode_set   = nwl_dsi_bridge_mode_set,
-	.mode_valid = nwl_dsi_bridge_mode_valid,
-	.attach	    = nwl_dsi_bridge_attach,
-	.detach	    = nwl_dsi_bridge_detach,
+	.atomic_duplicate_state	= drm_atomic_helper_bridge_duplicate_state,
+	.atomic_destroy_state	= drm_atomic_helper_bridge_destroy_state,
+	.atomic_reset		= drm_atomic_helper_bridge_reset,
+	.atomic_check		= nwl_dsi_bridge_atomic_check,
+	.atomic_enable		= nwl_dsi_bridge_atomic_enable,
+	.atomic_disable		= nwl_dsi_bridge_atomic_disable,
+	.mode_set		= nwl_dsi_bridge_mode_set,
+	.mode_valid		= nwl_dsi_bridge_mode_valid,
+	.attach			= nwl_dsi_bridge_attach,
+	.detach			= nwl_dsi_bridge_detach,
 };
 
 static int nwl_dsi_parse_dt(struct nwl_dsi *dsi)
-- 
2.7.4