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 unchange HS
clock rate and forcing a full modeset when only connector's DPMS is
brought out of "Off" status.

Cc: Andrzej Hajda <a.ha...@samsung.com>
Cc: Neil Armstrong <narmstr...@baylibre.com>
Cc: Robert Foss <robert.f...@linaro.org>
Cc: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
Cc: Jonas Karlman <jo...@kwiboo.se>
Cc: Jernej Skrabec <jernej.skra...@siol.net>
Cc: David Airlie <airl...@linux.ie>
Cc: Daniel Vetter <dan...@ffwll.ch>
Cc: Guido Günther <a...@sigxcpu.org>
Cc: Robert Chiras <robert.chi...@nxp.com>
Cc: NXP Linux Team <linux-...@nxp.com>
Signed-off-by: Liu Ying <victor....@nxp.com>
---
 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 66b67402f1ac..873995f0a741 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;
@@ -742,7 +743,9 @@ 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;
@@ -803,17 +806,6 @@ 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,
@@ -831,6 +823,29 @@ 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,
@@ -846,13 +861,6 @@ 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 */
@@ -860,14 +868,8 @@ 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;
@@ -877,27 +879,29 @@ 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;
@@ -942,14 +946,16 @@ 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)
-- 
2.25.1

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