drm/mediatek: Separate poweron/poweroff from enable/disable and define new funcs

In order to match the changes of "Use the drm_panel_bridge API",
the poweron/poweroff of dsi is extracted from enable/disable and
defined as new funcs (atomic_pre_enable/atomic_post_disable).

Since dsi_poweron is moved from dsi_enable to pre_enable function, in
order to avoid poweron failure, the operation of dsi register fails to
cause bus hang. Therefore, the protection mechanism is added to the
dsi_enable function.

Fixes: 2dd8075d2185 ("drm/mediatek: mtk_dsi: Use the drm_panel_bridge API")

Link: https://patchwork.kernel.org/project/linux-mediatek/patch/1653012007-11854-3-git-send-email-xinlei.lee@mediatek.com/
Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 6e7793f..966a472 100644 (file)
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -691,16 +691,6 @@ static void mtk_dsi_poweroff(struct mtk_dsi *dsi)
        if (--dsi->refcount != 0)
                return;
 
-       /*
-        * mtk_dsi_stop() and mtk_dsi_start() is asymmetric, since
-        * mtk_dsi_stop() should be called after mtk_drm_crtc_atomic_disable(),
-        * which needs irq for vblank, and mtk_dsi_stop() will disable irq.
-        * mtk_dsi_start() needs to be called in mtk_output_dsi_enable(),
-        * after dsi is fully set.
-        */
-       mtk_dsi_stop(dsi);
-
-       mtk_dsi_switch_to_cmd_mode(dsi, VM_DONE_INT_FLAG, 500);
        mtk_dsi_reset_engine(dsi);
        mtk_dsi_lane0_ulp_mode_enter(dsi);
        mtk_dsi_clk_ulp_mode_enter(dsi);
@@ -715,17 +705,9 @@ static void mtk_dsi_poweroff(struct mtk_dsi *dsi)
 
 static void mtk_output_dsi_enable(struct mtk_dsi *dsi)
 {
-       int ret;
-
        if (dsi->enabled)
                return;
 
-       ret = mtk_dsi_poweron(dsi);
-       if (ret < 0) {
-               DRM_ERROR("failed to power on dsi\n");
-               return;
-       }
-
        mtk_dsi_set_mode(dsi);
        mtk_dsi_clk_hs_mode(dsi, 1);
 
@@ -739,7 +721,16 @@ static void mtk_output_dsi_disable(struct mtk_dsi *dsi)
        if (!dsi->enabled)
                return;
 
-       mtk_dsi_poweroff(dsi);
+       /*
+        * mtk_dsi_stop() and mtk_dsi_start() is asymmetric, since
+        * mtk_dsi_stop() should be called after mtk_drm_crtc_atomic_disable(),
+        * which needs irq for vblank, and mtk_dsi_stop() will disable irq.
+        * mtk_dsi_start() needs to be called in mtk_output_dsi_enable(),
+        * after dsi is fully set.
+        */
+       mtk_dsi_stop(dsi);
+
+       mtk_dsi_switch_to_cmd_mode(dsi, VM_DONE_INT_FLAG, 500);
 
        dsi->enabled = false;
 }
@@ -776,13 +767,37 @@ static void mtk_dsi_bridge_atomic_enable(struct drm_bridge *bridge,
 {
        struct mtk_dsi *dsi = bridge_to_dsi(bridge);
 
+       if (dsi->refcount == 0)
+               return;
+
        mtk_output_dsi_enable(dsi);
 }
 
+static void mtk_dsi_bridge_atomic_pre_enable(struct drm_bridge *bridge,
+                                            struct drm_bridge_state *old_bridge_state)
+{
+       struct mtk_dsi *dsi = bridge_to_dsi(bridge);
+       int ret;
+
+       ret = mtk_dsi_poweron(dsi);
+       if (ret < 0)
+               DRM_ERROR("failed to power on dsi\n");
+}
+
+static void mtk_dsi_bridge_atomic_post_disable(struct drm_bridge *bridge,
+                                              struct drm_bridge_state *old_bridge_state)
+{
+       struct mtk_dsi *dsi = bridge_to_dsi(bridge);
+
+       mtk_dsi_poweroff(dsi);
+}
+
 static const struct drm_bridge_funcs mtk_dsi_bridge_funcs = {
        .attach = mtk_dsi_bridge_attach,
        .atomic_disable = mtk_dsi_bridge_atomic_disable,
        .atomic_enable = mtk_dsi_bridge_atomic_enable,
+       .atomic_pre_enable = mtk_dsi_bridge_atomic_pre_enable,
+       .atomic_post_disable = mtk_dsi_bridge_atomic_post_disable,
        .mode_set = mtk_dsi_bridge_mode_set,
 };