[PATCH] drm/tilcdc: If CRTC is enabled at init phase, disable it

[Jyri Sarha]

If the LCDC is already enabled (e.g. by the bootloader) at the
initialization phase, disable it before returning from the probe.

Signed-off-by: Jyri Sarha <jsarha at ti.com>
Reported-by: Emiliano Ingrassia <ingrassia at epigenesys.com>
---
This patch should fix the same issus as this patch does:
https://lists.freedesktop.org/archives/dri-devel/2017-March/137091.html

I do not like the above patch duplicating the already existing code
for CRTC disable. Another issue is making the check every time the
CRTC is turned on.

 drivers/gpu/drm/tilcdc/tilcdc_crtc.c | 21 +++++++++++++++++++++
 drivers/gpu/drm/tilcdc/tilcdc_drv.c  |  3 +++
 drivers/gpu/drm/tilcdc/tilcdc_drv.h  |  1 +
 3 files changed, 25 insertions(+)

diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
index afd2a7b..540378a 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
@@ -566,6 +566,26 @@ void tilcdc_crtc_shutdown(struct drm_crtc *crtc)
 	tilcdc_crtc_off(crtc, true);
 }
 
+void tilcdc_crtc_disable_init(struct drm_crtc *crtc)
+{
+	struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc);
+	struct drm_device *dev = crtc->dev;
+
+	/*
+	 * If the LCDC was already enabled (e.g. by the bootloader)
+	 * disable the CRTC before finishing the probe.
+	 */
+	pm_runtime_get_sync(dev->dev);
+	if (tilcdc_read(dev, LCDC_RASTER_CTRL_REG) & LCDC_RASTER_ENABLE) {
+		tilcdc_crtc->enabled = true;
+		tilcdc_crtc_enable_irqs(dev);
+		/* To match pm_runtime_put_sync() in tilcdc_crtc_off() */
+		pm_runtime_get_sync(dev->dev);
+		tilcdc_crtc_off(crtc, false);
+	}
+	pm_runtime_put_sync(dev->dev);
+}
+
 static bool tilcdc_crtc_is_on(struct drm_crtc *crtc)
 {
 	return crtc->state && crtc->state->enable && crtc->state->active;
@@ -1054,6 +1074,7 @@ int tilcdc_crtc_create(struct drm_device *dev)
 	}
 
 	priv->crtc = crtc;
+
 	return 0;
 
 fail:
diff --git a/drivers/gpu/drm/tilcdc/tilcdc_drv.c b/drivers/gpu/drm/tilcdc/tilcdc_drv.c
index d7ae5be..7dabe55 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_drv.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_drv.c
@@ -415,6 +415,9 @@ static int tilcdc_init(struct drm_driver *ddrv, struct device *dev)
 		goto init_failed;
 
 	priv->is_registered = true;
+
+	tilcdc_crtc_disable_init(priv->crtc);
+
 	return 0;
 
 init_failed:
diff --git a/drivers/gpu/drm/tilcdc/tilcdc_drv.h b/drivers/gpu/drm/tilcdc/tilcdc_drv.h
index 8caa11b..adde1e4 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_drv.h
+++ b/drivers/gpu/drm/tilcdc/tilcdc_drv.h
@@ -179,6 +179,7 @@ void tilcdc_crtc_set_simulate_vesa_sync(struct drm_crtc *crtc,
 int tilcdc_crtc_update_fb(struct drm_crtc *crtc,
 		struct drm_framebuffer *fb,
 		struct drm_pending_vblank_event *event);
+void tilcdc_crtc_disable_init(struct drm_crtc *crtc);
 
 int tilcdc_plane_init(struct drm_device *dev, struct drm_plane *plane);
 
-- 
1.9.1