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authorTomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>2024-12-17 07:31:36 +0200
committerTomi Valkeinen <tomi.valkeinen@ideasonboard.com>2024-12-17 15:12:35 +0200
commitbb5f268b7662469b47e9b518c2353803bc7f4ec9 (patch)
tree91efc2832bbf2bdcbcb92bd8900a46da84554a7f /drivers/gpu
parent6389e616fae8a101ce00068f7690461ab57b29d8 (diff)
drm/rcar-du: Write DPTSR only if the second source exists
Currently the driver always writes DPTSR when setting up the hardware. However, writing the register is only meaningful when the second source for a plane is used, and the register is not even documented for SoCs that do not have the second source. So move the write behind a condition. Signed-off-by: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Tested-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> # On R-Car M3-N Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> Link: https://patchwork.freedesktop.org/patch/msgid/20241217-rcar-gh-dsi-v5-2-e77421093c05@ideasonboard.com
Diffstat (limited to 'drivers/gpu')
-rw-r--r--drivers/gpu/drm/renesas/rcar-du/rcar_du_group.c20
1 files changed, 15 insertions, 5 deletions
diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_du_group.c b/drivers/gpu/drm/renesas/rcar-du/rcar_du_group.c
index 2ccd2581f544..1ec806c8e013 100644
--- a/drivers/gpu/drm/renesas/rcar-du/rcar_du_group.c
+++ b/drivers/gpu/drm/renesas/rcar-du/rcar_du_group.c
@@ -185,11 +185,21 @@ static void rcar_du_group_setup(struct rcar_du_group *rgrp)
dorcr |= DORCR_PG1T | DORCR_DK1S | DORCR_PG1D_DS1;
rcar_du_group_write(rgrp, DORCR, dorcr);
- /* Apply planes to CRTCs association. */
- mutex_lock(&rgrp->lock);
- rcar_du_group_write(rgrp, DPTSR, (rgrp->dptsr_planes << 16) |
- rgrp->dptsr_planes);
- mutex_unlock(&rgrp->lock);
+ /*
+ * DPTSR is used to select the source for the planes of a group. The
+ * first source is chosen by writing 0 to the respective bits, and this
+ * is always the default value of the register. In other words, writing
+ * DPTSR is only needed if the SoC supports choosing the second source.
+ *
+ * The SoCs documentations seems to confirm this, as the DPTSR register
+ * is not documented if only the first source exists on that SoC.
+ */
+ if (rgrp->channels_mask & BIT(1)) {
+ mutex_lock(&rgrp->lock);
+ rcar_du_group_write(rgrp, DPTSR, (rgrp->dptsr_planes << 16) |
+ rgrp->dptsr_planes);
+ mutex_unlock(&rgrp->lock);
+ }
}
/*