From: Koji Matsuoka <koji.matsuoka.xm@xxxxxxxxxxx>
According to hardware manual, LVDCR0 register must be cleared bit by bit
when disabling LVDS.
Signed-off-by: Koji Matsuoka <koji.matsuoka.xm@xxxxxxxxxxx>
Signed-off-by: LUU HOAI <hoai.luu.ub@xxxxxxxxxxx>
[tomi.valkeinen: simplified the code a bit]
Signed-off-by: Tomi Valkeinen <tomi.valkeinen+renesas@xxxxxxxxxxxxxxxx>
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
---
Changes since v3:
- Add comment explaining the register clear sequence
---
drivers/gpu/drm/rcar-du/rcar_lvds.c | 31 +++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
index a11201e4d31b..260ea5d8624e 100644
--- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
+++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
@@ -83,6 +83,11 @@ struct rcar_lvds {
#define bridge_to_rcar_lvds(b) \
container_of(b, struct rcar_lvds, bridge)
+static u32 rcar_lvds_read(struct rcar_lvds *lvds, u32 reg)
+{
+ return ioread32(lvds->mmio + reg);
+}
+
static void rcar_lvds_write(struct rcar_lvds *lvds, u32 reg, u32 data)
{
iowrite32(data, lvds->mmio + reg);
@@ -544,6 +549,32 @@ static void rcar_lvds_atomic_disable(struct drm_bridge *bridge,
struct drm_bridge_state *old_bridge_state)
{
struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
+ u32 lvdcr0;
+
+ /*
+ * Clear the LVDCR0 bits in the order specified by the hardware
+ * documentation, ending with a write of 0 to the full register to
+ * clear all remaining bits.
+ */
+ lvdcr0 = rcar_lvds_read(lvds, LVDCR0);
+
+ lvdcr0 &= ~LVDCR0_LVRES;
+ rcar_lvds_write(lvds, LVDCR0, lvdcr0);
+
+ if (lvds->info->quirks & RCAR_LVDS_QUIRK_GEN3_LVEN) {
+ lvdcr0 &= ~LVDCR0_LVEN;
+ rcar_lvds_write(lvds, LVDCR0, lvdcr0);
+ }
+
+ if (lvds->info->quirks & RCAR_LVDS_QUIRK_PWD) {
+ lvdcr0 &= ~LVDCR0_PWD;
+ rcar_lvds_write(lvds, LVDCR0, lvdcr0);
+ }
+
+ if (!(lvds->info->quirks & RCAR_LVDS_QUIRK_EXT_PLL)) {
+ lvdcr0 &= ~LVDCR0_PLLON;
+ rcar_lvds_write(lvds, LVDCR0, lvdcr0);
+ }
rcar_lvds_write(lvds, LVDCR0, 0);
rcar_lvds_write(lvds, LVDCR1, 0);
--
Regards,
Laurent Pinchart
