When the DSI is in video mode, all commands are rejected.

Detect current DSI mode in mtk_dsi_host_transfer() and switch modes
temporarily to allow commands to be sent.

Signed-off-by: Julien STEPHAN <jstephan@baylibre.com>
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 34 ++++++++++++++++++++++--------
 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 5d90d2eb0019..7d66fdc7f81d 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -891,24 +891,34 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
 	u8 read_data[16];
 	void *src_addr;
 	u8 irq_flag = CMD_DONE_INT_FLAG;
-
-	if (readl(dsi->regs + DSI_MODE_CTRL) & MODE) {
-		DRM_ERROR("dsi engine is not command mode\n");
-		return -EINVAL;
+	u32 dsi_mode;
+
+	dsi_mode = readl(dsi->regs + DSI_MODE_CTRL);
+	if (dsi_mode & MODE) {
+		mtk_dsi_stop(dsi);
+		if (mtk_dsi_switch_to_cmd_mode(dsi, VM_DONE_INT_FLAG, 500)) {
+			recv_cnt = -EINVAL;
+			goto restore_dsi_mode;
+		}
 	}
 
 	if (MTK_DSI_HOST_IS_READ(msg->type))
 		irq_flag |= LPRX_RD_RDY_INT_FLAG;
 
-	if (mtk_dsi_host_send_cmd(dsi, msg, irq_flag) < 0)
-		return -ETIME;
+	if (mtk_dsi_host_send_cmd(dsi, msg, irq_flag) < 0) {
+		recv_cnt = -ETIME;
+		goto restore_dsi_mode;
+	}
 
-	if (!MTK_DSI_HOST_IS_READ(msg->type))
-		return 0;
+	if (!MTK_DSI_HOST_IS_READ(msg->type)) {
+		recv_cnt = 0;
+		goto restore_dsi_mode;
+	}
 
 	if (!msg->rx_buf) {
 		DRM_ERROR("dsi receive buffer size may be NULL\n");
-		return -EINVAL;
+		recv_cnt = -EINVAL;
+		goto restore_dsi_mode;
 	}
 
 	for (i = 0; i < 16; i++)
@@ -933,6 +943,12 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
 	DRM_INFO("dsi get %d byte data from the panel address(0x%x)\n",
 		 recv_cnt, *((u8 *)(msg->tx_buf)));
 
+restore_dsi_mode:
+	if (dsi_mode & MODE) {
+		mtk_dsi_set_mode(dsi);
+		mtk_dsi_start(dsi);
+	}
+
 	return recv_cnt;
 }
 
-- 
2.34.1