drm/msm/dsi: Enable BURST_MODE for command mode for DSI 6G v1.3+

During a frame transfer in command mode, there could be frequent
LP11 <-> HS transitions when multiple DCS commands are sent mid-frame or
if the DSI controller is running on slow clock and is throttled. To
minimize frame latency due to these transitions, it is recommended to
send the frame in a single burst.

This feature is supported for DSI 6G 1.3 and above, thus enable burst
mode if supported.
Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/544551/
Link: https://lore.kernel.org/r/20230608-b4-add-burst-mode-v2-1-2ff468457d46@quicinc.com
[DB: fixed indentation]
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

drivers/gpu/drm/msm/dsi/dsi_host.c

@@ -752,6 +752,13 @@ static void dsi_ctrl_enable(struct msm_dsi_host *msm_host,
 		/* Always insert DCS command */
 		data |= DSI_CMD_CFG1_INSERT_DCS_COMMAND;
 		dsi_write(msm_host, REG_DSI_CMD_CFG1, data);
+
+		if (msm_host->cfg_hnd->major == MSM_DSI_VER_MAJOR_6G &&
+		    msm_host->cfg_hnd->minor >= MSM_DSI_6G_VER_MINOR_V1_3) {
+			data = dsi_read(msm_host, REG_DSI_CMD_MODE_MDP_CTRL2);
+			data |= DSI_CMD_MODE_MDP_CTRL2_BURST_MODE;
+			dsi_write(msm_host, REG_DSI_CMD_MODE_MDP_CTRL2, data);
+		}
 	}
 
 	dsi_write(msm_host, REG_DSI_CMD_DMA_CTRL,