drm/dsi: Implement some standard DCS commands

Add helpers for the {enter,exit}_sleep_mode, set_display_{on,off} and
set_tear_{on,off} DCS commands.

Signed-off-by: YoungJun Cho <yj44.cho@samsung.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
[treding: kerneldoc and other minor cleanup]
Signed-off-by: Thierry Reding <treding@nvidia.com>
diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
index 5246555..b2106ad 100644
--- a/include/drm/drm_mipi_dsi.h
+++ b/include/drm/drm_mipi_dsi.h
@@ -161,12 +161,31 @@
 ssize_t mipi_dsi_generic_read(struct mipi_dsi_device *dsi, const void *params,
 			      size_t num_params, void *data, size_t size);
 
+/**
+ * enum mipi_dsi_dcs_tear_mode - Tearing Effect Output Line mode
+ * @MIPI_DSI_DCS_TEAR_MODE_VBLANK: the TE output line consists of V-Blanking
+ *    information only
+ * @MIPI_DSI_DCS_TEAR_MODE_VHBLANK : the TE output line consists of both
+ *    V-Blanking and H-Blanking information
+ */
+enum mipi_dsi_dcs_tear_mode {
+	MIPI_DSI_DCS_TEAR_MODE_VBLANK,
+	MIPI_DSI_DCS_TEAR_MODE_VHBLANK,
+};
+
 ssize_t mipi_dsi_dcs_write_buffer(struct mipi_dsi_device *dsi,
 				  const void *data, size_t len);
 ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, u8 cmd,
 			   const void *data, size_t len);
 ssize_t mipi_dsi_dcs_read(struct mipi_dsi_device *dsi, u8 cmd, void *data,
 			  size_t len);
+int mipi_dsi_dcs_enter_sleep_mode(struct mipi_dsi_device *dsi);
+int mipi_dsi_dcs_exit_sleep_mode(struct mipi_dsi_device *dsi);
+int mipi_dsi_dcs_set_display_off(struct mipi_dsi_device *dsi);
+int mipi_dsi_dcs_set_display_on(struct mipi_dsi_device *dsi);
+int mipi_dsi_dcs_set_tear_off(struct mipi_dsi_device *dsi);
+int mipi_dsi_dcs_set_tear_on(struct mipi_dsi_device *dsi,
+			     enum mipi_dsi_dcs_tear_mode mode);
 
 /**
  * struct mipi_dsi_driver - DSI driver