OMAP: DSS2: DSI: Introduce generic read functions

Introduce read functions which use generic Processor-to-Peripheral
transaction types. These are needed by some devices which may not support
corresponding DCS commands.

Add function dsi_vc_generic_send_read_request() which can send
a short packet with 0, 1 or 2 bytes of request data and the corresponding
generic data type.

Rename function dsi_vc_dcs_read_rx_fifo() to dsi_vc_read_rx_fifo() and modify
it to take the enum "dss_dsi_content_type" as an argument to use either DCS
or GENERIC Peripheral-to-Processor transaction types while parsing data read
from the device.

Signed-off-by: Archit Taneja <archit@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/include/video/omapdss.h b/include/video/omapdss.h
index a8a43de..abe8b1e 100644
--- a/include/video/omapdss.h
+++ b/include/video/omapdss.h
@@ -241,6 +241,12 @@
 		u8 *data, int len);
 int dsi_vc_dcs_read(struct omap_dss_device *dssdev, int channel, u8 dcs_cmd,
 		u8 *buf, int buflen);
+int dsi_vc_generic_read_0(struct omap_dss_device *dssdev, int channel, u8 *buf,
+		int buflen);
+int dsi_vc_generic_read_1(struct omap_dss_device *dssdev, int channel, u8 param,
+		u8 *buf, int buflen);
+int dsi_vc_generic_read_2(struct omap_dss_device *dssdev, int channel,
+		u8 param1, u8 param2, u8 *buf, int buflen);
 int dsi_vc_set_max_rx_packet_size(struct omap_dss_device *dssdev, int channel,
 		u16 len);
 int dsi_vc_send_null(struct omap_dss_device *dssdev, int channel);