[RFC 01/11] OMAPDSS: Add writeback output driver

@@ -99,6 +99,19 @@ config OMAP2_DSS_DSI
 
 	  See http://www.mipi.org/ for DSI specifications.
 
+config OMAP4_DSS_WRITEBACK
+	bool "writeback support"
+	default n
+	help
+	  writeback is a DISPC pipeline that takes pixel data from an overlay
+	  output or a overlay manager output and writes it back into a specified
+	  address in memory.
+
+	  writeback pipeline allows us to take benefit of the hardware
+	  processing available inside the DISPC like color space conversion,
+	  rescaling, compositing etc and perform either a memory-to-memory
+	  transfer with data processing, or capture a displayed frame.
+
 config OMAP2_DSS_MIN_FCK_PER_PCK
 	int "Minimum FCK/PCK ratio (for scaling)"
 	range 0 32

@@ -8,4 +8,5 @@ omapdss-$(CONFIG_OMAP2_DSS_SDI) += sdi.o
 omapdss-$(CONFIG_OMAP2_DSS_DSI) += dsi.o
 omapdss-$(CONFIG_OMAP4_DSS_HDMI) += hdmi.o \
 				    hdmi_panel.o ti_hdmi_4xxx_ip.o
+omapdss-$(CONFIG_OMAP4_DSS_WRITEBACK) += writeback.o
 ccflags-$(CONFIG_OMAP2_DSS_DEBUG) += -DDEBUG

@@ -528,6 +528,9 @@ static int (*dss_output_drv_reg_funcs[])(void) __initdata = {
 #ifdef CONFIG_OMAP4_DSS_HDMI
 	hdmi_init_platform_driver,
 #endif
+#ifdef CONFIG_OMAP4_DSS_WRITEBACK
+	writeback_init_platform_driver,
+#endif
 };
 
 static void (*dss_output_drv_unreg_funcs[])(void) __exitdata = {

@@ -549,6 +552,9 @@ static void (*dss_output_drv_unreg_funcs[])(void) __exitdata = {
 #ifdef CONFIG_OMAP4_DSS_HDMI
 	hdmi_uninit_platform_driver,
 #endif
+#ifdef CONFIG_OMAP4_DSS_WRITEBACK
+	writeback_uninit_platform_driver,
+#endif
 };
 
 static bool dss_output_drv_loaded[ARRAY_SIZE(dss_output_drv_reg_funcs)];

@@ -528,6 +528,12 @@ bool hdmi_mode_has_audio(void);
 int hdmi_audio_config(struct omap_dss_audio *audio);
 #endif
 
+/* Writeback */
+#ifdef CONFIG_OMAP4_DSS_WRITEBACK
+int writeback_init_platform_driver(void) __init;
+void writeback_uninit_platform_driver(void) __exit;
+#endif
+
 /* RFBI */
 int rfbi_init_platform_driver(void) __init;
 void rfbi_uninit_platform_driver(void) __exit;

@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2012 Texas Instruments
+ * Author: Archit Taneja <archit@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#define DSS_SUBSYS_NAME "WB"
+
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <video/omapdss.h>
+
+#include "dss.h"
+
+struct writeback_data {
+	struct mutex lock;
+
+	struct omap_dss_output output;
+};
+
+static inline struct writeback_data *writeback_get_drv_data(struct platform_device *wbdev)
+{
+	return dev_get_drvdata(&wbdev->dev);
+}
+
+static inline struct platform_device *writeback_get_wbdev_from_output(struct omap_dss_output *out)
+{
+	return out->pdev;
+}
+
+struct omap_dss_output *omap_dss_get_writeback(void)
+{
+	return omap_dss_get_output(OMAP_DSS_OUTPUT_WB);
+}
+EXPORT_SYMBOL(omap_dss_get_writeback);
+
+static void __init writeback_init_output(struct platform_device *pdev,
+		struct writeback_data *wb_data)
+{
+	struct omap_dss_output *out = &wb_data->output;
+
+	dss_register_output(out);
+
+	out->pdev = pdev;
+	out->id = OMAP_DSS_OUTPUT_WB;
+	out->type = OMAP_DISPLAY_TYPE_NONE;
+}
+
+static int __init omap_writeback_probe(struct platform_device *pdev)
+{
+	struct writeback_data *wb_data;
+
+	wb_data = devm_kzalloc(&pdev->dev, sizeof(*wb_data), GFP_KERNEL);
+	if (!wb_data)
+		return -ENOMEM;
+
+	dev_set_drvdata(&pdev->dev, wb_data);
+
+	mutex_init(&wb_data->lock);
+
+	writeback_init_output(pdev, wb_data);
+
+	return 0;
+}
+
+static int __exit omap_writeback_remove(struct platform_device *pdev)
+{
+	return 0;
+}
+
+static struct platform_driver omap_writeback_driver = {
+	.remove         = __exit_p(omap_writeback_remove),
+	.driver         = {
+		.name   = "omapdss_writeback",
+		.owner  = THIS_MODULE,
+	},
+};
+
+int __init writeback_init_platform_driver(void)
+{
+	return platform_driver_probe(&omap_writeback_driver,
+			omap_writeback_probe);
+}
+
+void __exit writeback_uninit_platform_driver(void)
+{
+	platform_driver_unregister(&omap_writeback_driver);
+}

@@ -217,6 +217,7 @@ enum omap_dss_output_id {
 	OMAP_DSS_OUTPUT_DSI2	= 1 << 4,
 	OMAP_DSS_OUTPUT_VENC	= 1 << 5,
 	OMAP_DSS_OUTPUT_HDMI	= 1 << 6,
+	OMAP_DSS_OUTPUT_WB	= 1 << 7,
 };
 
 /* RFBI */

@@ -836,4 +837,13 @@ void omapdss_rfbi_set_data_lines(struct omap_dss_device *dssdev,
 void omapdss_rfbi_set_interface_timings(struct omap_dss_device *dssdev,
 		struct rfbi_timings *timings);
 
+#ifdef CONFIG_OMAP4_DSS_WRITEBACK
+struct omap_dss_output *omap_dss_get_writeback(void);
+#else
+static inline struct omap_dss_output *omap_dss_get_writeback(void)
+{
+	return NULL;
+}
+#endif
+
 #endif