[RFC 1/2] video: Add generic HDMI helpers

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Add generic helpers to pack HDMI infoframes into a binary buffers.

Signed-off-by: Thierry Reding <thierry.reding@xxxxxxxxxxxxxxxxx>
---
 drivers/video/Kconfig  |   3 ++
 drivers/video/Makefile |   1 +
 drivers/video/hdmi.c   |  84 ++++++++++++++++++++++++++++++++++
 include/linux/hdmi.h   | 119 +++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 207 insertions(+)
 create mode 100644 drivers/video/hdmi.c
 create mode 100644 include/linux/hdmi.h

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index fb9a14e..17ac897 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -52,6 +52,9 @@ config OF_VIDEOMODE
 	help
 	  helper to get videomodes from the devicetree
 
+config HDMI
+	bool
+
 menuconfig FB
 	tristate "Support for frame buffer devices"
 	---help---
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index b936b00..d1d38ea 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -5,6 +5,7 @@
 # Each configuration option enables a list of files.
 
 obj-$(CONFIG_VGASTATE)            += vgastate.o
+obj-$(CONFIG_HDMI)                += hdmi.o
 obj-y                             += fb_notify.o
 obj-$(CONFIG_FB)                  += fb.o
 fb-y                              := fbmem.o fbmon.o fbcmap.o fbsysfs.o \
diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c
new file mode 100644
index 0000000..3d6ee5e
--- /dev/null
+++ b/drivers/video/hdmi.c
@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2012 Avionic Design GmbH
+ *
+ * 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.
+ */
+
+#include <linux/bitops.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/hdmi.h>
+
+/**
+ * hdmi_avi_infoframe_pack() - write HDMI AVI infoframe to binary buffer
+ * @frame: HDMI AVI infoframe
+ * @buffer: destination buffer
+ * @size: size of buffer
+ *
+ * Packs the information contained in the @frame structure into a binary
+ * representation that can be written into the corresponding controller
+ * registers. Also computes the checksum as required by section 5.3.5 of the
+ * HDMI 1.4 specification.
+ */
+ssize_t hdmi_avi_infoframe_pack(struct hdmi_avi_infoframe *frame, void *buffer,
+				size_t size)
+{
+	u8 *ptr = buffer;
+	unsigned int i;
+	u8 csum = 0;
+
+	if (frame->length > 0x1f)
+		return -EINVAL;
+
+	ptr[0] = frame->type;
+	ptr[1] = frame->version;
+	ptr[2] = frame->length;
+	ptr[3] = 0; /* checksum */
+	ptr[4] = ((frame->colorspace & 0x3) << 5) | (frame->scan_mode & 0x3);
+
+	if (frame->active_info_valid)
+		ptr[4] |= BIT(4);
+
+	if (frame->horizontal_bar_valid)
+		ptr[4] |= BIT(3);
+
+	if (frame->vertical_bar_valid)
+		ptr[4] |= BIT(2);
+
+	ptr[5] = ((frame->colorimetry & 0x3) << 6) |
+		 ((frame->picture_aspect & 0x3) << 4) |
+		 (frame->active_aspect & 0xf);
+
+	ptr[6] = ((frame->extended_colorimetry & 0x7) << 4) |
+		 ((frame->quantization_range & 0x3) << 2) |
+		 (frame->nups & 0x3);
+
+	if (frame->itc)
+		ptr[6] |= BIT(7);
+
+	ptr[7] = frame->video_code & 0x7f;
+
+	ptr[8] = ((frame->ycc_quantization_range & 0x3) << 6) |
+		 ((frame->content_type & 0x3) << 4) |
+		 (frame->pixel_repeat & 0xf);
+
+	ptr[9] = frame->top_bar & 0xff;
+	ptr[10] = (frame->top_bar >> 8) & 0xff;
+	ptr[11] = frame->bottom_bar & 0xff;
+	ptr[12] = (frame->bottom_bar >> 8) & 0xff;
+	ptr[13] = frame->left_bar & 0xff;
+	ptr[14] = (frame->left_bar >> 8) & 0xff;
+	ptr[15] = frame->right_bar & 0xff;
+	ptr[16] = (frame->right_bar >> 8) & 0xff;
+
+	/* compute checksum */
+	for (i = 0; i < 4 + frame->length; i++)
+		csum += ptr[i];
+
+	ptr[3] = 256 - csum;
+
+	return 4 + frame->length;
+}
+EXPORT_SYMBOL_GPL(hdmi_avi_infoframe_pack);
diff --git a/include/linux/hdmi.h b/include/linux/hdmi.h
new file mode 100644
index 0000000..132556f
--- /dev/null
+++ b/include/linux/hdmi.h
@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2012 Avionic Design GmbH
+ *
+ * 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.
+ */
+
+#ifndef __LINUX_HDMI_H_
+#define __LINUX_HDMI_H_
+
+#include <linux/types.h>
+
+enum hdmi_infoframe_type {
+	HDMI_INFOFRAME_TYPE_AVI,
+};
+
+enum hdmi_colorspace {
+	HDMI_COLORSPACE_RGB,
+	HDMI_COLORSPACE_YUV422,
+	HDMI_COLORSPACE_YUV444,
+};
+
+enum hdmi_scan_mode {
+	HDMI_SCAN_MODE_NONE,
+	HDMI_SCAN_MODE_OVERSCAN,
+	HDMI_SCAN_MODE_UNDERSCAN,
+};
+
+enum hdmi_colorimetry {
+	HDMI_COLORIMETRY_NONE,
+	HDMI_COLORIMETRY_ITU_601,
+	HDMI_COLORIMETRY_ITU_709,
+	HDMI_COLORIMETRY_EXTENDED,
+};
+
+enum hdmi_picture_aspect {
+	HDMI_PICTURE_ASPECT_NONE,
+	HDMI_PICTURE_ASPECT_4_3,
+	HDMI_PICTURE_ASPECT_16_9,
+};
+
+enum hdmi_active_aspect {
+	HDMI_ACTIVE_ASPECT_16_9_TOP = 2,
+	HDMI_ACTIVE_ASPECT_14_9_TOP = 3,
+	HDMI_ACTIVE_ASPECT_16_9_CENTER = 4,
+	HDMI_ACTIVE_ASPECT_PICTURE = 8,
+	HDMI_ACTIVE_ASPECT_4_3 = 9,
+	HDMI_ACTIVE_ASPECT_16_9 = 10,
+	HDMI_ACTIVE_ASPECT_14_9 = 11,
+	HDMI_ACTIVE_ASPECT_4_3_SP_14_9 = 13,
+	HDMI_ACTIVE_ASPECT_16_9_SP_14_9 = 14,
+	HDMI_ACTIVE_ASPECT_16_9_SP_4_3 = 15,
+};
+
+enum hdmi_extended_colorimetry {
+	HDMI_EXTENDED_COLORIMETRY_XV_YCC_601,
+	HDMI_EXTENDED_COLORIMETRY_XV_YCC_709,
+	HDMI_EXTENDED_COLORIMETRY_S_YCC_601,
+	HDMI_EXTENDED_COLORIMETRY_ADOBE_YCC_601,
+	HDMI_EXTENDED_COLORIMETRY_ADOBE_RGB,
+};
+
+enum hdmi_quantization_range {
+	HDMI_QUANTIZATION_RANGE_DEFAULT,
+	HDMI_QUANTIZATION_RANGE_LIMITED,
+	HDMI_QUANTIZATION_RANGE_FULL,
+};
+
+/* non-uniform picture scaling */
+enum hdmi_nups {
+	HDMI_NUPS_UNKNOWN,
+	HDMI_NUPS_HORIZONTAL,
+	HDMI_NUPS_VERTICAL,
+	HDMI_NUPS_BOTH,
+};
+
+enum hdmi_ycc_quantization_range {
+	HDMI_YCC_QUANTIZATION_RANGE_LIMITED,
+	HDMI_YCC_QUANTIZATION_RANGE_FULL,
+};
+
+enum hdmi_content_type {
+	HDMI_CONTENT_TYPE_NONE,
+	HDMI_CONTENT_TYPE_PHOTO,
+	HDMI_CONTENT_TYPE_CINEMA,
+	HDMI_CONTENT_TYPE_GAME,
+};
+
+struct hdmi_avi_infoframe {
+	enum hdmi_infoframe_type type;
+	unsigned char version;
+	unsigned char length;
+	enum hdmi_colorspace colorspace;
+	bool active_info_valid;
+	bool horizontal_bar_valid;
+	bool vertical_bar_valid;
+	enum hdmi_scan_mode scan_mode;
+	enum hdmi_colorimetry colorimetry;
+	enum hdmi_picture_aspect picture_aspect;
+	enum hdmi_active_aspect active_aspect;
+	bool itc;
+	enum hdmi_extended_colorimetry extended_colorimetry;
+	enum hdmi_quantization_range quantization_range;
+	enum hdmi_nups nups;
+	unsigned char video_code;
+	enum hdmi_ycc_quantization_range ycc_quantization_range;
+	enum hdmi_content_type content_type;
+	unsigned char pixel_repeat;
+	unsigned short top_bar;
+	unsigned short bottom_bar;
+	unsigned short left_bar;
+	unsigned short right_bar;
+};
+
+ssize_t hdmi_avi_infoframe_pack(struct hdmi_avi_infoframe *frame, void *buffer,
+				size_t size);
+
+#endif /* _DRM_HDMI_H */
-- 
1.8.0

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