edid: Library of EDID decode and print

This implements a library for accessing EDID data from an LCD panel.
This is used to obtain information about the panel such as its
resolution and type.

This is a tidied-up version of the original code pulled from
https://github.com/ynezz/u-boot-edid.

The changes we made are:
 - removed bit fields in the struct;
 - removed endianness cases in the struct;
 - fixed some wrong definitions;
 - fixed to fit 80 columns;
 - fixed some code styles.

Signed-off-by: Tom Wai-Hong Tam <waihong@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>

1 files changed, 275 insertions, 0 deletions

diff --git a/include/edid.h b/include/edid.h
new file mode 100644
index 0000000..4788de9
--- /dev/null
+++ b/include/edid.h
@@ -0,0 +1,275 @@
+/*
+ * Copyright (c) 2012 The Chromium OS Authors.
+ *
+ * (C) Copyright 2010
+ * Petr Stetiar <ynezz@true.cz>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ *
+ * Contains stolen code from ddcprobe project which is:
+ * Copyright (C) Nalin Dahyabhai <bigfun@pobox.com>
+ *
+ */
+
+#ifndef __EDID_H_
+#define __EDID_H_
+
+#include <linux/types.h>
+
+#define GET_BIT(_x, _pos) \
+	(((_x) >> (_pos)) & 1)
+#define GET_BITS(_x, _pos_msb, _pos_lsb) \
+	(((_x) >> (_pos_lsb)) & ((1 << ((_pos_msb) - (_pos_lsb) + 1)) - 1))
+
+/* Aspect ratios used in EDID info. */
+enum edid_aspect {
+	ASPECT_625 = 0,
+	ASPECT_75,
+	ASPECT_8,
+	ASPECT_5625,
+};
+
+/* Detailed timing information used in EDID v1.x */
+struct edid_detailed_timing {
+	unsigned char pixel_clock[2];
+#define EDID_DETAILED_TIMING_PIXEL_CLOCK(_x) \
+	(((((uint32_t)(_x).pixel_clock[1]) << 8) + \
+	 (_x).pixel_clock[0]) * 10000)
+	unsigned char horizontal_active;
+	unsigned char horizontal_blanking;
+	unsigned char horizontal_active_blanking_hi;
+#define EDID_DETAILED_TIMING_HORIZONTAL_ACTIVE(_x) \
+	((GET_BITS((_x).horizontal_active_blanking_hi, 7, 4) << 8) + \
+	 (_x).horizontal_active)
+#define EDID_DETAILED_TIMING_HORIZONTAL_BLANKING(_x) \
+	((GET_BITS((_x).horizontal_active_blanking_hi, 3, 0) << 8) + \
+	 (_x).horizontal_blanking)
+	unsigned char vertical_active;
+	unsigned char vertical_blanking;
+	unsigned char vertical_active_blanking_hi;
+#define EDID_DETAILED_TIMING_VERTICAL_ACTIVE(_x) \
+	((GET_BITS((_x).vertical_active_blanking_hi, 7, 4) << 8) + \
+	 (_x).vertical_active)
+#define EDID_DETAILED_TIMING_VERTICAL_BLANKING(_x) \
+	((GET_BITS((_x).vertical_active_blanking_hi, 3, 0) << 8) + \
+	 (_x).vertical_blanking)
+	unsigned char hsync_offset;
+	unsigned char hsync_pulse_width;
+	unsigned char sync_offset_pulse_width;
+	unsigned char hsync_vsync_offset_pulse_width_hi;
+#define EDID_DETAILED_TIMING_HSYNC_OFFSET(_x) \
+	((GET_BITS((_x).hsync_vsync_offset_pulse_width_hi, 7, 6) << 8) + \
+	 (_x).hsync_offset)
+#define EDID_DETAILED_TIMING_HSYNC_PULSE_WIDTH(_x) \
+	((GET_BITS((_x).hsync_vsync_offset_pulse_width_hi, 5, 4) << 8) + \
+	 (_x).hsync_pulse_width)
+#define EDID_DETAILED_TIMING_VSYNC_OFFSET(_x) \
+	((GET_BITS((_x).hsync_vsync_offset_pulse_width_hi, 3, 2) << 4) + \
+	 GET_BITS((_x).vsync_offset_pulse_width, 7, 4))
+#define EDID_DETAILED_TIMING_VSYNC_PULSE_WIDTH(_x) \
+	((GET_BITS((_x).hsync_vsync_offset_pulse_width_hi, 1, 0) << 4) + \
+	 GET_BITS((_x).vsync_offset_pulse_width, 3, 0))
+	unsigned char himage_size;
+	unsigned char vimage_size;
+	unsigned char himage_vimage_size_hi;
+#define EDID_DETAILED_TIMING_HIMAGE_SIZE(_x) \
+	((GET_BITS((_x).himage_vimage_size_hi, 7, 4) << 8) + (_x).himage_size)
+#define EDID_DETAILED_TIMING_VIMAGE_SIZE(_x) \
+	((GET_BITS((_x).himage_vimage_size_hi, 3, 0) << 8) + (_x).vimage_size)
+	unsigned char hborder;
+	unsigned char vborder;
+	unsigned char flags;
+#define EDID_DETAILED_TIMING_FLAG_INTERLACED(_x) \
+	GET_BIT((_x).flags, 7)
+#define EDID_DETAILED_TIMING_FLAG_STEREO(_x) \
+	GET_BITS((_x).flags, 6, 5)
+#define EDID_DETAILED_TIMING_FLAG_DIGITAL_COMPOSITE(_x) \
+	GET_BITS((_x).flags, 4, 3)
+#define EDID_DETAILED_TIMING_FLAG_POLARITY(_x) \
+	GET_BITS((_x).flags, 2, 1)
+#define EDID_DETAILED_TIMING_FLAG_INTERLEAVED(_x) \
+	GET_BIT((_x).flags, 0)
+} __attribute__ ((__packed__));
+
+enum edid_monitor_descriptor_types {
+	EDID_MONITOR_DESCRIPTOR_SERIAL = 0xff,
+	EDID_MONITOR_DESCRIPTOR_ASCII = 0xfe,
+	EDID_MONITOR_DESCRIPTOR_RANGE = 0xfd,
+	EDID_MONITOR_DESCRIPTOR_NAME = 0xfc,
+};
+
+struct edid_monitor_descriptor {
+	uint16_t zero_flag_1;
+	unsigned char zero_flag_2;
+	unsigned char type;
+	unsigned char zero_flag_3;
+	union {
+		char string[13];
+		struct {
+			unsigned char vertical_min;
+			unsigned char vertical_max;
+			unsigned char horizontal_min;
+			unsigned char horizontal_max;
+			unsigned char pixel_clock_max;
+			unsigned char gtf_data[8];
+		} range_data;
+	} data;
+} __attribute__ ((__packed__));
+
+struct edid1_info {
+	unsigned char header[8];
+	unsigned char manufacturer_name[2];
+#define EDID1_INFO_MANUFACTURER_NAME_ZERO(_x) \
+	GET_BIT(((_x).manufacturer_name[0]), 7)
+#define EDID1_INFO_MANUFACTURER_NAME_CHAR1(_x) \
+	GET_BITS(((_x).manufacturer_name[0]), 6, 2)
+#define EDID1_INFO_MANUFACTURER_NAME_CHAR2(_x) \
+	((GET_BITS(((_x).manufacturer_name[0]), 1, 0) << 3) + \
+	 GET_BITS(((_x).manufacturer_name[1]), 7, 5))
+#define EDID1_INFO_MANUFACTURER_NAME_CHAR3(_x) \
+	GET_BITS(((_x).manufacturer_name[1]), 4, 0)
+	unsigned char product_code[2];
+#define EDID1_INFO_PRODUCT_CODE(_x) \
+	(((uint16_t)(_x).product_code[1] << 8) + (_x).product_code[0])
+	unsigned char serial_number[4];
+#define EDID1_INFO_SERIAL_NUMBER(_x) \
+	(((uint32_t)(_x).serial_number[3] << 24) + \
+	 ((_x).serial_number[2] << 16) + ((_x).serial_number[1] << 8) + \
+	 (_x).serial_number[0])
+	unsigned char week;
+	unsigned char year;
+	unsigned char version;
+	unsigned char revision;
+	unsigned char video_input_definition;
+#define EDID1_INFO_VIDEO_INPUT_DIGITAL(_x) \
+	GET_BIT(((_x).video_input_definition), 7)
+#define EDID1_INFO_VIDEO_INPUT_VOLTAGE_LEVEL(_x) \
+	GET_BITS(((_x).video_input_definition), 6, 5)
+#define EDID1_INFO_VIDEO_INPUT_BLANK_TO_BLACK(_x) \
+	GET_BIT(((_x).video_input_definition), 4)
+#define EDID1_INFO_VIDEO_INPUT_SEPARATE_SYNC(_x) \
+	GET_BIT(((_x).video_input_definition), 3)
+#define EDID1_INFO_VIDEO_INPUT_COMPOSITE_SYNC(_x) \
+	GET_BIT(((_x).video_input_definition), 2)
+#define EDID1_INFO_VIDEO_INPUT_SYNC_ON_GREEN(_x) \
+	GET_BIT(((_x).video_input_definition), 1)
+#define EDID1_INFO_VIDEO_INPUT_SERRATION_V(_x) \
+	GET_BIT(((_x).video_input_definition), 0)
+	unsigned char max_size_horizontal;
+	unsigned char max_size_vertical;
+	unsigned char gamma;
+	unsigned char feature_support;
+#define EDID1_INFO_FEATURE_STANDBY(_x) \
+	GET_BIT(((_x).feature_support), 7)
+#define EDID1_INFO_FEATURE_SUSPEND(_x) \
+	GET_BIT(((_x).feature_support), 6)
+#define EDID1_INFO_FEATURE_ACTIVE_OFF(_x) \
+	GET_BIT(((_x).feature_support), 5)
+#define EDID1_INFO_FEATURE_DISPLAY_TYPE(_x) \
+	GET_BITS(((_x).feature_support), 4, 3)
+#define EDID1_INFO_FEATURE_RGB(_x) \
+	GET_BIT(((_x).feature_support), 2)
+#define EDID1_INFO_FEATURE_PREFERRED_TIMING_MODE(_x) \
+	GET_BIT(((_x).feature_support), 1)
+#define EDID1_INFO_FEATURE_DEFAULT_GTF_SUPPORT(_x) \
+	GET_BIT(((_x).feature_support), 0)
+	unsigned char color_characteristics[10];
+	unsigned char established_timings[3];
+#define EDID1_INFO_ESTABLISHED_TIMING_720X400_70(_x) \
+	GET_BIT(((_x).established_timings[0]), 7)
+#define EDID1_INFO_ESTABLISHED_TIMING_720X400_88(_x) \
+	GET_BIT(((_x).established_timings[0]), 6)
+#define EDID1_INFO_ESTABLISHED_TIMING_640X480_60(_x) \
+	GET_BIT(((_x).established_timings[0]), 5)
+#define EDID1_INFO_ESTABLISHED_TIMING_640X480_67(_x) \
+	GET_BIT(((_x).established_timings[0]), 4)
+#define EDID1_INFO_ESTABLISHED_TIMING_640X480_72(_x) \
+	GET_BIT(((_x).established_timings[0]), 3)
+#define EDID1_INFO_ESTABLISHED_TIMING_640X480_75(_x) \
+	GET_BIT(((_x).established_timings[0]), 2)
+#define EDID1_INFO_ESTABLISHED_TIMING_800X600_56(_x) \
+	GET_BIT(((_x).established_timings[0]), 1)
+#define EDID1_INFO_ESTABLISHED_TIMING_800X600_60(_x) \
+	GET_BIT(((_x).established_timings[0]), 0)
+#define EDID1_INFO_ESTABLISHED_TIMING_800X600_72(_x) \
+	GET_BIT(((_x).established_timings[1]), 7)
+#define EDID1_INFO_ESTABLISHED_TIMING_800X600_75(_x) \
+	GET_BIT(((_x).established_timings[1]), 6)
+#define EDID1_INFO_ESTABLISHED_TIMING_832X624_75(_x) \
+	GET_BIT(((_x).established_timings[1]), 5)
+#define EDID1_INFO_ESTABLISHED_TIMING_1024X768_87I(_x) \
+	GET_BIT(((_x).established_timings[1]), 4)
+#define EDID1_INFO_ESTABLISHED_TIMING_1024X768_60(_x) \
+	GET_BIT(((_x).established_timings[1]), 3)
+#define EDID1_INFO_ESTABLISHED_TIMING_1024X768_70(_x) \
+	GET_BIT(((_x).established_timings[1]), 2)
+#define EDID1_INFO_ESTABLISHED_TIMING_1024X768_75(_x) \
+	GET_BIT(((_x).established_timings[1]), 1)
+#define EDID1_INFO_ESTABLISHED_TIMING_1280X1024_75(_x) \
+	GET_BIT(((_x).established_timings[1]), 0)
+#define EDID1_INFO_ESTABLISHED_TIMING_1152X870_75(_x) \
+	GET_BIT(((_x).established_timings[2]), 7)
+	struct {
+		unsigned char xresolution;
+		unsigned char aspect_vfreq;
+	} __attribute__((__packed__)) standard_timings[8];
+#define EDID1_INFO_STANDARD_TIMING_XRESOLUTION(_x, _i) \
+	(((_x).standard_timings[_i]).xresolution)
+#define EDID1_INFO_STANDARD_TIMING_ASPECT(_x, _i) \
+	GET_BITS(((_x).standard_timings[_i].aspect_vfreq), 7, 6)
+#define EDID1_INFO_STANDARD_TIMING_VFREQ(_x, _i) \
+	GET_BITS(((_x).standard_timings[_i].aspect_vfreq), 5, 0)
+	union {
+		unsigned char timing[72];
+		struct edid_monitor_descriptor descriptor[4];
+	} monitor_details;
+	unsigned char extension_flag;
+	unsigned char checksum;
+} __attribute__ ((__packed__));
+
+/**
+ * Print the EDID info.
+ *
+ * @param edid_info	The EDID info to be printed
+ */
+void edid_print_info(struct edid1_info *edid_info);
+
+/**
+ * Check the EDID info.
+ *
+ * @param info  The EDID info to be checked
+ * @return 0 on valid, or -1 on invalid
+ */
+int edid_check_info(struct edid1_info *info);
+
+/**
+ * Get the horizontal and vertical rate ranges of the monitor.
+ *
+ * @param edid	The EDID info
+ * @param hmin	Returns the minimum horizontal rate
+ * @param hmax	Returns the maxium horizontal rate
+ * @param vmin	Returns the minimum vertical rate
+ * @param vmax	Returns the maxium vertical rate
+ * @return 0 on success, or -1 on error
+ */
+int edid_get_ranges(struct edid1_info *edid, unsigned int *hmin,
+		    unsigned int *hmax, unsigned int *vmin,
+		    unsigned int *vmax);
+
+#endif /* __EDID_H_ */