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>

2 files changed, 308 insertions, 0 deletions

diff --git a/common/Makefile b/common/Makefile
index ce5ee6e..ebb7635 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -188,6 +188,7 @@ COBJS-$(CONFIG_BOOTSTAGE) += bootstage.o
 COBJS-$(CONFIG_CONSOLE_MUX) += iomux.o
 COBJS-y += flash.o
 COBJS-$(CONFIG_CMD_KGDB) += kgdb.o kgdb_stubs.o
+COBJS-$(CONFIG_I2C_EDID) += edid.o
 COBJS-$(CONFIG_KALLSYMS) += kallsyms.o
 COBJS-$(CONFIG_LCD) += lcd.o
 COBJS-$(CONFIG_LYNXKDI) += lynxkdi.o
diff --git a/common/edid.c b/common/edid.c
new file mode 100644
index 0000000..c82c298
--- /dev/null
+++ b/common/edid.c
@@ -0,0 +1,307 @@
+/*
+ * 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>
+ *
+ */
+
+#include <common.h>
+#include <edid.h>
+#include <linux/ctype.h>
+#include <linux/string.h>
+
+int edid_check_info(struct edid1_info *edid_info)
+{
+	if ((edid_info == NULL) || (edid_info->version == 0))
+		return -1;
+
+	if (memcmp(edid_info->header, "\x0\xff\xff\xff\xff\xff\xff\x0", 8))
+		return -1;
+
+	if (edid_info->version == 0xff && edid_info->revision == 0xff)
+		return -1;
+
+	return 0;
+}
+
+int edid_get_ranges(struct edid1_info *edid, unsigned int *hmin,
+		    unsigned int *hmax, unsigned int *vmin,
+		    unsigned int *vmax)
+{
+	int i;
+	struct edid_monitor_descriptor *monitor;
+
+	*hmin = *hmax = *vmin = *vmax = 0;
+	if (edid_check_info(edid))
+		return -1;
+
+	for (i = 0; i < ARRAY_SIZE(edid->monitor_details.descriptor); i++) {
+		monitor = &edid->monitor_details.descriptor[i];
+		if (monitor->type == EDID_MONITOR_DESCRIPTOR_RANGE) {
+			*hmin = monitor->data.range_data.horizontal_min;
+			*hmax = monitor->data.range_data.horizontal_max;
+			*vmin = monitor->data.range_data.vertical_min;
+			*vmax = monitor->data.range_data.vertical_max;
+			return 0;
+		}
+	}
+	return -1;
+}
+
+/**
+ * Snip the tailing whitespace/return of a string.
+ *
+ * @param string	The string to be snipped
+ * @return the snipped string
+ */
+static char *snip(char *string)
+{
+	char *s;
+
+	/*
+	 * This is always a 13 character buffer
+	 * and it's not always terminated.
+	 */
+	string[12] = '\0';
+	s = &string[strlen(string) - 1];
+
+	while (s >= string && (isspace(*s) || *s == '\n' || *s == '\r' ||
+			*s == '\0'))
+		*(s--) = '\0';
+
+	return string;
+}
+
+/**
+ * Print an EDID monitor descriptor block
+ *
+ * @param monitor	The EDID monitor descriptor block
+ * @have_timing		Modifies to 1 if the desciptor contains timing info
+ */
+static void edid_print_dtd(struct edid_monitor_descriptor *monitor,
+			   unsigned int *have_timing)
+{
+	unsigned char *bytes = (unsigned char *)monitor;
+	struct edid_detailed_timing *timing =
+			(struct edid_detailed_timing *)monitor;
+
+	if (bytes[0] == 0 && bytes[1] == 0) {
+		if (monitor->type == EDID_MONITOR_DESCRIPTOR_SERIAL)
+			printf("Monitor serial number: %s\n",
+			       snip(monitor->data.string));
+		else if (monitor->type == EDID_MONITOR_DESCRIPTOR_ASCII)
+			printf("Monitor ID: %s\n",
+			       snip(monitor->data.string));
+		else if (monitor->type == EDID_MONITOR_DESCRIPTOR_NAME)
+			printf("Monitor name: %s\n",
+			       snip(monitor->data.string));
+		else if (monitor->type == EDID_MONITOR_DESCRIPTOR_RANGE)
+			printf("Monitor range limits, horizontal sync: "
+			       "%d-%d kHz, vertical refresh: "
+			       "%d-%d Hz, max pixel clock: "
+			       "%d MHz\n",
+			       monitor->data.range_data.horizontal_min,
+			       monitor->data.range_data.horizontal_max,
+			       monitor->data.range_data.vertical_min,
+			       monitor->data.range_data.vertical_max,
+			       monitor->data.range_data.pixel_clock_max * 10);
+	} else {
+		uint32_t pixclock, h_active, h_blanking, v_active, v_blanking;
+		uint32_t h_total, v_total, vfreq;
+
+		pixclock = EDID_DETAILED_TIMING_PIXEL_CLOCK(*timing);
+		h_active = EDID_DETAILED_TIMING_HORIZONTAL_ACTIVE(*timing);
+		h_blanking = EDID_DETAILED_TIMING_HORIZONTAL_BLANKING(*timing);
+		v_active = EDID_DETAILED_TIMING_VERTICAL_ACTIVE(*timing);
+		v_blanking = EDID_DETAILED_TIMING_VERTICAL_BLANKING(*timing);
+
+		h_total = h_active + h_blanking;
+		v_total = v_active + v_blanking;
+		if (v_total * h_total)
+			vfreq = pixclock / (v_total * h_total);
+		else
+			vfreq = 1; /* Error case */
+		printf("\t%dx%d\%c\t%d Hz (detailed)\n", h_active,
+		       v_active, h_active > 1000 ? ' ' : '\t', vfreq);
+		*have_timing = 1;
+	}
+}
+
+/**
+ * Get the manufacturer name from an EDID info.
+ *
+ * @param edid_info     The EDID info to be printed
+ * @param name		Returns the string of the manufacturer name
+ */
+static void edid_get_manufacturer_name(struct edid1_info *edid, char *name)
+{
+	name[0] = EDID1_INFO_MANUFACTURER_NAME_CHAR1(*edid) + 'A' - 1;
+	name[1] = EDID1_INFO_MANUFACTURER_NAME_CHAR2(*edid) + 'A' - 1;
+	name[2] = EDID1_INFO_MANUFACTURER_NAME_CHAR3(*edid) + 'A' - 1;
+	name[3] = '\0';
+}
+
+void edid_print_info(struct edid1_info *edid_info)
+{
+	int i;
+	char manufacturer[4];
+	unsigned int have_timing = 0;
+	uint32_t serial_number;
+
+	if (edid_check_info(edid_info)) {
+		printf("Not a valid EDID\n");
+		return;
+	}
+
+	printf("EDID version: %d.%d\n",
+	       edid_info->version, edid_info->revision);
+
+	printf("Product ID code: %04x\n", EDID1_INFO_PRODUCT_CODE(*edid_info));
+
+	edid_get_manufacturer_name(edid_info, manufacturer);
+	printf("Manufacturer: %s\n", manufacturer);
+
+	serial_number = EDID1_INFO_SERIAL_NUMBER(*edid_info);
+	if (serial_number != 0xffffffff) {
+		if (strcmp(manufacturer, "MAG") == 0)
+			serial_number -= 0x7000000;
+		if (strcmp(manufacturer, "OQI") == 0)
+			serial_number -= 456150000;
+		if (strcmp(manufacturer, "VSC") == 0)
+			serial_number -= 640000000;
+	}
+	printf("Serial number: %08x\n", serial_number);
+	printf("Manufactured in week: %d year: %d\n",
+	       edid_info->week, edid_info->year + 1990);
+
+	printf("Video input definition: %svoltage level %d%s%s%s%s%s\n",
+	       EDID1_INFO_VIDEO_INPUT_DIGITAL(*edid_info) ?
+	       "digital signal, " : "analog signal, ",
+	       EDID1_INFO_VIDEO_INPUT_VOLTAGE_LEVEL(*edid_info),
+	       EDID1_INFO_VIDEO_INPUT_BLANK_TO_BLACK(*edid_info) ?
+	       ", blank to black" : "",
+	       EDID1_INFO_VIDEO_INPUT_SEPARATE_SYNC(*edid_info) ?
+	       ", separate sync" : "",
+	       EDID1_INFO_VIDEO_INPUT_COMPOSITE_SYNC(*edid_info) ?
+	       ", composite sync" : "",
+	       EDID1_INFO_VIDEO_INPUT_SYNC_ON_GREEN(*edid_info) ?
+	       ", sync on green" : "",
+	       EDID1_INFO_VIDEO_INPUT_SERRATION_V(*edid_info) ?
+	       ", serration v" : "");
+
+	printf("Monitor is %s\n",
+	       EDID1_INFO_FEATURE_RGB(*edid_info) ? "RGB" : "non-RGB");
+
+	printf("Maximum visible display size: %d cm x %d cm\n",
+	       edid_info->max_size_horizontal,
+	       edid_info->max_size_vertical);
+
+	printf("Power management features: %s%s, %s%s, %s%s\n",
+	       EDID1_INFO_FEATURE_ACTIVE_OFF(*edid_info) ?
+	       "" : "no ", "active off",
+	       EDID1_INFO_FEATURE_SUSPEND(*edid_info) ? "" : "no ", "suspend",
+	       EDID1_INFO_FEATURE_STANDBY(*edid_info) ? "" : "no ", "standby");
+
+	printf("Estabilished timings:\n");
+	if (EDID1_INFO_ESTABLISHED_TIMING_720X400_70(*edid_info))
+		printf("\t720x400\t\t70 Hz (VGA 640x400, IBM)\n");
+	if (EDID1_INFO_ESTABLISHED_TIMING_720X400_88(*edid_info))
+		printf("\t720x400\t\t88 Hz (XGA2)\n");
+	if (EDID1_INFO_ESTABLISHED_TIMING_640X480_60(*edid_info))
+		printf("\t640x480\t\t60 Hz (VGA)\n");
+	if (EDID1_INFO_ESTABLISHED_TIMING_640X480_67(*edid_info))
+		printf("\t640x480\t\t67 Hz (Mac II, Apple)\n");
+	if (EDID1_INFO_ESTABLISHED_TIMING_640X480_72(*edid_info))
+		printf("\t640x480\t\t72 Hz (VESA)\n");
+	if (EDID1_INFO_ESTABLISHED_TIMING_640X480_75(*edid_info))
+		printf("\t640x480\t\t75 Hz (VESA)\n");
+	if (EDID1_INFO_ESTABLISHED_TIMING_800X600_56(*edid_info))
+		printf("\t800x600\t\t56 Hz (VESA)\n");
+	if (EDID1_INFO_ESTABLISHED_TIMING_800X600_60(*edid_info))
+		printf("\t800x600\t\t60 Hz (VESA)\n");
+	if (EDID1_INFO_ESTABLISHED_TIMING_800X600_72(*edid_info))
+		printf("\t800x600\t\t72 Hz (VESA)\n");
+	if (EDID1_INFO_ESTABLISHED_TIMING_800X600_75(*edid_info))
+		printf("\t800x600\t\t75 Hz (VESA)\n");
+	if (EDID1_INFO_ESTABLISHED_TIMING_832X624_75(*edid_info))
+		printf("\t832x624\t\t75 Hz (Mac II)\n");
+	if (EDID1_INFO_ESTABLISHED_TIMING_1024X768_87I(*edid_info))
+		printf("\t1024x768\t87 Hz Interlaced (8514A)\n");
+	if (EDID1_INFO_ESTABLISHED_TIMING_1024X768_60(*edid_info))
+		printf("\t1024x768\t60 Hz (VESA)\n");
+	if (EDID1_INFO_ESTABLISHED_TIMING_1024X768_70(*edid_info))
+		printf("\t1024x768\t70 Hz (VESA)\n");
+	if (EDID1_INFO_ESTABLISHED_TIMING_1024X768_75(*edid_info))
+		printf("\t1024x768\t75 Hz (VESA)\n");
+	if (EDID1_INFO_ESTABLISHED_TIMING_1280X1024_75(*edid_info))
+		printf("\t1280x1024\t75 (VESA)\n");
+	if (EDID1_INFO_ESTABLISHED_TIMING_1152X870_75(*edid_info))
+		printf("\t1152x870\t75 (Mac II)\n");
+
+	/* Standard timings. */
+	printf("Standard timings:\n");
+	for (i = 0; i < ARRAY_SIZE(edid_info->standard_timings); i++) {
+		unsigned int aspect = 10000;
+		unsigned int x, y;
+		unsigned char xres, vfreq;
+
+		xres = EDID1_INFO_STANDARD_TIMING_XRESOLUTION(*edid_info, i);
+		vfreq = EDID1_INFO_STANDARD_TIMING_VFREQ(*edid_info, i);
+		if ((xres != vfreq) ||
+		    ((xres != 0) && (xres != 1)) ||
+		    ((vfreq != 0) && (vfreq != 1))) {
+			switch (EDID1_INFO_STANDARD_TIMING_ASPECT(*edid_info,
+					i)) {
+			case ASPECT_625:
+				aspect = 6250;
+				break;
+			case ASPECT_75:
+				aspect = 7500;
+				break;
+			case ASPECT_8:
+				aspect = 8000;
+				break;
+			case ASPECT_5625:
+				aspect = 5625;
+				break;
+			}
+			x = (xres + 31) * 8;
+			y = x * aspect / 10000;
+			printf("\t%dx%d%c\t%d Hz\n", x, y,
+			       x > 1000 ? ' ' : '\t', (vfreq & 0x3f) + 60);
+			have_timing = 1;
+		}
+	}
+
+	/* Detailed timing information. */
+	for (i = 0; i < ARRAY_SIZE(edid_info->monitor_details.descriptor);
+			i++) {
+		edid_print_dtd(&edid_info->monitor_details.descriptor[i],
+			       &have_timing);
+	}
+
+	if (!have_timing)
+		printf("\tNone\n");
+}