From 76e836df7fe737f6c2761c7b91327c71ddd7709c Mon Sep 17 00:00:00 2001
From: Simon Ser <contact@emersion.fr>
Date: Fri, 21 Apr 2023 12:05:02 +0200
Subject: [PATCH] edid: encode vendor & product information

Signed-off-by: Simon Ser <contact@emersion.fr>
---
 edid.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/edid.c b/edid.c
index d2bf74e..0ef67ed 100644
--- a/edid.c
+++ b/edid.c
@@ -1708,6 +1708,62 @@ error:
 	return NULL;
 }
 
+static bool
+encode_vendor_product(const struct di_edid_vendor_product *vendor_product,
+		      uint8_t data[static EDID_BLOCK_SIZE])
+{
+	size_t i;
+	uint16_t man;
+	char ch;
+	int year;
+
+	for (i = 0; i < 3; i++) {
+		ch = vendor_product->manufacturer[i];
+		if (ch < '@' || ch > '@' + 0x1F) {
+			return false;
+		}
+	}
+
+	man = (uint16_t)((vendor_product->manufacturer[0] - '@') << 10) |
+	      (uint16_t)((vendor_product->manufacturer[1] - '@') << 5) |
+	      (uint16_t)((vendor_product->manufacturer[2] - '@') << 0);
+	data[0x08] = (uint8_t)(man >> 8);
+	data[0x09] = (uint8_t)man;
+
+	data[0x0A] = (uint8_t)vendor_product->product;
+	data[0x0B] = (uint8_t)(vendor_product->product >> 8);
+
+	data[0x0C] = (uint8_t)vendor_product->serial;
+	data[0x0D] = (uint8_t)(vendor_product->serial >> 8);
+	data[0x0E] = (uint8_t)(vendor_product->serial >> 16);
+	data[0x0F] = (uint8_t)(vendor_product->serial >> 24);
+
+	if (vendor_product->manufacture_year != 0 && vendor_product->model_year != 0) {
+		return false;
+	}
+	if (vendor_product->manufacture_week != 0) {
+		if (vendor_product->manufacture_week < 1 ||
+		    vendor_product->manufacture_week > 54 ||
+		    vendor_product->model_year != 0) {
+			return false;
+		}
+		data[0x10] = (uint8_t)vendor_product->manufacture_week;
+	} else {
+		if (vendor_product->model_year != 0) {
+			data[0x10] = 0xFF;
+			year = vendor_product->model_year;
+		} else {
+			year = vendor_product->manufacture_year;
+		}
+		if (year <= 1990 || year >= 1990 + 0xFF) {
+			return false;
+		}
+		data[0x11] = (uint8_t)(year - 1990);
+	}
+
+	return true;
+}
+
 ssize_t
 di_edid_format(const struct di_edid *edid, void *buf, size_t buf_size)
 {
@@ -1728,6 +1784,10 @@ di_edid_format(const struct di_edid *edid, void *buf, size_t buf_size)
 	data[0x12] = (uint8_t) edid->version;
 	data[0x13] = (uint8_t) edid->revision;
 
+	if (!encode_vendor_product(&edid->vendor_product, data)) {
+		return -1;
+	}
+
 	/* TODO */
 
 	return (ssize_t) size;