From e52c38f0515adbc51e8b2c4d5addde2be4ea1067 Mon Sep 17 00:00:00 2001
From: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Date: Tue, 20 Aug 2024 11:42:12 +0200
Subject: [PATCH] edid-decode: check if linux/i2c-dev.h is available

Skip building ddc.cpp and disable related options if linux/i2c-dev.h
is not found. This makes it easier to build on non-linux environments.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
---
 ddc.cpp         |  4 ----
 edid-decode.cpp | 19 +++++++------------
 edid-decode.h   | 10 ++++++++++
 meson.build     |  7 ++++++-
 4 files changed, 23 insertions(+), 17 deletions(-)

diff --git a/ddc.cpp b/ddc.cpp
index 6bdd50b..939e968 100644
--- a/ddc.cpp
+++ b/ddc.cpp
@@ -5,8 +5,6 @@
  * Author: Hans Verkuil <hverkuil-cisco@xs4all.nl>
  */
 
-#ifndef __EMSCRIPTEN__
-
 #include <cctype>
 #include <cerrno>
 #include <csignal>
@@ -346,5 +344,3 @@ int read_hdcp_ri(int adapter_fd, double ri_time)
 	}
 	return 0;
 }
-
-#endif
diff --git a/edid-decode.cpp b/edid-decode.cpp
index 11c85c7..d565da0 100644
--- a/edid-decode.cpp
+++ b/edid-decode.cpp
@@ -107,10 +107,12 @@ static struct option long_options[] = {
 	{ "fbmode", no_argument, 0, OptFBModeTimings },
 	{ "v4l2-timings", no_argument, 0, OptV4L2Timings },
 	{ "diagonal", required_argument, 0, OptDiag },
+#ifdef __HAS_I2C_DEV__
 	{ "i2c-adapter", required_argument, 0, OptI2CAdapter },
 	{ "i2c-edid", no_argument, 0, OptI2CEDID },
 	{ "i2c-hdcp", no_argument, 0, OptI2CHDCP },
 	{ "i2c-hdcp-ri", required_argument, 0, OptI2CHDCPRi },
+#endif
 	{ "std", required_argument, 0, OptSTD },
 	{ "dmt", required_argument, 0, OptDMT },
 	{ "vic", required_argument, 0, OptVIC },
@@ -164,10 +166,12 @@ static void usage(void)
 	       "  -u, --utf8            Convert strings in EDIDs to UTF-8.\n"
 	       "  --version             Show the edid-decode version (SHA).\n"
 	       "  --diagonal <inches>   Set the display's diagonal in inches.\n"
+#ifdef __HAS_I2C_DEV__
 	       "  -a, --i2c-adapter <num> Use /dev/i2c-<num> to access the DDC lines.\n"
 	       "  --i2c-edid		Read the EDID from the DDC lines.\n"
 	       "  --i2c-hdcp		Read the HDCP from the DDC lines.\n"
 	       "  --i2c-hdcp-ri=<t>	Read and print the HDCP Ri information every <t> seconds.\n"
+#endif
 	       "  --std <byte1>,<byte2> Show the standard timing represented by these two bytes.\n"
 	       "  --dmt <dmt>           Show the timings for the DMT with the given DMT ID.\n"
 	       "  --vic <vic>           Show the timings for this VIC.\n"
@@ -2329,7 +2333,7 @@ int main(int argc, char **argv)
 		case OptDiag:
 			state.diagonal = strtod(optarg, NULL);
 			break;
-#ifndef __EMSCRIPTEN__
+#ifdef __HAS_I2C_DEV__
 		case OptI2CAdapter: {
 			unsigned num = strtoul(optarg, NULL, 0);
 
@@ -2446,26 +2450,17 @@ int main(int argc, char **argv)
 
 	if (optind == argc) {
 		if (adapter_fd >= 0 && options[OptI2CEDID]) {
-#ifndef __EMSCRIPTEN__
 			ret = read_edid(adapter_fd, edid);
-#else
-			ret = -ENODEV;
-#endif
 			if (ret > 0) {
 				state.edid_size = ret * EDID_PAGE_SIZE;
 				state.num_blocks = ret;
 				ret = 0;
 			}
 		} else if (adapter_fd >= 0) {
-#ifndef __EMSCRIPTEN__
 			if (options[OptI2CHDCP])
-				read_hdcp(adapter_fd);
+				ret = read_hdcp(adapter_fd);
 			if (options[OptI2CHDCPRi])
-				read_hdcp_ri(adapter_fd, hdcp_ri_sleep);
-#else
-			ret = -ENODEV;
-#endif
-			ret = 0;
+				ret = read_hdcp_ri(adapter_fd, hdcp_ri_sleep);
 		} else if (options[OptInfoFrame] && !options[OptGTF]) {
 			ret = 0;
 		} else {
diff --git a/edid-decode.h b/edid-decode.h
index c62650e..926fa33 100644
--- a/edid-decode.h
+++ b/edid-decode.h
@@ -615,9 +615,19 @@ char *extract_string(const unsigned char *x, unsigned len, bool is_cp437);
 #define oneoui(c,k,n) const unsigned kOUI_##k = __LINE__<<12;
 #include "oui.h"
 
+#ifdef __HAS_I2C_DEV__
+
 int request_i2c_adapter(unsigned adapnr);
 int read_edid(int adapter_fd, unsigned char *edid);
 int read_hdcp(int adapter_fd);
 int read_hdcp_ri(int adapter_fd, double ri_time);
 
+#else
+
+static inline int read_edid(int adapter_fd, unsigned char *edid) { return -ENODEV; }
+static inline int read_hdcp(int adapter_fd) { return -ENODEV; }
+static inline int read_hdcp_ri(int adapter_fd, double ri_time) { return -ENODEV; }
+
+#endif
+
 #endif
diff --git a/meson.build b/meson.build
index 513ba93..5cd94cd 100644
--- a/meson.build
+++ b/meson.build
@@ -50,7 +50,6 @@ endif
 edid_decode_sources = [
 	'calc-gtf-cvt.cpp',
 	'calc-ovt.cpp',
-	'ddc.cpp',
 	'edid-decode.cpp',
 	'parse-base-block.cpp',
 	'parse-cta-block.cpp',
@@ -61,6 +60,12 @@ edid_decode_sources = [
 	'parse-if.cpp',
 ]
 
+cc = meson.get_compiler('cpp')
+if cc.has_header('linux/i2c-dev.h')
+	edid_decode_sources += ['ddc.cpp']
+	edid_decode_args += ['-D__HAS_I2C_DEV__']
+endif
+
 edid_decode = executable(
 	'edid-decode',
 	sources: edid_decode_sources,
-- 
2.11.4.GIT