Brightness (FreeBSD): adds ddc-ci detection support (WIP)

src/detection/brightness/brightness_bsd.c

@@ -1,28 +1,108 @@
 #include "brightness.h"
+#include "common/arrayUtils.h"
+#include "common/io.h"
+#include "common/kmod.h"
+#include "common/debug.h"
+
+#include <sys/ioctl.h>
+#include <sys/fcntl.h>
+#include <unistd.h>
+
+#include <dev/iicbus/iic.h>
+
+const char* detectWithDdcci(FF_A_UNUSED FFBrightnessOptions* options, FFlist* result) {
+    // FIXME: doesn't work for me
+    for (char i = '0'; i <= '9'; ++i) {
+        char path[] = "/dev/iic0";
+        path[ARRAY_SIZE(path) - 2] = i;
+
+        FF_AUTO_CLOSE_FD int fd = open(path, O_RDWR | O_CLOEXEC);
+        if (fd < 0) {
+            int err = errno;
+            if (err == ENOENT) {
+                FF_DEBUG("No more I2C devices");
+                break;
+            } else if (i == '0' && !ffKmodLoaded("iicbus")) {
+                FF_DEBUG("iicbus module is not loaded");
+                return "No I2C devices found and iicbus module is not loaded";
+            }
+            FF_DEBUG("open(/dev/iic%c) failed: %s", i, strerror(errno));
+            continue;
+        }
+
+        uint8_t i2cIn[] = { 0x51, 0x82, 0x01, 0x10 /* luminance */, 0 };
+        i2cIn[4] = 0x6E ^ i2cIn[0] ^ i2cIn[1] ^ i2cIn[2] ^ i2cIn[3];
+        uint8_t i2cOut[12] = {};
+        struct iic_msg msgs[] = {
+            {
+                .slave = 0x6E,
+                .flags = IIC_M_WR,
+                .len = ARRAY_SIZE(i2cIn),
+                .buf = i2cIn
+            },
+            {
+                .slave = 0x6F,
+                .flags = IIC_M_RD,
+                .len = ARRAY_SIZE(i2cOut),
+                .buf = i2cOut
+            }
+        };
+
+        int ret = ioctl(fd, I2CRDWR, &(struct iic_rdwr_data) {
+            .msgs = msgs,
+            .nmsgs = ARRAY_SIZE(msgs)
+        });
+        if (ret < 0) {
+            FF_DEBUG("ioctl(/dev/iic%c, I2CRDWR) failed: %s", i, strerror(errno));
+            continue;
+        }
+        if (i2cOut[2] != 0x02 || i2cOut[3] != 0x00) {
+            FF_DEBUG("i2c out validation failed: i2cOut[2] = 0x%02x, i2cOut[3] = 0x%02x", i2cOut[2], i2cOut[3]);
+            continue;
+        }
+
+        uint32_t current = ((uint32_t) i2cOut[8] << 8u) + (uint32_t) i2cOut[9];
+        uint32_t max = ((uint32_t) i2cOut[6] << 8u) + (uint32_t) i2cOut[7];
+
+        FFBrightnessResult* brightness = FF_LIST_ADD(FFBrightnessResult, *result);
+        brightness->max = max;
+        brightness->min = 0;
+        brightness->current = current;
+        ffStrbufInitS(&brightness->name, path + strlen("/dev/"));
+        brightness->builtin = false;
+    }
+
+    return NULL;
+}
 
 #if __has_include(<sys/backlight.h>)
 
-    #include "common/io.h"
-
     #include <sys/backlight.h>
-    #include <sys/ioctl.h>
-    #include <sys/fcntl.h>
-    #include <unistd.h>
 
-const char* ffDetectBrightness(FF_A_UNUSED FFBrightnessOptions* options, FFlist* result) {
+
+const char* detectWithBacklight(FF_A_UNUSED FFBrightnessOptions* options, FFlist* result) {
     // https://man.freebsd.org/cgi/man.cgi?query=backlight&sektion=9
     char path[] = "/dev/backlight/backlight0";
 
     for (char i = '0'; i <= '9'; ++i) {
         path[ARRAY_SIZE(path) - 2] = i;
 
-        FF_AUTO_CLOSE_FD int blfd = open(path, O_RDONLY | O_CLOEXEC);
-        if (blfd < 0) {
+        FF_AUTO_CLOSE_FD int fd = open(path, O_RDONLY | O_CLOEXEC);
+        if (fd < 0) {
+            int err = errno;
+            if (err == ENOENT) {
+                FF_DEBUG("No more backlight devices");
+                break;
+            } else if (i == '0' && !ffKmodLoaded("backlight")) {
+                FF_DEBUG("backlight module is not loaded");
+                return "No backlight devices found and backlight module is not loaded";
+            }
+            FF_DEBUG("open(/dev/backlight/backlight%c) failed: %s", i, strerror(errno));
             continue;
         }
 
         struct backlight_props status;
-        if (ioctl(blfd, BACKLIGHTGETSTATUS, &status) < 0) {
+        if (ioctl(fd, BACKLIGHTGETSTATUS, &status) < 0) {
             continue;
         }
 
@@ -35,7 +115,7 @@ const char* ffDetectBrightness(FF_A_UNUSED FFBrightnessOptions* options, FFlist*
         brightness->builtin = true;
 
         struct backlight_info info;
-        if (ioctl(blfd, BACKLIGHTGETINFO, &info) == 0) {
+        if (ioctl(fd, BACKLIGHTGETINFO, &info) == 0) {
             ffStrbufAppendS(&brightness->name, info.name);
         } else {
             ffStrbufAppendS(&brightness->name, path + strlen("/dev/backlight/"));
@@ -46,8 +126,18 @@ const char* ffDetectBrightness(FF_A_UNUSED FFBrightnessOptions* options, FFlist*
 
 #else
 
-const char* ffDetectBrightness(FF_A_UNUSED FFBrightnessOptions* options, FF_A_UNUSED FFlist* result) {
+const char* detectWithBacklight(FF_A_UNUSED FFBrightnessOptions* options, FF_A_UNUSED FFlist* result) {
+    FF_DEBUG("Backlight support is not available on this system");
     return "Backlight is supported only on FreeBSD 13 and newer";
 }
 
 #endif
+
+
+const char* ffDetectBrightness(FF_A_UNUSED FFBrightnessOptions* options, FFlist* result) {
+    detectWithBacklight(options, result);
+    if (result->length == 0) {
+        detectWithDdcci(options, result);
+    }
+    return NULL;
+}