Initial Contribution
diff --git a/led/led_trout.c b/led/led_trout.c
new file mode 100644
index 0000000..847b6bc
--- /dev/null
+++ b/led/led_trout.c
@@ -0,0 +1,100 @@
+#include <hardware/led.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stdio.h>
+
+#define LOG_TAG "LED"
+#include <utils/Log.h>
+
+const char* const AMBER_BRIGHTNESS_FILE = "/sys/class/leds/amber/brightness";
+const char* const RED_BRIGHTNESS_FILE = "/sys/class/leds/red/brightness";
+const char* const GREEN_BRIGHTNESS_FILE = "/sys/class/leds/green/brightness";
+const char* const BLUE_BRIGHTNESS_FILE = "/sys/class/leds/blue/brightness";
+const char* const BLINK_ENABLE_FILE = "/sys/class/leds/red/device/blink";
+const char* const BLINK_FREQ_FILE = "/sys/class/leds/red/device/grpfreq";
+const char* const BLINK_PWM_FILE = "/sys/class/leds/red/device/grppwm";
+
+static int
+write_string(const char* file, const char* string, int len)
+{
+ int fd;
+ ssize_t amt;
+
+ fd = open(file, O_RDWR);
+ if (fd < 0) {
+ LOGE("open failed errno: %d\n", errno);
+ return errno;
+ }
+
+ amt = write(fd, string, len);
+ if (amt < 0) {
+ LOGE("write failed errno: %d\n", errno);
+ }
+
+ close(fd);
+ return amt >= 0 ? 0 : errno;
+}
+
+int set_led_state(unsigned colorARGB, int onMS, int offMS)
+{
+ int len;
+ char buf[30];
+ int alpha, red, green, blue;
+ int blink, freq, pwm;
+
+ LOGV("set_led_state colorARGB=%08X, onMS=%d, offMS=%d\n", colorARGB, onMS, offMS);
+
+ // alpha of 0 or color of 0 means off
+ if ((colorARGB & 0xff000000) == 0 || (colorARGB & 0x00ffffff) == 0) {
+ onMS = 0;
+ offMS = 0;
+ }
+
+ red = (colorARGB >> 16) & 0xFF;
+ green = (colorARGB >> 8) & 0xFF;
+ blue = colorARGB & 0xFF;
+
+ len = sprintf(buf, "%d", red);
+ write_string(RED_BRIGHTNESS_FILE, buf, len);
+ len = sprintf(buf, "%d", green);
+ write_string(GREEN_BRIGHTNESS_FILE, buf, len);
+ len = sprintf(buf, "%d", blue);
+ write_string(BLUE_BRIGHTNESS_FILE, buf, len);
+
+ if (onMS > 0 && offMS > 0) {
+ int totalMS = onMS + offMS;
+
+ // the LED appears to blink about once per second if freq is 20
+ // 1000ms / 20 = 50
+ freq = totalMS / 50;
+ // pwm specifies the ratio of ON versus OFF
+ // pwm = 0 -> always off
+ // pwm = 255 => always on
+ pwm = (onMS * 255) / totalMS;
+
+ // the low 4 bits are ignored, so round up if necessary
+ if (pwm > 0 && pwm < 16)
+ pwm = 16;
+
+ blink = 1;
+ } else {
+ blink = 0;
+ freq = 0;
+ pwm = 0;
+ }
+
+ if (blink) {
+ len = sprintf(buf, "%d", freq);
+ write_string(BLINK_FREQ_FILE, buf, len);
+ len = sprintf(buf, "%d", pwm);
+ write_string(BLINK_PWM_FILE, buf, len);
+ }
+
+ len = sprintf(buf, "%d", blink);
+ write_string(BLINK_ENABLE_FILE, buf, len);
+
+ return 0;
+}