Add the algorithm to switch the ALS report mode

We may want to reduce the HID report event, so add the algorithm to
switch the ALS report mode

Polling mode is for initial
Threshold mode is for reducing the HID report event

Signed-off-by: Josh Tsai <josh_tsai@compal.com>

Author: Josh Tsai

board/hx30/i2c_hid_mediakeys.c

@@ -13,6 +13,7 @@
 #include "timer.h"
 #include "chipset.h"
 #include "hwtimer.h"
+#include "math_util.h"
 #include "util.h"
 #include "i2c_hid.h"
 #include "i2c_hid_mediakeys.h"
@@ -350,16 +351,29 @@ void i2c_hid_als_init(void)
 	als_sensor.illuminanceValue = 0x0000;
 }
 
+static int als_polling_mode_count;
 void report_illuminance_value(void)
 {
-	/* bypass the EC_MEMMAP_ALS value to input report */
-	als_sensor.illuminanceValue = *(uint16_t *)host_get_memmap(EC_MEMMAP_ALS);
+	uint16_t newIlluminaceValue = *(uint16_t *)host_get_memmap(EC_MEMMAP_ALS);
 
-	/* wait 6s to change mode from polling to threshold */
+	/* We need to polling the ALS value at least 6 seconds */
+	if (als_polling_mode_count <= 60) {
+		als_polling_mode_count++; /* time base 100ms */
 
+		/* bypass the EC_MEMMAP_ALS value to input report */
+		als_sensor.illuminanceValue = newIlluminaceValue;
+		task_set_event(TASK_ID_HID, ((1 << HID_ALS_REPORT_LUX) |
+			EVENT_REPORT_ILLUMINANCE_VALUE), 0);
+	} else {
+		if (ABS(als_sensor.illuminanceValue - newIlluminaceValue) > 5) {
+			als_sensor.illuminanceValue = newIlluminaceValue;
+			task_set_event(TASK_ID_HID, ((1 << HID_ALS_REPORT_LUX) |
+				EVENT_REPORT_ILLUMINANCE_VALUE), 0);
+		} else {
+			task_set_event(TASK_ID_HID, EVENT_REPORT_ILLUMINANCE_VALUE, 0);
+		}
+	}
 
-	task_set_event(TASK_ID_HID, ((1 << HID_ALS_REPORT_LUX) |
-		EVENT_REPORT_ILLUMINANCE_VALUE), 0);
 }
 DECLARE_DEFERRED(report_illuminance_value);
 
@@ -380,6 +394,7 @@ static void als_report_control(uint8_t report_mode)
 	} else {
 		/* stop report als value */
 		hook_call_deferred(&report_illuminance_value_data, -1);
+		als_polling_mode_count = 0;
 	}
 }