powermgmt: Add battery current measurement

This allows targets to report the actual discharging or
charging current if they are able to.

Change-Id: I0b538e6ac94346f1434e45f83c8da8c1260a53a3

firmware/export/config.h

@@ -208,6 +208,8 @@
                                  Usually application ports, and only
                                  if the estimation is better that ours
                                  (which it probably is) */
+#define CURRENT_MEASURE     8 /* Target can report battery charge and/or
+                               * discharge current */
 /* CONFIG_LCD */
 #define LCD_SSD1815   1 /* as used by Sansa M200 and others */
 #define LCD_S1D15E06  3 /* as used by iRiver H100 series */

firmware/export/powermgmt.h

@@ -94,6 +94,11 @@ void powermgmt_init(void) INIT_ATTR;
 #define BATT_AVE_SAMPLES 128
 #endif
 
+#ifndef BATT_CURRENT_AVE_SAMPLES
+/* TODO may need tweaking */
+#define BATT_CURRENT_AVE_SAMPLES 16
+#endif
+
 #ifndef POWER_THREAD_STEP_TICKS
 /* 2HZ sample rate unless otherwise specified */
 #define POWER_THREAD_STEP_TICKS (HZ/2)
@@ -118,6 +123,8 @@ int battery_current(void); /* battery current in milliamps
 int _battery_level(void); /* percent */
 int _battery_time(void); /* minutes */
 int _battery_voltage(void); /* voltage in millivolts */
+int _battery_current(void); /* (dis)charge current in milliamps */
+
 #if CONFIG_CHARGING >= CHARGING_TARGET
 void powermgmt_init_target(void);
 void charging_algorithm_close(void);

firmware/powermgmt.c

@@ -110,7 +110,8 @@ static int percent_now; /* Cached to avoid polling too often */
 #if !(CONFIG_BATTERY_MEASURE & TIME_MEASURE)
 int _battery_time(void) { return -1; }
 #endif
-#if (CONFIG_BATTERY_MEASURE & TIME_MEASURE) || defined(CURRENT_NORMAL)
+#if (CONFIG_BATTERY_MEASURE & TIME_MEASURE) || \
+    defined(CURRENT_NORMAL) || (CONFIG_BATTERY_MEASURE & CURRENT_MEASURE)
 static int time_now; /* Cached to avoid polling too often */
 #endif
 
@@ -121,6 +122,12 @@ int _battery_voltage(void) { return -1; }
 static int voltage_avg, voltage_now;
 #endif
 
+#if !(CONFIG_BATTERY_MEASURE & CURRENT_MEASURE)
+int _battery_current(void) { return -1; }
+#else
+static int current_avg, current_now;
+#endif
+
 /* The battery level can be obtained in two ways. If the target reports
  * voltage, the battery level can be estminated using percent_to_volt_*
  * curves. If the target can report the percentage directly, then that
@@ -142,7 +149,8 @@ int battery_level(void)
  * on the battery level and the actual current usage. */
 int battery_time(void)
 {
-#if (CONFIG_BATTERY_MEASURE & TIME_MEASURE) || defined(CURRENT_NORMAL)
+#if (CONFIG_BATTERY_MEASURE & TIME_MEASURE) || \
+    defined(CURRENT_NORMAL) || (CONFIG_BATTERY_MEASURE & CURRENT_MEASURE)
     return time_now;
 #else
     return -1;
@@ -166,7 +174,9 @@ int battery_voltage(void)
  * the power consumed by the backlight, remote display, SPDIF, etc. */
 int battery_current(void)
 {
-#if defined(CURRENT_NORMAL)
+#if CONFIG_BATTERY_MEASURE & CURRENT_MEASURE
+    return current_now;
+#elif defined(CURRENT_NORMAL)
     int current = CURRENT_NORMAL;
 
 #ifndef BOOTLOADER
@@ -223,8 +233,8 @@ int battery_current(void)
 #endif
 }
 
-/* Initialize the battery voltage filter. This is called once
+/* Initialize the battery voltage/current filters. This is called
- * by the power thread before entering the main polling loop. */
+ * once by the power thread before entering the main polling loop. */
 static void average_init(void)
 {
 #if CONFIG_BATTERY_MEASURE & VOLTAGE_MEASURE
@@ -244,9 +254,14 @@ static void average_init(void)
 
     voltage_avg = voltage_now * BATT_AVE_SAMPLES;
 #endif /* CONFIG_BATTERY_MEASURE & VOLTAGE_MEASURE */
+
+#if CONFIG_BATTERY_MEASURE & CURRENT_MEASURE
+    current_now = _battery_current();
+    current_avg = current_now * BATT_CURRENT_AVE_SAMPLES;
+#endif
 }
 
-/* Sample the battery voltage and update the filter.
+/* Sample the battery voltage/current and update the filters.
  * Updated once every POWER_THREAD_STEP_TICKS. */
 static void average_step(bool low_battery)
 {
@@ -262,6 +277,11 @@ static void average_step(bool low_battery)
 #else
     (void)low_battery;
 #endif
+
+#if CONFIG_BATTERY_MEASURE & CURRENT_MEASURE
+    current_avg += _battery_current() - current_avg / BATT_CURRENT_AVE_SAMPLES;
+    current_now = current_avg / BATT_CURRENT_AVE_SAMPLES;
+#endif
 }
 
 /* Send system battery level update events on reaching certain significant
@@ -353,7 +373,7 @@ static void battery_status_update(void)
 
 #if CONFIG_BATTERY_MEASURE & TIME_MEASURE
     time_now = _battery_time();
-#elif defined(CURRENT_NORMAL)
+#elif defined(CURRENT_NORMAL) || (CONFIG_BATTERY_MEASURE & CURRENT_MEASURE)
     int current = battery_current();
     if(level >= 0 && current > 0 && battery_capacity > 0) {
 #if CONFIG_CHARGING >= CHARGING_MONITOR
@@ -455,6 +475,11 @@ void reset_battery_filter(int millivolts)
 {
     voltage_avg = millivolts * BATT_AVE_SAMPLES;
     voltage_now = millivolts;
+#if CONFIG_BATTERY_MEASURE & CURRENT_MEASURE
+    /* current would probably be inaccurate too */
+    current_now = _battery_current();
+    current_avg = current_now * BATT_CURRENT_AVE_SAMPLES;
+#endif
     battery_status_update();
 }
 #endif /* HAVE_BATTERY_SWITCH */
@@ -589,7 +614,6 @@ static inline bool detect_charger(unsigned int pwr)
 }
 #endif /* CONFIG_CHARGING */
 
-
 #if CONFIG_BATTERY_MEASURE & VOLTAGE_MEASURE
 static int power_hist_item(void)
 {

uisimulator/common/powermgmt-sim.c

@@ -43,6 +43,7 @@ static bool charging = false;
 static unsigned int batt_millivolts = BATT_MAXMVOLT;
 static unsigned int batt_percent = 100;
 static unsigned int batt_runtime = BATT_MAXRUNTIME;
+static unsigned int batt_current = 0;
 
 void powermgmt_init_target(void) {}
 
@@ -97,6 +98,8 @@ static void battery_status_update(void)
 
     batt_percent = (batt_millivolts - BATT_MINMVOLT) / (BATT_MAXMVOLT - BATT_MINMVOLT);
     batt_runtime = batt_percent * BATT_MAXRUNTIME;
+    /* current is completely bogus... */
+    batt_current = charging ? BATT_CHARGE_STEP : BATT_DISCHARGE_STEP;
 }
 
 const unsigned short battery_level_dangerous[BATTERY_TYPES_COUNT] = { 3200 };
@@ -132,6 +135,14 @@ int _battery_time(void)
 }
 #endif
 
+#if (CONFIG_BATTERY_MEASURE & CURRENT_MEASURE)
+int _battery_current(void)
+{
+    battery_status_update();
+    return batt_current;
+}
+#endif
+
 #if CONFIG_CHARGING
 unsigned int power_input_status(void)
 {