PowerD: Add a framework to report the status of auxiliary batteries

Implement it on the Kobo Sage, for the PowerCover

TouchMenu: Display auxiliary battery status

Kobo: More accurately report the PowerCover's charging status

i.e., try to actually figure out if the auxiliary battery is charging
instead of just checking the reader's battery (because that one will
often swap between the charging and discharging state as it drains the
aux battery...).

PowerD: Use a cached timestamp when doing battery pull checks

frontend/device/generic/device.lua

@@ -33,6 +33,7 @@ local Device = {
 
     -- hardware feature tests: (these are functions!)
     hasBattery = yes,
+    hasAuxBattery = no,
     hasKeyboard = no,
     hasKeys = no,
     hasDPad = no,

frontend/device/generic/powerd.lua

@@ -1,12 +1,15 @@
+local TimeVal = require("ui/timeval")
 local logger = require("logger")
 local BasePowerD = {
     fl_min = 0,                       -- min frontlight intensity
     fl_max = 10,                      -- max frontlight intensity
     fl_intensity = nil,               -- frontlight intensity
-    battCapacity = 0,                 -- battery capacity
+    batt_capacity = 0,                -- battery capacity
+    aux_batt_capacity = 0,            -- auxiliary battery capacity
     device = nil,                     -- device object
 
-    last_capacity_pull_time = 0,      -- timestamp of last pull
+    last_capacity_pull_time = TimeVal:new{ sec = 0, usec = 0},      -- timestamp of last pull
+    last_aux_capacity_pull_time = TimeVal:new{ sec = 0, usec = 0},  -- timestamp of last pull
 
     is_fl_on = false,                 -- whether the frontlight is on
 }
@@ -27,9 +30,12 @@ end
 function BasePowerD:init() end
 function BasePowerD:setIntensityHW(intensity) end
 function BasePowerD:getCapacityHW() return 0 end
+function BasePowerD:getAuxCapacityHW() return 0 end
+function BasePowerD:isAuxBatteryConnectedHW() return false end
 function BasePowerD:getDismissBatteryStatus() return self.battery_warning end
 function BasePowerD:setDismissBatteryStatus(status) self.battery_warning = status end
 function BasePowerD:isChargingHW() return false end
+function BasePowerD:isAuxChargingHW() return false end
 function BasePowerD:frontlightIntensityHW() return 0 end
 function BasePowerD:isFrontlightOnHW() return self.fl_intensity > self.fl_min end
 function BasePowerD:turnOffFrontlightHW() self:setIntensityHW(self.fl_min) end
@@ -133,18 +139,41 @@ function BasePowerD:setIntensity(intensity)
 end
 
 function BasePowerD:getCapacity()
-    local now_ts = os.time()
-    if now_ts - self.last_capacity_pull_time >= 60 then
-        self.battCapacity = self:getCapacityHW()
+    -- NOTE: UIManager *should* be loaded at this point.
+    --       If that doesn't hold, c.f., :stateChanged below.
+    local UIManager = require("ui/uimanager")
+    local now_ts = UIManager:getTime()
+
+    if (now_ts - self.last_aux_capacity_pull_time):tonumber() >= 60 then
+        self.batt_capacity = self:getCapacityHW()
         self.last_capacity_pull_time = now_ts
     end
-    return self.battCapacity
+    return self.batt_capacity
 end
 
 function BasePowerD:isCharging()
     return self:isChargingHW()
 end
 
+function BasePowerD:getAuxCapacity()
+    local UIManager = require("ui/uimanager")
+    local now_ts = UIManager:getTime()
+
+    if (now_ts - self.last_aux_capacity_pull_time):tonumber() >= 60 then
+        self.aux_batt_capacity = self:getAuxCapacityHW()
+        self.last_aux_capacity_pull_time = now_ts
+    end
+    return self.aux_batt_capacity
+end
+
+function BasePowerD:isAuxCharging()
+    return self:isAuxChargingHW()
+end
+
+function BasePowerD:isAuxBatteryConnected()
+    return self:isAuxBatteryConnectedHW()
+end
+
 function BasePowerD:stateChanged()
     -- BasePowerD is loaded before UIManager. So we cannot broadcast events before UIManager has been loaded.
     if package.loaded["ui/uimanager"] ~= nil then

frontend/device/kobo/device.lua

@@ -354,6 +354,8 @@ local KoboCadmus = Kobo:new{
     },
     boot_rota = C.FB_ROTATE_CW,
     battery_sysfs = "/sys/class/power_supply/battery",
+    hasAuxBattery = yes,
+    aux_battery_sysfs = "/sys/class/misc/cilix",
     ntx_dev = "/dev/input/by-path/platform-ntx_event0-event",
     touch_dev = "/dev/input/by-path/platform-0-0010-event",
     isSMP = yes,
@@ -431,6 +433,7 @@ function Kobo:init()
     self.powerd = require("device/kobo/powerd"):new{
         device = self,
         battery_sysfs = self.battery_sysfs,
+        aux_battery_sysfs = self.aux_battery_sysfs,
     }
     -- NOTE: For the Forma, with the buttons on the right, 193 is Top, 194 Bottom.
     self.input = require("device/input"):new{

frontend/device/kobo/powerd.lua

@@ -14,6 +14,7 @@ local KoboPowerD = BasePowerD:new{
     fl = nil,
 
     battery_sysfs = nil,
+    aux_battery_sysfs = nil,
     fl_warmth_min = 0, fl_warmth_max = 100,
     fl_warmth = nil,
     fl_was_on = nil,
@@ -93,6 +94,28 @@ function KoboPowerD:init()
     self.batt_capacity_file = self.battery_sysfs .. "/capacity"
     self.is_charging_file = self.battery_sysfs .. "/status"
 
+    if self.device:hasAuxBattery() then
+        self.aux_batt_capacity_file = self.aux_battery_sysfs .. "/cilix_bat_capacity"
+        self.aux_batt_connected_file = self.aux_battery_sysfs .. "/cilix_conn" -- or "active"
+        self.aux_batt_charging_file = self.aux_battery_sysfs .. "/charge_status" -- "usb_conn" would not allow us to detect the "Full" state
+
+        self.getAuxCapacityHW = function(this)
+            return this:read_int_file(this.aux_batt_capacity_file)
+        end
+
+        self.isAuxBatteryConnectedHW = function(this)
+            return this:read_int_file(this.aux_batt_connected_file) == 1
+        end
+
+        self.isAuxChargingHW = function(this)
+            -- 0 when not charging
+            -- 3 when full
+            -- 2 when charging via DCP and/or when battery is high (> 70%)
+            local charge_status = this:read_int_file(this.aux_batt_charging_file)
+            return charge_status ~= 0 and charge_status ~= 3
+        end
+    end
+
     -- Default values in case self:_syncKoboLightOnStart() does not find
     -- any previously saved setting (and for unit tests where it will
     -- not be called)

frontend/ui/widget/touchmenu.lua

@@ -636,6 +636,36 @@ function TouchMenu:_recalculatePageLayout()
     self.page_num = math.ceil(#self.item_table / self.perpage)
 end
 
+local function getBatterySymbol(is_charging, capacity)
+    if is_charging then
+        return ""
+    else
+        if capacity >= 100 then
+            return ""
+        elseif capacity >= 90 then
+            return ""
+        elseif capacity >= 80 then
+            return ""
+        elseif capacity >= 70 then
+            return ""
+        elseif capacity >= 60 then
+            return ""
+        elseif capacity >= 50 then
+            return ""
+        elseif capacity >= 40 then
+            return ""
+        elseif capacity >= 30 then
+            return ""
+        elseif capacity >= 20 then
+            return ""
+        elseif capacity >= 10 then
+            return ""
+        else
+            return ""
+        end
+    end
+end
+
 function TouchMenu:updateItems()
     local old_dimen = self.dimen and self.dimen:copy()
     self:_recalculatePageLayout()
@@ -687,37 +717,16 @@ function TouchMenu:updateItems()
 
     local time_info_txt = util.secondsToHour(os.time(), G_reader_settings:isTrue("twelve_hour_clock"))
     local powerd = Device:getPowerDevice()
-    local batt_lvl = powerd:getCapacity()
-    local batt_symbol
-    if powerd:isCharging() then
-        batt_symbol = ""
-    else
-        if batt_lvl >= 100 then
-            batt_symbol = ""
-        elseif batt_lvl >= 90 then
-            batt_symbol = ""
-        elseif batt_lvl >= 80 then
-            batt_symbol = ""
-        elseif batt_lvl >= 70 then
-            batt_symbol = ""
-        elseif batt_lvl >= 60 then
-            batt_symbol = ""
-        elseif batt_lvl >= 50 then
-            batt_symbol = ""
-        elseif batt_lvl >= 40 then
-            batt_symbol = ""
-        elseif batt_lvl >= 30 then
-            batt_symbol = ""
-        elseif batt_lvl >= 20 then
-            batt_symbol = ""
-        elseif batt_lvl >= 10 then
-            batt_symbol = ""
-        else
-            batt_symbol = ""
-        end
-    end
     if Device:hasBattery() then
+        local batt_lvl = powerd:getCapacity()
+        local batt_symbol = getBatterySymbol(powerd:isCharging(), batt_lvl)
         time_info_txt = BD.wrap(time_info_txt) .. " " .. BD.wrap("⌁") .. BD.wrap(batt_symbol) ..  BD.wrap(batt_lvl .. "%")
+
+        if Device:hasAuxBattery() and powerd:isAuxBatteryConnected() then
+            local aux_batt_lvl = powerd:getAuxCapacity()
+            local aux_batt_symbol = getBatterySymbol(powerd:isAuxCharging(), aux_batt_lvl)
+            time_info_txt = time_info_txt .. " " .. BD.wrap("+") .. BD.wrap(aux_batt_symbol) ..  BD.wrap(aux_batt_lvl .. "%")
+        end
     end
     self.time_info:setText(time_info_txt)