[Kobo, Mk. 7] Enable the power LED when charging (#6810)

frontend/device/generic/device.lua

@@ -56,6 +56,7 @@ local Device = {
     canToggleGSensor = no,
     isGSensorLocked = no,
     canToggleMassStorage = no,
+    canToggleChargingLED = no,
     canUseWAL = yes, -- requires mmap'ed I/O on the target FS
     canRestart = yes,
     canSuspend = yes,
@@ -412,6 +413,9 @@ function Device:lockGSensor(toggle)
     end
 end
 
+-- Device specific method for toggling the charging LED
+function Device:toggleChargingLED(toggle) end
+
 --[[
 prepare for application shutdown
 --]]

frontend/device/kobo/device.lua

@@ -189,6 +189,7 @@ local KoboPika = Kobo:new{
 -- Kobo Clara HD:
 local KoboNova = Kobo:new{
     model = "Kobo_nova",
+    canToggleChargingLED = yes,
     hasFrontlight = yes,
     touch_snow_protocol = true,
     display_dpi = 300,
@@ -213,6 +214,7 @@ local KoboNova = Kobo:new{
 --       There's also a CM_ROTARY_ENABLE command, but which seems to do as much nothing as the STATUS one...
 local KoboFrost = Kobo:new{
     model = "Kobo_frost",
+    canToggleChargingLED = yes,
     hasFrontlight = yes,
     hasKeys = yes,
     hasGSensor = yes,
@@ -236,6 +238,7 @@ local KoboFrost = Kobo:new{
 -- NOTE: Assume the same quirks as the Forma apply.
 local KoboStorm = Kobo:new{
     model = "Kobo_storm",
+    canToggleChargingLED = yes,
     hasFrontlight = yes,
     hasKeys = yes,
     hasGSensor = yes,
@@ -259,6 +262,7 @@ local KoboStorm = Kobo:new{
 --- @fixme: Untested, assume it's Clara-ish for now.
 local KoboLuna = Kobo:new{
     model = "Kobo_luna",
+    canToggleChargingLED = yes,
     hasFrontlight = yes,
     touch_snow_protocol = true,
     display_dpi = 212,
@@ -338,6 +342,12 @@ function Kobo:init()
             self:initEventAdjustHooks()
         end
     end
+
+    -- We have no way of querying the current state of the charging LED, so, our only sane choices are:
+    -- * Do nothing
+    -- * Turn it off on startup
+    -- I've chosen the latter, as I find it vaguely saner, more useful, and it matches Nickel's behavior (I think).
+    self:toggleChargingLED(false)
 end
 
 function Kobo:setDateTime(year, month, day, hour, min, sec)
@@ -740,6 +750,62 @@ function Kobo:toggleGSensor(toggle)
     end
 end
 
+function Kobo:toggleChargingLED(toggle)
+    if not self:canToggleChargingLED() then
+        return
+    end
+
+    -- We have no way of querying the current state from the HW!
+    if toggle == nil then
+        return
+    end
+
+    -- NOTE: While most/all Kobos actually have a charging LED, and it can usually be fiddled with in a similar fashion,
+    --       we've seen *extremely* weird behavior in the past when playing with it on older devices (c.f., #5479).
+    --       In fact, Nickel itself doesn't provide this feature on said older devices
+    --       (when it does, it's an option in the Energy saving settings),
+    --       which is why we also limit ourselves to "true" Mk. 7 devices.
+    local f = io.open("/sys/devices/platform/ntx_led/lit", "w")
+    if not f then
+        logger.err("cannot open /sys/devices/platform/ntx_led/lit for writing!")
+        return false
+    end
+
+    -- c.f., strace -fittvyy -e trace=ioctl,file,signal,ipc,desc -s 256 -o /tmp/nickel.log -p $(pidof -s nickel) &
+    -- This was observed on a Forma, so I'm mildly hopeful that it's safe on other Mk. 7 devices ;).
+    if toggle == true then
+        -- NOTE: Technically, Nickel forces a toggle off before that, too.
+        --       But since we do that on startup, it shouldn't be necessary here...
+        f:write("ch 4")
+        f:flush()
+        f:write("cur 1")
+        f:flush()
+        f:write("dc 63")
+        f:flush()
+    else
+        f:write("ch 3")
+        f:flush()
+        f:write("cur 1")
+        f:flush()
+        f:write("dc 0")
+        f:flush()
+        f:write("ch 4")
+        f:flush()
+        f:write("cur 1")
+        f:flush()
+        f:write("dc 0")
+        f:flush()
+        f:write("ch 5")
+        f:flush()
+        f:write("cur 1")
+        f:flush()
+        f:write("dc 0")
+        f:flush()
+    end
+
+    io.close(f)
+end
+
 -------------- device probe ------------
 
 local codename = Kobo:getCodeName()

frontend/ui/elements/common_settings_menu_table.lua

@@ -48,6 +48,19 @@ if Device:canToggleMassStorage() then
     common_settings.mass_storage_actions = MassStorage:getActionsMenuTable()
 end
 
+if Device:canToggleChargingLED() then
+    -- Charging LED settings
+    common_settings.charging_led = {
+        text = _("Turn on the power LED when charging"),
+        checked_func = function()
+            return G_reader_settings:nilOrTrue("enable_charging_led")
+        end,
+        callback = function()
+            G_reader_settings:flipNilOrTrue("enable_charging_led")
+        end
+    }
+end
+
 -- Associate OS level file extensions (must be off by default, because we're not associated initially)
 if Device:canAssociateFileExtensions() then
     common_settings.file_ext_assoc = {

frontend/ui/elements/filemanager_menu_order.lua

@@ -41,12 +41,13 @@ local order = {
         "keyboard_layout",
         "time",
         "battery",
+        "charging_led", -- if Device:canToggleChargingLED()
         "autostandby",
         "autosuspend",
         "autoshutdown",
         "ignore_sleepcover",
         "ignore_open_sleepcover",
-        "mass_storage_settings",
+        "mass_storage_settings", -- if Device:canToggleMassStorage()
         "file_ext_assoc",
         "screenshot",
     },

frontend/ui/elements/reader_menu_order.lua

@@ -62,12 +62,13 @@ local order = {
         "keyboard_layout",
         "time",
         "battery",
+        "charging_led", -- if Device:canToggleChargingLED()
         "autostandby",
         "autosuspend",
         "autoshutdown",
         "ignore_sleepcover",
         "ignore_open_sleepcover",
-        "mass_storage_settings",
+        "mass_storage_settings", -- if Device:canToggleMassStorage()
         "file_ext_assoc",
         "screenshot",
     },

frontend/ui/uimanager.lua

@@ -1312,10 +1312,16 @@ function UIManager:_afterResume()
 end
 
 function UIManager:_beforeCharging()
+    if G_reader_settings:nilOrTrue("enable_charging_led") then
+        Device:toggleChargingLED(true)
+    end
     self:broadcastEvent(Event:new("Charging"))
 end
 
 function UIManager:_afterNotCharging()
+    if G_reader_settings:nilOrTrue("enable_charging_led") then
+        Device:toggleChargingLED(false)
+    end
     self:broadcastEvent(Event:new("NotCharging"))
 end